ISSN: 2346-3775 Vol. 7 No. 4 July – September 2019 SPECIAL ISSUE II International Leucaena Conference 1–3 November 2018, Brisbane, Queensland, Australia Published by: Centro Internacional de Agricultura Tropical (CIAT), Cali, Colombia In association with: Chinese Academy of Tropical Agricultural Sciences (CATAS), Hainan, P.R. China This issue of Tropical Grasslands-Forrajes Tropicales is the second of two “Special Issues ILC2018” published under a publication agreement with the Organizing Committee of the International Leucaena Conference held at The University of Queensland, Brisbane, Australia, 1‒3 November 2018. It contains the 36 papers presented during Sessions 5‒8 of the Conference. Papers presented during Sessions 1‒4 were published in the first “Special Issue ILC2018” that can be accessed by clicking here. International Center for Tropical Agriculture (CIAT) retains copyright of articles with the work simultaneously licensed under the Creative Commons Attribution 4.0 International License (to view a copy of this license, visit creativecommons.org/licenses/by/4.0/). Accordingly, users/readers are free to share (to copy, distribute and transmit) and to remix (to adapt) the work under the condition of giving the proper attribution. i Editors Rainer Schultze-Kraft, Lyle Winks, International Center for Tropical Agriculture (CIAT), Former editor of “Tropical Grasslands”, Colombia Australia Management Committee Robert J. Clements, Rainer Schultze-Kraft, Agricultural Consultant, International Center for Tropical Agriculture (CIAT), Australia Colombia Huan Hengfu, Cacilda B. do Valle, Chinese Academy of Tropical Agricultural Sciences Empresa Brasileira de Pesquisa Agropecuária (Embrapa), (CATAS), Brazil P.R. China Lyle Winks, Asamoah Larbi, Former editor of “Tropical Grasslands”, Agricultural Consultant, Australia Ghana Michael Peters, International Center for Tropical Agriculture (CIAT), Kenya Editorial Board Caterina Batello, Orlando Guenni, Food and Agriculture Organization of the United Nations Universidad Central de Venezuela (UCV), (FAO), Venezuela Italy Jean Hanson, Michael Blümmel, International Livestock Research Institute (ILRI), International Livestock Research Institute (ILRI), Ethiopia India Michael David Hare, Robert J. Clements, Ubon Ratchathani University, Agricultural Consultant, Thailand Australia Huan Hengfu, Myles Fisher, Chinese Academy of Tropical Agricultural Sciences International Center for Tropical Agriculture (CIAT), (CATAS), Colombia P.R. China Albrecht Glatzle, Mario Herrero, Iniciativa para la Investigación y Transferencia de Commonwealth Scientific and Industrial Research Tecnología Agraria Sostenible (INTTAS), Organisation (CSIRO), Paraguay Australia ii Masahiko Hirata, Bruce Pengelly, University of Miyazaki, Agricultural Consultant, Japan Australia Peter Horne, T. Reginald Preston, Australian Centre for International Agricultural Research University of Tropical Agriculture Foundation (UTA), (ACIAR), Colombia Australia Johann Huguenin, Kenneth Quesenberry, Centre de Coopération Internationale en Recherche University of Florida, Agronomique pour le Développement (CIRAD), USA France H. Max Shelton, Muhammad Ibrahim, The University of Queensland, Australia Centro Agronómico Tropical de Investigación y Enseñanza (CATIE), Werner Stür, Costa Rica Australian Centre for International Agricultural Research (ACIAR), Asamoah Larbi, Australia Agricultural Consultant, Ghana Cacilda B. do Valle, Carlos E. Lascano, Empresa Brasileira de Pesquisa Agropecuária (Embrapa), Universidad Nacional de Colombia - Sede Bogotá, Brazil Colombia Robert Paterson, Agricultural Consultant, Spain Principal Contacts Rainer Schultze-Kraft International Center for Tropical Agriculture (CIAT) Colombia Phone: +57 2 4450100 Ext. 3036 Email: CIAT-TGFT-Journal@cgiar.org Technical Support José Luis Urrea Benítez International Center for Tropical Agriculture (CIAT) Colombia Phone: +57 2 4450100 Ext. 3354 Email: CIAT-TGFT-Journal@cgiar.org iii Table of Contents ILC2018 Session 5: Leucaena and the environment Intensive silvopastoral systems with Leucaena leucocephala in Latin America 259-266 Julián Chará, Julián Rivera, Rolando Barahona, Enrique Murgueitio, Zoraida Calle, Carolina Giraldo Greenhouse gas implications of leucaena-based pastures. Can we develop an emissions reduction 267-272 methodology for the beef industry? Nigel Tomkins, Matthew Harrison, Chris S. McSweeney, Stuart Denman, Ed Charmley, Cristopher J. Lambrides, Ram Dalal Linking leucaena to carbon abatement opportunities in Australia 273-279 Karen King, Rachel Burgess Weed leucaena and its significance, implications and control 280-289 Shane Campbell, Wayne Vogler, Dannielle Brazier, Joseph Vitelli, Simon Brooks A short review of leucaena as an invasive species in Hawaii 290-294 Travis Idol Leucaena leucocephala introduction into a tropical pasture in the Chaco region of Argentina. Effects on soil 295-302 carbon and total nitrogen Natalia Banegas, Roberto Corbella, Emilce Viruel, Adriana Plasencia, Belen Roig, Alejandro Radrizzani ILC2018 Session 6: Leucaena systems in Australia Adoption, profitability and future of leucaena feeding systems in Australia 303-214 Stuart Buck, Joe Rolfe, Craig Lemin, Bernie English Current and future adoption of leucaena-grass pastures in northern Australia 315-330 Sean Kenny, Geoff Drysdale The Leucaena Network and The Leucaena Code of Practice 331-332 Bron Christensen Evaluating leucaena in timbered northern basalt country in Queensland, Australia 333-335 Joe Rolfe, Mark Keating, Craig Lemin, Bernie English, Robert Caird, Emma Black, Lindsey Perry, Greg Brown, Tom & Christine Saunders, Darcy & Lynda O'Brien Pioneer of leucaena development in Queensland, Australia: Nyanda, Carnarvon Gorge 336-338 John & Del O'Neill Leucaena production in the Fitzroy River catchment, central Queensland, Australia 339-341 Paul & Clare Harris Leucaena in southern Queensland, Australia 342-344 Craig Antonio iv Irrigated leucaena in the Burdekin catchment produces high quality cattle for premium markets 345-347 Don Heatley Leucaena production in central Queensland, Australia 348-349 Billy-Joe Rea, Amelia Rea, Wally Rea Ingelara Grazing: Leucaena in speargrass country, Queensland, Australia 350-352 Stuart & Sheree Ogg ILC2018 Session 7: Leucaena systems in tropical America Leucaena intensive silvopastoral system: The CIPAV experience in Colombia 353-358 Álvaro Zapata Cadavid, Carlos Mejía, Luis Solarte, Juan F. Suárez, Carlos H. Molina, Enrique J. Molina, Fernando Uribe, Enrique Murgueitio, César Navarro, Julián Chará, Leonardo Manzano The inclusion of Leucaena diversifolia in a Colombian beef cattle production system: An economic 359-369 perspective Karen Enciso, Mauricio Sotelo, Michael Peters, Stefan Burkart Feeding leucaena to dairy cows in intensive silvopastoral systems in Colombia and Mexico 370-374 Julián Esteban Rivera, Julián Chará, Enrique Murgueitio, Juan José Molina, Rolando Barahona Leucaena leucocephala feeding systems for cattle production in Mexico 375-380 Luis Ramírez-Avilés, Francisco J. Solorio-Sánchez, Carlos F. Aguilar-Pérez, Armin J. Ayala-Burgos, Juan C. Ku-Vera Leucaena feeding systems in Argentina. I. Five decades of research and limitations for adoption 381-388 Alejandro Radrizzani, Nahuel A. Pachas, Luis Gándara, Cristina Goldfarb, Alejandro Perticari, Santiago Lacorte, Dante Pueyo Leucaena feeding systems in Argentina. II. Current uses and future research priorities 389-396 Alejandro Radrizzani, Nahuel A. Pachas, Luis Gándara, Fernando Nenning, Dante Pueyo Leucaena feeding systems in Paraguay 397-402 Albrecht F. Glatzle, Antero N. Cabrera, Alberto Naegele, Norman Klassen Leucaena feeding systems in Cuba 403-406 Tomás E. Ruiz, Gustavo J. Febles, Emilio Castillo, Leonel Simón, Luis Lamela, Ismael Hernández, Humberto Jordán, Juana L. Galindo, Bertha B. Chongo, Denia C. Delgado, Gustavo Jacinto Crespo, Nurys Valenciaga, Orestes La O, Jatnel Alonso, Delia M. Cino, Sandra Lok, Francisco Reyes, Marcos Esperance, Jesús Iglesias, Marta Hernández, Tania Sánchez, Arístides Pérez, Mildrey Soca Use and performance of leucaena (Leucaena leucocephala) in Venezuelan animal production systems 407-409 Eduardo E. Escalante ILC2018 Session 8: Leucaena systems across Asia Tarramba leucaena: A success story for smallholder bull fattening in eastern Indonesia 410-414 Jacob Nulik, Debora Kana Hau, Michael J. Halliday, H. Max Shelton v Leucaena feeding systems in India 415-419 Nandini Nimbkar Leucaena as basal feed for meat goats in Prachuapkhirikhan Province, Thailand 420-422 G. Nakamanee, S. Poathong, T. Chanwarin, S. Harrison Leucaena feeding systems in Myanmar 423-427 A. Aung Adoption of leucaena-based feeding systems in Sumbawa, eastern Indonesia and its impact on cattle 428-436 productivity and farm profitability Dahlanuddin, Tanda Panjaitan, Scott Waldron, Michael J. Halliday, Andrew Ash, Steve T. Morris, H. Max Shelton Economic analysis of cattle fattening systems based on forage tree legume diets in eastern Indonesia 437-444 Scott Waldron, Johanis Ngongo, Silvia Kusuma Putri Utami, Michael J. Halliday, Tanda Panjaitan, Baik Tutik Yuliana, Dahlanuddin, Jacob Nulik, Debora Kana Hau, H. Max Shelton Preliminary assessment of rearing male buffalo calves on Leucaena leucocephala-buffel grass pasture in 445-448 Maharashtra State, India Nandini Nimbkar, Sharad Choudhari, Bon Nimbkar Potential of Leucaena spp. as a feed resource for ruminant animals in Thailand 449-454 G. Nakamanee, S. Harrison, K. Janthibordee, W. Srisomporn, C. Phaikaew Production of Leucaena leucocephala ‘silage’ for sale as animal feed: A case study from Sikiew District, 455-458 Northeast Thailand S. Harrison, W. Srisomporn, G. Nakamanee Leucaena in West Timor, Indonesia: A case study of successful adoption of cv. Tarramba 459-464 Debora Kana Hau, Jacob Nulik Seasonal growth of Leucaena leucocephala cv. Tarramba in dry land of west Sumbawa, Indonesia 465-468 Yusuf Akhyar Sutaryono, Dedi Supriadi, Imran, Ryan Aryadin Putra Summary and conclusions International Leucaena Conference 2018: Highlights and priorities 469-478 H. Max Shelton vi Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):259–266 259 DOI: 10.17138/TGFT(7)259-266 ILC2018 Plenary Paper* Intensive silvopastoral systems with Leucaena leucocephala in Latin America Sistemas silvopastoriles intensivos con Leucaena leucocephala en América Latina JULIÁN CHARÁ1, JULIÁN RIVERA1, ROLANDO BARAHONA2, ENRIQUE MURGUEITIO1, ZORAIDA CALLE1 AND CAROLINA GIRALDO1 1Centro para la Investigación en Sistemas Sostenibles de Producción Agropecuaria, Cali, Colombia. cipav.org.co 2Universidad Nacional de Colombia, Medellín, Colombia. medellin.unal.edu.co Abstract Leucaena leucocephala has played a key role in the development of sustainable cattle ranching in Latin America. This species is the backbone of the so-called Intensive Silvopastoral Systems (ISPS) that combine high-density cultivation of leucaena as fodder shrubs (4,000–40,000 plants/ha) with grasses and trees. The layers of vegetation added by shrubs and trees increase the system’s capacity for transforming solar energy into biomass and enhance habitat complexity. Although part of the biomass is transformed into livestock products, a significant amount is deposited as litter on the soil and, along with the nitrogen fixed by leucaena and other trees, has positive effects on soil properties and grass production. The increased complexity of the system has measurable effects on biodiversity. ISPS with leucaena support more species of birds, ants, dung beetles and woody plants than conventional pasture monocultures, contribute to landscape-scale connectivity and provide environmental services. They also enhance animal welfare through reduced heat stress and improved availability and quality of fodder resources. ISPS contribute to climate change mitigation by improving above- and below-ground carbon sequestration and by cutting down greenhouse gas emissions per units of dry matter consumed and cattle product. Although these systems have been successfully implemented in Colombia, Mexico and other countries, their adoption is still limited in relation to the area suitable for their introduction. Keywords: Biodiversity, carbon capture, environmental services, GHG emissions, soil protection. Resumen Leucaena leucocephala ha jugado un papel crucial en el desarrollo de sistemas sostenibles de producción ganadera en América Latina. Esta especie es la columna vertebral de los llamados Sistemas Silvopastoriles Intensivos (SSPi) que combinan el cultivo de leucaena como un arbusto forrajero en alta densidad (4,000 a 40,000 plantas/ha) con pastos y árboles. Los estratos de vegetación adicionados con los arbustos y los árboles incrementan la capacidad del sistema para transformar la energía solar en biomasa y aumentan la complejidad del hábitat. Aunque una parte de la biomasa es transformada en productos animales, una cantidad importante es depositada en el suelo como hojarasca y, junto con el nitrógeno fijado por la leucaena y otros árboles, tiene efectos positivos sobre las propiedades del suelo y la producción del pasto. El incremento de la complejidad del sistema tiene efectos medibles sobre la biodiversidad. Los SSPi con leucaena sirven de hábitat para más especies de aves, hormigas, escarabajos del estiércol y plantas que los sistemas convencionales, contribuyen a la conectividad a escala del paisaje y proveen servicios ambientales. También contribuyen a mejorar el bienestar animal a través de la reducción del estrés calórico y una mayor disponibilidad y calidad de recursos forrajeros. Los SSPi contribuyen a mitigar el cambio climático al mejorar la captura de carbono en la biomasa aérea y en el suelo y al reducir las emisiones de gases de efecto invernadero por unidad de materia seca consumida y por unidad de producto. Aunque han sido implementados con éxito en Colombia, México y otros países, su adopción es aun limitada en la región en relación con el área apta para su introducción. Palabras clave: Biodiversidad, captura de carbono, emisiones de GEI, protección del suelo, servicios ambientales. ___________ Correspondence: J. Chará, Centro para la Investigación en Sistemas *Plenary paper presented at the International Leucaena Conference, Sostenibles de Producción Agropecuaria (CIPAV), Carrera 25 # 6- 1‒3 November 2018, Brisbane, Queensland, Australia. 62, Cali, Colombia. Email: julian@fun.cipav.org.co Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 260 J. Chará, J. Rivera, R. Barahona, E. Murgueitio, Z. Calle and C. Giraldo Introduction branches, fruits, resins and exudates with beneficial effects on soil organic matter, nutrients and biota (Vallejo Silvopastoral systems (SPS) are defined by the intentional et al. 2012; Martínez et al. 2014). Such benefits are integration of livestock, trees, shrubs and grasses on the complemented by the effects of nitrogen-fixing trees and same land unit in order to optimize the beneficial interactions shrubs and other associations between trees and between components (modified from Jose et al. 2019). SPS microorganisms that increase the availability of vital allow the intensification of cattle production through natural nutrients for biomass production (Malchair et al. 2010; processes and are acknowledged as an integrated approach Rey et al. 2014). Soil microorganisms and fungi, in to sustainable land use (Chará et al. 2019). Globally, the particular mycorrhizal fungi, enhance the formation and main SPS include live fences, windbreaks, scattered trees in stability of soil aggregates, which further improves pasturelands, managed plant successions, fodder tree banks aeration and root penetration (Gupta and Germida 1988). (e.g. areas of cultivated protein-rich fodder plants), cut-and- ISPS improve decomposition and mineralization carry systems, tree plantations with livestock grazing, processes carried out by the soil microbiota. Vallejo et al. pastures between tree alleys and intensive silvopastoral (2010) found a higher activity of β-glucoxidase, acid systems (ISPS) (Murgueitio and Ibrahim 2008; Murgueitio phosphatase and alkaline phosphatase in soils under ISPS et al. 2011; Calle et al. 2012). with leucaena compared with pasture monocultures in the Intensive silvopastoral systems (ISPS) are a type of Cauca Valley, Colombia. This not only indicated higher SPS that combines high-density cultivation of fodder microbial activity in soils with leucaena, but also shrubs (4,000–40,000 plants/ha) with improved tropical explained why these systems were able to sustain forage grasses and tree or palm species at densities of 100–600 and milk yields even without the application of external trees/ha. These systems are managed under rotational fertilizers, since these enzymes play a key role in the grazing with ad libitum provision of water and recycling and availability of nutrients and energy in the mineralized salt in each paddock, and 12–24 hour grazing soil (Vallejo et al. 2010; Sierra et al. 2017). These periods that alternate with 40–50 day resting periods processes were enhanced in ISPS when a third layer of (Calle et al. 2012; Murgueitio et al. 2016). Prosopis juliflora trees was added to the leucaena-pasture Such silvopastoral systems with high density of system, e.g. Vallejo et al. (2012) found significantly Leucaena leucocephala have been promoted in several Latin higher levels of organic C, total N, nitrates and available American countries, mainly Colombia and Mexico, but also P and microbial biomass under the canopy of these trees. in Paraguay and Argentina where they have shown As a consequence, soils under leucaena ISPS had a higher important production and environmental benefits (Chará et organic matter content, lower bulk density and lower al. 2019). However, their adoption is still very limited in penetration resistance than soils under pasture relation to the area suitable for their introduction. According monocultures (Vallejo et al. 2012). to Pachas et al. (2019) the area planted in Latin America Vallejo et al. (2010) found higher densities of macro- and ranges between 45,000 and 55,000 ha. micro-pores, lower bulk density (<1.4 vs. 1.52 g/cm3) and Here we review recent studies carried out in Latin lower penetration resistance (<3.3 vs. 3.98 MPa) in soils America (with emphasis on Colombia) regarding the under leucaena than in soils under pasture monocultures. environmental benefits of leucaena-based ISPS, including These traits are associated with improved water retention their effects on soil, biodiversity, environmental services and reduced runoff. Studies carried out in Costa Rica and and climate change mitigation. Nicaragua showed water runoff equivalent to 28–48% of the precipitation in pastures without trees compared with less Soil and water conservation of Leucaena leucocephala than 10% in SPS (Ríos et al. 2007). silvopastoral systems Atmospheric nitrogen fixation Several studies have shown positive effects of SPS on physical, chemical and microbiological soil properties During the establishment phase of ISPS L. leucocephala (Martínez et al. 2014). The layers of woody vegetation seeds are inoculated with specific strains of Rhizobium to added by shrubs and trees accelerate the transformation of enhance the fixation of atmospheric nitrogen and avoid solar energy into biomass and the penetration of roots into the use of synthetic fertilizers. Nitrogen fixed by this deep soil layers, from where they extract nutrients and mechanism becomes available for the system and water (Nair 2011; Chará et al. 2015). This structural contributes to increasing the productivity and nutritional complexity allows for more abundant and heterogeneous quality of its components. Bueno and Camargo (2015) plant residues being deposited on the soil as dry leaves, found an increment from 0.39 to 0.74% in the total soil N Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena in Latin American ISPS 261 content 28 weeks after sowing leucaena, which represents trend was found in the Cesar Valley in northern 249 kg/ha of additional nitrogen. This economy in Colombia, where ISPS with leucaena had 18 dung beetle nitrogen fertilizer requirement contributes to meat and species (50% of which were also found in forest milk production, reduces financial costs and cuts down fragments), while the neighboring treeless pastures held atmospheric N2O emissions. only 10 species (Montoya-Molina et al. 2016). Higher biodiversity in the grazing areas and their Contribution of systems with leucaena to the surroundings can provide important benefits for the protection of biodiversity and the provision of farming system through enhanced pollination, pest environmental services control and soil water retention, among other environmental services. In the study by Giraldo et al. In general, shrubs and trees in SPS have been shown to (2011), the higher abundance and richness of dung beetles enhance biodiversity by creating complex habitats for wild were accompanied by a significant increase in the animals and plants (Harvey et al. 2006; Moreno and Pulido amounts of excavated soil and buried manure. This study 2009), harboring a richer soil biota (Rivera et al. 2013; showed an additional benefit of ISPS by reducing the Montoya-Molina et al. 2016) and increasing connectivity abundance of hematophagous flies that affect cattle. between forest fragments (Rice and Greenberg 2004). In ISPS with leucaena have a range of positive effects on farmed landscapes, SPS provide food and cover for birds, animal welfare. Nutrient availability and quality are serving as wildlife corridors where unique species enhanced compared with grass-only systems of the same assemblages are found (McAdam 2005; Murgueitio et al. age (Table 1). Shade reduces heat stress while complex 2011; Greenler and Ebersole 2015). In the Quindío region of vegetation offers the possibility of concealment for the Colombia, areas with SPS were found to have 3 times as cattle, reducing fear and anxiety (Broom et al. 2013). As many bird species as treeless pastures (Fajardo et al. 2010) mentioned above, animals also benefit from reduced and complemented the conservation value of forest populations of ectoparasites in ISPS (Giraldo et al. 2011; fragments by providing temporary habitat for forest- Bacab et al. 2013). dependent birds (Tarbox et al. 2018). This type of effects was also found in ISPS with Contribution of leucaena ISPS to ecological leucaena. In the Quindío region of Colombia, ant species restoration richness was 62% higher in ISPS with leucaena than in treeless pastures, and the ISPS held 55% of the ant fauna Intensive silvopastoral systems contribute to ecological present in adjacent forests (Rivera et al. 2013). This study restoration in cattle ranching landscapes through three showed that, although forests play an irreplaceable role in complementary mechanisms (Calle et al. 2011; Chará et preserving unique species, the introduction of ISPS with al. 2015): 1) The farm-scale natural intensification of shrubs and trees enhances the persistence of biodiversity cattle production on the most suitable land allows the at a landscape scale by facilitating movement between release of fragile or strategic land for the recovery of forest fragments. In the same region of Colombia, dung forests and other ecosystems; 2) ISPS generate beetle abundance and diversity were significantly higher environmental services, and their complex vegetation in ISPS with high density of leucaena than in control sites supports part of the local biodiversity; and 3) the high with pasture monoculture (Giraldo et al. 2011). A similar density of shrubs and shade trees in ISPS provides a Table 1. Average composition of diets for cattle grazing in ISPS with Leucaena leucocephala (Ll) and a pasture monoculture in Colombia (forages were sampled at 45 days of regrowth). Nutrient Ll + Cynodon Ll + C. Ll + Megathyrsus Ll + C. plectostachyus Control C. plectostachyus1 plectostachyus2 maximus3 + M. maximus4 plectostachyus diet1 Crude protein (%) 13.9 15.7 14.2 15.5 10.8 NDF (%) 64.9 60.8 60.1 60.7 74.6 ADF (%) 41.9 38.6 41.2 38.4 43.0 Ether extract (%) 1.17 1.58 2.24 1.55 1.16 Gross energy (MJ/kg) 18.3 17.0 17.6 16.9 17.9 Ash (%) 9.6 10.8 12.3 11.9 10.2 Calcium (%) 0.42 0.45 0.61 0.43 0.37 Phosphorus (%) 0.33 0.27 0.27 0.26 0.33 1Molina et al. 2016; 2Rivera et al. 2015; 3Gaviria et al. 2015; 4Molina et al. 2015. NDF: Neutral detergent fiber; ADF: Acid detergent fiber. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 262 J. Chará, J. Rivera, R. Barahona, E. Murgueitio, Z. Calle and C. Giraldo permeable matrix and facilitates the movement of plants leucaena behaved as a ruderal species at their Brazilian and animals. In turn, this enhances seed dispersal and the study site, where it does not invade or threaten natural spontaneous recovery of forests and ecosystem services at ecosystems or cause economic damage. the landscape scale. Contribution to climate change mitigation Invasive behavior of L. leucocephala? The contribution of ISPS involving leucaena to climate Leucaena leucocephala is native to the Yucatán peninsula change mitigation is a result of the improved carbon in Mexico. Invasive behavior of this species has been storage both above- and below-ground and the lower observed in the Galapagos Islands, Taiwan, Hawaii and emissions of methane (CH4) per unit of DM consumed the Ogasawara Islands, where it is considered a weed of and per unit of livestock product. riparian and coastal habitats because it forms dense stands and can inhibit the regeneration of native species (Calle et Carbon storage al. 2011; Campbell et al. 2019; Idol 2019). Based mostly on studies done in islands, some environmental agencies Several studies have shown that incorporating trees in have expressed concern about the use of L. leucocephala croplands and pastures results in greater net C storage in various types of livestock systems. above- and below-ground (Montagnini and Nair 2004; In Colombia, L. leucocephala grows spontaneously, Montagnini et al. 2013). The above-ground carbon forming homogeneous stands in disturbed sites, where it storage potential for SPS ranges between 1.5 t/ha/yr accelerates the recovery of degraded land. Native tree (Ibrahim et al. 2010) and 6.55 t/ha/yr (Kumar et al. 1998). species that are unable to regenerate in open areas can In the Patagonia region of Argentina, 148.4 t C/ha were become established under leucaena trees. Thus, instead of stored in SPS, approximately 85% of which was stored in inhibiting the growth of native species, leucaena the soil, 7% in below-ground biomass (understory and facilitates the establishment of shade-tolerant trees and tree roots) and 8% in above-ground biomass. Below- woody plants, as has been shown to occur in the ground biomass thus represented an important C storage understory of tree plantations in Puerto Rico (Parrotta pool in that ecosystem (Peri et al. 2017). These values are 1999) and experimental plots in Malaysian slopes (Osman a direct manifestation of the ecological production and Barakbah 2011). In addition, nutrient-poor soils potential of SPS, depending on factors such as site and affected by severe degradation achieve a rapid physical, soil characteristics, species involved, stand age and chemical and biological recovery under leucaena trees management practices (Nair et al. 2010). The amount of (Parrotta 1999). soil organic carbon (SOC) can be increased between 20 Leucaena leucocephala has not invaded mature and and 100% when N2-fixing tree legumes are incorporated, well-preserved ecosystems in Colombia. As a typical since they enhance plant productivity (Kaye et al. 2000). pioneer tree, it will not spread in habitats with a dense To take full advantage of the sequestration potential and canopy. Seeds require bare soil to germinate and young other benefits of trees, a careful selection of the species is seedlings cannot tolerate light interception from grasses required and both density and design of the arrangement or weeds. Flooding, high elevation and soil acidity will should be managed to avoid competition for light or also prevent its successful establishment. In short, water. although in other environments L. leucocephala could Regarding SPS with high-density leucaena (10,000 become a weed, in Colombia, far from behaving as an plants/ha), Arias et al. (2015) found a mean carbon invasive species, it has played a key role in the content in the biomass of 33.14 t CO2-eq/ha, compared rehabilitation or ecological restoration of degraded lands with 10.7 t CO2-eq/ha in a conventional pasture mono- (Calle et al. 2011). culture in Colombia. Similarly, in Mexico López- Costa and Durigan (2010) surveyed 11 distinct forest Santiago et al. (2019) found that an ISPS with 36,000 patches in Brazil covering 200 ha around a leucaena plants/ha had 106.5 t CO2-eq/ha in the biomass L. leucocephala stand established in 1983 without finding (above- and below-ground) compared with only 17.2 t a single individual of the species beyond the limits of the CO2-eq/ha in an adjacent grass monoculture. Soil organic planted stand. Even though leucaena regenerated carbon showed a similar pattern with 335.3 and 268.6 t abundantly under the planted trees in Brazil, the relative CO2-eq/ha in the ISPS and the pasture monoculture, density of the species in the understory decreased with respectively (López-Santiago et al. 2019). In ISPS, time and shade-tolerant native species gradually began to although part of the above-ground biomass is periodically dominate. Costa and Durigan (2010) concluded that consumed by cattle, the trees remain in the system and the Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena in Latin American ISPS 263 average amount of biomass is higher than that of a pasture and fiber digestibility (Barahona 1999; Barahona et al. monoculture. 2003). In an in vitro experiment, Rivera et al. (2015) reported a reduction of 13% in the production of CH4 per Reduction of GHG emissions kg degraded DM (P = 0.0016) when 25% of leucaena was included in a C. plectostachyus diet. GHG emissions in cattle systems are explained largely by Regarding GHG emissions from the soil and pastures, the formation of enteric CH4, made worse by low ISPS with leucaena generated 30% less CO2, 98% less digestibility of feed and low productive parameters. Slow CH4 and 89% less N2O soil emissions per ha per month, growth and high age at slaughter contribute to a longer when compared with an adjacent conventional farm with life and to higher emissions per kg of meat produced irrigation and high fertilizer input (Rivera et al. 2019). As (Gerber et al. 2013). a result of this and of the lower enteric CH4 production, In ISPS with leucaena, animals can consume between the emissions of CO2-eq per kg of fat and protein 24 and 27% of fresh biomass of this species (Molina et al. corrected milk (FPCM) and per kg of energy corrected 2015, 2016; Gaviria et al. 2015), so the diet contains milk (ECM) were 13.4 and 12.5% lower, respectively, higher protein and lower neutral detergent fiber (NDF) than in a conventional high-input system similar to the concentrations than when animals are restricted to the farm’s baseline condition (Rivera et al. 2016). Since no resources available in pasture monocultures (Table 1). chemical fertilizers are applied usually and concentrate An improved diet with a lower NDF concentration feed requirements are greatly reduced, ISPS can use 55– reduces CH4 formation in the rumen. Additionally, 62% less non-renewable energy than a conventional production becomes more efficient in terms of lower age system to produce a kg of ECM and FPCM. at first calving, shorter calving intervals, higher weight gains and increased milk yields, as a result of the higher Conclusions DM consumption and improved energy, protein and calcium concentrations in diets in SPS with leucaena Intensive silvopastoral systems with leucaena respond to (Chará et al. 2019). the urgent need of providing beef and dairy products With regard to enteric emissions, a trial in Colombia, while delivering environmental services. They restore where diets of 25% L. leucocephala, 75% Cynodon soils, sequester carbon and reduce the negative impacts of plectostachyus and 100% C. plectostachyus were fed to cattle on natural resources and climate. In Latin America, heifers, CH4 emissions fell from 30.8 to 26.6 g CH4/kg ISPS can also play a crucial role in improving the DM consumed on the diet containing leucaena, with efficiency, resilience and profitability of cattle an ensuing reduction in energy loss (Molina et al. 2016). production, while enhancing product quality and animal Similar results were found by Molina et al. (2015) when welfare. Leucaena leucocephala has been essential in the they included 24% L. leucocephala foliage in a diet based development of ISPS due to its rapid growth and biomass on C. plectostachyus and Megathyrsus maximus. In both production, high nutrient quality and tolerance to cattle cases, animals fed diets containing L. leucocephala had browsing, among other characteristics. 15‒20% higher DM intakes and daily weight gains than However, technical, cultural and financial barriers those with the grass-only diet, but CH4 emissions did not have limited the adoption of ISPS and only a small increase to the same extent (149.4 vs. 144.9 g/animal/day proportion of the suitable land in Latin America is for the ISPS and control system, respectively, according currently under these systems despite all proven and to Molina et al. 2016). Thus, heifers in ISPS emitted at potential benefits. National policies should support ISPS least 33% less CH4 per kg of weight gain than those in adoption by providing specialized credit lines and grass-only pastures. A possible explanation for these technical support and facilitating the access to technical results is that L. leucocephala contains less NDF/unit of assistance, supplies and markets. DM consumed (Table 1), which lowers CH4 emissions (Archimède et al. 2011). The reduction could also be caused by the condensed tannin content of References (Note of the editors: All hyperlinks were verified 8 August 2019.) L. leucocephala (Barahona et al. 2003; Naranjo 2014), since tannins inhibit the growth of some ruminal Archimède H; Eugène M; Marie-Magdeleine C; Boval M; microorganisms that produce CH4 (Archimède et al. Martin C; Morgavi DP; Lecomte P; Doreau M. 2011. 2011; Huang et al. 2011). Condensed tannins present in Comparison of methane production between C3 and C4 L. leucocephala have lower molecular weight than those grasses and legumes. 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Agroforestry Agriculture, Ecosystems & Environment 150:139–148. doi: Systems 93:915–928. doi: 10.1007/s10457-018-0187-9 10.1016/j.agee.2012.01.022 (Accepted 7 August 2019 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):267–272 267 DOI: 10.17138/TGFT(7)267-272 ILC2018 Keynote Paper* Greenhouse gas implications of leucaena-based pastures. Can we develop an emissions reduction methodology for the beef industry? ¿Podemos desarrollar una metodología para la reducción de las emisiones de gases de efecto invernadero para pasturas con leucaena? NIGEL TOMKINS1, MATTHEW HARRISON2, CHRIS S. McSWEENEY3, STUART DENMAN3, ED CHARMLEY4, CHRISTOPHER J. LAMBRIDES5 AND RAM DALAL5 1Meat & Livestock Australia, Bowen Hills, QLD, Australia. mla.com.au 2Tasmanian Institute of Agriculture, University of Tasmania, Burnie, TAS, Australia. utas.edu.au/tia 3CSIRO Agriculture & Food, Brisbane, QLD, Australia. csiro.au 4CSIRO Agriculture & Food, Townsville, QLD, Australia. csiro.au 5School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD, Australia. agriculture.uq.edu.au Abstract The perennial legume leucaena (Leucaena leucocephala) is grown across the subtropics for a variety of purposes including livestock fodder. Livestock in Australia emit a significant proportion of the methane produced by the agriculture sector and there is increasing pressure to decrease emissions from beef cattle production systems. In addition to direct productivity gains for livestock, leucaena has been shown to lower enteric methane production, suggesting an opportunity for emissions mitigation and Commonwealth Emissions Reduction Fund (ERF) methodology development, where leucaena browse is adopted for high value beef production. Determining the proportion of leucaena in the diet may be one of the more challenging aspects in attributing mitigation. Current enteric emission relationships for cattle consuming mixed grass-leucaena diets are based on intensive respiration chamber work. Herd-scale methane flux has also been determined using open path laser methodologies and may be used to validate an on-farm herd-scale methodology for leucaena feeding systems. The methodology should also address increased potential for soil organic carbon storage by leucaena grazing systems, and changes in nitrous oxide production. This paper outlines the background, justification, eligibility requirements and potential gaps in research for an emissions quantification protocol that will lead to the adoption of a leucaena methodology by the Australian beef industry. Development of a methodology would be supported by research conducted in Australia. Keywords: CO2 mitigation, cattle, grazing, methane, modelling, nitrous oxide, ruminants. Resumen La leguminosa perenne leucaena (Leucaena leucocephala) se cultiva a lo largo del subtrópico para una variedad de propósitos, incluido el forraje para el ganado. El ganado en Australia genera una proporción significativa del metano producido por el sector agrícola y existe una presión creciente para reducir las emisiones procedentes de los sistemas de producción de ganado de carne. Además de las ganancias directas en la productividad ganadera, se ha demostrado que leucaena reduce la producción de metano entérico. Esto sugiere una oportunidad para la mitigación de emisiones y el desarrollo de metodologías en el marco del Commonwealth Emissions Reduction Fund (ERF), adoptando tecnologías de leucaena para la producción de carne de res de alto valor. Determinar su proporción en la dieta animal es posiblemente uno de los desafíos más importantes para cuantificar la contribución de la leucaena a la mitigación de las emisiones. Los conocimientos actuales relacionados con las emisiones de metano por el ganado que consume dietas mixtas de gramíneas con leucaena, se basan en trabajos intensivos en cámaras respiratorias. Para medir el flujo de metano a escala de rebaño ___________ Correspondence: Nigel Tomkins, Meat & Livestock Australia, 45 King *Keynote paper presented at the International Leucaena St, Bowen Hills, QLD 4006, Australia. Email: ntomkins@mla.com.au Conference, 1‒3 November 2018, Brisbane, Queensland, Australia. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 268 N. Tomkins, M.T. Harrison, C.S. McSweeney, S. Denman, E. Charmley, C.J. Lambrides and R. Dalal existen metodologías láser (OP-FTIR laser) con las que se pueden validar metodologías a nivel de sistemas de producción que incluyen leucaena como alimento. La metodología también debería considerar el potencial de sistemas de pastoreo con leucaena tanto para la acumulación de carbono orgánico en el suelo como para cambios en la producción de óxido nitroso. Este documento resume los antecedentes, la justificación, los requisitos para la elegibilidad y las necesidades de investigación para un protocolo de cuantificación de emisiones que llevará a la adopción de una metodología de leucaena por parte de la industria australiana de carne bovina. El desarrollo de esta metodología se apoyaría principalmente en investigaciones realizadas en el pasado en Australia. Palabras clave: Ganado, metano, mitigación de CO2, modelación, óxido nitroso, pastoreo, rumiantes. Introduction this emitted by ruminants as methane. Cattle are responsible for about 70% of the enteric methane The perennial leguminous shrub leucaena (Leucaena produced (Commonwealth of Australia 2014) and there leucocephala) is grown across the tropical and subtropical are increasing efforts to decrease intensity of emissions regions of South/Southeast Asia and northern Australia for from the livestock sector (MLA 2015b). A number of livestock fodder, nitrogen fixation, firewood and paper pulp plants, plant products and plant secondary compound (Shelton and Brewbaker 1994). In Australia, the shrub can fractions have been demonstrated to have potential to be incorporated in grass pastures for beef cattle, providing reduce enteric methanogenesis (Vercoe 2015) when liveweight gains superior to those from most other legume- consumed by ruminants. The main compounds in grass pastures and comparable with feedlot finishing. leucaena that confer antimethanogenic effects in vitro Across Queensland, approximately 125,000 ha has been and in vivo include phenolic compounds such as identified by satellite imagery as dedicated to leucaena condensed tannins and flavanol glycosides (Kennedy and pastures (Beutel et al. 2018). Recent research has Charmley 2012; Vercoe 2015; McSweeney and Tomkins demonstrated additional benefits in the form of potential 2015). reduction of enteric methane production and increased soil Kennedy and Charmley (2012) demonstrated that the carbon (C) storage, implying that the shrub may also level of readily fermentable crude protein (RFCP) in reduce greenhouse gas (GHG) emissions at the farm level legumes can be negatively correlated with methane (McSweeney and Tomkins 2015; Harrison et al. 2015; production. Whether this indicates the operation of Vercoe 2015; Conrad et al. 2017). This presents an hydrogen (H) sinks associated with the RFCP fraction is emissions-mitigation opportunity that would apply across uncertain, but it does indicate a need to incorporate a the industry where leucaena is managed. To reduce the factor such as legume content of the diet in predictive carbon footprint of the Australian beef industry, equations for methane production, especially where particularly for northern bioregions where emissions per plants such as leucaena are a significant proportion of the livestock unit are typically higher than for southern cattle diet. Determining the proportion of leucaena in the diet (Charmley et al. 2008), there is justification for developing would be one of the more challenging aspects in an ‘emissions-reduction methodology’ based on leucaena. attributing methane mitigation. Current options to A proposed methodology is supported by research con- estimate grass:legume proportion in the diet include the ducted under the National Livestock Methane Program use of faecal NIRS methodologies and δ13C ratios (Coates (MLA 2015a), modelling work undertaken under the and Dixon 2007). Whole Farm Systems Abatement Modelling program If the legume content of the diet of the northern beef (WFM 2017) and a series of independent studies. herd could be accounted for, then estimates of aggregate This paper outlines the background, justification, herd emissions may be reduced by around 30% (Kennedy eligibility requirements and potential gaps in research for and Charmley 2012). In addition, growth rates of cattle an emissions-quantification protocol that will lead to the grazing leucaena-Rhodes grass (Chloris gayana) pastures adoption of a methodology. A methodology would are substantially higher and methane production recognize reduced methane emissions by animals grazing commensurately lower than those of cattle grazing a leucaena. Rhodes grass-dominated pasture (Harrison et al. 2015), particularly when leucaena is irrigated (Taylor et al. Emissions-reduction potential and attribution 2016). A proposed methodology may be specific to a Approximately 16% of Australia's greenhouse gas production system as defined by herd composition (class, (CO2-eq) emissions come from agriculture, with 65% of age, live weight), where leucaena is used to finish steers Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) GHG emissions methodologies for leucaena systems 269 to a target live weight or support breeding animals during resulting in an apparent increase in microbial protein periods of low pasture availability. The duration of synthesis and a sink for metabolic H (McSweeney and leucaena feeding and intake or proportion of the diet will Tomkins 2015). In addition, a shift in fermentation from also be critical in revising the Herd Management acetate to longer chain fatty acids has been reported and Calculator (http://bit.ly/2SZf2qI). can be expected to result in greater energy capture for the animal. Increased soil carbon storage opportunities DNA sequencing of the rumen microbiota has demon- strated a consistent difference in the diversity of methano- Incorporating leucaena into a grass grazing system gens in cattle foraging leucaena-grass systems compared increases biomass production (Radrizzani et al. 2016) and with grass pastures for both irrigated and dryland systems C inputs to soil, which leads to increasing organic C (McSweeney and Tomkins 2015). The relative abundance of storage, especially in N-depleted soils. Conrad et al. Methanosphaera spp. alone as a proportion of the total (2017) estimated that a leucaena-buffel grass grazing methanogen population was higher in leucaena-fed animals system had an increase in soil C storage of 280 kg C/ha/yr and may be responsible for differences in methane in the top 30 cm of a Vertisol soil over a 40-year period. emissions. Methanosphaera spp. have been previously This equates to 1.03 t CO2-eq/ha/yr with 50% of this C reported to be enriched in ‘low methane’ emitting ruminants incorporated in the top 15 cm horizon (Radrizzani et al. (Shi et al. 2014). Analyses at the bacterial family level have 2011). This increase in C storage occurs primarily from shown that some species belonging to Lachnospiraceae, the increased C inputs from biomass increase due to Prevotellaceae, Spirochaetaceae, Desulfovibrionaceae, symbiotic N2 fixation, which can account for up to 36 kg Ruminococcaceae, Bacteroidaceae and Veillonellaceae N/ha/yr in the soil (Resh et al. 2002; Conrad et al. 2018). increased significantly in cattle grazing leucaena, while Increased grass yield, C inputs, humus formation, slowing other species belonging to Erysipelotrichaceae and also C decomposition and providing for increase in C storage Prevotellaceae and Bacteroidaceae decreased significantly become co-benefits for leucaena-based pastures (Kopittke relative to pasture-fed cattle (McSweeney and Tomkins et al. 2018). However, the increase in soil C storage in 2015). This indicates a specific response to leucaena in the leucaena-grass grazing systems may be limited due to diet. It is likely that the shift in bacterial populations and nutrient deficiencies of P and S, which occur frequently metabolism associated with the presence of leucaena results in Australia (Radrizzani et al. 2016), indicating that in less metabolic H being produced for hydrogeno- periodic application of nutrients other than N may be trophic methanogens because microbial protein and longer beneficial to increased soil C storage. chain fatty acids become sinks for H. These shifts in the Mineralization of leucaena-N2 fixed organic N bacterial and methanogen populations are the likely basis for produces nitrate-N and NO - 3 and results in nitrous oxide alterations in methanogenesis in leucaena-fed cattle. (N2O) and di-nitrogen (N2) production. Nitrous oxide is a potent GHG, with a global warming potential of 296 Modelling whole-farm impacts on production, CO2-eq on a 100-year time horizon (Dalal et al. 2003; profitability and net emissions EPA 2018). It is possible that N2O emissions from soil supporting a leucaena-grass pasture may partially negate Modelling of leucaena-based production systems can the positive impact of increase in soil C storage on GHG provide estimates of impacts on farm profitability of changes mitigation. Quantitative estimates of N2O emissions from in liveweight gain (LWG), increase in soil C storage, a leucaena-grass pasture system are scarce. It is likely that methane emissions and urinary nitrogen concentration. To the nitrate-N level in soil remains relatively low due to the compute GHG emissions on a whole-farm basis, herd uptake by grasses, thereby minimizing N2O production numbers and age/class structures can be used in static GHG (Conrad et al. 2017). emissions calculators, such as the Beef-Greenhouse Accounting Framework (B-GAF) (Doran-Browne and Rumen microbial structure and function of leucaena- Eckard 2018). The diversified emissions profiles fed cattle encompassed by B-GAF are essential for estimating whole- farm emissions from leucaena systems. Alternatives to static Understanding effects of leucaena on rumen microbial tools for estimating steady-state herd structures and GHG populations is an important factor in developing an emissions include APSIM (Keating et al. 2003). APSIM can emissions methodology. Analyses of rumen metabolism simulate temporal changes, which static models do not. have indicated that leucaena-fed steers had an increased Inclusion of a leucaena module in a dynamic farming system supply of amino acids and soluble carbohydrates, model such as APSIM would allow further investigation of Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 270 N. Tomkins, M.T. Harrison, C. McSweeney, S. Denman, E. Charmley, C. Lambrides and R. Dalal how leucaena growth and defoliation through grazing to account for methane and nitrous oxide emissions and influence LWG and profitability. soil C components. These components of a methodology Measurements of the nutritional value of leucaena and will need to be measured or estimated from models. A potential to increase soil C storage at depth are required for methodology for measuring reductions in GHG emissions model parameterization. The nutritive value of leucaena by grazing cattle on leucaena-based pastures has potential (Bassala et al. 1991; Agbede and Aletor 2004) and effects on to complement the existing Beef Cattle Herd LWG (Shelton and Brewbaker 1994; Harrison et al. 2016) Management methodology (Commonwealth of Australia have been well described. Few experiments simultaneously 2015), which captures reductions in emissions through measure leucaena nutritive value, LWG, increase in soil increasing LWG and earlier turnoff achieved by cattle organic C storage and GHG emissions, although these data provided with supplementary feed (including improved are critical for parameterizing and developing model pastures). While the current Beef Cattle Herd formulae for leucaena grazing systems. Management method quantifies the reduction in lifetime Since leucaena generally provides more available forage emissions through earlier turnoff, a method proposed than comparable pasture grasses, higher stocking rates are specifically for leucaena would target: direct reduction in sustainable, but this results in greater total emissions per unit enteric methane emissions caused by leucaena in the diet area (Harrison et al. 2016). Model-specific metrics are of grazing cattle; increase in soil C storage; and losses required to standardize comparisons. Harrison et al. (2015) from N2O. described the comparison between 3 leucaena grazing The current emissions relationship is based on scenarios and a baseline scenario in terms of: 1) average respiration chamber work (Kennedy and Charmley 2012) annual stocking rates; 2) total LW production; and 3) net and is the basis for estimating emissions from farm emissions. To maintain the same average annual cattle consuming grass-leucaena diets. Herd-scale stocking rate or LW production, Scenarios 1 and 2 carried 5 methodologies are available for validation on-farm based or 12% fewer cattle than the baseline because animals on on methane flux determination using open path, OP-FTIR leucaena grew faster and had greater mean LW. In contrast, laser technologies (Jones et al. 2011; Tomkins and the number of animals carried and LW production in Charmley 2015; Phillips et al. 2016) or eddy covariance Scenario 3 increased by 15 and 31% relative to the baseline, methods. The use of the SF6 tracer technique or respectively, due to enteric methane abatement and greater Greenfeed system (C-Lock Inc., Rapid City, SD, USA) LWG of animals grazing leucaena. In all scenarios, could also be applied in the field and offer an alternative emissions intensity (net farm emissions per unit LW sold) approach to quantify individual methane production data was reduced by more than 23% relative to baseline (Arbre et al. 2015). These techniques provide a measure emissions. Other modelling studies incorporating leucaena of emissions relativity and are currently the only on-farm have demonstrated that: reducing the ratio of breeding cows non-invasive methods available to corroborate the effects relative to steers and unmated heifers; higher female of leucaena inclusion in pasture on enteric methane fecundity; and earlier joining of maiden heifers, were emissions for grazing cattle. conducive to increased profitability (Harrison et al. 2016), but only higher fecundity and/or early joining of maiden Conclusions heifers resulted in lower emissions per unit of live weight, especially when combined with existing interventions. Research and modelling, that have been reported under Although calibration data are required for reliable the National Livestock Methane Program, the Whole parameterization, models can contrast various scenarios Farm Systems Abatement Modelling program and with baseline systems, or simulate long-term implications previous and ongoing independent studies, provide of climate change on whole-farm emissions intensities. justification to expand methodology opportunities. This is Future modelling aspects for leucaena could develop particularly relevant for those parts of Australia’s beef more dynamic biophysical models that incorporate industry, where leucaena feeding systems are adopted. In livestock rotations between paddocks and seasonal addition to the benefits associated with livestock climatic effects on leucaena growth and emissions from production gains and efficiencies, the co-benefits in the grazing system. increasing soil C storage, humus formation and pasture improvement are well documented. Advances in Methodology development, validation and limitations methodologies to measure methane flux on-farm at a herd scale and analyses of rumen metabolism at the individual Any methodology has to be cost-effective to implement animal scale are sufficiently advanced to validate a and readily verifiable. A leucaena methodology will need methodology based on leucaena feeding. Future Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) GHG emissions methodologies for leucaena systems 271 modelling must develop more dynamic biophysical Dalal RC; Wang W; Robertson GP; Parton WJ. 2003. 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Fan C; Deutsch S; Gagic D; Seedorf H; Kelly WJ; Atua R; bit.ly/2OwlOWp (Accepted 4 February 2019 by the ILC2018 Editorial Panel and the Journal editors; published 03 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):273–279 273 DOI: 10.17138/TGFT(7)273-279 ILC2018 Keynote Paper* Linking leucaena to carbon abatement opportunities in Australia Leucaena: Una oportunidad para la reducción de carbono en Australia KAREN KING1 AND RACHEL BURGESS2 1Climate Change Division, Australian Department of the Environment and Energy, Canberra, ACT, Australia. environment.gov.au 2International Climate Change and Energy Innovation Division, Australian Department of the Environment and Energy, Canberra, ACT, Australia. environment.gov.au Abstract The Australian Government has committed to reducing its greenhouse gas (GHG) emissions by 26‒28% below 2005 levels by 2030. The Emissions Reduction Fund (ERF), a center-piece of Australia’s climate change policies, provides incentives to reduce GHG emissions through economy-wide eligible activities, such as energy efficiency, waste management, revegetation, livestock management and savanna fire management. Emissions Reduction Fund methods define eligible activities, how to quantify abatement resulting from the activity and the required compliance measures. The requirements for developing ERF methods that quantify GHG abatement estimates resulting from eligible activities are described. Leucaena planting is used as an example. For an ERF method to be made and maintained, the activity must meet all the legislative requirements. This includes meeting the offsets integrity standards and having regard to any adverse environmental, economic and social impacts. Keywords: Climate change, emissions, Emissions Reduction Fund, greenhouse gas, national inventory, offsets integrity standards. Resumen El gobierno australiano se ha comprometido a reducir, para el año 2030, las emisiones de gases de efecto invernadero (GEI) de Australia en un 26‒28% por debajo de los niveles de 2005. El Emissions Reduction Fund (ERF), una pieza central de las políticas de cambio climático de Australia, proporciona incentivos para reducir las emisiones de GEI, a través de actividades elegibles relacionadas a la eficiencia energética, el manejo de residuos, la revegetación, el manejo de ganado y el manejo de incendios de sabana. Los métodos ERF definen las actividades elegibles, cómo cuantificar la reducción resultante de la actividad, y las medidas de cumplimiento requeridas. Los requisitos para desarrollar los métodos ERF que cuantifiquen las estimaciones de reducción de GEI resultantes de las actividades elegibles se describen en este trabajo. El cultivo de la leucaena para forraje se utilizó como ejemplo. Para que se pueda realizar y mantener un método ERF, la actividad debe cumplir con todos los requisitos legislativos. Esto incluye cumplir con las normas de integridad (offsets integrity standards) y tener en cuenta cualquier impacto ambiental, económico y social adverso. Palabras clave: Cambio climático, emisiones, Fondo de Reducción de Carbono, gases de efecto invernadero, inventario nacional. Introduction gas (GHG) emissions by 26‒28% below 2005 levels by 2030 (Department of Environment and Energy 2015). In In line with international frameworks, the Australian 2016, agricultural emissions contributed 12.6% of Government has committed to reducing its greenhouse Australia’s total emissions. For the 2030 targets to be ___________ Correspondence: Karen King, Climate Change Division, Department *Keynote paper presented at the International Leucaena of the Environment and Energy, GPO Box 787, Canberra, ACT 2601, Conference, 1‒3 November 2018, Brisbane, Queensland, Australia. Australia. Email: Karen.King@environment.gov.au Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 274 K. King and R. Burgess reached, agricultural industries must make a contribution Domestic climate change policy in an international and opportunities for the agricultural sector to reduce setting emissions must be identified. One possibility in northern Australia is the planting of Australia’s National Greenhouse Gas Inventory (NGGI) leucaena, which could both increase livestock (Department of the Environment and Energy 2018a) is productivity and reduce enteric methane emissions. The compiled using methodologies consistent with the combination of reductions in enteric emissions and international guidelines and reporting rules prepared by possible increases in soil carbon would contribute to the Intergovernmental Panel on Climate Change (IPCC) reducing Australia’s GHG emissions. and adopted by the United Nations Framework For an Emissions Reduction Fund (ERF) method to be Convention on Climate Change (UNFCCC). designed that provides incentives for using leucaena as a Australia’s National Inventory Report (NIR) is submitted livestock feed, the activity must meet all legislative to the UNFCCC as part of Australia's reporting obligations requirements. Importantly, methods must meet the offsets under the UNFCCC and the Kyoto Protocol. The NIR integrity standards as stated in Section 133 of the Carbon contains both national GHG emission estimates and Credits (Carbon Farming Initiative) Act 2011 (Australian estimation methods from 1990 onwards. The annual NIR Government 2017) to maintain scheme integrity and (Department of the Environment and Energy 2018a) and the deliver credible abatement. The offsets integrity standards annual GHG projections (Department of the Environment require that endorsed methods must credit only abatement and Energy 2017) enable the Government to track progress that: (a) is additional to that which would occur normally; against Australia's emissions reduction commitments. (b) is measurable and verifiable; (c) contributes to Under international reporting obligations, sources of reducing Australia’s GHG emissions; (d) is supported by agricultural emissions are: enteric fermentation; clear and convincing evidence; (e) accounts for project agricultural soils; manure management; liming and urea emissions; and (f) results in a conservative estimate of net application; rice cultivation; and field burning of abatement. In addition, before establishing a method the agricultural residues. In 2016, emissions from Australia’s Minister for the Environment must consider whether agricultural industries contributed an estimated 69.1 Mt activities under endorsed methods are likely to result in CO2-eq, which represents 12.6% of Australia’s total adverse economic, environmental or social outcomes emissions (Figure 1) (Department of the Environment and [Subsection 106(4) CFI Act] (Australian Government Energy 2018b). Enteric fermentation was the main source 2017). All ERF methods are regularly reviewed to ensure of agricultural emissions and was estimated to be 49.7 Mt they continue to meet the offsets integrity standards and CO2-eq or 71.9% of all emissions from agriculture. The other legislative requirements, and reflect new scientific next largest source was agricultural soils (18.5%), knowledge. followed by manure management (5.2%). 287 Stationary energy 97.5 Transport 69.1 Agriculture 49 Fugitive emissions from fuel 34.2 Industrial processes and product use 12.3 Waste -24.1 Land use, land use change and forestry -25 25 75 125 175 225 275 325 Total net CO2-e emissions by sector for Australia in 2016 Figure 1. Total net CO2-eq emissions by sector for Australia in 2016 (Department of the Environment and Energy 2018b). Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Linking leucaena to carbon abatement opportunities in Australia 275 In Australia, many in the agricultural sector are adverse environmental, social or economic impacts, when endeavoring to identify opportunities to reduce emissions. deciding whether to make an ERF method [Subsection Large agricultural organizations such as Meat and 106(4) CFI Act] (Australian Government 2017). Existing Livestock Australia (MLA) are exploring opportunities to ERF methods are reviewed periodically by the ERAC to achieve net zero emissions, i.e. carbon neutrality (Meat & ensure they continue to meet the offsets integrity Livestock Australia 2017). standards and other legislative requirements. These reviews may indicate that an activity that was The Emissions Reduction Fund initially assessed as eligible may no longer be eligible. This may occur if there are changes in other legislation or The Emissions Reduction Fund (Department of the unforeseen adverse economic, environmental or social Environment and Energy 2018c) is a voluntary scheme impacts occur. Methods can be suspended by the ERAC that establishes methods which provide incentives for if they have reasonable evidence that one or more of the land managers, businesses, local councils and state offsets integrity standards is not being met. The Minister governments to adopt new practices and technologies that can also revoke and vary methods. will reduce Australia’s GHG emissions. Methods have The Clean Energy Regulator administers ERF projects been developed for improved land management in forests and contracts (Clean Energy Regulator 2018). and agriculture, savanna fire management, improved Applications can be made for projects to be registered transport efficiency and energy efficiency, facilities, under an ERF method, and for a project to be registered mining and waste to landfill and waste water management under a method it must meet a number of individual practices. Methods may be varied as new technologies project eligibility requirements. Projects must be new, become available, to add new eligible activities and to and not required by law or already funded under a listed reduce unnecessary regulatory burden. government program. There is also a list of ‘excluded The Australian Government develops ERF methods offsets projects’, which could lead to particular adverse that estimate GHG abatement resulting from impacts, such as the planting of certain defined weed implementing technologies and management practices species. (Department of the Environment and Energy 2018c). ERF Once projects are registered under an ERF method, methods describe: eligible activities that generate proponents are required to undertake the eligible activity abatement by avoiding GHG emissions or sequestering or activities and regularly report to the Clean Energy carbon; how to quantify abatement resulting from the Regulator on the amount of abatement they have activity; and the required compliance measures. achieved. Projects are periodically audited to ensure they Registered projects allow proponents to use approved are undertaking the activity and estimating abatement as ERF methods to earn Australian carbon credit units prescribed in the method. (ACCUs). Once earned, ACCUs can be sold to the Australian Government or to other businesses seeking to Potential for planting leucaena as an eligible ERF offset their emissions. project activity Methods are legislative instruments and must be adhered to by scheme participants. To ensure ACCUs are Planting leucaena in agricultural systems is used here as credible and the abatement generated contributes toward an example to demonstrate the types of considerations Australia’s emissions reduction targets, ERF methods when assessing whether activities would be eligible under must comply with the Carbon Credits (Carbon Farming an ERF method. This activity is assessed against the Initiative) Act 2011 (Australian Government 2017). Each offsets integrity standards (s133 CFI Act) (Australian project must comply with a number of individual project Government 2017). There are also other legislative eligibility requirements in that Act along with the Carbon requirements for consideration such as whether the Credits (Carbon Farming Initiative) Regulations 2011 activity is likely to have adverse impacts [Subsection (Australian Government 2015) and Carbon Credits 106(4) CFI Act] (Australian Government 2017) – also (Carbon Farming Initiative) Rule 2015 (Australian assessed here. These requirements maintain the integrity Government 2018). of the ERF and ensure that the value of ACCUs remains An independent Emissions Reduction Assurance comparable across sectors. Requirements are: Committee (ERAC) provides advice to the Minister for 1. Abatement must be additional to that which would the Environment on whether proposed new methods meet occur in the absence of the project: Emissions the offsets integrity standards, as specified in Section 133 Reduction Fund methods cannot permit activities that of the CFI Act. The Minister must have regard to any are likely to occur in the absence of the ERF, such as Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 276 K. King and R. Burgess being undertaken prior to project application. The where inputs and outputs can be accurately measured combination of method eligibility and individual (e.g. Hulshof et al. 2012; Newbold et al. 2014; project eligibility requirements applies appropriate Charmley et al. 2015). In contrast, Tomkins et al. filters, so that only genuinely additional projects can (2018) estimated herd-scale methane fluxes using be credited. For leucaena, this means that ERF open path laser technologies and Coates and Dixon projects should not be eligible if there is no additional (2007) applied faecal NIRS methodologies and δ13C planting of leucaena, or where non-carbon drivers ratios. These and other studies (e.g. Charmley et al. would ensure that leucaena would be planted in the 2008) have demonstrated there is a reduction in absence of the carbon market. enteric methane and improved emissions intensity 2. Estimates of net abatement must be measurable and resulting from a change in diets for livestock, verifiable: Emissions Reduction Fund methods must including livestock change to feeding leucaena. describe a measured or modelled approach for It is difficult however to extrapolate these calculating the net abatement resulting from the laboratory results to grazing herds, as it is not easy to project activity. This approach must be supported by determine the preferential leucaena or grass grazing robust scientific evidence. Estimates of net abatement practices for herds and individual cattle. must be verifiable by an auditor and the Clean Energy Implementing these approaches to estimate net Regulator. In the case of leucaena any approach abatement could be complex and costly, thereby would need to take into account variables affecting reducing the potential for uptake of the activity for the extent to which methane emissions are reduced, generating carbon credits. such as preferential grazing (the proportional 5. Methods must account for all material emissions consumption of leucaena in the diet); and possible resulting from undertaking the project activity in variability in enteric methane production between estimating the net carbon abatement: Performing cattle breeds, leucaena species and geographic activities that reduce emissions or sequester carbon locations. Calculations must account for natural may generate additional emissions. Under the ERF, variability and credit only that abatement resulting all material emissions that result from the project directly from the project activity. activity must be accounted for and must be deducted 3. The net abatement resulting from projects using ERF from the abatement resulting from the activity to methods must contribute to Australia’s GHG targets: determine the net abatement amount. For example, Abatement credited under ERF methods must for leucaena, GHG emissions resulting from the use contribute to Australia meeting its international GHG of machinery involved with planting and managing targets. To achieve this, the change in emissions leucaena, and the use of irrigation and fertilizer must resulting from the project activity must be evident in be calculated and deducted from the gross abatement. Australia’s annual GHG accounts. Currently the Carbon and nitrogen interactions during growth of national accounts do not estimate enteric emissions at both grass and leucaena (Conrad et al. 2017) that a farm scale, and therefore do not detect differences differ from those occurring before the project was in enteric emissions resulting from local changes to implemented must also be accounted for. the composition of feed intake. The national 6. Estimates of the net abatement amount must be inventory would require data on the scope and type of conservative: It is important that the estimates, these changes for it to be sensitive to farm-scale projections and assumptions in the calculations in differences in feed practices. This accounting ERF methods do not overestimate the credits that approach must be consistent with the IPPC should be issued for a project. ‘Conservative Guidelines for national inventories. estimates’ help ensure that estimates of net abatement 4. There must be clear and convincing evidence that do not credit more abatement than is evident in supports the estimates of net abatement: Emissions Australia’s national accounts. That is, when 1 t Reduction Fund methods estimate methane emissions CO2-eq is estimated to have been abated due to an by direct measurement or using models that must ERF project, the national inventory report should also provide robust estimates of the net abatement amount. account for at least 1 t CO2-eq of emissions reduction. Models must be calibrated with appropriate empirical All assumptions and estimates for parameters used to data. calculate abatement must result in a conservative Studies to quantify enteric methane emissions estimate of net abatement. Discounts are sometimes from livestock fed different diets have largely been applied to net abatement estimates where there is conducted using intensive respiration chambers, uncertainty in the science. These discounts may be Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Linking leucaena to carbon abatement opportunities in Australia 277 reduced over time, with additional research outcomes other mixed fodders or pasture grasses (Tomkins et al. contributing to more refined estimates of parameters. 2018). Leucaena provides highly digestible protein and 7. Methods must address any likely adverse environ- the grass provides a source of roughage and energy. The mental, economic or social impacts from carrying out improved liveweight gains result in earlier turn-off ages the project: The Government seeks to avoid activities or heavier turn-off weights. As a result, the enteric under ERF methods that result in any adverse emissions generated per unit of meat production are environmental, social or economic outcomes lower. This is known as the emissions intensity for each [Subsection 106(4) CFI Act] (Australian Government unit of production. 2017). To address any potential unintended adverse A reduction in the emissions intensity can be credited outcomes resulting from undertaking ERF projects, under the ERF as is the case for more efficient energy use methods are assessed at the time of their development in the industrial sector (Department of the Environment and again during periodic reviews. Leucaena is and Energy 2018d). Eligible activities under the ERF beef currently classified as an environmental weed as it cattle herd management method (Department of the spreads rapidly and can form dense thickets. In some Environment and Energy 2018d) include those that regions, regulations support appropriate management promote more efficient liveweight gain in pasture-fed to prevent or minimize its spread. The potential risk beef cattle herds and increase the weight:age ratio of the of adverse environmental outcomes as a result of herd. Under the ERF beef cattle herd management method promoting the planting of leucaena under a carbon the focus is on the outcomes resulting from the activity, scheme will need to be periodically reviewed. In rather than identifying specific eligible activities. addition, the inclusion of leucaena in carbon schemes Pastures containing a mix of leucaena and grass contain must consider minimizing the risk of leucaena higher crude protein concentration and more biomass than toxicity to livestock. If the weed classification of straight pasture grasses. This results in the potential to leucaena was changed in the future, such that planting sustainably increase stocking rates (Harrison et al. 2016). it as part of an ERF project activity becomes an Despite improvements in emissions intensity per animal, excluded offset activity, then new projects would not an increase in stocking rates has the potential to increase be eligible under the ERF. overall emissions from the herd. Emissions Reduction Fund methodologies credit the abatement resulting from Potential carbon abatement using leucaena improved emissions intensity per animal, but this can be offset by increased stocking rates and hence increased Leucaena is a perennial legume that originates from overall emissions by the herd or per unit area. Central America. It grows best in areas with deep, well- As a perennial legume, leucaena fixes nitrogen and drained, alkaline soils high in phosphorus and receiving increases the store of carbon in the soil. For example, more than 600 mm of annual rainfall that occurs through- Conrad et al. (2017) demonstrated an increase in soil out the year. Leucaena is more drought-tolerant than most carbon of 280 kg C/ha/yr in the top 30 cm of a vertisol soil other pasture species, and is relatively frost-intolerant. In in a leucaena-buffel grass grazing system over a 40-year Australia, about 125,000 ha have been sown with period. Improvements in soil carbon concentrations are leucaena (Beutel et al. 2018), the majority being in central most evident when legumes are planted in nitrogen- Queensland. depleted soils (Conrad et al 2018), and where there are Enteric methane emissions from livestock can be minimal or no deficiencies of soil phosphorus and sulphur reduced by increasing the fermentable crude protein in the (Radrizzani et al. 2016). Where soils are low in P and S, diet. Legumes like leucaena are high in crude protein and nitrogen fixation and carbon storage can be improved methane emissions per unit of feed consumed are lower by applying fertilizers. However, where improved on diets containing legumes (Kennedy and Charmley management practices focus on carbon abatement, 2012; McSweeney and Tomkins 2015; Harrison et al. consideration must be given to the potential for additional 2015; Vercoe 2015; Conrad et al. 2017). Kennedy and emissions from this use of fertilizer. Charmley (2012) demonstrated a 30% reduction in enteric An increase in soil carbon sequestration as a methane produced by livestock fed an optimal leucaena consequence of planting legumes is an eligible activity and grass diet relative to a pure grass diet, while Harrison under the ERF measurement of soil carbon sequestration et al. (2015) observed reductions of more than 23%, in agricultural systems (Department of the Environment relative to baseline emissions, in animals fed leucaena. and Energy 2018d). This method focuses on the outcomes Liveweight gains are greater when livestock are fed a resulting from the activity, rather than defining specific leucaena-pasture grass combination, compared with many activities that are eligible. Only carbon that is sequestered Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 278 K. King and R. Burgess as a result of undertaking the ERF project activity is Conrad KA; Dalal RC; Dalzell SA; Allen DE; Fujinuma R; considered to be genuine abatement. Menzies NW. 2018. Soil nitrogen status and turnover in subtropical leucaena-grass pastures as quantified by δ15N Conclusion natural abundance. Geoderma 313:126‒134. doi: 10.1016/ j.geoderma.2017.10.029 Department of the Environment and Energy. 2015. Australia’s Scientific evidence demonstrates that inclusion of 2030 Climate Change Target. Australian Government, leucaena in the diet of cattle in northern Australia can Canberra, ACT, Australia. bit.ly/2KnzuxQ result in improved productivity, reduced enteric methane Department of the Environment and Energy. 2017. Australia’s emissions and improvements in soil carbon levels. If Emissions Projections. Australian Government, Canberra, promoting leucaena plantings were to be considered ACT, Australia. bit.ly/2YLDTDO under the ERF, a method of crediting needs to be Department of the Environment and Energy. 2018a. Tracking developed consistent with the offsets integrity standards. Australia's greenhouse gas emissions. Australian Each project would have to meet the individual project Government, Canberra, ACT, Australia. bit.ly/2LZecKc eligibility requirements. A key challenge for all potential Department of the Environment and Energy. 2018b. National Inventory Report 2016. Australian Government, Canberra, methods is getting the balance right between accuracy, ACT, Australia. bit.ly/2YJoDr6 simplicity and practicality so that genuine projects can be Department of the Environment and Energy. 2018c. Emissions rewarded for their contribution to lowering GHG Reduction Fund. Australian Government, Canberra, ACT, emissions. Australia. bit.ly/2M6wNEj Department of the Environment and Energy. 2018d. Eligible References activities. Australian Government, Canberra, ACT, (Note of the editors: All hyperlinks were verified 4 August 2019.) Australia. bit.ly/2GMzt5q Harrison MT; McSweeney C; Tomkins NW; Eckard RJ. 2015. Australian Government. 2015. Carbon Credits (Carbon Improving greenhouse gas emissions intensities of Farming Initiative) Regulations 2011. Department of the subtropical and tropical beef farming systems using Environment, Canberra, ACT, Australia. bit.ly/2Zz7PR0 Leucaena leucocephala. Agricultural Systems 136:138‒ Australian Government. 2017. Carbon Credits (Carbon 146. doi: 10.1016/j.agsy.2015.03.003 Farming Initiative) Act 2011. Department of the Harrison MT; Cullen BR; Tomkins NW; McSweeney C; Cohn Environment, Canberra, ACT, Australia. bit.ly/2YBrKNO P; Eckard RJ. 2016. The concordance between greenhouse Australian Government. 2018. Carbon Credits (Carbon gas emissions, livestock production and profitability of Farming Initiative) Rule 2015. Department of the extensive beef farming systems. Animal Production Science Environment, Canberra, ACT, Australia. bit.ly/2ME2p3x 56:370‒384. doi: 10.1071/AN15515 Beutel T; Corbet D; Hoffmann MB; Buck SR; Kienzle M. 2018. Hulshof RBA; Berndt A; Gerrits WJJ; Dijkstra J; van Quantifying leucaena cultivation extent on grazing land. Zijderveld SM; Newbold JR; Perdok HB. 2012. Dietary The Rangeland Journal 40:31‒38. doi: 10.1071/RJ17085 nitrate supplementation reduces methane emission in beef Charmley E; Stephens ML; Kennedy PM. 2008. Predicting cattle fed sugarcane-based diets. Journal of Animal Science livestock productivity and methane emissions in northern 90:2317–2323. doi: 10.2527/jas.2011-4209 Australia: Development of a bio-economic modelling Kennedy P; Charmley E. 2012. Methane yields from Brahman approach. Australian Journal of Experimental Agriculture cattle fed tropical grasses and legumes. Animal Production 48:109‒113. doi: 10.1071/EA07264 Science 52:225‒239. doi: 10.1071/AN11103 Charmley E; Williams SRO; Moate PJ; Hegarty RS; Herd RM; Meat & Livestock Australia. 2017. Red meat industry can be Oddy VH; Reyenga P; Staunton KM; Anderson A; Hannah carbon neutral by 2030. bit.ly/2GLHaZD MC. 2015. A universal equation to predict methane McSweeney C; Tomkins N. 2015. Impacts of Leucaena production of forage-fed cattle in Australia. Animal plantations on greenhouse gas emissions in northern Production Science 56:169‒180. doi: 10.1071/AN15365 Australian cattle production systems. Final Report. Meat & Clean Energy Regulator. 2018. Emissions Reduction Fund. Livestock Australia, Sydney, Australia. bit.ly/2KfLxgy bit.ly/2MC9uBB Newbold JR; van Zijderveld SM; Hulshof RBA; Fokkink WB; Coates D; Dixon R. 2007. Faecal near infrared reflectance Leng RA; Terencio P; Powers WJ; van Adrichem PSJ; spectroscopy (F.NIRS) measurements of non-grass Paton ND; Perdok HB. 2014. The effect of incremental proportions in the diet of cattle grazing tropical rangelands. levels of dietary nitrate on methane emissions in Holstein The Rangeland Journal 29:51‒63. doi: 10.1071/RJ07011 steers and performance in Nelore bulls. Journal of Animal Conrad KA; Dalal RC; Dalzell SA; Allen DE; Menzies NW. 2017. Science 92:5032–5040. doi: 10.2527/jas.2014-7677 The sequestration and turnover of soil organic carbon in Radrizzani A; Shelton HM; Kravchuk O; Dalzell SA. 2016. subtropical leucaena-grass pastures. Agriculture, Ecosystems Survey of long-term productivity and nutritional status of and Environment 248:38‒47. doi: 10.1016/j.agee.2017.07.020 Leucaena leucocephala-grass pastures in subtropical Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Linking leucaena to carbon abatement opportunities in Australia 279 Queensland. Animal Production Science 56:2064‒2073. Tropical Grasslands-Forrajes Tropicales 7:267‒272. doi: doi: 10.1071/AN15084 10.17138/TGFT(7)267-272 Tomkins N; Harrison MT; McSweeney C; Denman S: Vercoe P. 2015. The mechanism of antimethanogenic Charmley E; Lambrides C; Dalal R. 2019. Greenhouse gas bioactivity of plants in the rumen. Final Report. Meat & implications of leucaena-based pastures. Can we develop an Livestock Australia, Sydney, Australia. bit.ly/2YD5tPE. emissions reduction methodology for the beef industry? (Accepted 23 December 2018 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):280–289 280 DOI: 10.17138/TGFT(7)280-289 ILC2018 Keynote Paper* Weed leucaena and its significance, implications and control Leucaena como maleza: Importancia, implicaciones y control SHANE CAMPBELL1, WAYNE VOGLER2, DANNIELLE BRAZIER2, JOSEPH VITELLI3 AND SIMON BROOKS2 1School of Agriculture and Food Sciences, The University of Queensland, Gatton, QLD, Australia. agriculture.uq.edu.au 2Invasive Plant and Animal Science Unit, Biosecurity Sciences, Department of Agriculture and Fisheries, Tropical Weeds Research Centre, Charters Towers, QLD, Australia. daf.qld.gov.au 3Invasive Plant and Animal Science Unit, Biosecurity Sciences, Department of Agriculture and Fisheries, Eco-Sciences Precinct, Brisbane, QLD, Australia. daf.qld.gov.au Abstract Leucaena (Leucaena leucocephala) is widely recognized in many countries as a commercially valuable plant, particularly when used as a nutritious fodder in subtropical and tropical regions. However, it is also considered an environmental weed in some countries due to its ability to form dense infestations in disturbed areas, where it is not proactively managed or grazed. These different perspectives have made leucaena a contentious species. Ideally, landholders and relevant jurisdictions in charge of invasive species need to work together to minimize its spread as a weed and manage existing infestations. To date, the response has been varied, ranging from no action through to some jurisdictions formally recognizing leucaena as an environmental weed within relevant legislation and applying requirements to minimize its impact. Between these extremes, there are initiatives such as an industry Code of Practice (i.e. The Leucaena Network in Australia), recommending that those growing leucaena adhere to certain principles and practices to minimize the risk of spread from their operations. The biology of weed leucaena (e.g. large seed production, relatively long-lived seed banks) and the situations in which it spreads (e.g. roadsides and riparian systems) pose management challenges to landholders and relevant jurisdictions. Adaptive management and experimental research are necessary to identify effective control strategies for a range of situations. Keywords: Conflict, contentious, ecology, herbicide, management, tree legumes. Resumen Leucaena (Leucaena leucocephala) es ampliamente reconocida en muchos países como una planta económicamente valiosa, particularmente cuando se usa como forraje de alto valor nutritivo en regiones subtropicales y tropicales. Sin embargo, en algunos países también es considerada una maleza ambiental debido a su capacidad para formar infestaciones densas en áreas perturbadas donde las poblaciones no son pastoreadas ni manejadas en forma proactiva. Estas diferentes perspectivas han hecho de la leucaena una especie contenciosa. Idealmente, los usuarios de las tierras y las autoridades a cargo del control de especies invasoras deberían trabajar juntos para minimizar la diseminación de la especie como maleza y manejar adecuadamente las infestaciones existentes. Hasta la fecha, las reacciones han sido variadas, desde la no acción por parte de algunas autoridades hasta el reconocimiento formal de la leucaena como una maleza ambiental dentro de la legislación existente y la aplicación de normas para minimizar su impacto. Entre estos extremos existen iniciativas tales como el Código de Prácticas desarrollado por la Red de Leucaena en Australia, que recomienda que los que cultivan leucaena se adhieran a ciertos principios y prácticas para minimizar el riesgo de su diseminación. La biología de la leucaena como maleza (p.ej., alta producción de semillas, relativamente larga viabilidad de la semilla en el suelo) y las situaciones en las que se disemina (p. ej., bordes de carretera y sistemas ribereños) plantean ___________ Correspondence: S. Campbell, School of Agriculture and Food *Keynote paper presented at the International Leucaena Sciences, The University of Queensland, Gatton Campus, Gatton, Conference, 1‒3 November 2018, Brisbane, Queensland, Australia. QLD 4343, Australia. Email: shane.campbell@uq.edu.au Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Weediness of leucaena 281 desafíos de manejo para los productores y las autoridades. Formas de manejo adaptativo e investigación experimental son necesarios para identificar estrategias de control efectivas que deben considerar una variedad de situaciones. Palabras clave: Conflicto, controversia, ecología, herbicida, leguminosas arbóreas, manejo. Introduction as a global weed and consider actions and activities that are being or could be implemented to minimize its Leucaena (Leucaena leucocephala) is increasingly impacts. Key aspects of the biology/ecology of leucaena recognized around the world for its beneficial properties, and available control options are also discussed in the particularly as a source of nutritional fodder, timber, context of developing management strategies to prevent fuelwood and shade (Walton 2003a, 2003b; Shelton and its spread and/or control infestations having negative Dalzell 2007; Olckers 2011). It has also been used in environmental impacts. restoration programs to restore degraded lands, improve soils, reduce erosion and stabilize sand (e.g. Shelton and The significance of leucaena as a weed Dalzell 2007; Normaniza et al. 2008; Roose et al. 2011; Wolfe and Bloem 2012; CABI 2018). Its ability to invade While the native distribution of leucaena (i.e. Mexico and areas where it is not wanted, i.e. may become a weed, is Central America) is relatively restricted on a global scale, also becoming increasingly recognized (Walton 2003a, a combination of deliberate and non-deliberate dispersal 2003b; Shelton and Dalzell 2007; Olckers 2011). has led to it becoming one of the more widely naturalized Leucaena production in most countries occupies only species around the world (Figure 1). In a comprehensive a small percentage of the potential area where it could be review of the pest status of leucaena, Walton (2003a) grown. The risk of it becoming an even more problematic suggested that it could be naturalized in more than 105 species could therefore increase greatly if steps are not put countries throughout the world’s subtropics and tropics. in place to minimize the risk of it escaping from existing This number appears to have increased since then to more naturalized infestations and cultivated plantations. than 125 countries according to some global invasive In this paper, we discuss the significance of leucaena species databases (GISD 2015; CABI 2018). Figure 1. Global distribution of Leucaena leucocephala; sourced from the Invasive Species Compendium (CABI 2018). Individual points are representative of either a region, jurisdiction, country or continent. For example, this map shows that in Australia, leucaena is present in Queensland, New South Wales, The Northern Territory and Western Australia, but does not give specific locations of all known infestations. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 282 S. Campbell, W. Vogler, D. Brazier, J. Vitelli and S. Brooks In terms of world regions, the largest numbers of problematic (Clarkson et al. 2010; Olckers 2011). Of the countries with naturalized populations of leucaena are 3 subspecies of L. leucocephala, subspecies leucocephala located in the Pacific Ocean region, Africa, Asia and is generally considered to have the greatest weed potential South America, followed by the Caribbean, Central and is the most widely naturalized. The more recently America, the Indian Ocean region, Australasia, North cultivated L. leucocephala ssp. glabrata is considered to America and to a lesser extent Europe and the Middle East have fewer weedy attributes but is still recognized as (Walton 2003a; CABI 2018). Walton (2003a) suggested having the potential to become a weed if not adequately that leucaena was considered a weed in more than 25 of managed (Shelton et al. 2003; Walton 2003a; Olckers these countries, while the more recent Invasive Species 2011). Infestations of L. leucocephala ssp. glabrata have Compendium database (CABI 2018) lists more than 50 been reported at several locations in Australia (Shelton et countries where leucaena has been reported to be al. 2003; Walton 2003a, 2003b). invasive. Based on a recent review of the potential Leucaena is predominantly recognized as being a distribution of 10 invasive alien trees, it appears that weed of roadsides (Figure 2), forest margins, riparian leucaena is globally distributed across a large portion of habitats, ruderal areas in peri-urban environments and its potential range (Wan et al. 2018). Further expansion of other disturbed areas (Shelton et al. 2003; Walton 2003a, its current range is most likely to occur predominantly 2003b; Olckers 2011; CABI 2018). Despite its through continued spread within already invaded widespread distribution, its impact is not well countries. documented in the scientific literature. It is generally Not all countries recognize leucaena solely as a weed, reported as having an ability to form dense monospecific with some categorizing it as being a ‘contentious’ or thickets that could render extensive areas of disturbed ’conflict’ species (FAO 2009; Clarkson et al. 2010; ground essentially unusable and inaccessible, reduce Olckers 2011). Plants given these classifications are biodiversity and potentially threaten endemic species of recognized as having some attributes that make them conservation value (Walton 2003b; Yoshida and Oka useful or desirable and other attributes that make them 2004; Costa et al. 2015; GISD 2015). Figure 2. Roadside infestation of leucaena near Brisbane (Australia). Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Weediness of leucaena 283 Biology and ecology of leucaena from a weed In contrast, a study undertaken by Marques et al. (2014) perspective in a Brazilian forest found that leucaena formed a persistent short-lived seed bank (viability 1–5 years). Many tetraploid leucaena species such as Leucaena They suggested that under typically hot and humid leucocephala have biological and ecological attributes conditions, such as those experienced at the field site in that facilitate their ability to become invasive weeds in Brazil, seeds of tropical legumes may break dormancy areas where they are not proactively managed. Plants can faster, leading to more rapid depletion of soil seed banks live for a relatively long time (>30 years) under favorable (McDonald 2000). conditions, even if regularly grazed (Jones and Bunch A study of the potential longevity of seed banks of 1995; 2000). Once mature, they frequently produce large more than 10 weeds, including leucaena, was initiated in quantities of seed (Raghu et al. 2005; Marques et al. 2009 in the dry tropics of north Queensland. Seeds placed 2014). Tetraploid plants such as leucaena are self-fertile, in mesh packets were buried under a range of conditions with only a small percentage of out-crossing, so even an including different soil types, burial depths and levels of isolated plant can produce pods with viable seeds and be pasture cover [see Bebawi et al. (2015) for details on the the source of a new infestation (Walton 2003b; Olckers methodology]. At 96 months a small percentage (<4%) of 2011). While it appears that most seed falls and stays viable leucaena seed remained in some treatments if within close proximity to the parent plants, several seeds were buried below ground (between 2.5 and 20 cm), dispersal mechanisms can facilitate the movement of but no surface-located seeds remained viable (Figure 3) seeds into new areas, including human activity, animals (F. Bebawi et al. unpublished data). A seedling- and water dispersal (Shelton et al. 2003; Walton 2003a, emergence trial has also been running conjointly since 2003b).The longevity of an established seed bank in the May 2016. Preliminary results indicate that there have absence of further replenishment becomes important for been approximately 9 discrete rainfall periods over the those tasked with managing infestations. It helps first 2 years that have been favorable for germination and determine the potential duration of control activities, seedling establishment; yet only around 20% of the initial particularly if eradication of the infestation is the end seed has germinated and emerged. The ability of leucaena goal (Campbell and Grice 2000; Panetta 2004; Panetta et to germinate multiple times throughout a year while al. 2011). Having a hard seed coat, leucaena seeds are maintaining a persistent seed bank enhances the long-lived with several sources in the literature likelihood of establishment and recruitment occurring suggesting periods of 10–20 years and some even over a prolonged period, making it more challenging to potentially longer (Walton 2003a, 2003b; Olckers 2011). control (Campbell and Grice 2000). 100 90 Surface Below ground 80 70 60 50 40 30 20 10 0 0 12 24 36 48 60 96 Months Figure 3. Changes in the viability of Leucaena leucocephala seeds over time following placement on the soil surface or burial below ground (2.5‒20 cm). Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Viability (%) 284 S. Campbell, W. Vogler, D. Brazier, J. Vitelli and S. Brooks Knowing the time for leucaena seedlings to reach The basal bark technique, which involves spraying the reproductive maturity will aid effective management. stem of plants up to a height of around 30–40 cm from Weeds with short timelines to maturity pose greater ground-level with herbicides mixed with diesel or oil- difficulty, with more frequent control activities required based products is consistently one of the most effective to prevent new plants from reaching reproductive treatments on larger plants. Cutting plants off close to maturity and replenishing soil seed reserves (Campbell ground level and spraying the cut stem immediately and Grice 2000). Leucaena appears to be capable of afterwards is another effective option (Figure 4) but it is reaching reproductive maturity within 12 months in many expensive and impractical for large areas unless situations, but potentially as quickly as 4 months under machinery is used such as a mulcher with the herbicide ideal conditions (Walton 2003a, 2003b; Olckers 2011). applied immediately after treatment. In Australia, a triclopyr/picloram- (Access™) based product mixed with Control options for leucaena diesel is registered for both basal bark and cut stump applications on leucaena (Queensland Government 2016). Up until the present time there has been limited In Hawaii triclopyr is recommended for basal bark and cut investment into research on control of weedy leucaena stump applications (Leary et al. 2012). with research organizations tending to focus on higher priority species such as those declared under legislation. The main research has been to identify effective herbicides that could be applied to individual plants and scattered infestations (Walton 2003a). Some preliminary investigations into biological control options have been explored in South Africa (Olckers 2011). Some adaptive research has also been undertaken by landholders and natural resource management and community-based organizations trying to deal with specific situations where leucaena has become a problem within their jurisdictions (e.g. Folkers 2010). Despite limited information on specific control options for weedy leucaena, several of the mechanical and chemical techniques developed for other woody weeds (Vitelli and Pitt 2006) may be relevant. If available, mechanical control would be an appropriate option for treating dense infestations of leucaena using equipment such as bulldozers Figure 4. A roadside infestation of leucaena near Townsville (with blade, stick-rake or blade-plough attachments) or (Australia) treated using the cut stump method. tractors and excavator-style machinery fitted with mulching devices or other destructive equipment. Any equipment that In Australia, early screening work and more recent severs the root system below ground should cause high adaptive-style trials have shown that foliar applications of mortality but, if the plant is cut off at ground level such as glyphosate, clopyralid and triclopyr/picloram-based during mulching, there is a higher likelihood of significant products can kill leucaena. However, results were often re-shooting occurring. In a series of control trials undertaken variable, and mortality tended to decrease with increasing in the Mackay region of Queensland, the use of a cutter bar plant size (Pest Management Research 2002; Walton operating 30 cm below ground resulted in 100% mortality 2003a; Folkers 2010). There are no current label (Folkers 2010). This is likely to be followed by extensive registrations for any herbicides to be applied using foliar seedling emergence. applications in Australia but permits have been approved Control of re-shooting plants and seedling regrowth previously by the Australian Pesticides and Veterinary can be undertaken with herbicides applied using a few Medicines Authority (APVMA) for certain situations. For different techniques. However, leucaena is a fairly example, minor use permit PER9395 was issued by difficult plant to control with herbicides compared with APVMA in 2007 for the control of leucaena seedlings on some other woody weeds, with highest mortality usually mine rehabilitation sites using a foliar application of achieved by controlling younger plants, particularly if triclopyr/picloram (150/50 g a.i./100 L water) (APVMA foliar spraying is the preferred method. 2018). In Hawaii triclopyr is recommended for foliar Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Weediness of leucaena 285 application on leucaena plants that are less than 6 feet tall (Wolfe and van Bloem 2012). Nevertheless large-scale (Leary et al. 2012). seedling regrowth should be expected with seed To increase the range of herbicide options to control scarification potentially occurring as a result of exposure leucaena in Australia, a collaborative exercise between to high temperatures for a short period (Walton 2003a). industry, producers, government and Dow AgroSciences While this has the potential to exacerbate the problem, it (now Corteva AgriscienceTM) resulted in 3 trials being can be advantageous as part of an integrated management implemented during December 2015 and January 2016 strategy by increasing the rate of depletion of soil seed with final assessments undertaken 12 months later. A total reserves, when combined with follow-up control of 18 herbicide treatments (including an untreated control) (Campbell and Grice 2000). were applied using either basal bark, cut stump, gas gun (low-volume, high-concentration), stem blaze or frill, or the ground application of residual herbicides. The results showed that the registered basal bark techniques (both the traditional and newer thin-line method which involves spraying a more concentrated mix to the bottom 5 cm of stem) using triclopyr/picloram (Access™) consistently gave the best results but some other options also showed promise. In particular, cut stump applications of aminopyralid/metsulfuron-methyl (Stinger™) mixed with water and an aminopyralid/picloram gel (Vigilant™ II) provided greater than 80 and 60% efficacy, respectively. Ground applications of picloram granules (Tordon™ Granules) also showed promise, with limited impact on surrounding grasses and legumes. Ineffective treatments included cut stump applications using glyphosate (Glyphosate 360®) and metsulfuron-methyl (Brush-Off®), gas gun applications using metsulfuron-methyl (Brush- Figure 5. Leucaena re-shooting after a fire in Central Off®) and aminopyralid/metsulfuron-methyl (Stinger™) Queensland (Australia). and ground applications of tebuthiuron (Graslan®) and hexazinone (Velpar® L). Based on these results, the gas gun Given the benefits of leucaena, biological control has application method (low-volume, high-concentration) does not been a high research priority. A biological control not appear to be an effective option for leucaena control, program in South Africa in 1999 resulted in the release of possibly due to the small bi-pinnate leaf and insufficient a seed beetle Acanthoscelides macrophthalmus Schaeffer, herbicide translocating into the large biomass of mature with the aim of trying to prevent establishment/ plants (M. Vitelli pers. comm.). replenishment of persistent soil seed banks (Olckers 2011). A relatively new and novel stem injection technique The beetle has now established in another 13 countries that uses a specialized applicator and encapsulated dry (Australia, Benin, Ethiopia, India, Japan, China, Cyprus, herbicides is currently showing promise for a range Senegal, Taiwan, Thailand, Togo, Vanuatu and Vietnam) of woody plants, including leucaena. It could have as a result of seed contamination or accidental application for treating unwanted plants, particularly in introductions (Raghu et al. 2005; Wu et al. 2013; sensitive areas such as waterways and national parks and iBiocontrol 2018). The beetle reduces the viability of seeds, in areas that are inaccessible to other equipment, such as but its effectiveness is variable depending on a range of hillslopes (Goulter et al. 2018). In Hawaii, stem injection factors (Olckers 2011; Egli and Olckers 2012; Sharratt and applications using aminopyralid are an available option Olckers 2012; Ramanand and Olckers 2013; English and for leucaena control (Leary et al. 2012). Olckers 2014). In many instances, soil seed banks are still The use of fire as a control option for leucaena sufficient for seedling recruitment to occur. A sap-sucking has not been formally tested, but warrants investigation. psyllid, Heteropsylla cubana Crawford, has also been Anecdotal reports are variable, ranging from nil effects accidentally introduced into many countries, where it is (Figure 5) to reasonable mortality, but this could be having negative impacts on the productivity of leucaena for reflective of variability in the fires implemented. It commercial purposes, but has not reduced the weediness of appears that, if relatively high-intensity fires are imposed, leucaena, as infestations are still expanding where the plant mortality is possible, particularly for smaller plants psyllid is present (Olckers 2011). Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 286 S. Campbell, W. Vogler, D. Brazier, J. Vitelli and S. Brooks A range of land management practices can also play an Given the beneficial attributes of leucaena, few important role in the management of leucaena. It is not an countries have used legislative powers as a strategy to overly competitive species (particularly in the seedling prevent, minimize or manage its impacts within their and juvenile stages), so maintaining a healthy pasture jurisdictions. An exception is South Africa where it is within leucaena paddocks and in surrounding areas will listed as a Category 2 weed under the National Environ- greatly reduce seedling recruitment and spread into new mental Management: Biodiversity Act 2004 (Act No. 10 areas. Furthermore, if commercial plantings and/ of 2004). Category 2 weeds include species that have or infestations of leucaena are grazed in a manner that economic benefits (e.g. agroforestry and fodder species) defoliates the plants and prevents/minimizes the and are not otherwise prohibited. According to the Act, production of pods, this will greatly reduce the amount of such species may be imported, harbored, propagated and seed that can be dispersed into other areas (Walton 2003a; traded only if a permit is obtained. This classification 2003b). Periodic cutting back of leucaena in paddocks allows leucaena to be planted and commercially grown in may be required if an increasing proportion of plants grow demarcated areas provided steps are taken to control beyond the reach of livestock and start producing large spread (Nel et al. 2004). Outside of demarcated areas, quantities of seed. Incorporation of grazing as part of leucaena is considered the equivalent of a Category 1b management strategies for weed infestations of leucaena invasive species, which means that it must be controlled is an option that could be explored, either initially to or eradicated where possible (L. Henderson pers. comm.). reduce its abundance or as a follow-up technique to utilize While not declared at a national or even a state/territory the regrowth. The use of goats to control leucaena also level in Australia, leucaena has been declared by several warrants further investigation as anecdotal evidence local government authorities in Queensland (Walton suggests that they will consume not only available foliage 2003a; 2003b), which is the equivalent of the third tier of but also bark and will keep ring-barking plants, resulting government in a national context. At the higher levels of in many eventually dying (M. Shelton pers. comm.). In government, relevant states and territories provide the absence of grazing, utilization of infestations such as information (e.g. fact sheets) on the potential weed impacts through harvesting for fuelwood and fodder has proven of leucaena as well as options to control infestations. In highly effective in minimizing the impacts and spread of Queensland, the Biosecurity Act 2014 also legislates that leucaena in some countries (e.g. Thailand and parts of everyone has a general biosecurity obligation (GBO) to Indonesia) (M. Shelton pers. comm.). Nevertheless, given take reasonable and practical steps to minimize the risks the ecology of leucaena, land managers planning on associated with invasive plants and animals under their tackling large established infestations need to be prepared control, including leucaena (Queensland Government to make a long-term commitment, irrespective of the 2016). In Western Australia, L. leucocephala is a permitted techniques to be used. Many weed management programs species, but it has been classified as a very high fail because a large area is treated initially. This is often environmental weed risk in the Pilbara and Kimberley the easiest part, with follow-up treatment being much regions (Revell et al. 2019). Consequently, in these regions more difficult, particularly if environmental conditions leucaena is not approved for use on the extensive areas of favor large-scale germination and seedling growth. pastoral lease (government-owned crown land) but can be Control of isolated or small patches before they get the grown on freehold land (though this represents less than opportunity to spread and establish large and persistent 2% of the area). seed banks is the best preventative strategy. For contentious plants such as leucaena, Clarkson et al. (2010) suggested that a range of non-legislative options Mitigation strategies could be considered, including the use of codes of practice, subsidies, compensation, bonds, levies or Leucaena has been included in formal weed prioritization insurance schemes. A voluntary Code of Practice was and/or risk assessment processes (e.g. Pheloung et al. 1999; developed in 2000 by The Leucaena Network, a group of Walton 2003a; Nel et al. 2004; Gordon et al. 2011; Reddy graziers, scientists and extension officers dedicated to 2014) within several countries to determine appropriate advocating the responsible use of leucaena in northern strategies to minimize its potential or current impacts at Australia (Shelton and Dalzell 2007; Christensen 2019). various jurisdictional levels (e.g. local, regional, provincial It has the key principle that leucaena should be planted or national). Depending on its classification or the level of only if it is to be proactively managed and if responsibility risk, the response has been varied, ranging from no action is accepted to control plants that establish outside planted through to some jurisdictions formally recognizing leucaena areas. Eleven recommended practices are identified with as an environmental weed within relevant legislation. a focus on avoiding planting leucaena near potential Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Weediness of leucaena 287 weed-risk zones, minimizing seed set in grazed stands, (e.g. competitive pastures and strategic grazing), diminishing the risk of live-seed dispersal and control of biological, chemical and mechanical control and perhaps escaped plants from grazed stands. Although voluntary, the use of fire in some situations. However, ongoing the implementation of a self-auditing process or some sort research to improve control options for a range of of certification measures would be beneficial for the situations and to develop sterile leucaena varieties is leucaena industry to demonstrate a level of compliance necessary if future expansion of leucaena is to be allowed with the Code of Practice. in areas where jurisdictions currently restrict/prevent its The recent investment in Australia by industry and use due to weed concerns. An on-going dialogue between government into research aimed at developing sterile all organizations with a vested interest in leucaena from leucaena varieties (McMillan et al. 2019; Real et al. 2019) both positive and negative perspectives is also critical if is a positive and proactive initiative. If the environmental industry expansion of leucaena is to occur in a manner risks associated with sterile leucaena can be demonstrated that minimizes environmental impacts. to be minimal, jurisdictions that currently ban or discourage the growing of leucaena, may consider Acknowledgments allowing the introduction of sterile varieties in certain situations. This would lead to an expansion of the We gratefully acknowledge the contributions of those leucaena industry not only in Australia but also who have directly and indirectly contributed to this paper. potentially in other countries where weed concerns In particular, Michael Burgis, Marie Vitelli and Chris are preventing it from being grown or promoted for Love were responsible for undertaking the more recent commercial purposes. herbicide research that is summarized in the control section. We are grateful to Dr Faiz Bebawi who initiated Conclusion a long-term weed seed burial trial that included leucaena, with some preliminary results presented in this paper. Dr Leucaena is a very good example of a contentious plant Terence Olckers and Lesley Henderson kindly gave their given its many beneficial attributes, while also having the input on the legislative status of leucaena in South Africa. potential to become a major environmental weed. It has Similarly, Drs Clinton Revell and Daniel Real provided biological and ecological attributes that allow it to advice on restrictions associated with growing leucaena disperse from its source and to establish in new areas, in Western Australia. Associate Professor Max Shelton particularly disturbed environments. Once it becomes provided information which enhanced the manuscript. entrenched in an area, the relatively long-lived nature We are also appreciative of input from Drs Hayley of plants and soil seed banks, combined with an ability McMillan and Joe Scanlan who gave valuable feedback for new plants to reach reproductive maturity within a on earlier drafts of the paper. short timeframe, makes successful control a difficult, prolonged and expensive proposition. Legislation at an References (Note of the editors: All hyperlinks were verified 4 August 2019.) appropriate jurisdictional level has been used sparingly and often aimed at minimizing the environmental impacts APVMA (Australian Pesticides and Veterinary Medicines of leucaena, while still allowing its commercial use, albeit Authority). 2018. PER9395, Access & Grazon DS/Mine with certain restrictions/requirements. For leucaena rehabilitation/Leucaena leucocephala. Australian Pesticides growers, proactive management of leucaena to minimize and Veterinary Medicines Authority Permits Search. spread from their land will greatly reduce the likelihood Australian Government, Canberra, ACT, Australia. of new infestations establishing from commercial portal.apvma.gov.au/permits operations. Practices identified in the Code of Practice, Bebawi FF; Campbell SD; Mayer RJ. 2015. Seed bank developed by The Leucaena Network in Australia, are a longevity and age to reproductive maturity of Calotropis good starting point and could be modified to suit specific procera (Aiton) W.T. Aiton in the dry tropics of northern situations within different countries. For successful Queensland. The Rangeland Journal 37:239–247. doi: 10.1071/RJ14130 management of weed infestations of leucaena, an CABI (Centre for Agriculture and Bioscience International). integrated approach will be required in most instances to 2018. 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Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(2):290–294 290 DOI: 10.17138/TGFT(7)290-294 ILC2018 Keynote Paper* A short review of leucaena as an invasive species in Hawaii Una breve reseña de leucaena como especie invasora en Hawái TRAVIS IDOL Dept. of Natural Resources and Environmental Management, University of Hawaii-Manoa, Honolulu, USA. manoa.hawaii.edu Abstract Leucaena leucocephala subsp. leucocephala was introduced to Hawaii after European settlement and spread widely for cattle fodder and fuelwood. As in many other tropical locations where it has been introduced, it has naturalized and spread in disturbed and drier habitats. While it is common in disturbed areas, it is much less common in intact native dry forests. It is resilient to wildfire and mammalian grazing, which conversely threaten the integrity of remnant native dryland forest. The successional trajectory of areas dominated by leucaena has not been well studied in Hawaii, but it is probable that other non-native rather than native species will replace it. As a result of its widespread distribution, especially on steep slopes, priority for its eradication or control is low. Current biocontrol options are limited in effectiveness. Control of leucaena can and should be given greater priority to protect native dryland forests and inhibit spread of seeds. Restoration of dryland habitats requires intensive, sustained efforts, usually involving volunteers. Combining cultural and/or use values in restoration projects holds promise for stimulating and sustaining community involvement. Keywords: Forest disturbance, forest succession, shrub legumes, species introduction. Resumen Leucaena leucocephala subsp. leucocephala se introdujo en Hawái después del asentamiento europeo y se extendió ampliamente para uso como forraje y leña. Como en muchos otros lugares tropicales donde se ha introducido, se ha naturalizado y extendido hacia hábitats perturbados y más secos. Si bien es común su presencia en áreas perturbadas, es mucho menos común en bosques nativos intactos. Es resistente a los incendios forestales y al ramoneo de mamíferos, que, a la inversa, amenazan la integridad del bosque nativo remanente de tierras secas. El proceso sucesional de áreas dominadas por leucaena no se ha estudiado bien en Hawái, pero es probable que otras especies no nativas, en lugar de nativas, la reemplacen. Como resultado de su amplia distribución, especialmente en pendientes pronunciadas, su erradicación o control se considera de baja prioridad. La efectividad de opciones actuales de control biológico es limitada. El control de la leucaena puede y debe recibir mayor prioridad para proteger los bosques nativos de tierras secas e inhibir la dispersión de semillas. La restauración de los hábitats de las tierras secas requiere esfuerzos intensivos y sostenidos, generalmente con la participación de voluntarios. La combinación de valores culturales y/o de uso en proyectos de restauración es una estrategia promisoria para estimular y mantener la participación de la comunidad. Palabras clave: Introducción de especies, leguminosa arbustiva, perturbación forestal, sucesión forestal. Hawaii as a model system for studying invasive species any terrestrial location. Despite these isolated and unique characteristics, diversity of soil types and land forms and The Hawaiian archipelago is globally the most isolated the wide range in elevation (sea level to >3,000 m) and group of islands from any continental land mass; hence, it mean annual precipitation (<250 to 10,000 mm) within and has one of the highest proportions of endemic species of across the islands make it a near-ideal natural laboratory for ___________ Correspondence: T. Idol, Department of Natural Resources and *Keynote paper presented at the International Leucaena Conference, Environmental Management, University of Hawaii-Manoa, 1910 East 1‒3 November 2018, Brisbane, Queensland, Australia. West Road, Honolulu, HI 96822, USA. Email: idol@hawaii.edu Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Invasive leucaena in Hawaii 291 studying patterns of biological and ecological function and Geographic extent and conditions favoring invasion adaptation across environmental gradients (Vitousek 2004). Unfortunately, these characteristics also make it It is clear from these few reports that the widespread extremely vulnerable to the naturalization and spread of distribution of leucaena in Hawaii today is a combination introduced plant and animal species. of deliberate introduction and spread on multiple islands, As in most places in the world colonized by humans, coupled with naturalization via wind and water dispersal Hawaii has a wealth of introduced plant species adapted of seeds mostly into disturbed habitats. Leucaena is found to chronic human-associated disturbances, such as land primarily at lower elevations (<300 m) and drier habitats clearing, wildfires, soil disturbance, agriculture and in the Hawaiian Islands (Little and Skolmen 2003), grazing, plus the built environment. Of these one of the especially those that have been subject to chronic most common woody species is Leucaena leucocephala disturbance by humans and grazing or browsing subsp. leucocephala, known locally by its Hawaiian mammals. Based on statewide forest inventory estimates, epithet ‘koa haole’ (in English ‘foreign koa’), given the there are approximately 61 million leucaena trees in superficial similarity of seedlings to the native species, Hawaii, with stem diameter ranging in size from 2.5 to 22 Acacia koa. As elsewhere in the tropics, leucaena was cm and totaling over 200,000 t of dry matter (USFS deliberately introduced to Hawaii, where it was 2018). This ranks as the third-most numerous tree in distributed widely as animal fodder and fuelwood. It Hawaii but is not in the top 10 in terms of total volume or subsequently became naturalized and spread into biomass. It is common or dominant on 10% of the total disturbed habitats, especially drier forest and scrub land area of the state (USGS 2015). habitats. The history and study of its introduction and Ecologist Frank Egler described leucaena as common in spread, current geographic distribution, successional 3 distinct moisture-elevation zones in Hawaii, sharing status and possible replacement with other species in dominance with different species in each zone (Egler 1947). Hawaii provide a spatial and temporal microcosm to All 3 zones experience xeric precipitation regimes, where understand and guide the study of other pioneer woody mean annual precipitation is less than potential evapo- invasive species in the tropics. transporation, and the majority of rainfall occurs in the cooler autumn and winter seasons. Egler, partly relying on Introduction and spread reports from early European explorers, also hypothesized that Polynesian settlers had cleared coastal lowlands As in most places in the world, the exact date of first extensively and converted them to agriculture, even in dry introduction of leucaena to Hawaii is disputed. In his book areas. These conditions would favor the naturalization of a of Hawaiian plants, Flora Hawaiiensis, botanist Otto species like leucaena, which is adapted to disturbed sites. It Degener claims that it was first introduced in 1864 and would also encourage deliberate spreading of seeds of was widespread 20 years later (Degener 1946). Cuddihy leucaena and other useful plants onto sparsely vegetated and Stone (1990) cite reports as early as 1837 of areas or those covered in ‘weeds’, i.e. species that were not deliberate spreading of seed for cattle grazing and considered useful, in order to improve them. fuelwood. Regardless of the exact date of introduction, by Grazing and browsing mammals, including livestock the early 1930s, agricultural researchers and extension and wild game animals, were introduced soon after specialists reported on and recommended the use of European ‘discovery’ of the islands. Captain James Cook leucaena for pastures to improve forage quality (Henke led the first European ship to reach the Hawaiian Islands 1929; Ripperton et al. 1933) and to stop erosion of gullies in 1788. In 1793, Captain George Vancouver gave a few (Zschokke 1931). Zschokke (1931) acknowledged cattle to the chief of the Island of Hawaii as a gift. Harvest concerns about wind and water dispersal of leucaena of the cattle was forbidden to allow the population to seeds down slopes into agricultural fields, where it was grow, so herd numbers increased quickly and cattle considered a major weed. Despite these concerns, he roamed freely on Hawaii and the other islands where they recommended establishment of leucaena on dry hillslopes were introduced. Other domestic livestock, such as goats to replace cactus (no scientific name given but likely and sheep, and even game animals, like the Eurasian wild prickly pear cactus, Opuntia ficus-indica) and lantana pig (Sus scrofa), Axis deer (Axis axis) and mouflon sheep (Lantana camara) as part of a conversion to pasture for (Ovis orientalis), were introduced to various islands grazing by beef cattle. He reported that large areas on the throughout the archipelago. With their lower rainfall and islands of Kauai and Hawaii had been seeded with thus productivity, dryland areas suffered most from the leucaena. population growth of introduced mammals. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 292 T. Idol The eventual introduction of fencing and active lowlands would eventually be replaced by native species. livestock management reduced the damage these animals Part of his reasoning was that Hawaii’s ecosystems are caused, but also removed the only significant biological protected from major disturbances such as hurricanes or control over leucaena and other disturbance-adapted fires resulting from lightning strikes and, prior to human species. While low-lying areas suitable for agriculture contact, were free of grazing or browsing mammals. While soon were sown to pineapple and sugarcane plantations, the islands were created by volcanic uplift, only Hawaii leucaena and other non-native species spread onto and Island has active volcanoes at present. Therefore, Hawaii dominated the dry hillsides. As mentioned by Zschokke should have a diversity of late-successional native species. (1931), leucaena was regarded as a ‘boon’ for livestock In the Caribbean island of Martinique, Egler (1942) grazing on these hills but as a ‘weed’ for the down-slope observed leucaena in similar dry lowland environments; farmers, who struggled to control it in their agricultural however, it was much less dominant than in other fields. As Hawaii's human population has expanded and environments and it appeared that it was being replaced by the state has become more of a tourist destination, native species. Thus, given adequate protection from livestock grazing has slowly declined, leaving leucaena human-associated disturbances, including grazing completely uncontrolled on hillsides, dry stream beds and mammals, native Hawaiian species should eventually abandoned agricultural land. As in many other populated replace non-native pioneers like leucaena. areas of the tropics, leucaena is a common ‘roadside A related hypothesis proposed by Hatheway (1952) was weed’ and is found more generally along open edges of that native Hawaiian dryland forest should be resistant to fields, fence lines, empty urban and suburban lots, invasion by non-native species in the absence of major riparian forests and similar disturbed but open habitats. disturbances. He surveyed a native dryland forest within a Unlike most native dryland plant species, leucaena protected reserve on Oahu that already included non-native benefits from periodic wildfires. Its ability to resprout woody species. He hypothesized that over time the native vigorously from the stump allows it to recover quickly species should be able to maintain their dominance and after fire. Its recalcitrant seeds can withstand fast-moving even expand into the surrounding forest dominated by non- fires common in dry scrub or grassland habitats. In Puerto native species within the reserve. Resurveys of this area in Rico, Wolfe (2012) observed that leucaena saplings in 1970 and again in 2016 showed a slow decline in native dryland areas grew better than native saplings in species dominance and a subsequent increase in non-native competition with introduced grasses and were less species (J. Hibit pers. comm.). There also was no evidence affected by grass-fueled wildfires. Despite its reputation of spread of native species into the surrounding forest as a verdant tropical paradise, 40% of Hawaii’s land dominated by non-natives. surface is classified as either grassland, shrubland or dry While present in each of the surveys, leucaena was not forest (USGS 2015). Wildfires in Hawaii annually burn as one of the dominant species. Its abundance declined over much area proportionally as any other US state, including time, but surviving trees grew larger, suggesting little, if any, those of the western US (Trauernicht et al. 2015). successful reproduction was occurring. This agrees with Although these are generally smaller fires, they are observations by this author that leucaena can persist in the concentrated in dry scrub and forest land, the very habitats understory of dry to mesic forests but does not produce seed that favor leucaena dominance. Since most of these fires or grow into the overstory in the absence of large openings are a result of human activity, they reinforce the in the forest canopy. More generally, it suggests that other association of leucaena with human-disturbed areas. non-native rather than native species are likely to replace Native Hawaiian species evolved in the absence of leucaena in Hawaii’s dryland forests. Where wildfires and frequent wildfires, as would be caused by lightning mammalian grazing persist, these successional changes are strikes. No woody species have evolved the thick bark likely to be inhibited or reset, and leucaena will continue to necessary to survive moderate-intensity fires, and only a be a dominant species in these ecosystems. few have seeds that are stimulated to germinate in response to wildfire. Priorities and options for control Successional replacement Leucaena leucocephala is listed as one of the “100 Worst Invaders” globally (ISSG 2010), and is classified as a Since leucaena is associated with disturbed, open habitats, highly invasive species in Hawaii (HPWRA 2018). it is considered an early-successional pioneer species in Olckers (2011) classified it as a ‘conflict species’ because forest development. Egler (1942) hypothesized that of the tension between its value for human use and its leucaena and other common non-native species in Hawaii’s propensity to naturalize and spread in dry and disturbed Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Invasive leucaena in Hawaii 293 habitats. In Hawaii, its abundance throughout the islands Network 2018) provides practical guidelines to reduce causes authorities to give it a low priority for eradication seed production and the likelihood of spread off farms and or control. Newly introduced species, those with limited pastures that mirror these general recommendations. spatial distribution or those that invade and disrupt native Finally, dryland forest restoration is inherently more ecosystems or threaten native species are higher priorities difficult than in mesic areas because of the low rainfall for control (HISC 2018). and thus relatively slow growth of naturally colonizing or Manual or mechanical eradication of leucaena is planted native species. Wildfire risks are also higher, challenging. Its resilience to repeated and frequent especially when surrounded by invasive grasses and grazing means that livestock or wild game animals can at shrubs that are adapted to fire. In Hawaii, efforts have most control its vegetative growth and production of focused on protection of remaining native forest seeds. Indeed, one reason Zschokke (1931) recommended combined with small-scale restoration of high-priority it for control of gully erosion was the well-founded belief areas. Such efforts can be successful in reducing non- that, once established, it could survive and function under native species cover, establishing healthy populations of regular grazing pressure. Leucaena is resistant to many native species and encouraging natural recruitment of common herbicides but is sensitive to others, in particular native seedlings. This usually requires years of effort by triclopyr and picloram (Jim and Santo 1990; Cook et al. professionals and coordinated volunteers, and it is usually 2005). Recommendations are generally for basal bark or confined to just a few hectares in areas that are reasonably cut stump application of a herbicide mix or repeated accessible (e.g. Medeiros et al. 2014). However, given applications of glyphosate to resprouting shoots. that leucaena is associated with human-disturbed habitats, Natural or assisted biocontrol of leucaena has been there are many areas in drier parts of the state close to both studied in Australia (Raghu et al. 2005) and South Africa remnant native forest and residential neighborhoods that (Olckers 2011). The leaf-sucking leucaena psyllid could be sites for community-based restoration. (Heteropsylla cubana) is now widespread globally and Successful examples of such projects often include can cause slow growth or dieback of growing shoot tips. important cultural aspects, such as perpetuating cultural However, its effects tend to be seasonal and are usually history or practices (HFI 2016) or reviving traditional not sufficient to kill established trees or prevent seed agricultural and land management systems as part of a production during at least part of the year. A seed-boring larger watershed restoration and management strategy bruchid beetle, Acanthoscelides macrophthalmus, is (Ka’ala Farms 2018). relatively specific to leucaena and is common in many areas of leucaena infestation. It was introduced to South References Africa, evaluated for host specificity and eventually (Note of the editors: All hyperlinks were verified 08 August 2019.) released in 1999 (Olckers 2011). It established well in the area of release, but appears incapable of achieving Cook BG; Pengelly BC; Brown SD; Donnelly JL; Eagles DA; consistent and adequate seed predation to prevent spread Franco MA; Hanson J; Mullen BF; Partridge IJ; Peters M; of leucaena. The fact that leucaena coexists with both Schultze-Kraft R. 2005. Tropical Forages: An interactive H. cubana and A. macrophthalmus throughout much of selection tool. CSIRO, DPI&F(Qld), CIAT and ILRI, its range and is still considered an invasive species Brisbane, QLD, Australia. www.tropicalforages.info suggests these options are unlikely to be effective in most Cuddihy LW; Stone CP. 1990. Alteration of native Hawaiian places. Both natural observations and management vegetation: Effects of humans, their activities and recommendations emphasize that grazing and browsing introductions. Pacific Cooperative National Parks Studies are more effective measures to control growth and Unit, University of Hawaii, Honolulu, HI, USA. goo.gl/ seeding of leucaena. ZLdrsn Given the scale of leucaena coverage in Hawaii and the Degener O. 1932. Flora Hawaiiensis: The new illustrated flora intensity of control measures required, eradication and of the Hawaiian Islands. Honolulu, HI, USA. goo.gl/ S6TYck replacement or restoration of native vegetation will have Egler FE. 1942. Indigene vs alien in the development of arid to be highly prioritized. Hillsides dominated by leucaena vegetation in Hawaiian vegetation. Ecology 23:14–23. doi: will be a low priority. Clearing fire breaks, riparian zones 10.2307/1930868 and the edges of remaining native dry forest habitat Egler FE. 1947. Arid Southeast Oahu vegetation, Hawaii. should be given higher priority to reduce wildfire risks, Ecological Monographs 17:384–435. doi: 10.2307/1948595 inhibit its movement into native forests after disturbance Hatheway WH. 1952. Composition of certain native dry forests: and provide a buffer along waterways to reduce seed Mokuleia, Oahu, T.H. Ecological Monographs 22:153–168. dispersal. The leucaena Code of Practice (The Leucaena doi: 10.2307/1943515 Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 294 T. Idol Henke LA. 1929. A survey of livestock in Hawaii. Research Raghu S; Wiltshire C; Dhileepan K. 2005. Intensity of pre- Publication No. 5. University of Hawaii, Honolulu, HI, dispersal seed predation in the invasive legume Leucaena USA. hdl.handle.net/10125/31078 leucocephala is limited by the duration of pod retention. HFI (Hawaii Forest Institute). 2016. Dryland forest projects. Austral Ecology 30:310–318. doi: 10.1111/j.1442-9993. HFI, O`okala, HI, USA. goo.gl/crtkqu 2005.01475.x HISC (Hawaii Invasive Species Council). 2018. Invasive Ripperton J; Goff R; Davis W. 1933. Range grasses of Hawaii. species profiles. HISC, Honolulu, HI, USA. goo.gl/2D1gJ9 Hawaii Agricultural Experiment Station Bulletin No. 65. HPWRA (Hawaii Pacific Weed Risk Assessment). 2018. U.S. Department of Agriculture, Washington, DC, USA. Leucaena leucocephala. HPWRA. hear.org/wra doi: 10.5962/bhl.title.87631 GISD (Global Invasive Species Database). 2019. Species The Leucaena Network. 2018. Code of practice. Fact sheet 8. The profile: Leucaena leucocephala. IUCN/SSC Invasive Leucaena Network, Queensland, Australia. goo.gl/p72M3K Species Specialist Group (ISSG). goo.gl/H7MSMV Trauernicht C; Pickett E; Giardina CP; Litton CM; Cordell S; Jim RK; Santo LT. 1990. Herbicides to control haole koa in Beavers A. 2015. The contemporary scale and context of sugarcane. Keys to our future: Combining the basics with wildfire in Hawaii. Pacific Science 69:427–444. doi: new technology. Hawaiian Sugar Technologists 48th annual 10.2984/69.4.1 conference reports, 6–8 November 1989. Aiea, HI. USFS (United States Forestry Service). 2018. Pacific Northwest Hawaiian Sugar Technologists: A44–A45. Forest Inventory and Analysis. United States Department of Ka’ala Farms. 2018. Cultural Learning Center, Ka’ala Farm, Agriculture, Portland, OR, USA. goo.gl/REhVSM Wai'anae, HI, USA. goo.gl/zJr1oS USGS (United States Geological Survey). 2015. Land Cover Little EL; Skolmen RG. 2003. Common forest trees of Hawaii. Data Portal. National Gap Analysis Program (GAP), Boise, CTAHR reprint of Agriculture Handbook 679, May 1989, ID, USA. goo.gl/jRXdzJ Forest Service, US Department of Agriculture. College of Vitousek PM. 2004. Nutrient cycling and limitation: Hawaii as Tropical Agriculture and Human Resources, University of a model system. Princeton University Press, Princeton, NJ, Hawaii, Manoa, Honolulu, HI, USA. USA. jstor.org/stable/j.ctv39x77c Medeiros AC; von Allmen EI; Chimera CG. 2014. Dry forest Wolfe BT; Van Bloem SJ. 2012. Subtropical dry forest restoration and unassisted native tree seedling recruitment at regeneration in grass-invaded areas of Puerto Rico: Auwahi, Maui. Pacific Science 68:33–45. doi: 10.2984/ Understanding why Leucaena leucocephala dominates and 68.1.3 native species fail. Forest Ecology and Management 267: Olckers T. 2011. Biological control of Leucaena leucocephala 253–261. doi: 10.1016/j.foreco.2011.12.015 (Lam.) de Wit (Fabaceae) in South Africa: A tale of Zschokke T. 1931. The problem of soil saving in the Hawaiian opportunism, seed feeders and unanswered questions. African Islands. Extension Bulletin No. 11. University of Hawaii, Entomology 19:356–365. doi: 10.4001/003.019.0219 Honolulu, HI, USA. hdl.handle.net/10125/25512 (Accepted 5 January 2019 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):295–302 295 DOI: 10.17138/TGFT(7)295-302 ILC2018 Keynote Paper* Leucaena leucocephala introduction into a tropical pasture in the Chaco region of Argentina. Effects on soil carbon and total nitrogen Introducción de Leucaena leucocephala en una pastura tropical en el Chaco argentino. Efectos en el carbono y nitrógeno total del suelo NATALIA BANEGAS1,2, ROBERTO CORBELLA2, EMILCE VIRUEL1, ADRIANA PLASENCIA2, BELEN ROIG2 AND ALEJANDRO RADRIZZANI1 1Instituto de Investigación Animal del Chaco Semiárido (IIACS), Centro de Investigaciones Agropecuarias (CIAP), Instituto Nacional de Tecnología Agropecuaria (INTA), Leales, Tucumán, Argentina. inta.gob.ar/iiacs 2Facultad de Agronomía y Zootecnia, Universidad Nacional de Tucumán, Tucumán, Argentina. faz.unt.edu.ar Abstract The introduction of leucaena (Leucaena leucocephala), apart from increasing animal production, improves soil fertility through biological nitrogen (N) fixation and its deep-rooted system. There is limited information on carbon and N dynamics in hedgerow silvopastoral systems, particularly in the subsoil profile. The concentrations and vertical distribution of organic carbon (OC) and total N , and their fractions (particulate and associate forms) in the profile (0‒100 cm) of a 4-year-old leucaena stand in a Urochloa brizantha-Chloris gayana pasture were compared with those in the adjacent pure tropical grass (U. brizantha) pasture. Leucaena introduction increased the OC concentration in the subsoil (20‒100 cm) by 45%, particularly the stable form (associate OC) in the deepest horizon (50‒100 cm). This was attributed to a greater abundance of leucaena roots deeper in the profile than for grass. Leucaena also enhanced by 7.6% the N concentration (from 0.131 to 0.141%) in the topsoil (0‒20 cm) associated with an increment in the labile form (particulate organic N), due to leaf deposition, recycling of animal feces and nodule-N turnover from N fixation. Leucaena establishment has the potential to improve soil fertility and hence availability of N to companion grass growth, and can be utilized as a greenhouse gas mitigation strategy. Keywords: C sequestration, leguminous trees, soil carbon fractions, tropical grasses. Resumen La introducción de leucaena (Leucaena leucocephala), además de incrementar la producción animal, aumenta la fertilidad del suelo por fijación simbiótica de nitrógeno (N) y por sus raíces profundas. Existe poca información sobre la dinámica de carbono y N en sistemas silvopastoriles, particularmente en el subsuelo. La cantidad y distribución vertical de carbono orgánico (CO) y N total, y sus fracciones en el perfil del suelo (0‒100 cm) de una pastura de leucaena de 4 años de edad en asociación con Urochloa brizantha y Chloris gayana, fueron comparadas con una pastura adyacente de U. brizantha en monocultivo. Leucaena incrementó en un 45% la concentración de CO (0.98 a 1.42%) en el subsuelo (20‒100 cm), particularmente la forma estable (CO asociado) en el horizonte más profundo (50‒100 cm), efecto atribuido a sus raíces profundas. Leucaena también acrecentó en un 7.6% la concentración de N (de 0.131 a 0.141%) en el horizonte superficial del suelo (0‒20 cm), asociado al incremento de la forma lábil (N orgánico particulado), atribuido a deposición de hojas, reciclado de excreta animal y descomposición de nódulos. La implantación de leucaena tiene el potencial de mejorar la fertilidad del suelo, la disponibilidad de N para gramíneas asociadas, y puede ser una estrategia de mitigación de gases de efecto invernadero. Palabras clave: Secuestro de carbono, árboles leguminosos, fracción de carbono, pastos tropicales. ___________ Correspondence: Alejandro Radrizzani, Instituto de Investigación *Keynote paper presented at the International Leucaena Conference, Animal del Chaco Semiárido, INTA, Chañar Pozo s/n, CP 4113, Leales, 1‒3 November 2018, Brisbane, Queensland, Australia. Tucumán, Argentina. Email: radrizzani.alejandro@inta.gob.ar Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 296 N. Banegas, R. Corbella, E. Viruel, A. Plasencia, B. Roig and A. Radrizzani Introduction March). Average maximum/minimum temperatures are 32/20 ºC in January and 22/7 ºC in July; on average 16 Sustaining or enhancing soil organic carbon (OC) and frosts occur each year, with an average ground surface total nitrogen (TN) in grazing systems is essential for temperature of -2.2 ºC and minimum temperature of -7 ºC. maintaining the chemical, biological and physical Mean evaporation exceeds mean rainfall in all months. properties of soils, as well as mitigating greenhouse gases Soil type is Fluvaquentic Haplustoll, US Soil Taxonomy emitted by agriculture (Franzluebbers and Stuedemann System (Soil Survey Staff 1999). 2009). Tropical grass pastures are typically constrained in their capacity to store soil C due to limited plant-available Pasture description N in soils under pure grass pastures and frequent overgrazing, which leads to low primary biomass The soil samples were collected from 4 parcels of 1 ha production and OC losses (Dalal and Carter 2000). each: 2 parcels with pure grass pasture (PP) and the other 2 Legume introduction in mixtures with grasses increases parcels with leucaena-grass pasture (LP). These 4 parcels soil OC and TN in grazing systems (Fisher et al. 1994; had been established with a pasture of Urochloa brizantha Peoples et al. 2001; Tarré et al. 2001). Planting the (syn. Brachiaria brizantha) cv. Marandú (brachiaria) in multipurpose forage tree legume, leucaena (Leucaena 1995. In December 2009, leucaena cv. K636 was planted leucocephala ssp. glabrata), has been reported to improve in 2 of these 4 brachiaria parcels, selected at random, to topsoil fertility in hedgerows in silvopastoral systems evaluate the effect of leucaena introduction into ageing (Radrizzani et al. 2011; Conrad et al. 2017) and to pure grass pastures. Leucaena seed was zero till-planted in increase livestock productivity (Radrizzani and Nasca double row hedgerows (1 m apart) with 5 m between the 2014). Although there is some information in the Chaco twin hedgerows. Eight months after leucaena region on carbon sequestration in tropical grass pastures establishment, high grazing pressure was imposed to avoid (Banegas 2014) and in silvopastoral systems (Corbella et leucaena plants growing too tall (Radrizzani and Nasca al. 2015), there is no published information on changes in 2014), which caused a decline in grass cover and soil OC and TN levels and their fractions (particulate and production (visual observation but not measured in this associate forms) under grazed leucaena pastures. study) in the inter-row space. In December 2011, the inter- Particulate organic carbon (POC) comprises OC particles row pasture was cultivated and overseeded with Chloris <2 mm and >53 µm in size (Cambardella and Elliot 1992). gayana cv. Finecut (Rhodes grass) forming a brachiaria- POC is biologically and chemically active and is part of Rhodes grass pasture. Thereafter, the high stocking rate the labile (easily decomposable) pool of soil organic regime continued to maintain a dense leafy canopy within matter. Associate organic carbon (AOC) comprises OC browse height. Both pastures (PP and LP) have been particles <53 µm in size, and is chemically and physically rotationally grazed at a variable stocking rate, according to protected from microbial degradation, being more stable fodder availability from early spring (October) to late and persistent in the soil. The quantity and vertical autumn (June). For most of the grazing periods, LP was distribution of OC and total nitrogen (TN) stocks, and heavily grazed with a stocking rate around 3 times that in their fractions (particulate and associate forms), in the soil PP in order to restrict height growth of leucaena, leading to profile (0‒100 cm) of a 4-year-old leucaena-grass pasture, overgrazing of the inter-row grass. were compared with those in soil of the adjacent pure tropical grass pasture in the Chaco region of Argentina. Soil sampling Materials and Methods Soil samples were collected in both pastures in March 2014 from 12 transects 10 m in length (3 in each parcel; 6 per Site description pasture). In the leucaena pasture, transects were placed obliquely from leucaena hedgerows to the middle of the This study was carried out at the Animal Research inter-row (2.5 m from the hedgerow) following the sampling Institute of the Semi-arid Chaco Region (IIACS), procedure described by Radrizzani et al. (2011). Along each operated by the National Institute of Agricultural transect, 5 soil cores (0 to 1 m deep) divided into 3 depths: Technology (INTA), located at Leales, Tucumán (27º11' 0‒20 cm, 20‒50 cm and 50‒100 cm, were collected at equal S, 65º14' W; 335 masl), in the west of the Chaco region, distances along the 2.5 m (i.e. in the leucaena pasture: 0, Northwest Argentina. The climate is subtropical sub- 0.63, 1.25, 1.88 and 2.50 m from hedgerow). The 5 soil humid with a dry season from April to September and samples collected for each depth were mixed to form average annual rainfall of 880 mm (75% in October‒ 1 composite sample per depth and transect (3 and 6 Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) SOC and total N under a leucaena pasture 297 composite samples per parcel and pasture, respectively). The and 0.71±0.05% vs. 0.40±0.05% in the 50‒100 cm assumption underlying the comparisons was that both the LP horizon). For LP and PP soils, 53% and 43%, and PP pastures had similar soil properties before leucaena respectively, of the total OC in the first meter of soil was establishment. Therefore, the difference in soil fertility contained in the combined subsoil horizons (20‒100 cm parameters between pastures could be attributed to the depth). introduction of leucaena into the pure grass pasture. Particulate organic carbon (POC) Measurements and analytical techniques Concentrations of POC were also stratified in both pasture Soil samples were air-dried (40 °C), and coarse fragments soil profiles but stratification was different from that for (>2 mm) including gravel, plant residues and roots were OC (Figure 1B). In contrast with OC concentrations, POC removed before grinding samples to pass a 2-mm sieve. was higher in PP than in LP in the topsoil horizon Organic carbon (OC) concentration was determined by (0.48±0.08% vs. 0.40±0.05%, respectively) and Walkey Black (Nelson and Sommers 1996). Total represented 61.5% of total POC for PP and 45.5% of total nitrogen (TN) concentration was determined by Kjeldahl POC for LP. In the 20‒50 cm horizon, POC was higher in (Bremner 1965). Fractions of OC and TN were measured LP than in PP (0.28±0.08% vs. 0.17±0.04%, respectively) in 50 g of each composite sample through particle size and in the 50‒100 cm horizon POC was again higher in analysis, following the technique described by LP than in PP (0.20±0.05% vs. 0.13±0.03%). Cambardella and Elliot (1992); organic carbon associated with particles <53 µm was entrapped into clay and silt, Associate organic carbon (AOC) and therefore, considered as associate organic carbon (AOC), with a similar arrangement for associate total Concentrations of AOC were also stratified, but nitrogen (ATN). Particulate organic carbon (POC) was differences between pasture soils were restricted to the calculated by subtracting AOC from OC, and particulate 50‒100 cm horizon where AOC was higher in LP than in total nitrogen (PTN) was determined by subtracting ATN PP (0.51±0.03% vs. 0.27±0.05%, respectively) (Figure from TN. 1C). The topsoil horizon contained 47.5% of total AOC for LP and 55% of total AOC for PP. Statistical analyses Total nitrogen (TN) Analysis of variance of soil fertility parameters (OC, POC, AOC, TN, PTN and ATN) and mean comparisons Concentrations of TN followed a similar trend to OC (Tukey, P<0.05) within pastures were performed to assess (Figure 1D). However, TN was higher in LP than in PP the effects of leucaena introduction. All statistical only in the topsoil horizon (0.141±0.0039% vs. analyses were carried out using InfoStat software (Di 0.131±0.0035%, respectively). In the subsoil horizon, Rienzo et al. 2016). no differences were observed between LP and PP (20‒50 cm depth: 0.070±0.0030% vs. 0.069±0.0033%, Results respectively; and 50‒100 cm depth: 0.054±0.0040% vs. 0.050±0.0038%, respectively). Total organic carbon (OC) Particulate organic nitrogen (PON) In both pastures, stratification of OC was observed in the soil profile, with higher levels in the topsoil (0‒20 cm Concentrations of PON were also stratified in both horizon) than in the subsoil (20‒50 cm and 50‒100 cm pasture soil profiles but followed different patterns from horizons) (Figure 1A). This stratification was more those for the TN concentrations in the subsoil (Figure 1E). pronounced in soil supporting PP than in soil supporting In the 0‒20 cm horizon, PON was greater in LP than in LP, since OC concentrations continued to decline with PP (0.08±0.002% vs. 0.06±0.003%, respectively), depth in PP but no differences were observed between showing that most of the TN in this horizon was in the subsoil depths in LP. In the topsoil horizon, OC labile ON form. A similar result was observed in the 20‒ concentrations were similar for LP and PP (1.25±0.05% 50 cm horizon, where PON was also higher in LP than in vs. 1.31±0.06%, respectively). However, in the subsoil PP (0.04±0.001% vs. 0.02±0.001%). In contrast, PON horizons, OC concentrations were higher for LP than for was higher in PP than in LP in the 50‒100 cm horizon PP (0.71±0.07% vs. 0.58±0.03% in the 20‒50 cm horizon; (0.02±0.002% vs. 0.01±0.002%). Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 298 N. Banegas, R. Corbella, E. Viruel, A. Plasencia, B. Roig and A. Radrizzani Figure 1. Concentrations of: A, organic carbon (OC); B, particulate OC (POC); C, associate OC (AOC); D, total nitrogen (TN); E, particulate organic nitrogen (PON); and F, associate organic nitrogen (AON), in relation to soil depth (0‒20, 20‒50 and 50‒100 cm horizons) in soils under leucaena-grass pasture (filled squares) and pure grass pasture (open squares) at IIACS-INTA. Means followed by different letters are significantly different (P<0.05); bars represent standard error. Associate organic nitrogen (AON) Ratios of carbon to nitrogen (OC:TN, POC:PON and AOC:AON) Concentrations of AON were also stratified as were TN and PON but the relationships were the mirror images of The OC:TN ratio increased with depth in the LP pasture, those for PON (Figure 1F). AON was higher in PP than while it decreased with depth in the PP pasture (Table 1a). in LP in the 0‒20 cm (0.071±0.003% vs. 0.06±0.002%, While this ratio was higher in PP than in LP in the surface respectively) and 20‒50 cm (0.049±0.003% vs. horizon, the reverse was the case in the 20‒50 cm and 50‒ 0.03±0.001%) horizons. In contrast, AON was higher in 100 cm horizons. The POC:PON ratio also increased with LP than in PP in the 50‒100 cm horizon (0.044±0.004% depth in LP and decreased in PP (Table 1b). While the vs. 0.03±0.003%). ratio was narrower in LP than in PP for the 0‒20 and 20‒ Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) SOC and total N under a leucaena pasture 299 50 cm horizons, the reverse was the case in the 50‒100 leucaena increased the percentage of total OC contained cm horizon, with a very high ratio for LP. The AOC:AON in the subsoil from 43% to 53%, and most of this OC was ratios declined with depth under both pastures and were in the most stable form (AOC). Similar increments in higher in LP than in PP for all soil horizons (Table 1c). subsoil OC have been reported by Carter et al. (1998) in leucaena and Stylosanthes spp. pastures in northern Table 1. Organic carbon:total nitrogen (OC:TN), particulate Australia; 10 years after the woody forage legumes were organic carbon:particulate organic nitrogen (POC:PON) and introduced, they had accumulated more OC in the 20‒65 associate organic carbon:associate organic nitrogen cm soil horizon than the adjacent native grass pastures. (AOC:AON) ratios in soils for leucaena-grass pasture (LP) and Comparable results were observed 9–16 years after pure grass pasture (PP) at IIACS-INTA. Means within Desmodium ovalifolium (Tarré et al. 2001) and parameters followed by different letters are significantly Stylosanthes capitata and Arachis pintoi (Fisher et al. different (P<0.05). 1994) were oversown into tropical grass pastures. Soil depth (cm) LP PP Although it is known that leucaena establishment can a) Mean OC:TN ± s.e. enhance OC concentrations in topsoil via its N 0‒20 contribution, which increases tropical grass growth, litter 8.9±0.19c 10.0±0.15b 20‒50 recycling and humus formation (Radrizzani et al. 2011; 10.1±0.35b 8.4±0.32c 50‒100 13.2±0.18a 8.0±0.22c Conrad et al. 2017), in this study the most labile C form b) Mean POC:PON ± s.e. (POC) was lower in topsoil for LP than for PP. This 0‒20 5.0±0.33d 8.0±0.38b unexpected result could be mainly attributed to two 20‒50 7.0±0.29c 8.5±0.68b causes: a) the higher stocking rate imposed on the 50‒100 20.0±1.24a 6.5±0.44c leucaena-grass pasture in comparison with the pure grass c) Mean AOC:AON ± s.e. pasture (Radrizzani and Nasca 2014) caused overgrazing 0‒20 14.2±0.77a 11.7±0.61b and a decline in the inter-row grass cover (visual 20‒50 14.3±0.81a 8.4±0.48c observation but not measured in this study), hence 50‒100 11.6±0.55b 9.0±0.38c reducing grass litter deposition and grass root turnover; and b) the cultivation done in December 2011 (only in LP Discussion pasture) might have accelerated mineralization of the labile OC form (POC) and 2.5 years might have been This study generated data from a real grazing system that insufficient time to recover the original value (POC in PP described the effects on soil properties of the introduction pasture) in the inter-row area. of a forage tree legume into a tropical grass pasture. The high concentration of the stable OC form (AOC) However, a lack of an accurate baseline measurement of in the deepest horizon (50‒100 cm) is consistent with the initial pasture soil properties did prevent rigorous studies that show that root turnover in deep soil enhances statistical comparison before and after leucaena the pool of less-labile soil OC (Fisher et al. 1994; Follett introduction. Results demonstrated the increase in OC et al. 2003). This increment of stable C in the subsoil concentration in the subsoil (20‒100 cm depth), could be attributed to leucaena’s deep-root system (not particularly the stable OC form (AOC) in the deepest measured in this study), since a larger proportion of fine horizon (50‒100 cm), 4 years after leucaena introduction roots (>60%) of leucaena have been observed below 40 into a grass pasture. Results also showed that the cm in soil compared with the adjacent grass pastures introduction of leucaena enhances the TN in the topsoil (Radrizzani 2009). Pachas et al. (2018) determined associated with an increment of the labile ON form (PON). abundance of roots of leucaena and Rhodes grass (Chloris gayana) and found that leucaena had a greater abundance Changes in organic carbon and its fractions of roots deeper in the profile than the grass. Moreover, it is known that defoliation promotes significant turnover of Overall, OC concentrations for leucaena-grass pastures fine roots (Jayasundara et al. 1997; Franzluebbers and were similar to values reported by Banegas (2014) in Stuedemann 2005). Root carbon turnover would have similar soil types of the same area. The 43% of the total contributed significantly to the increment in subsoil OC, OC in the subsoil (20‒100 cm depth) of the pure grass particularly under the high stocking rate applied in this pasture was similar to the percentages reported by leucaena pasture (Radrizzani and Nasca 2014). Banegas (2014) in grazed pure grass pastures in the same Although sampling up to 3 or 4 m depth is recommend- area and by Babujia et al. (2010) in Brazilian oxisols with ed to assess OC in systems where shrubs or trees grow tropical grass pastures. Within 4 years from planting, (Jobbágy and Jackson 2000), in this study available funds Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 300 N. Banegas, R. Corbella, E. Viruel, A. Plasencia, B. Roig and A. Radrizzani did not permit collecting deeper soil samples. showed that C:N ratio increased with depth in the Consequently, the sampling depth to a meter leucaena pasture but decreased with depth in the grass underestimated the OC concentrations, particularly in the pasture, showing inverse relationships between C:N ratio leucaena pasture where the OC concentration did not and soil depth for the 2 pastures. In the leucaena-grass decline from 20 to 100 cm (Figures 1A, 1B and 1C); pasture, higher inter-row grass production and quality additional soil OC might be accumulated below the top than in the pure grass pasture could be expected. It is meter. Therefore, in further surveys of silvopastoral known that biomass production of pure grass pastures is systems soil samples should be collected to a depth of at limited due to soil N being immobilized in litter and soil least 3‒4 meters to take account of the whole OC organic matter (Graham et al. 1981; Robbins et al. 1989). contribution from leucaena. The increase in TN of topsoil via deposition of N-rich leaf and biological N fixation by leucaena might enhance Changes in total nitrogen and organic nitrogen fractions available N for grass growth, leading to an increase in inter-row grass yield and quality. Overall, soil TN concentrations and organic nitrogen In relation to the ratios of various parameters, the main fractions for leucaena-grass pastures and grass pastures contribution of leucaena was in the PON (labile N form) were within the range reported in the same area by in the top 50 cm of the LP soil profile (0‒20 and 20‒50 Banegas (2014), Corbella et al. (2015) and Conrad et al. cm horizons), with lower POC:PON ratios than in the (2018). Like soil OC concentrations, soil TN declined deeper soil (50‒100 cm). Similar findings were reported with depth in both pastures, since most of the N (~90%) by Luce et al. (2013) with significant increases in the was bound up with OC in organic matter. However, in labile fractions of N attributed to both recycling of N-rich leucaena pasture, TN did not follow the same trend as soil residues and biological N fixation after legume OC concentrations, associated with the great increase in introductions; they highlighted that PON is the N form the labile PON form in both the 0‒20 cm and 20‒50 cm most sensitive to management-induced changes and has horizons. This result is consistent with higher soil TN the potential to predict N availability for plant growth. concentrations in topsoil (0‒15 cm) reported by Furthermore, Griffin and Porter (2004) showed that the Radrizzani et al. (2011) and Conrad et al. (2018) in inclusion of red clover as a cover crop in 2-year potato leucaena pastures in comparison with adjacent pure grass (Solanum tuberosum) rotations increased the proportion pastures in northern Australia. A similar result was of total soil N as PON by 1,320% compared with rotations reported by Mahecha et al. (1999), who observed that did not contain a legume cover crop. In the deepest significant increases in TN concentration in topsoil (0‒20 soil horizon (50‒100 cm) of the leucaena-grass pasture, cm) of leucaena silvopastoral systems relative to pure POC:PON ratio was considerably higher than in other grass pastures in the Valle del Cauca region, Colombia. treatments associated with the high POC concentration The increase in N concentration in the topsoil of that might be formed by deep roots of leucaena. leucaena-grass pasture, mainly in the labile PON form, The high ratios of the associate fractions (AOC:AON) could be attributed to deposition of leucaena leaf which in the topsoil of both pastures and the low variability with is high in N (e.g. frost causes leucaena leaf shedding), depth of these ratios, is consistent with the high stability leaf recycling via animal feces (e.g. high grazing of the associate fractions. pressure) and nodule-N turnover from biological N fixation. Grazing management (e.g. rotational, seasonal Conclusions or continuous grazing) and weather conditions (e.g. frost and drought) can influence the quantities and the Introduction of leucaena into a grass pasture promoted proportions of leucaena leaf fall and leaf recycled via substantial capture of OC in the subsoil (20‒100 cm), dung (Burle et al. 2003). In the 20‒50 cm horizon, the especially the most stable form (AOC), which has greater proportion of PON compared with AON could minimal susceptibility to mobilization in the deepest be attributed mainly to nodule-N turnover from horizon (50‒100 cm), attributed to a greater abundance of biological N fixation. leucaena roots deeper in the soil profile than of the grass. Leucaena introduction also enhanced N concentration Changes in carbon:nitrogen ratios in the topsoil (0‒20 cm), particularly the most labile form (PON) that promotes improvement in grass growth and Overall, soil C:N ratios for leucaena-grass pastures and quality, attributed to N-rich leucaena leaf deposition, leaf grass pastures were within the range reported in the same recycled via animal feces and nodule-N turnover from area by Banegas (2014) and Corbella et al.(2015). Results biological N fixation. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) SOC and total N under a leucaena pasture 301 Accordingly, the establishment of hedgerow leucaena Conrad KA; Dalal RC; Dalzell SA; Allen DE; Menzies NW. silvopastoral systems can increase cattle production 2017. The sequestration and turnover of soil organic carbon directly through the diet, as well as improving soil fertility in subtropical Leucaena-grass pastures. Agriculture, and hence availability of N to companion grasses. Ecosystems & Environment 248:38–47. doi: 10.1016/ j.agee.2017.07.020 Through the increased growth rates of animals and greater Conrad K; Dalal RC; Fujinuma R; Menzies NW. 2018. Soil production per head and per unit area, this strategy can organic carbon and nitrogen sequestration and turnover in serve as a long-term greenhouse gas mitigation strategy. aggregates under subtropical Leucaena-grass pastures. Soil Research 56:632–647. doi: 10.1071/SR18016 Acknowledgments Corbella RD; Banegas N; Caldez LB; Luchina J; Plasencia AM; Martínez Calsina L; Ceballos RB; García JR. 2015. We are grateful to Jeremías Luchina, Martín Requena Influencia de las formas de carbono orgánico en las Cerra and Enrique Oviedo for assistance in field propiedades edáficas en un sistema silvopastoril de sampling. This work was supported by the Animal Tucumán, Argentina. 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Plant MH; McCormick KM; Norton RM; Rochester IJ; Scammell and Soil 234:15–26. doi: 10.1023/A:1010533721740 (Accepted 25 October 2018 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):303–314 303 DOI: 10.17138/TGFT(7)303-314 ILC2018 Keynote Paper* Adoption, profitability and future of leucaena feeding systems in Australia Adopción, rentabilidad y futuro de sistemas de alimentación con leucaena en Australia STUART BUCK1, JOE ROLFE2, CRAIG LEMIN2 AND BERNIE ENGLISH2 1Department of Agriculture and Fisheries, Rockhampton, QLD, Australia. daf.qld.gov.au 2Department of Agriculture and Fisheries, Mareeba, QLD, Australia. daf.qld.gov.au Abstract Leucaena (Leucaena leucocephala ssp. glabrata) is a highly palatable and productive forage used mainly by beef producers on extensive properties in northern Australia. When sown into native or sown grass pastures, leucaena provides significant production, economic, environmental and social benefits. Adoption of leucaena was slow initially due to a range of technical, agronomic and landscape factors. These have now been largely overcome through extensive research, development, producer experience and other advances, resulting in around 130,000 ha of cultivated leucaena being utilized across northern Australia. A range of aspects will need to be addressed if the adoption of leucaena is to be accelerated into the future. These include environmental concerns, especially potential weediness, and a range of technological needs, including soil nutritional requirements, grazing and toxicity management, opportunities for companion fodder systems and conservation options. Advances in technology and the ongoing need for a high-quality, profitable and sustainable perennial forage will ensure the continued adoption of leucaena across northern Australia for the foreseeable future. Keywords: Improved feeding systems, legume-grass systems, liveweight gain, tree legumes. Resumen Leucaena (Leucaena leucocephala ssp. glabrata) es un forraje muy palatable y productivo que es utilizado principalmente por productores de ganado de carne en extensas áreas del norte de Australia. Una vez establecida en pasturas nativas o sembradas, la leucaena proporciona significativos beneficios de producción, económicos, ambientales y sociales. Inicialmente la adopción de leucaena fue lenta debido a una serie de factores técnicos, agronómicos y otros relacionados con la vegetación nativa y el suelo. Estos se han superado en gran medida gracias a extensas actividades de investigación y desarrollo, experiencias a nivel de productor y otros avances, resultando en que actualmente se están utilizando alrededor de 130,000 ha de leucaena en el norte de Australia. Si se quiere acelerar la adopción de leucaena, será necesario abordar una serie de aspectos. Estos incluyen consideraciones ambientales, en particular el potencial de leucaena como maleza, y una gama de factores tecnológicos que incluyen aspectos nutricionales de la planta, manejo del pastoreo y de la toxicidad por mimosina, oportunidades para sistemas forrajeros asociados y opciones de conservación de forraje. Se considera que avances tecnológicos y la continua necesidad de un forraje perenne de alta calidad, rentable y sostenible, garantizarán la continua adopción de leucaena en un futuro previsible en el norte de Australia. Palabras clave: Ganancias de peso vivo, leguminosas arbóreas, sistemas de alimentación mejorados, sistemas leguminosa-gramínea. ___________ Correspondence: Stuart Buck, Department of Agriculture and Fisheries, *Keynote paper presented at the International Leucaena Rockhampton, QLD 4700, Australia. Email: stuart.buck@daf.qld.gov.au Conference, 1‒3 November 2018, Brisbane, Queensland, Australia. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 304 S. Buck, J. Rolfe, C. Lemin and B. English Introduction Middleton et al. 1995; Larsen et al. 1998; Shelton and Dalzell 2007). The area of cultivated leucaena currently Leucaena (Leucaena leucocephala ssp. glabrata) is a utilized by graziers across northern Australia is estimated high-quality perennial forage used primarily in extensive at 130,000 ha, with the majority in central and southern beef production systems across tropical and subtropical Queensland (Beutel et al. 2018). However, this area is environments in northern Australia. When sown with small compared with the potential area suitable for native or exotic companion grasses, leucaena provides growing leucaena (Peck et al. 2011; Beutel et al. 2018). significant production, economic, environmental and The most recent study into the current and potential social benefits to grazing businesses. Owing to suitable adoption of leucaena (Kenny and Drysdale 2019) climate and extensive areas of fertile soils, leucaena has indicates a doubling of the existing area sown in central been sown predominantly in Queensland, where the and southern Queensland would be achievable within 20 majority is found in the central region of the state (Fitzroy years of the commencement of a new extension program. River basin). When successfully established and This paper reviews the current adoption, profitability appropriately managed, adding leucaena into rundown and future of leucaena feeding systems in northern grass-only sown pastures in tropical and subtropical Australia. environments can improve both stocking rate and animal liveweight gain by up to 100%, providing up to 4 times Adoption of leucaena feeding systems across Australia higher total beef production per hectare per year (Dalzell et al. 2006; Bowen et al. 2018). While leucaena was first recorded in Australia at the end of Incorporating leucaena into grass-only pastures also the nineteenth century (Hutton and Gray 1959), interest in produces considerable environmental benefits, such as: (i) leucaena as a forage plant for grazing occurred only some 50 improved soil health with higher carbon and fertility levels years later in the 1940s and 1950s (Gray 1968). Testing of through nitrogen fixation (Radrizzani et al. 2011; Conrad et germplasm by CSIRO started in the mid-1950s and by 1967 al. 2017); (ii) minimization of water movement through the more than 100 accessions had been examined (Gray 1968). soil profile and subsequent mobilization of salts in particular The initial cultivars, Peru and El Salvador, were released in soils due to the deep and extensive root system (Poole 2003; 1962. Despite the availability of these productive cultivars, Pachas et al. 2016); (iii) greater water infiltration, in only 24 ha of commercial leucaena was established by 1979 association with reduced run-off and soil loss during heavy (Wildin 1993). This initial slow adoption rate was due to: (i) rains due to higher ground cover and water-receptive soil a general lack of awareness of the plant; (ii) concerns about conditions (Pachas et al. 2016); (iv) reduction in methane the negative effects of mimosine and DHP toxicity on production (g/kg digestible organic matter intake) as the animal performance; (iii) poor knowledge of soil, climatic proportion of leucaena in the diet increases (Kennedy and and management requirements of leucaena; (iv) a lack of Charmley 2012); and (v) a significant reduction in confidence in the production potential of leucaena; and (v) a greenhouse gas emissions intensities per unit of beef high rate of establishment failure (Lesleighter and Shelton produced (Harrison et al. 2015; 2016). 1986; Pratchett and Triglone 1989; Middleton et al. 1995). The long-term economic benefits of perennial pasture Once the success of early leucaena plantations was reported grazing systems with leucaena are also substantial, even (Wildin 1986) and mimosine and DHP toxicity issues were when the high cost of establishment is included. Gross overcome (Jones and Megarrity 1986), sowings of margins per hectare can be doubled (Bowen et al. 2018) commercial plantations expanded to an estimated 8,000 ha compared with grass-only pastures, and whole-farm by 1985 (Wildin 1986), 20,000 ha by 1992 (Wildin 1994), profitability (annualized net present value) for a breeding 35,000 ha by 1995 (Middleton et al. 1995) and 100,000 ha and finishing enterprise containing around 1,500 adult by 2005 (Mullen et al. 2005). Despite the reporting of an equivalents (AE = 450 kg dry animal at maintenance) can estimated 150,000 ha of established leucaena in 2007, and a be improved by more than $40,000/annum for 30 years projected expansion to 300,000‒500,000 ha by 2017 when compared with the same grazing business without (Shelton and Dalzell 2007), a recent study estimated the area leucaena (Bowen and Chudleigh 2018a; 2018b). sown to leucaena and utilized by graziers in the main Despite grazing cultivars being available since 1962 growing areas of central and southern Queensland was (Gray 1968) and subsequent research demonstrating the approximately 123,500 ha (Beutel et al. 2018). Added to this production, profitability and environmental benefits of is an estimated 2,500 ha of sown leucaena in north leucaena when sown into perennial grass pastures, the Queensland (Mark Keating pers. comm. 2018) and about adoption of leucaena by graziers in northern Australia has 500 ha in the Northern Territory (Peter Shotten pers. comm. been slow (Wildin 1981; Lesleighter and Shelton 1986; 2018). While an appreciable area of leucaena was sown in Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Adoption of leucaena feeding systems in Australia 305 the Kununurra district (Ord River irrigation area) of Western seedling stage and to achieve reliable establishment seed Australia, most if not all of this has been replaced by higher must be sown into the soil. However achieving this is value crops (Clinton Revell pers. comm. 2018). Therefore problematic when trees and other vegetation hinder the use an estimate of the total area sown to leucaena and utilized by of machinery and compete with leucaena seedlings for soil graziers in northern Australia is currently around 130,000 ha. nutrients and moisture. During the period following the A range of studies have estimated the area suitable for clearing of large areas of these woodlands, when leucaena establishment across Australia. These projected productive grazing cultivars were released (1960s and areas have varied considerably based on the choice of 1970s), the freshly sown grass pastures were very climatic conditions and soil parameters included in the productive in terms of both pasture and animal analysis as being suitable for leucaena: 78 million ha in performance (Walker and Weston 1990). This meant coastal and subcoastal Australia (Hutton and Gray 1959); adoption of leucaena remained slow. When attempts to greater than 13 million ha in Queensland (Shelton and establish leucaena did occur, a general lack of agronomic Dalzell 2007); 8.4 million ha in Queensland (Peck et al. understanding and inappropriate practices caused high 2011); and 25.4 million ha in northern Australia (Kenny failure rates (Buck et al. 2019). Legumes typically failed and Drysdale 2019). On the basis of the above estimates when incorporated into highly productive pastures owing of 126,000 ha of cultivated leucaena currently established to the competition (predominantly for moisture) from the across Queensland and using the (conservative) potential established sown grasses (typically Chloris, Megathyrsus/ area of 8.4 million ha, only 1.5% of the total area suitable Panicum and Cenchrus spp.) (Peck et al. 2011). These for leucaena in Queensland has actually been sown at establishment issues were not overcome until the 2000s present. Further, if the total area sown in northern when research and grazier collaboration provided the Australia is around 130,000 ha, and the potential area is technology to formulate extension packages detailing 25.4 million ha, then only 0.5% of the potential area has agronomic techniques for reliable establishment (Dalzell et actually been sown. The logical conclusion must be that al. 2006; Shelton and Dalzell 2007). Today, when graziers there is huge, yet to be realized, potential for leucaena follow the recommended practices, leucaena establishes sowings across northern Australia. reliably across a range of pasture and landscape situations. A lack of animal performance data stifled adoption Central Queensland during the early development of leucaena feeding systems in central Queensland, but adoption increased as research Containing large areas of suitable soils plus favorable was conducted to demonstrate responses in animal climatic conditions, central Queensland is now known as production during the 1980s and results were the heartland of leucaena in Australia. However before the communicated to the grazing industry (Wildin 1986). availability of heavy machinery to clear areas of trees, a Nonetheless, the high cost of establishment (exacerbated large proportion of the suitable soils for leucaena in central by failures) was still a barrier to adoption well into the (and southern) Queensland supported native woodlands of 1990s (Larsen et al. 1998). Even today the high brigalow (Acacia harpophylla). This lack of cleared land establishment costs of leucaena, compared with other on suitable soils impeded the initial sowing of leucaena. forage options, remain an impediment to leucaena Leucaena competes poorly with other species in the adoption (Stuart Buck unpublished data 2018). An extensive area of leucaena sown into fertile clay soils in the Cattle grazing leucaena with buffel grass (Cenchrus ciliaris) Fitzroy River basin of central Queensland. pasture in central Queensland. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 306 S. Buck, J. Rolfe, C. Lemin and B. English Other regions in northern Australia leucaena and have been widely sown due to ease of establishment without soil preparation and significant Adoption of leucaena in north Queensland, Northern productivity gains achieved on infertile soils. However Territory and northern Western Australia has been stylos are not suited to highly-productive soils with moderate significantly lower than that in central and southern to high clay content, and research and development studies Queensland, with only an estimated 2,500 ha sown in north in the 1990s demonstrated the benefits of leucaena in the Queensland (Mark Keating pers. comm. 2018). In the monsoonal environments of north Queensland. Since the Northern Territory, approximately 700 ha has been planted 2000s adoption of leucaena has expanded into north since the early 1990s, primarily in the Douglas Daly and Queensland’s seasonally dry tropics, the Atherton Tableland Victoria River districts, with leucaena stands now and coastal zones (Innisfail-Mackay), where there is a surviving across ~500 ha (Peter Shotton pers. comm. combination of sufficient annual average rainfall and 2018). In northern Western Australia 400 ha of leucaena suitable soils. The uncleared inland basalt provinces (Mount was being utilized for beef cattle production in the Surprise to Charters Towers) and cleared alluvial soils Kimberley in the late 1980s (Pratchett and Triglone 1989), (Gilbert and Burdekin catchments) are also emerging areas and this quickly expanded to around 2,000 ha after the for establishing leucaena. The impetus for this expansion threat of mimosine toxicity was solved by the release of followed the successful Producer Demonstration Site (PDS) rumen inoculum containing the detoxifying bacterium at ‘Meadowbank’ station (Middleton 1998, 1999; Hasker Synergistes jonesii (Petty et al. 1994). However the area of 2000) in the 1990s, where increased carrying capacity and leucaena has declined since that time and the legume has cattle performance (annual liveweight gain) on leucaena been fully replaced with other high value crops (Clinton were double those observed on native pastures alone (Kernot Revell pers. comm. 2018). 1998). More recently, a co-ordinated research, development Impediments to leucaena adoption in north and extension (RD&E) program has been in place to raise Queensland (Mark Keating pers. comm. 2018; Craig the profile of leucaena in north Queensland and includes: (i) Lemin unpublished data 2018), Northern Territory and an experiment comparing the palatability of new psyllid- Western Australia include: (i) a predominance of resistant breeding lines and commercial leucaena cultivars extensive breeding enterprises not focussed on producing (Wondergraze and Cunningham), which led to the selection slaughter cattle; (ii) poor awareness amongst producers of of the psyllid-resistant Redlands variety (Shelton et al. the production benefits of leucaena combined with a 2016); (ii) producer demonstration sites to show local corresponding lack of farming expertise and confidence; graziers the benefits of sowing leucaena on both cleared (iii) the general unsuitability of the landscape (shallow country and uncleared basalt woodlands; (iii) a 61 ha grazing and/or infertile soils, thick vegetation or standing timber); trial comparing the performance of cattle grazing Redlands (iv) the monsoonal climate (intense wet season, long dry with that of cattle grazing Wondergraze; and (iv) trial areas season) and associated establishment risks; (v) high of Redlands on commercial properties across northern prevalence of competition from weeds; (vi) high cost of coastal areas, Atherton Tableland and seasonally dry tropics establishment including foregone grazing for up to 12 sites (supported by MLA). months and the need for prepared seedbeds; (vii) In order to increase leucaena adoption rates across relatively favorable climate for proliferation of psyllids; northern Australia, ongoing RD&E programs must focus (viii) limited availability of suitable machinery; (ix) a lack on: (i) improving the farming skills and confidence of of qualified advisors or other specialists with agronomic graziers; (ii) quantifying long-term competitive effects of knowledge and skills; (x) high transport costs of inputs to native woodland species on the productivity of leucaena- property; and (xi) the lack of local marketing options for grass pastures established in uncleared basalt woodlands; store or finished cattle. When leucaena production (iii) helping graziers understand the cost-benefits of systems are attempted in these environments, these sowing leucaena; and (iv) quantifying the marginal constraints often translate to lower economic performance productivity gains of leucaena established on the Atherton compared with the more favored localities in central and Tableland relative to existing highly productive pastures southern Queensland (Chudleigh et al. 2018). achieving annual liveweight gains up to 250 kg/hd. Local Owing to these constraints, other tropical perennial government declarations of leucaena as a weed and legumes have been commonly promoted and adopted by competing land uses in higher rainfall coastal zones will graziers across the top end of northern Australia, especially potentially influence adoption in the region. north Queensland and Northern Territory. For example There are specific districts in northern Australia where shrubby and Caribbean stylos (Stylosanthes spp.) were leucaena has been highly productive, and there is initially developed and promoted at a similar time to significant scope for further adoption, particularly Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Adoption of leucaena feeding systems in Australia 307 following the release of the highly psyllid-tolerant cultivar in the past, these areas all face the same constraints, Redlands. These districts include the coastal and seasonally including: the seasonally dry monsoonal climate; limited dry tropical zones in north Queensland (cleared coastal and access to specialist advisors; difficulties and costs Atherton Tableland soils, fertile alluvials, basalt and associated with accessing and transporting machinery; and possibly red duplex soils), the Douglas Daly region of the increased input costs linked to geographic isolation. Northern Territory (red loam soils) and the Kununurra However, if soils and rainfall are suitable for leucaena district of northwest Western Australia (heavy clay soils). establishment, capable and motivated producers and While cattle marketing options are now more diverse than industry personnel will overcome these challenges. Leucaena with native grass pasture in north Queensland. Leucaena and predominantly Mulato II (Urochloa hybrid) grass pasture in the Douglas Daly region of Northern Territory. Leucaena sown into native grass pasture and open Eucalypt Leucaena sown into native pastures at Meadowbank, north forest in north Queensland. Queensland. Young leucaena, planted into fully cultivated seedbed prior to Leucaena with buffel grass, southern Queensland. grass inclusion, in southern Queensland. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 308 S. Buck, J. Rolfe, C. Lemin and B. English New South Wales Garnet indicate leucaena sown at 8‒10 m inter-row spacing with perennial native pastures (Themeda and The adoption of leucaena in New South Wales has been Heteropogon spp.) in the inter-row spaces on basalt soils virtually non-existent due to persistent views that leucaena significantly boosts annual liveweight gains. In this study, is suited to tropical climates and would therefore be 30 Charbray steers grazing leucaena-grass pasture during unproductive in temperate climates or subtropical climates June–November 1997 (167 days during the dry season) with long cold winters. However, following recent gained an average of 0.84 kg/hd/d or 141 kg/hd successful establishment and production of leucaena in (Middleton 1998; Hasker 2000). In July 1998, despite southern inland Queensland (Antonio 2019; Ogg and Ogg significant psyllid damage, the 12-month (366 days) 2019), an investigation into the establishment, persistence weight gains by 25 Charbray steers from this same cohort and comparative performance of leucaena in inland northern averaged 235 kg/hd or 0.64 kg/hd/d (Middleton 1999). New South Wales indicates leucaena is both productive and Unpublished data for 2005 indicate daily liveweight gains persistent and compares favorably with other perennial of Charbray steers during the wet season and the full year tropical legume options such as desmanthus (Desmanthus were 1.16 and 0.7 kg/hd, respectively (Table 1), which spp.) in this environment (Boschma et al. 2018). Despite the were double the weight gains observed on native pastures demonstrated ability of leucaena to persist with regular alone (Kernot 1998). frosting and produce significant forage yields during An additional advantage was that in this study stocking extended periods of low rainfall, it will not be recommended rates increased from one Adult Equivalent/5 ha on native to graziers until sterile cultivars are available to mitigate the pastures to one AE/3.2 ha on native pastures with weed risk in this region (Boschma et al. 2018). leucaena. Subsequent herd modelling using the Breedcow Dynama package (Holmes 2013) suggested gross margins Productivity and profitability of leucaena feeding for the total enterprise could improve by 25% if 2,000 ha systems of leucaena was established on a typical 25,000 ha breeding and fattening beef operation on basalt soils in When sown into highly-suitable situations and with north Queensland (Bernie English and Joe Rolfe appropriate management, leucaena feeding systems are unpublished data 2018). highly-productive and profitable. In central Queensland, Since only limited research has been conducted, the leucaena-grass pastures can be 2.6 times more productive general lack of long-term productivity data in north (kg/ha liveweight gain) and 1.9 times more profitable ($/ha Queensland, Northern Territory and Western Australia gross margin) than grass-only pastures (Bowen et al. 2018). has meant a scarcity of published information on the Further, whole farm economic analyses indicate that a profitability of leucaena feeding systems for these regions profitable outcome from leucaena establishment can be (Fred Chudleigh pers. comm. 2018). Generating generated over a 30 year period in suitable growing regions productivity data is a priority, as the potential for leucaena of northern Australia, even when high establishment costs to transform beef industry profitability in northern are taken into account, including: (i) fallowing land prior to Australia has been boosted with the release of the sowing; (ii) seed, fertilizer, chemical and machinery inputs; Redlands cultivar, which may be significantly more (iii) foregone income from absence of grazing during the productive in these tropical environments, in part because leucaena establishment phase; and (iv) ongoing inputs such of its psyllid resistance. To drive future adoption, further as mechanical pruning and fertilizer (Bowen and research is needed to: identify the most productive Chudleigh 2018a). landscapes; develop practical and cost-effective cultural In north Queensland, well-managed leucaena sown methods; refine reliable establishment techniques; and into suitable landscapes can be very productive. Cattle improve grazing management to maximize cattle and performance data from the Meadowbank PDS near Mt system performance. Table 1. Average liveweight gains of steers grazing leucaena-native pastures on Meadowbank Station (Mount Surprise) in north Queensland in 2005. Approximate stocking rates of 1 Adult Equivalent (AE) to 3.2 ha were applied to leucaena-native pastures compared with traditional stocking rates of 1 AE to 5 ha on native pastures alone. Grazing period (days) No. of steers Average total weight gain Average daily weight gain (average entry weight, kg) (kg/hd) (kg/hd/d) 19/12/2004 – 17/04/2005 (119) 48 (243) 139 1.16 20/04/2004 – 17/04/2005 (362) 9 (403) 256 0.7 Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Adoption of leucaena feeding systems in Australia 309 In the cooler southern Queensland environment, strategic adoption rates to date remain modest compared with the placement of leucaena on higher, warmer sites on the potential area suitable for leucaena. Why many graziers northeastern Darling Downs can significantly boost have not adopted leucaena in these preferred locations production and economic outcomes compared with grass- should be determined so that research and extension only pastures in a similar location. In a study conducted over programs can address these issues to overcome the road- 2 years, leucaena-grass pastures produced an average blocks and unlock the production potential across large economic return (partial return on livestock capital, which is areas. Some graziers have planted all sections of their the value added by the stock less the variable and some property suitable for leucaena, whereas others are overhead costs) of 22% compared with grass-only pasture of reluctant to plant additional areas until their stock 6.5% (Emery and Sneath 2015). This was bettered in the numbers and turnoff increase sufficiently to finance the same study only by the average economic return (partial establishment of additional paddocks. Other reports return on livestock capital) of 27% delivered by cattle indicate some graziers, primarily located in non-frost- finished in a feedlot during the same period. While increases prone locations, are still developing grazing management in capital value are generally not included in economic techniques to effectively control the height of their current modelling scenarios, an increase in property values is leucaena stands and to reduce seed production, weed considered, and often realized, by graziers who establish spread risk and the need for mechanical trimming. significant areas of leucaena on their properties. Across north Queensland and the Northern Territory a As previously discussed, research data regarding the range of research projects/demonstrations are required in productivity of leucaena pasture systems in more areas suited to leucaena to overcome local challenges and southerly environments (New South Wales) were limited boost future adoption. Investigations should include the until the recent completion of an empirical research study collection of data on leucaena and cattle production across a into the productivity of tropical legume and grass species range of locations and seasons. Economic analyses of in inland New South Wales (Boschma et al. 2018). Owing production systems in these environments will enable to the recent nature of this study, there has not been advisors and graziers to evaluate how incorporating leucaena sufficient time to develop and undertake research to fully can improve the profitability of existing production systems. understand the economic performance of leucaena While more research investment is required, an existing feeding systems in these colder subtropical regions. project aims to measure and compare the liveweight gains of weaner steers grazing the psyllid-resistant cultivar Redlands Future of leucaena feeding systems in Australia and the most recently released psyllid-susceptible cultivar Wondergraze near Mount Garnet in north Queensland Adoption (Lemin et al. 2019). Outcomes from this grazing trial will broadly improve the understanding of leucaena Leucaena feeding systems already add significant value to establishment, management, fertilizer requirements and the northern Australian beef industry. Expanding these production economics in northern environments. While there industry benefits will rely mainly on lifting leucaena are limited data on the economics of incorporating legumes adoption rates through concerted RD&E activities. The generally into grass-only pasture systems in northern influence of a recent RD&E campaign in north Queensland Australia, a recent desktop modelling analysis by Ash et al. is evident as the number of producers utilizing leucaena has (2015) clearly demonstrates that legume incorporation is the increased from 3 prior to 2000 to 15 at present (Joe Rolfe most profitable strategy for adoption by graziers. and Bernie English unpublished data). There were 127 In recent years, high seed prices combined with landholder inspections of local leucaena research sites in shortages of seed and appropriate rhizobium have north Queensland during 2014–2018. Many of these were constrained leucaena plantings. Unfortunately the repeat visits by local producers highlighting the appeal and relatively small demand for inputs such as seed and insights provided by on-property trials and demonstrations rhizobium, compared with other legumes like lucerne (Coutts and Roberts 2003). (Medicago sativa), which is regularly re-sown, means There is now extensive advisor and producer these issues could re-emerge in the future. Although knowledge of the productivity and profitability of rhizobium is now readily available, seed supply of some leucaena feeding systems in central, and to a lesser extent, leucaena varieties is still limited. The anticipated future southern Queensland. In these regions, there are ample expansion of leucaena across Australia will place suitable soils for leucaena and research highlights the increasing pressure on industry suppliers to match the economic advantages of sowing leucaena into rundown demands for critical inputs. This could result in structural sown grass pastures. While leucaena is still being planted, changes to business models, for example the emergence Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 310 S. Buck, J. Rolfe, C. Lemin and B. English of dedicated seed producers of openly traded cultivars sowings, it is critical to determine soil nutrient levels prior rather than opportunistic harvesting of seed, to ensure to sowing to determine appropriate fertilizer application reliability and continuity of supply. rates and placement in relation to the planted rows. In existing stands, measurements of plant nutrient status Environmental considerations (leaf analyses) together with soil nutrient stores are required before fertilizer rates, placement and application Leucaena is considered an environmental weed by many frequency can be determined. local government and natural resource management The basalt provinces in north Queensland are an organizations. Managing the real and perceived weed risk emerging establishment area for leucaena. Fertilizer of leucaena is critical for ongoing adoption through applications are essential to overcome inherent sulfur industry and community acceptance. The Leucaena deficiencies on these soils, both at planting and in the longer Network (TLN) was formed by graziers in 2000 to term. Practical methods for fertilizer application in these promote the sustainable adoption of leucaena while timbered and rocky landscapes, as well as the frequency and minimizing unplanned spread. A Code of Practice (CoP) optimum rates, all require further investigation. was released by TLN in 2000 to encourage the responsible planting and management of leucaena and is regularly Filling feed gaps with winter forages reviewed and updated (Christensen 2019). While leucaena is regarded as a weed by many, several Business enhancements might arise from the production important environmental benefits for grazing landscapes of high-quality feed throughout the year by incorporating are critical to the future adoption of leucaena. Benefits annual winter forages into a perennial leucaena-pasture include: (i) improved soil health and fertility through system, either during years with high winter rainfall or increased organic carbon levels; (ii) higher sustainable where irrigation is available. One of the perceived issues pasture utilization through increased biomass production with a leucaena-grass pasture in the tropics and subtropics (Bowen and Chudleigh 2018c); (iii) ground-cover is poor grass growth, pasture quality and weight gains maintenance, particularly during dry conditions; (iv) during the drier (and cooler) winter months. One concept reduction in methane production per unit of beef being investigated by industry practitioners is to sow production; and (v) potential for carbon sequestration and annual winter forages, e.g. oats (Avena sativa) in the inter- payments through associated accreditation schemes. row spaces, either direct drilled into the dormant grass or These benefits could be potentially overlooked unless sown after cultivation. This system has the potential to fill strongly advocated by the industry. The recently the winter feed gap to maintain high weight gains for instigated project ‘Development of a sterile Leucaena to close to 12 months of the year, compared with only 7‒9 enhance red-meat production in new regions of Australia’ months without winter forages. While field research into (MLA donor company project code P.PSH.0884), if the productive capacity and resulting economic outcomes successful, could result in the removal of restrictions on of such systems needs to be undertaken, economic leucaena plantings across many areas of Australia, analysis of a system, involving grazing cattle on oats in particularly in Western Australia and New South Wales. the winter months and leucaena-grass pasture for the remainder of the year in central Queensland (Bowen and Nutritional requirements Chudleigh 2018b), indicates costs of establishing and managing the winter forage could out-weigh the increased There is an emerging need to improve understanding of weight gains and additional income potential from the nutritional requirements of leucaena and determine marketing heavy cattle earlier. Without irrigation, such a the timing, placement and quantity of fertilizer system may have production merits only in higher rainfall applications for existing leucaena-grass pasture stands. A years. Unfortunately the ability to accurately predict these considerable area of leucaena has been sown into nutrient- suitable years is difficult with current seasonal forecasting depleted paddocks previously utilized for dryland tools and, while irrigating leucaena could guarantee cropping. In this situation leucaena production is adequate soil water for optimum forage growth, this could restricted by limited availability of soil nutrients rather come at a prohibitive cost. than rainfall received. Considerable improvements in annual dry matter production, pasture quality and Fodder conservation stocking rates can be made when adequate soil nutrients (particularly phosphorus and sulfur) are available to the Techniques to improve the utilization efficiency of pasture system (Radrizzani et al. 2010). For new leucaena leucaena, especially in irrigated situations, could be Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Adoption of leucaena feeding systems in Australia 311 critical to future profitability. Innovative graziers are Halliday et al. 2013, 2019) indicates a range of bacteria already exploring effective techniques to either ensile or other than Synergistes jonesii are capable of degrading pelletize leucaena to increase the utilization efficiency dihydroxypyridine (DHP) and may already be present in and conserve fodder for use at a later date. Young, fresh the rumen of grazing animals in Australia. In addition leucaena biomass has been cut and wrapped into silage other metabolic processes (conjugation) may allow cattle bales with reasonable success (Stuart Buck unpublished to consume high levels of mimosine yet still grow at data 2018). Other innovators have attempted to pelletize levels expected on a particular dietary intake and the same material (Ernie Young pers. comm. 2015). composition (Halliday et al. 2013). These investigations Undoubtedly feeding such material during the dry season must continue to provide graziers with recommendations will improve weight gains, but the costs associated with for practical management options to minimize production cutting, wrapping-pelletizing, handling, transporting and losses associated with toxicity. feeding may exceed the benefits and must be analyzed. Plant breeding Grazing management Innovative plant breeding technologies will ensure new Future research must include a focus on refining grazing leucaena cultivars are developed by introducing specific management of leucaena-grass pastures to ensure traits into existing cultivars. While a new project in sufficient pasture supply to maximize dietary selection Western Australia is endeavoring to breed a sterile and liveweight gains. Research into dietary selection by leucaena, the opportunity and feasibility of breeding a cattle through fecal analysis over a number of years has cold- or frost-tolerant cultivar should also be investigated. provided important insights into the quantity and timing This could expand the area suitable for leucaena in both of leucaena intake in a mixed pasture sward. Specifically, the colder areas of existing growing regions, and multiple on-farm trials in central and southern importantly the colder climates of New South Wales, Queensland environments with stock on leucaena and where leucaena is currently not sown, mainly due to predominantly buffel grass pastures indicated leucaena temperature limitations. Ultimately it may be desirable to can comprise about 50% of dietary intake on average have a cultivar which has multiple attributes such as during the year (Bowen et al. 2018). However intakes can psyllid resistance, sterility and cold tolerance. These range from around 10% to greater than 80%, depending combined attributes would enable high production from on time of year, supply of edible leucaena and quantity leucaena plantations extending from the northern regions and quality of the companion grasses. Therefore, graziers of Australia through to southern latitudes where cooler and advisors need to look beyond the notion of an ‘ideal’ winter temperature patterns are dominant. level of leucaena intake (30% is commonly asserted), and recognize leucaena consumption by cattle will, and Cattle management technologies should, fluctuate significantly with grass quality and seasonal conditions. As such, management of the Some of the production enhancements previously leucaena-grass pasture system should aim to maximize discussed will be made easier or enabled through the supply of edible leucaena at times of high leucaena advances in electronics. Electronic ear tags with global intake (typically when grass quality is low in autumn and positioning systems (GPS) capability will revolutionize spring) and ensure adequate grass forage is available the ability to manage individual animals within large when grass consumption is high (typically when grass mobs of cattle. Walk-over-weighing and auto-drafting quality is high in summer). To this end there will be systems are already commercially available and can important implications for pasture (grass and leucaena) provide significant management and time-saving budgets, stocking rates, grazing periods, row widths, row advantages, including: sorting of similar weight groups of direction to minimize grass shading, fertilizer cattle for marketing purposes; targeting cost-effective requirements and selection of companion grass species in supplementation programs; and grouping similar-sized new plantings and existing stands. animals for breeding or pasture-budgeting purposes. Toxicity to grazing animals Conclusions Considerable research into leucaena toxicity, dynamics of While leucaena is already making a significant rumen microflora and management in recent years contribution to the level and profitability of beef (Dalzell et al. 2012; Davis et al. 2012; Graham et al. 2013; production in northern Australia, there is potential for Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 312 S. Buck, J. Rolfe, C. Lemin and B. English enormous increase in the area sown. Research will subtropical leucaena-grass pastures. Agriculture, Ecosystems continue to develop superior cultivars and refine the and Environment 248:38‒47. doi: 10.1016/j.agee.2017.07.020 methodologies for establishing and utilizing this valuable Coutts J; Roberts K. 2003. Extension models and best practice legume in the years ahead. With continual improvements in extension. 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Ingelara Grazing: Leucaena in speargrass Congress, Rockhampton, Australia, 8–21 February 1993. p. country, Queensland, Australia. Tropical Grasslands- 2070–2071. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 314 S. Buck, J. Rolfe, C. Lemin and B. English Wildin J. 1994. Beef production from broadacre leucaena in Forage tree legumes in tropical agriculture. CAB central Queensland. In: Gutteridge RC; Shelton HM, eds. International, Wallingford, UK. p. 352–356. (Accepted 2 May 2019 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):315–330 315 DOI: 10.17138/TGFT(7)315-330 ILC2018 Keynote Paper* Current and future adoption of leucaena-grass pastures in northern Australia Adopción actual y futura de pasturas de leucaena-gramíneas en el norte de Australia SEAN KENNY AND GEOFF DRYSDALE Rural Consulting Group, Warrnambool, VIC, Australia. www.ruralconsultinggroup.com.au Abstract The leucaena-grass pastures and target markets for adoption project was commissioned by Meat & Livestock Australia (MLA) to examine the scope for further adoption of leucaena-grass pastures in northern Australia. Drawing upon stakeholder and producer interviews, focus groups, mapping of biophysical factors critical to growing leucaena and a review of existing literature, regional adoption profiles were developed using the ADOPT model. This work outlines the current and future potential for adoption of leucaena in northern Australia and recommends 5 interrelated strategic actions designed to support the ongoing adoption. These actions have been designed to address the complex technical, social and biophysical requirements for successful adoption and will require collaboration between investors, The Leucaena Network, producers, government agencies and the private sector to be effective. Keywords: ADOPT, beef, central Queensland, extension, technology transfer. Resumen Meat & Livestock Australia (MLA) encargó este estudio con el fin de examinar las perspectivas de incrementar la adopción de pasturas de leucaena-gramíneas en el norte de Australia. Con base en entrevistas con productores individuales y en grupos, y con personal de agencias gubernamentales, mapeo de factores biofísicos críticos para el cultivo de leucaena y una revisión de la literatura existente, se desarrollaron perfiles de adopción regionales utilizando el modelo ADOPT. Este trabajo describe el potencial actual y futuro para la adopción de leucaena en el norte de Australia y recomienda 5 acciones estratégicas interrelacionadas, diseñadas para apoyar la adopción en curso. Estas acciones fueron diseñadas para abordar los complejos requisitos técnicos, sociales y biofísicos para una adopción exitosa. Para ser efectivas, requerirán la colaboración entre inversionistas, la Red de Leucaena (The Leucaena Network), los productores, agencias gubernamentales y el sector privado. Palabras clave: ADOPT, extensión, ganado bovino, Queensland central, transferencia de tecnología. Introduction 2017). These northern production systems are based in the summer-dominant rainfall zones, with highest The northern Australian beef industry stocking densities in southeast Queensland decreasing further north and into the Northern Territory, the More than two-thirds of Australia’s beef herd is located Kimberley and Pilbara. in northern Australia, covering subtropical northern Cattle production and turnoff across the north are New South Wales (NSW) (6%), Queensland (QLD) tailored to a variety of ‘production sectors’ from breeding (47%), Northern Territory (NT) (10%) and the and sale of weaners or store yearlings through to rangelands area of Western Australia (WA) (5%) (ABS backgrounding and finishing for specific domestic and ___________ Correspondence: Sean Kenny, 1 Ardlie St, Warrnambool, VIC 3280, *Keynote paper presented at the International Leucaena Australia. Email: sean@ruralconsultinggroup.com.au Conference, 1‒3 November 2018, Brisbane, Queensland, Australia. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 316 S. Kenny and G. Drysdale export markets (Ausvet 2005). A key challenge faced by  Susceptible to psyllids in humid/coastal conditions. northern producers is to obtain the rapid weight gains  Costly to establish. required to meet market specifications because of the  Mimosine toxicity requiring additional management. relatively poor nutritional value of tropical grass pastures. Objectives and method Leucaena as a forage option The purpose of the leucaena-grass pastures adoption Amidst the search for more nutritious species the forage project is to inform the development of an industry legume leucaena, used in combination with grass pastures, strategy to increase the adoption of leucaena-grass was reported by Dalzell et al. (2006) to be the most pastures across suitable regions of northern Australia. productive, sustainable and profitable system for producing This study was commissioned with 4 objectives: grassfed beef in northern Australia. These pronouncements 1. Describe the potential for future leucaena production of the virtues of leucaena were reinforced by Bowen et al. in northern Australia; (2015) in a study of forage systems on 24 producer sites in 2. Examine current production levels of leucaena-grass the Fitzroy region. The study found that leucaena-grass pastures in Australia; pastures resulted in the highest average total beef production 3. Explore the barriers and incentives to adoption and highest gross margins. Production/ha from leucaena- (scope) and the return on investment Meat & grass pastures was 2.6 times greater than the average annual Livestock Australia (MLA) can expect from its beef production from perennial grass pastures and 1.6 times RD&E investments into leucaena; and higher than the next most productive legume pasture, with 4. Make recommendations on a strategy to increase the less variability between sites and years in total beef produced. adoption of leucaena-grass pastures. Leucaena, while being highly productive and profitable, Throughout this paper we refer to 5 regions in northern presents significant challenges to establish and manage, Australia, each with a unique combination of adoption and is suited to only a particular range of soil and characteristics. These regions differ in one or more key rainfall zones in northern Australia. Producer Demonstration elements critical to the potential adoption of leucaena, Sites (PDS) and research projects have demonstrated the namely: farming system types; psyllid risk; access to challenges involved in managing and establishing markets; and producer density/critical mass. The regions are leucaena, highlighting a 3‒7 year payback time to recover central Queensland, the Queensland High Rainfall Coastal zone, Queensland Gulf Country, Northern Territory and establishment costs for leucaena-grass systems (Bowen et al. Western Australia. 2015). In summary, the strengths and weaknesses of To understand the geo-climatic potential for leucaena in leucaena as defined by Dalzell et al. (2006) are: these regions, we reviewed the published literature. From this review, the geo-climatic potential of leucaena was Strengths mapped, based on soil depth >1 m and pH >5.5 as per the methodology of Beutel et al. (2018) and annual rainfall ≥400  Very high nutritive quality for ruminant livestock. mm. To determine the upper limit of beef properties and  Highly productive on suitable soils. cattle numbers in suitable areas, Australian Bureau of  Drought-tolerant, retaining leaf during dry periods. Statistics (ABS) SA2 polygons that fall within Natural  Long life meaning lower lifetime cost overall. Resource Management (NRM) regions were used, with  Enables targeting of higher value markets. counts being apportioned based on the percentage of area  Reduces soil erosion and prevents rising water tables within an NRM region where boundaries do not align. due to deep root system. In terms of actual adoption, the paper draws on the work  Reduces greenhouse gases via carbon sequestration of Beutel et al. (2018) in central Queensland and input from and reduced methane production. local operatives in the other zones to assess the extent of current plantings. The next component of this project was to Limitations explore barriers and incentives to adoption. This was assessed by multiple ‘data’ sources including: producer  Poorly adapted to acid and infertile soils. interviews and focus groups in central Queensland;  Grows poorly at low temperatures and is susceptible discussions with R&D personnel involved with leucaena; to frosting. review of literature on the attributes of leucaena; and an  Poorly competitive in seedling stage and slow to analysis of MLA producer segmentation work. These data establish. were then incorporated into the ADOPT model (Adoption Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena adoption in northern Australia 317 and Diffusion Outcome Prediction Tool; Kuehne et al. 2017)  The 600–800 mm rainfall zone is likely to provide to better understand the potential scope and rate of adoption. greatest potential so long as soil and temperature Upon developing these adoption ‘profiles’ for each conditions are suitable. The 400–600 mm zone may region, a rationale for investment in extension and adoption also be suitable, depending upon annual rainfall activities was developed, with 5 interrelated strategic actions distribution, but is deemed ‘marginal’ in terms of its being recommended to support the consolidation of appropriateness. knowledge associated with leucaena management and  The 800 mm plus rainfall zone offers huge production ongoing adoption. potential with the new Redlands psyllid-tolerant variety; however a greater prevalence of acid soils, Results opportunities for higher-value crop production, perceptions in coastal areas of leucaena being a weed Scope for leucaena and establishment and management challenges mean that these areas are also seen as marginal for adoption. Geographic potential for leucaena production is  Average minimum temperatures and frosts are dependent upon 4 key biophysical elements: 1) growing unlikely to be a barrier in northern Australia, except temperature; 2) frost incidence; 3) annual rainfall; and 4) for a small area around Charleville. soil type, as described by Dalzell et al. (2006):  Soil depth >1 m and pH >5.5 appear to provide a best- 1. Temperature – growth slows when daily maximum bet option for land suitability. temperatures fall below 25 °C in autumn, and stops  Suitable areas in NSW fall into Local Government when minimum temperatures fall below 10 °C. Soil Areas (LGAs) which prohibit the use of leucaena. temperatures need to be above 18 °C for leucaena In order to quantify the upper limit with regards to seed to germinate rapidly. potential area in northern Australia suitable for growing 2. Frost – can kill seedlings of all cultivars; however leucaena, data from the CSIRO National Soils Grid for mature plants recover after leaf drop caused by mild pH(CaCl2) and soil depth, along with Bureau of frosts (0 to -3 °C) and after death of above-ground Meteorology (BoM) annual rainfall data were collated to stems from severe frosts (below -3 °C). form maps and data tables and results are represented in 3. Rainfall – can tolerate and produce leaf during dry spells Table 1 and Figure 1 below. and droughts; however performs best in areas that From these data it can be seen that: receive >600 mm annual rainfall. Above 800 mm rainfall psyllid insect damage becomes problematic with  16% of northern Australia or 88,106,354 ha fits the current varieties. The new psyllid-tolerant Redlands broadest temperature/rainfall/soils requirement for variety has potential to address this issue. growing leucaena; 4. Soils – grows best on deep, fertile, well-drained,  only 5% or 25,351,588 ha fits the ideal rainfall and neutral to alkaline soils. soil characteristics; and From these data, the following can be concluded with  of the total ideal area suitable for leucaena, 5% is in regard to the geographic potential of leucaena across NSW, 14% is in the NT, 79% is in Queensland and northern Australia: 2% is in WA. Table 1. Total area suitable for growing leucaena in northern Australia. State Total area (ha) % of ideal area Rainfall zone area1 with suitable soils2 (ha) 400–600 mm 600–800 mm >800 mm New South Wales 10,103,329 5 543,964 1,218,044 145,696 Northern Territory 134,735,520 14 2,697,013 3,523,638 11,344,726 Queensland 172,935,408 79 36,125,260 20,106,218 8,765,528 Western Australia 220,803,174 2 16,235 503,689 3,116,343 Total (ha) 538,577,432 Total potential (ha) 88,106,354 39,382,471 25,351,588 23,372,294 Total potential (%) 16 7 5 4 All areas are calculated using GDA 94 Albers Projection. 1Rainfall based on BoM 30 year annual mean from 1976 to 2005. 2Suitable soils based on a combination of soil depth >1 m and pH(CaCl2) >5.5 (in soils >1 m); data sourced from CSIRO - National Soils Grid of Australia (90 m resolution). Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 318 S. Kenny and G. Drysdale Figure 1. Soils suited to leucaena (depth >1 m with pH >5.5) in rainfall zones across northern Australia. Beef enterprises and cattle numbers in areas suited to  20% of properties and 16% of cattle are in the ‘ideal’ leucaena zone for leucaena with regard to rainfall and soils. This equates to 3,080 properties and 2,377,086 cattle; The beef industry across northern Australia encompasses and almost 16,000 producers and over 15 million cattle. In  Queensland is the dominant area with regard to ideal order to estimate beef cattle numbers and the number of conditions for leucaena, containing 92% of properties beef properties in areas suited to leucaena, we have and 91% of all cattle in areas highly suitable for mapped the distribution of cattle and producers across the growing leucaena. 17 NRM zones in northern Australia. We then overlaid In summary: the area with the rainfall and soil suitability characteristics  16% (88,106,354 ha) of northern Australia fits the in order to evaluate the upper level of producers who may broadest temperature-rainfall-soils requirements for adopt leucaena, along with the number of cattle this growing leucaena, comprising 6,048 properties and represents. Figures 2 and 3 show the cattle producers and 6,302,595 cattle; cattle numbers for each NRM region and Tables 2 and 3 show overall producer and cattle numbers for each state  5% (25,351,588 ha) of northern Australia fits the ideal and in areas potentially suited to leucaena. requirements for growing leucaena, comprising 3,080 From these data we concluded that: properties and 2,377,086 cattle; and  40% of properties comprising 42% of cattle in  79% of the ideal area is in Queensland, which equates northern Australia have the potential to grow to 20,106,216 ha, 92% of properties (2,835) and 91% leucaena. This represents 6,266 properties and of all cattle (2,168,123) in areas highly suitable for 6,329,606 head of cattle; growing leucaena. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena adoption in northern Australia 319 Figure 2. Number of beef cattle producers in NRM regions across northern Australia. Figure 3. Number of beef cattle in NRM regions across northern Australia. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 320 S. Kenny and G. Drysdale Table 2. Beef cattle properties suitable for growing leucaena in northern Australia. State Beef cattle % ideal Beef cattle properties1 in rainfall zone areas2 with suitable soils3 properties1 properties 400–600 mm 600–800 mm >800 mm New South Wales 4,086 8 68 238 85 Northern Territory 197 0.2 3 7 35 Queensland 11,125 92 2,131 2,835 860 Western Australia 280 0 0 0 4 Total properties 15,688 Total potential properties 6,266 2,202 3,080 984 Total potential (%) 40 14 20 6 1Counts are based on ABS SA2 polygons that fall within NRM regions, rainfall areas and combined rainfall/suitable soils areas. Note that SA2 areas do not coincide with NRM regions. ABS counts have therefore been apportioned based on the percentage within an NRM region. 2Rainfall based on BoM 30 year annual means from 1976 to 2005. 3Suitable soils based on a combination of soil depth >1 m and pH(CaCl2) >5.5 (in soils >1 m); data sourced from CSIRO - National Soils Grid of Australia (90 m resolution). Table 3. Beef cattle numbers in areas suitable for growing leucaena in northern Australia. State Beef cattle % cattle in Beef cattle numbers1 in rainfall zone area2 with suitable soils3 numbers1 ideal zone 400–600 mm 600–800mm >800 mm New South Wales 1,271,236 4 25,214 92,770 21,457 Northern Territory 2,237,031 5 75,727 107,773 220,657 Queensland 10,387,505 91 3,024,138 2,168,123 541,025 Western Australia 1,148,951 0.4 170 8,420 44,132 Total cattle 15,044,723 Total cattle in potential zone 6,329,606 3,125,249 2,377,086 827,271 Total potential (%) 42 21 16 5 1Counts are based on ABS SA2 polygons that fall within NRM regions, rainfall areas and combined rainfall/suitable soils areas. Note that SA2 areas do not coincide with NRM regions. ABS counts have therefore been apportioned based on the percentage of area within an NRM region. 2Rainfall based on BoM 30 year annual means from 1976 to 2005. 3Suitable soils based on a combination of soil depth >1 m and pH(CaCl2) >5.5 (in soils >1 m); data sourced from CSIRO - National Soils Grid of Australia (90 m resolution). Exploring adoption of leucaena using regional Central Queensland segmentation For the purposes of this study we have used the The vast majority of leucaena plantings in northern geographical boundary defined by Beutel et al. (2018) to Australia are in what is variously known as the Brigalow describe the central Queensland beef region. This area (Acacia harpophylla) belt, central Queensland, or the comprises the Fitzroy, Burnett Mary, Border Rivers Fitzroy/Mary/Burnett region of Queensland. In addition to Maranoa Balonne, Condamine and the western subregion this we have identified 4 other primary geographic zones in of the southeastern Queensland NRM regions. Bray et al. northern Australia, i.e. High Rainfall Coastal zone, Gulf (2014) described the climate of this region as subtropical Country, Northern Territory and Western Australia. These to tropical, varying from humid near the coast to semi- 5 zones differ in 1 or more key elements critical to the arid inland. The wet season occurs in summer with potential adoption of leucaena, namely: farming system frequent flood events after cyclones and monsoonal types; psyllid risk; access to markets; and producer downpours. Brigalow and buffel grass (Cenchrus ciliaris) density/critical mass. The following section will outline the are synonymous with central Queensland but many other current understanding of the history and extent of leucaena land types and native grasses exist in the region. adoption in each of these geographic zones. The central Approximately 95% of the area is utilized by agriculture, Queensland section is naturally larger than the others, with 87% grazing and 8% cropping (Cobon and Toombs given the history of leucaena production in this region. 2007). Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena adoption in northern Australia 321 To examine the extent of leucaena plantings in the  3.9% of properties (103) adopting leucaena in the region, Beutel et al. (2018) mapped the geographic study area; potential in the region using a combination of rainfall and  2.9% of these properties (80) being in the ‘ideal’ zone soil attributes. In addition they mapped the actual with 600‒800 mm rainfall; and distribution of leucaena stands which provides an ideal  1.0% of properties (24) being in the <600 mm zone. test of actual locations against recommended parameters. Views from adopters in central Queensland. To gain From this work the following can be noted: greater context for the adoption of leucaena in central 1. Temperature. The majority of plantings of leucaena Queensland, field work was conducted in the region, which are in areas which have minimum average involved meetings with Queensland Department of temperatures of 6 °C or above. The average minimum Agriculture and Fisheries staff at Toowoomba, Biloela and temperature in the coldest month within the study area Rockhampton, and with members of The Leucaena falls to 6 °C, which is below the 10 °C minimum Network, who provided insights and helped arrange focus threshold for winter growth. The limited prevalence groups and property visits from Millmerran to Wandoan of leucaena in these cooler areas suggests that, while and Taroom, then south of Banana, west to Moura and east producers may push the limits of leucaena’s to Thangool. Interviews were conducted with individuals temperature tolerance, it is not a common occurrence. or in focus groups from 20 cattle properties in central 2. Frost. The majority of leucaena is planted in areas which Queensland. Leucaena is currently grown on 15 of these are least frost-prone. While some plantings occur in the and owners are advocates for the technology (adopters). moderate frost-prone area southeast of Charleville (10‒ Three owners do not currently have any leucaena and have 20 frosts of less than 0 °C), more-severe frosts of less reservations about it (non-adopters), while 2 have than -2 °C are less likely to occur in this band. purchased properties where it was sown many years ago, is 3. Rainfall. Three-quarters of leucaena plantings were out of control and efforts to eradicate it or get it back into found in the ‘ideal’ 600‒800 mm zone, with almost a rows have been unsuccessful. In addition, the views of quarter of plantings occurring in the ‘suboptimal’ 6 individuals involved in either leucaena R&D or extension rainfall zone of less than 600 mm. This suggests that were also garnered and recorded. a significant proportion of producers value leucaena in more marginal areas. As could be expected, no Benefits and advantages. Those interviewed had planted leucaena plantings were located in the >800 mm zone, leucaena on 3‒44% of their properties with a mean which Beutel et al. (2018) suggest reflects challenges planting of 18%. The majority considered the best to leucaena production in wetter parts of the study economic advantage gained from leucaena-grass pastures area, which include: a) susceptibility to psyllid was through finishing weaner cattle and weight gains of predation; b) acidic soils with high exchangeable 1–1.3 kg/d were regularly quoted with production gains aluminum levels; c) opportunities for higher-value of 30‒100%. Gains of 0.7 kg/d were recorded in older crop production; and d) higher weed burdens during cattle. The ability to meet target markets was enhanced crop establishment. and young cattle could be regularly turned off 12 months 4. Soils. Cultivated leucaena was not found in more acid earlier than off grass pastures. soils of pH <5.5 comprising 11.3% of the study area, Leucaena was most often used on lighter country with and was under-represented on shallow soils, with low soil nitrogen levels as the legume raised protein only 1.2% of the leucaena cultivation occurring on production. With the introduction of vegetation clearance 31.6% of the study area. Not surprisingly, 98% of all laws leucaena was also seen as a way of getting increased leucaena was found on the ‘ideal’ soils with depth production from existing land without further purchases. greater than 1 m and pH >5.5. Leucaena’s ability to provide nutritional feed after grasses Beutel et al. (2018) detected leucaena on 94 quadrats, mature and diet quality tapers off and its ability to fill the which included 103 cadastral sites in southeast autumn-winter feed gap were widely recognized. Queensland using a random sampling of aerial images, Drawbacks and limitations (potential barriers to where presence was confirmed before image inspection. adoption). The high cost of establishment, including the Based on ABS data, there are 8,359 beef properties cost of land being out of production, and the associated located across these 5 NRM regions with 2,640 in the risks of establishment failure were important ideal rainfall-soil zone and 1,289 in the marginal zone considerations, although many felt the risks of failure (rainfall of 400‒600 mm). Given the 103 properties were greatly reduced by hiring contractors and were less successfully identified by Beutel et al. (2018), this equates likely with experienced croppers. Leucaena has a weak to: seedling that competes poorly with weeds and grasses, Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 322 S. Kenny and G. Drysdale which means a long lead time in preparation and attention advocate that paddocks should be ploughed fence-to- to detail with establishment. fence after which leucaena is planted in rows, with careful The frost impact on production reduces the benefits but attention to weed control; it is only when plants are planting on higher ground and utilizing the leaf prior to established that grass should be sown in the inter-row frosts were common strategies to overcome this issue. spaces. This extends the time before the paddock reaches The region’s history of land clearing and difficulties in full production and is more costly because of the maintaining the land free of regrowth (suckers) has opportunity cost of grazing forgone. The alternative view produced a mindset in some against trees, e.g. leucaena. held equally strongly is to plant into established grass “Grandfather and father spent their lives clearing this pasture, by treating strips (with herbicide and cultivation) country and I’m not going to be putting trees back.” and then sowing leucaena into the prepared seedbed. Grazing management is important and requires proper Wider inter-row spacings would increase the probability infrastructure, e.g. fences and watering points, which is of success with this approach. One grower suggested the seen as too much additional work and expense by some. amount of nitrogen that leucaena contributes to the soil “It is a big decision and almost a lifetime commitment, may be over-estimated, and said it does not share its N which cannot be reversed and reduces land flexibility. If with grasses like other legumes, while it also extracts a lot not managed appropriately leucaena can get away and of moisture from the soil at the expense of the grasses. get out of control and this is almost impossible to rectify.” Cunningham, Tarramba and Wondergraze were the 3 Much of the Brigalow belt suffers from scrub varieties commonly grown in the study area. As a general regrowth, which requires blade-ploughing from time to comment several producers preferred Cunningham, time and people consider this will be difficult in leucaena considering it was more palatable, and more easily stands and scrub will reinfest their land. Along with this, controlled through grazing. One producer thought leucaena is perceived as not being as profitable as Tarramba was more productive, while cold tolerance of cropping and does not produce the cash flow on arable Wondergraze was seen as an advantage by some. country that cropping does, so it is often confined to less- Several landowners mentioned that leucaena was fertile soils and production decline is being witnessed. initially thought to be useful as a drought reserve, but in Learnings from experience. Early extension recommen- practice it is not. Certainly, it ‘hangs on’ after the grasses dations were to plant twin rows 1 m apart with an inter-row dry off and fills a feed gap but in extended dry periods it spacing of 6 m. A common theme emerging from drops its leaves and is unproductive. Two of the non-land experience is that many prefer much wider inter-row owner professionals we spoke to had examined spacing, commonly 12–15 m. There are several reasons phosphorus depletion under leucaena; they considered behind this thinking. Flexibility is mentioned in terms of that, as it was often planted on poorer soils and P removal management of the inter-row space, e.g. slashing or was significant, without fertilizer application this was a cultivation of the space for weed control and even cropping potential and emerging issue. this space, requiring sufficient width to operate appropriate implements. However, some think leucaena is too ‘thirsty’ High Rainfall Coastal zone for this, i.e. it draws too much moisture from the soil. The leucaena-grass balance is of significant interest The High Rainfall Coastal zone can be categorized as and is seen as a key to maximizing production. While this areas with greater than 800 mm average annual rainfall issue is unresolved, approaches by different graziers (AAR), on the coastal fringes of northern Australia, differ. Some graziers consider that the area sown to stretching from Cooktown in the north to Maryborough in leucaena should be limited or inter-row spaces should be the south. The region currently supports approximately wide, especially in areas with lower rainfall. Others 2.5 million cattle on 817 properties. Current levels of consider that leucaena is the most nutritious component leucaena production in this zone are hard to define of available forage so the more leucaena the better. accurately, but anecdotal evidence would suggest that it is Sowing with an inter-row spacing of 6 m or less can mean very small in comparison with plantings in central that grass is overgrazed if stock numbers are high enough Queensland. A key reason for this is the susceptibility of to prevent leucaena from becoming too tall. In addition, current cultivars to psyllid damage. The psyllid, which leucaena is very competitive for nutrients and moisture appeared first in Australia in 1986, is a leaf-sucking insect and can shade the grass, the combined effects limiting specific to the leucaena genus, feeding on the growing tips grass growth. of susceptible cultivars (Bray 1994). Psyllid damage can The third issue relating to paddock preparation is more reduce production by 50‒70% in humid regions and 20‒ complex and views are divided. Some graziers strongly 50% in subhumid environments (Bray 1994; Mullen and Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena adoption in northern Australia 323 Shelton 2003), and as such is a significant impediment to in the 600‒800 mm zone. Three properties are in the 400‒ leucaena production in the high rainfall zone. Shelton et 600 mm zone. al. (2017) suggest that the availability of a psyllid- Lemcke and Shotton (2018), in their Agnote on resistant variety could increase the range of adaptation of leucaena, reported that the deep sandy red Kandosols leucaena by 30%. The current ‘Redlands for Regions’ (Blain soils) and deep clay red Kandosols (Tippera soils) project is exploring the establishment of the new of the Douglas Daly and Katherine regions appear most Redlands variety on 5 properties in the High Rainfall suitable for growth and production of leucaena [see Smith Coastal zone and is providing data for clarifying key and Hill (2011) for soil characteristics]. In contrast they establishment and management requirements. note that, on the gravelly laterite soils further north and closer to the coast, severe leaf fall occurs within 4‒6 Gulf Country weeks following the last of the wet season rains, and suggest that supplementary irrigation would be needed The Northern Gulf region comprises the catchments of the during the dry season on those soils. They note that the Norman, Gilbert, Staaten and Mitchell River systems, all deeper red earth soils in the north may be more successful. of which flow into the Gulf of Carpentaria. Around 60% Research at Douglas Daly Research Farm (AAR = of the region is contained in the Northern Gulf Plains 1,200 mm) has focused on the production of introduced bioregion, while the remaining 40% falls within the pastures for many years. Grazing trials indicated that best Northern Einasleigh Uplands bioregion (Sattler and liveweight gains came from grass-leucaena pastures with Williams 1999). There are approximately 196 grazing an average of 200 kg/hd/yr @ 1.25–1.5 hd/ha. Over 12 businesses, covering an area of about 12.4 M ha. These months straight buffel grass produced LWG of 171 kg/hd businesses rely on (principally) native pastures to turn off (179 kg LWG/ha), while buffel-leucaena produced LWG about 260,000 head of cattle per year with a value of of 222 kg/hd (278 kg LWG/ha) (Shotton 2012). The approximately $180 million. A range of markets are irrigated grass-leucaena results (non-replicated) were about targeted including live export, the store market, the US 0.5 kg/hd/d or 2.7 kg/ha/d (P. Shotton pers. comm. 2018). grinding beef trade and the transfer of weaners to growing According to Peter Shotton (pers. comm. 2018), and fattening areas in southern and central Queensland. despite interest being shown in establishing leucaena, Total herd size in the Northern Gulf Region is very few graziers have taken up the opportunity, with only approximately 834,000 head, of which about 520,000 are relatively small areas of leucaena planted in the breeders and heifers 12 months and older. Rolfe et al. Katherine-Daly Basin and Victoria River District. Best (2016) found that high female mortalities, poor estimates are that less than 1,000 ha has been planted in reproductive performance and low annual liveweight the Territory to date, many as small plantings which have gains are commonly recorded with low annual liveweight been neglected or superseded by horticulture or forestry. gain (70–90 kg/hd) being a major constraint for those production systems located solely in the northern Gulf Western Australia savannas. Low profitability and debt-servicing pressures in these areas make pasture improvement and the In Western Australia, leucaena can be found near installation of additional infrastructure unaffordable for wetlands and riverine sites in Halls Creek, Kununurra, most businesses. It is therefore not surprising that Cockatoo Island, Christmas and Coolan Islands, Broome currently leucaena plantings in the Gulf country are and Derby (Hussey et al. 1997; Cowan 1998). Leucaena limited despite large areas being in the ‘ideal’ zone has been planted as a pasture in the Ord River Irrigation agroclimatically. Current estimates suggest there is in the Area of the Kimberley (Larsen et al. 1998), since CSIRO vicinity of 700 ha either recently planted or being planted plantings in the 1970s. After the discovery of the DHP- as of December 2018 (Rolfe et al. 2019; J. Rolfe pers. detoxifying bacteria, an industry began to develop, and comm.). more than 2,000 ha of cv. Cunningham was planted and grazed; however this area has declined in recent years, Northern Territory with several properties removing the planted trees and converting to horticultural crop production. Leucaena has The Northern Territory has 197 beef cattle properties with spread over 60 km along the Ord River, between the Ord approximately 2,237,031 beef cattle. In areas with soils River Dam and the Diversion dam and downstream from suitable for leucaena (>1 m deep and pH >5.5), most the Diversion dam, to create dense riparian thickets. properties (35) are in the >800 mm zone, with 7 properties Currently there are no commercial plantings of leucaena Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 324 S. Kenny and G. Drysdale in WA and current regulations prevent any new plantings horizon and financial constraints (Q’s 1‒6). on leasehold land (basically all of WA).  Relative advantage of the practice – including profitability, risk level, upfront costs, reversibility Exploring potential adoption of leucaena in northern and ease of management (Q’s 14‒22). Australia using the ADOPT model Time to Peak Adoption driven by ‘Learning of Relative ADOPT is an acronym for ‘Adoption and Diffusion Advantage’ Outcome Prediction Tool’, which was constructed to quantitatively predict adoption to assist in planning  Population-specific influences on the ability to learn agricultural research, development, extension and policy about the practice – such as advisory support, group (Kuehne et al. 2017). Based on past research and conceptual involvement, additional skills required and general thinking, the ADOPT model identifies and utilizes variables awareness of the practice (Q’s 10‒13). that are considered to contribute to either Peak Adoption  Learnability characteristics of the practice – such as Level (scope) and/or Time to Peak Adoption (rate) using trialing ease, observability of benefits prior to use and both characteristics of the population and the practice of complexity of evaluating benefits after use (Q’s 7‒9). interest described below (Figure 4). Input to the ADOPT model was provided by population data interpreted from MLA’s producer Peak Adoption Level driven by ‘Relative Advantage‘ segmentation survey and ‘innovation-practice’ response data derived from literature on leucaena (MLA 2016). An  Relative advantage for the population – including example of reasoning used for each element is outlined in business and environmental orientation, planning Tables 4 and 5. Figure 4. The conceptual framework of influences on peak adoption level and time to peak adoption (from Kuehne et al. 2017). Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena adoption in northern Australia 325 Table 4. Example input for factors affecting level of peak adoption. Question Response Reasoning Relative advantage for the population 1. Profit orientation 3. About half have maximizing Based on weighted scaling of MLA producer profit as a strong motivation segmentation category ‘Commercial orientation’ 2. Environmental orientation 2. A minority have protection of the Based on weighted scaling of MLA producer environment as a strong motivation segmentation category ‘Environmental benefits’ 3. Risk orientation 2. A minority have risk Based on weighted scaling of MLA producer minimization as a strong motivation segmentation category ‘Risk attitude’ 4. Enterprise scale 4. A majority of the target farms Assumes producers in the climatic zones could benefit have a major enterprise that could benefit 5. Management horizon 3. About half have a long-term Based on weighted scaling of MLA producer management horizon segmentation category ‘Five year outlook’ 6. Short-term constraints 4. A minority currently have a severe Based on weighted scaling of MLA producer short-term financial constraint segmentation category ‘Relevant financial outlay’ Relative advantage of the practice 14. Relative upfront cost of 3. Moderate initial investment Requirement for specialized sowing equipment/ practice contracting 15. Reversibility of practice 3. Moderately difficult to reverse Removal of plants would require spraying and possibly cutting, taking time and money 16. Profit benefit in years that 7. Large profit advantage in years Significantly more profitable than other species on it is used that it is used areas planted 17. Future profit benefit 5. Small profit advantage in the Assume small specific additional profits such as future carbon sequestration 18. Time until any future profit 3. 3‒5 years Takes 3–7 years to reach full potential benefits are likely to be realized 19. Environmental costs & 2. Moderate environmental Specific need to manage to the Code of Practice benefits disadvantage considered to be an ‘environmental disadvantage’ 20. Time to environmental 3. 3‒5 years Environmental disadvantage relates to spread of seeds benefit from this age onwards 21. Risk exposure 6. Moderate reduction in risk Leucaena more likely used to increase growth rates/fatten, but drought tolerance offers degree of risk reduction 22. Ease and convenience 2. Moderate decrease in ease and More difficult to manage than pastures alone, tending to convenience leucaena and managing stock access/timing to access Table 5. Factors affecting rate of peak adoption. Learnability characteristics of the practice 7. Trialable 2. Difficult to trial Trialing requires specialized sowing equipment, seeds need inoculating, specialized animal, weed and pest management 8. Practice complexity 4. Slightly difficult to evaluate Benefits should be reasonably self-evident so only effects of use due to complexity slightly difficult to evaluate performance 9. Observability 4. Easily observable Fairly easy to observe on other producer properties Learnability of population 10. Advisory support 3. About half use a relevant Based on weighted scaling of MLA producer advisor segmentation category ‘Paid consultants’ 11. Group involvement 3. About half are involved with a Based on weighted scaling of MLA producer group that discusses farming segmentation category ‘Networks’ 12. Relevant existing skills & 1. Almost all need new skills and Requires a whole new suite of cropping and pasture knowledge knowledge management skills and animal management 13. Practice awareness 4. A majority are aware that it has Based on weighted percentages of MLA producer been used or trialed in their district segmentation category attending ‘Field days’ Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 326 S. Kenny and G. Drysdale Sensitivities within the ADOPT model profitability, combined with excellent enterprise fit and social learning support, has the highest predicted upper The model predicts that 4 key aspects of leucaena’s adoption level of 18% and shortest time to peak adoption ‘relative advantage’ have the largest impact on of 14 years. Note that the percentage for scope should be adoption with Profitability (Q16, Q17 and Q18) being applied to those properties within the ‘ideal’ zone the standout, while Reduction in risk exposure (Q21), identified previously. Compared with CQ the 2 key Ease and convenience (Q22) and Environmental adoption drivers of profit and enterprise fit are costs/benefits (Q19, Q20) also significantly impact the considerably lower, moderated in areas where leucaena model’s output. offers greater risk reduction [Gulf country, NT and WA]. Regarding those producers most likely to adopt leucaena, A key qualifier here is the lack of information on farm Profit orientation (Q1) is an important precursor for adoption systems profitability in areas outside of CQ. and based on MLA producer segmentation, about half have Areas other than CQ, particularly more remote areas, ‘Maximizing profit’ as a strong motivation. However, within have considerably reduced social learning opportunities this profit-motivated farmer cohort the Enterprise scale (Q4), in terms of advisory support, group involvement and more broadly interpreted as enterprise fit or farming systems general awareness of leucaena, and typically have a lower fit, has huge potential to influence adoption because of: base knowledge and skills for leucaena management, all  Technology ‘fit’ in the system re: scale, intensity, farm extending the time to peak adoption. layout, labour, machinery and access to markets; and While weed-related considerations confer a small  Property-specific attributes of leucaena on environmental disadvantage in CQ, the Gulf and possibly profitability, risk exposure, ease of use and the NT, risks are higher in Higher Rainfall Coastal (HRC) integration within the system, plus environmental and totally exclude leucaena in most of WA. Across all considerations. regions, altering the model to have no net environmental Note ‘systems fit’ is not adequately addressed through disadvantage has potential to increase adoption by about the model with this function being rather coarse in its a third, and double adoption in more environmentally application. sensitive areas. Factors impacting time to peak adoption Building a rationale for investment in extension Major factors affecting time to peak adoption include Rationale for investment in extension essentially revolves characteristics of leucaena which limit the capacity of around the benefit:cost ratio of the intervention, where producers to learn about the technology. These include: benefits are characteristically economic but also take into  Learnability characteristics of using leucaena, account social and environmental impacts arising from particularly trialing ease and complexity of the intervention. Extension benefits are derived from the evaluating benefits after use (Q7 and Q8); combination of per-farm benefits and the defined scope of  Social learning including advisory support, group adoption. involvement, additional skills required and general Table 7 reports the estimated ‘scope’ for leucaena awareness of the practice (Qs 10‒13); and adoption based on the ADOPT model output and uses  Short-term financial constraints (Q6) combined with property data based on ABS SA2 polygons that fall within upfront costs (Q14). NRM regions and combined rainfall-suitable soils areas. Note that SA2 areas do not coincide with NRM regions. Exploring upper limits of adoption at a regional level ABS counts have therefore been apportioned based on the percentage of area within an NRM region. In this section, we explore the upper limits of adoption at a regional level, using sensitivities in the ADOPT model Regional- and industry-scale economic benefits of described above. Table 6 summarizes the way in which leucaena adoption we adjusted the model for sensitivities on a regional basis along with the model output for upper levels of both rate Industry-scale economic benefits are a product of and scope. Note that all other factors apart from these adoption rates and per-farm benefit, both of which will sensitivities remained constant within the model and did differ between regions. In this section we explore regional not change from region to region. benefits based on the data above and summarize by In central Queensland (CQ) we can see that high collating these into an industry-scale benefit. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena adoption in northern Australia 327 Table 6. Regional ADOPT output accounting for the key sensitivities within the model. Central High Rainfall Gulf Northern Western Queensland Coastal Country Territory Australia Profit +++ +++ +? +? +? Environment X XX X ? XXX Enterprise fit +++ ++ +? +? +? Risk + +++ +++ +++ Social learning +++ XX XXX XXX XXX Scope (peak adoption) 18% 6% 8% 8% 5% Rate (time to peak) 14 yr 15 yr 17 yr 20 yr 21 yr Seedless (remove envt disadvantage) 23% 10% 9% 9% 9% The + symbols indicate enabling influence on adoption, whereas the X symbols depict restraining influence on adoption. Table 7. Estimated scope for leucaena adoption based on ADOPT model output for regional segments. Central High Rainfall Gulf Northern Western Queensland Coastal Country Territory Australia Peak adoption % as predicted by 18% 6% 8% 8% 5% ADOPT Estimated no. properties with ideal 2,640 817 124 42 4 rainfall/soils Estimated no. properties to adopt 475 (371*) 49 10 3 0 leucaena Time to peak adoption (yr) 14 19 22 25 36 *371 is the number of properties yet to adopt leucaena allowing for the estimate of current adoption from Beutel et al. (2018). Central Queensland psyllid damage. However, the recent release of the psyllid- resistant variety Redlands has paved the way for increased If we take the modeled farm assessment of net annualized leucaena usage in this zone. Based on our modeling and the benefit per farm from investing in leucaena of $40,336 associated assumptions, it is estimated that 6% of these (Chudleigh et al. 2018), and multiply this by the 371 properties, i.e. 49 properties, are potential adopters. properties in CQ based on our ADOPT model output, Regarding per-farm economic benefits, current trials which represents the upper scope for additional leucaena show early indications of psyllid resistance and adoption in CQ, a total maximum, annualized benefit of impressive forage growth; however there is still a lack of $15 million is calculated. cattle production data on which to base reliable estimates If we then consider the upper level for the time to peak of economic benefit. adoption generated by the ADOPT model of 14 years, an The industry-scale benefit in the HRC zone is therefore annual increase in properties adopting leucaena of 27 per based on a significant pool of producers likely to adopt if year would be required to reach peak adoption in this time farm trials prove profitable, and if appropriate extension frame, which would deliver an annualized benefit of $1.1 support and strategies are delivered. Further investment million. This equates to a cumulative value over the into extension in this zone calls for a stepped approach, expected time to peak adoption (14 years) of $115 million. with the first step aimed at establishing farm-level Taken together, the large pool of likely adopters and profitability and systems fit. robust estimates of significant per-farm benefits, coupled with significant existing extension support, suggest Gulf and Northern Territory reliable returns from investment into appropriate adoption strategies for central Queensland. The Queensland Gulf country contains significant areas of land suitable for leucaena, encompassing an estimated High Rainfall Coastal zone 124 properties. There are also some 42 properties on suitable soils in the NT. Based on our modeling and the Approximately 817 properties with suitable soils are located associated assumptions, we estimate that 8% of properties in the HRC zone. Up until now leucaena usage has been in both regions are potential adopters, which equates to restricted because of likelihood of yield reductions due to approximately 10 properties in the Gulf and 3 in the NT. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 328 S. Kenny and G. Drysdale Although leucaena has been used on some properties in to a greater extent in areas with less exposure to the Northern Territory, and is being trialed on a handful of farming, i.e. Gulf, parts of the HRC and NT. properties in the Gulf, there is a lack of reliable data on the  The availability of cleared country outside of CQ is a farm systems fit and management of leucaena and its clear limitation to leucaena’s use, given the profitability in these environments. Notwithstanding a lack Queensland vegetation management laws (bit.ly/ of real-world data on the performance of leucaena in these 2MEuSWP). regions, there has been considerable interest, particularly  The harshness of the climate in both the Gulf and NT from corporate enterprises. These entities may ‘go it alone’ means that, while soils may be suitable and AAR on minimal information; however opportunity exists for suggests moisture will not be limiting, extremes of heat some form of funded support to enhance success as and periodic inundation increase the risks of sowing discussed in the next section. failures and the overall perceptions of how risky it is to plant leucaena (Rolfe et al. 2019). Western Australia  Extension and expertise: CQ is in the fortunate position of having a pool of leucaena knowledge gained over In contrast to the NT and the Gulf, leucaena has been used many years and embedded in advisory personnel, successfully on a number of farms in the Ord River district growers and The Leucaena Network. Knowledge, but it has since been replaced by alternative land uses in support and grower experience are far more limited this area. Suitable soils and climate for leucaena do exist and fragmented in other areas. outside the Ord catchment, but virtually all properties are  The precarious position of many beef businesses on leasehold land (from the Government), where growing across northern Australia means that they are not well of leucaena is forbidden. Given this scenario, it is difficult placed to cope with establishment, market and climatic to mount a case to support these extremely limited risks in the absence of significant advisory support and opportunities for leucaena under current state legislation. ‘proof-of-concept’.  The fact that 25% of adoption in CQ has occurred in Discussion ‒ Systems fit adoption considerations the 400‒600 mm rainfall zone is significant, as all assessment to date has focused on the 600 mm+ Throughout this review, the complexity of integrating rainfall zones. This factor may balance out the negative leucaena into farming systems has become increasingly aspects of the considerations above. apparent, with potential adopters needing to firstly be  The lack of marketing options in WA, NT and parts of convinced of its suitability for their properties (soils, the Gulf is an issue as the traditional market for cattle climate, profitability), assess its fit within the farm system in NT is the live cattle export trade. The Livingstone (marketing approach, labor and resources), and have the meatworks established 50 km south of Darwin around skills and equipment to establish and manage it. Other key 2015 reportedly processed about 500 head of cattle a considerations, based on field work and discussions with day (ABC 2018) presenting some opportunities for regional experts, which may impact on ADOPT outputs marketing stock, but has recently suspended operations and therefore need to be addressed via strategy, are: owing to lack of profitability. Yeeda abattoir in the  Competition for land: high land prices and suitability Kimberley has recommenced operations and has a for alternative high-value crops and timber species similar capacity to the Livingstone meatworks, offer- have reduced the portion of potential areas sown to ing some access to the slaughter market for northwest leucaena in the Ord and parts of the NT and this is WA. Without such access to slaughter markets the likely to be the case in the HRC zone. benefits of leucaena may not be fully realized.  The need for the 3 Cs, i.e. cashflow to survive the Clearly the fundamental challenge is to enable property production gap that new-sown leucaena could present; owners and their advisors to balance the pros and cons of capital to invest in the machinery to develop land; and planting leucaena, compare it with other alternatives and capability to ‘farm’ – the fear of farming as a barrier to make decisions based on how they envisage the future of adoption seems to increase with distance from their business. In CQ where there is a growing pool of cropping country. expertise and experience based on 30 years of RD&E, this  Perceptions associated with key management and challenge is largely process-based, i.e. development of grazing issues – agronomy, rotational grazing, height strategic forage plans. For regions outside of CQ, there is management, broad-leaf weed control and cattle also a requirement for detailed forage planning; however mustering – may have a negative impact on adoption these property owners lack the basic inputs to support such Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena adoption in northern Australia 329 a process. As such, further investment is required to ‘prove  Action 3 is a critical component of any ‘knowledge’ and codify’ the fundamental aspects of a profitable system and has been occurring to a certain extent leucaena system for these regions. Given this, we see already, albeit not in a strategic and coordinated 2 primary tasks for the strategy: fashion. An ongoing investment linked to broader 1. Codification of the process to explore systems fit for strategic objectives at an industry scale is required to the new generation of adopters; and ensure rigor around knowledge resource management. 2. Enhancing the understanding of what constitutes  Action 4 is critical to the longevity of the leucaena systems fit in regions where little or no experience with industry given the ongoing decline in publicly-funded leucaena exists. extension. Given the potential for leucaena to deliver significant value to producers, it is highly likely that Conclusions and Recommendations for action once Actions 1‒3 are achieved the viability of private support services will be enhanced. Required however The combined effects of the comments listed above lead is an ongoing investment in the skills and capability to 5 interrelated strategic actions designed to support of the support sector, given the well-known ongoing adoption of leucaena. As can be seen from the limitations of many service providers to invest in skill diagram below, these actions have been developed to development. An additional requirement is ongoing address the 2 primary tasks outlined in the previous investment in the integrity of key elements of the section. leucaena supply chain, particularly seed production and distribution. 5. Drive  Action 5 will ensure that current and future 3. Support awareness and 1. Codify investments in leucaena RD&E are realized and continuous understanding systems fit improvement of potential leveraged for industry benefit over the long term. planning of knowledge benefits and process The critical next step for investors is to work closely resources support services with The Leucaena Network and other stakeholders to 2. Develop 4. Ensure plan further action designed to support the enhancement proof of sustainability of adoption and management of leucaena in Australia. concept of support The key questions to consider are: outside of CQ industry 1. Do the potential benefits of investment warrant the actions outlined in this paper?; and 2. What systems will be put in place to monitor progress The logic of the 5 actions can be understood as follows: to ensure the adoption targets linked to these benefits  Action 1 is designed to support the process of analysis are tracked and the strategy is modified if they are not at the property level to assess the appropriateness or being met? otherwise of changes to the forage base. This action aims to address the key issue of systems fit identified Acknowledgments at multiple stages in this report. It is intended that investment in this action would be a discrete period The authors acknowledge MLA as the funder of this work and that the process itself would become embedded and the organizers of the International Leucaena in practice over time. Conference 2018 in Brisbane for including this paper in  Action 2 will deliver the fundamental elements its proceedings. necessary to enable Action 1 to be implemented in areas outside of CQ. Key elements of systems fit such References as establishment best practice, weight gain potential (Note of the editors: All hyperlinks were verified 4 August 2019.) across various stock classes, realizing benefits of ABC (Australian Broadcasting Corporation). 2018. Australia's leucaena through systems change and risk associated largest cattle company AACo mothballs Darwin abattoir. with establishment and management are yet to be ab.co/2OETMZ6 adequately codified for the HRC, Gulf and NT. ABS (Australian Bureau of Statistics). 2017. 7121.0 - Investment in this action would also be for a discrete Agricultural Commodities, 2015-16. Australian Bureau of time period as, by definition, once the concept is Statistics, Canberra, ACT, Australia. bit.ly/31kSAv8 ‘proved’, producers can then move confidently on to Ausvet (Ausvet Animal Health Services). 2005. A review of the investment and implementation. structure and dynamics of the Australian beef cattle industry. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 330 S. Kenny and G. Drysdale AusVet DRAFT Report to DAFF. AusVet, Canberra, ACT, and policy. Agricultural Systems 156:115–125. doi: Australia. bit.ly/31gvaaq 10.1016/j.agsy.2017.06.007 Beutel T; Corbet D; Hoffmann MB; Buck SR; Kienzle M. 2018. Larsen PH; Middleton CH; Bolam MJ; Chamberlain J. 1998. Quantifying leucaena cultivation extent on grazing land. The Leucaena in large-scale grazing systems: Challenges for Rangeland Journal 40:31‒38. doi: 10.1071/RJ17085 development. In: Shelton HM; Gutteridge R; Mullen B; Bray Bowen MK; Buck S; Chudleigh F. 2015. Feeding forages in the R, eds. Leucaena – adaptation, quality and farming systems. Fitzroy: A guide to profitable beef production in the Fitzroy Proceedings of a workshop held in Hanoi, Vietnam, 9‒14 river catchment. Department of Agriculture and Fisheries, February 1998. ACIAR Proceedings No. 86. ACIAR, Brisbane, QLD, Australia. era.daf.qld.gov.au/id/eprint/ Canberra, ACT, Australia. p. 324‒330. purl.umn.edu/135197 6189 Lemcke B; Shotton P. 2018. Leucaena: An extremely valuable Bray RA. 1994. The leucaena psyllid. In: Gutteridge RC; Shelton browse legume for cattle in the top end. AgNote. Department HM, eds. Forage tree legumes in tropical agriculture. CAB of Primary Industries and Resources, Northern Territory International, Wallingford, UK. p. 283‒291. hdl.handle.net/ Government, Darwin, NT, Australia. bit.ly/2Jh5Zil 10568/49375 MLA (Meat & Livestock Australia). 2016. MLA stakeholder Bray S; Walsh D; Rolfe J; Daniels B; Phelps D; Stokes C; Broad segmentation and value proposition project ‒ Producer KC; English B; Foulkes D; Gowen R; Gunther R; Rohan P. segmentation and satisfaction. Meat & Livestock Australia, 2014. Climate Clever Beef: On-farm demonstration of Sydney, Australia. adaptation and mitigation options for climate change in Mullen BF; Shelton HM. 2003. Psyllid resistance in Leucaena. northern Australia. Final report. Meat & Livestock Australia, Part 2. Quantification of production losses from psyllid Sydney, Australia. era.daf.qld.gov.au/id/eprint/6106 damage. Agroforestry Systems 58:163−171. doi: 10.1023/ Chudleigh F; Oxley T; Bowen M. 2018. Improving the A:1026081307893 performance of beef production systems in northern Australia Rolfe JW; Larard AH; English BH; Hegarty ES; McGrath TB; – Part 1. Queensland Government, Brisbane, QLD, Australia. Gobius NR; De Faveri J; Srhoj JR; Digby MJ; Musgrove RJ. bit.ly/2MCHoWH 2016. Rangeland profitability in the northern Gulf region of Cobon DH; Toombs NR. 2007. Practical adaptation to climate Queensland: Understanding beef business complexity and the change in regional natural resource management: Queensland subsequent impact on land resource management and case studies – Fitzroy Basin report – Part A. Production and environmental outcomes. The Rangeland Journal 38:261‒272. natural resource indicators in beef systems under climate doi: 10.1071/RJ15093 change conditions. Project EP08. Australian Greenhouse Rolfe JW; Lemin C; English B; Caird R; Black E; Perry L; Henry Office, Canberra. R&C; Connolly G&C. 2019. Leucaena establishment on Cowan RS. 1998. Mimosaceae. In: Flora of Australia. Volume 12: frontage country in the Queensland Gulf. Tropical Grasslands- Mimosaceae (excluding Acacia), Caesalpiniaceae. CSIRO Forrajes Tropicales 7:133‒135. doi: 10.17138/tgft(7)133-135 Publishing, Melbourne, Australia. bit.ly/2M0lFIN Sattler PS; Williams R. 1999. The conservation status of Dalzell SA; Shelton HM; Mullen BF; Larsen PH; McLaughlin Queensland's bioregional ecosystems. Queensland Environ- KG. 2006. Leucaena: A guide to establishment and mental Protection Agency, Brisbane, QLD, Australia. management. Meat & Livestock Australia, Sydney, Australia. Shelton HM; Giles G; Lambrides C. 2017. Psyllid resistant bit.ly/2YHs66P leucaena to market. Final report. Meat & Livestock Australia, Hussey BMJ; Keighery GJ; Cousens RD; Dodd J; Lloyd SG. 1997. Sydney, Australia. bit.ly/2ZyiUBF Western weeds: A guide to the weeds of Western Australia. Shotton P. 2012. Leucaena in the Northern Territory. Presentation Plant Protection Society of Western Australia, Victoria Park, at Beef Week, Rockhampton, QLD, Australia, 7‒12 May 2012. WA, Australia. bit.ly/2YIiXJY Smith S; Hill J. 2011. Supporting sustainable development – risks Kuehne G; Llewellyn R; Pannell DJ; Wilkinson R; Dolling P; and impacts of plant industries on soil condition. Technical Ouzman K; Ewinge M. 2017. Predicting farmer uptake of Bulletin No. 340, Northern Territory Government, Australia. new agricultural practices: A tool for research, extension bit.ly/2KqwzEz (Accepted 25 May 2019 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):331–332 331 DOI: 10.17138/TGFT(7)331-332 ILC2018 Poster and Producer paper* The Leucaena Network and The Leucaena Code of Practice La Red de Leucaena y el Código de Prácticas para el cultivo de leucaena BRON CHRISTENSEN The Leucaena Network, Theodore, QLD, Australia. www.leucaena.net Keywords: Environment, extension, research, responsibility. Introduction of Agriculture and Fisheries (QDAF) in the MDC/PIFT ‘Redlands for Regions’ establishment trials; the Wandoan- The Leucaena Network was formed in July 2000 by a based ‘Improving the Productivity of Leucaena in Grass group of producers and industry representatives who Pastures with Fertiliser’ Producer Demonstration Site wished to progress the leucaena industry and address (PDS); and the provision of input into the UQ/UWA sterile environmental concerns. leucaena project (Figures 1‒3). The feasibility of research The organization’s aim is to “promote the responsible projects into the management and maintenance of development of leucaena in productive and sustainable established leucaena is currently being investigated. ecosystems to build stronger rural communities”. In September of that year, the Network developed The Leucaena Code of Practice to promote responsible management of the legume in response to the environmental concerns (reproduced at the end of this paper). Today, The Leucaena Network is a leading producer group in the grass-fed beef industry in Queensland. Members include livestock producers, leucaena and pasture seed growers, researchers and extension personnel. The Network remains true to its message, continuing to focus on the responsible management of the legume while working to promote the industry and provide current and relevant information and research to its members. Figure 1. QDAF, MLA and Leucaena Network representatives The Network encourages everyone who is involved join ‘Redlands for Regions’ producers at Quincan Springs. with the leucaena industry to take up Network membership to foster ongoing activities and research to assist the industry to prosper. Currently due to demand, much of The Leucaena Network’s focus is on the promotion of strategies for successful leucaena establishment for new producers. However, the Network continues to strive to provide established producers with research and extension information. A linchpin of The Leucaena Network’s information provision is its website, www.leucaena.net. Current Research Projects Figure 2. QDAF officer Bernie English joins ‘Redlands for Currently, The Leucaena Network is partnering with Meat Regions’ producers Rob Ahern and Gerard Lyons at ‘The Four & Livestock Australia (MLA) and Queensland Department Mile’. ___________ Correspondence: B. Christensen, The Leucaena Network, PO Box *Poster presented at the International Leucaena Conference, 240, Theodore, Queensland 4719, Australia. 1‒3 November 2018, Brisbane, Queensland, Australia. Email: admin@leucaena.net Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 332 B. Christensen 4. Fully fence leucaena paddocks to avoid the unlikely risk of stock spreading ripe seed. 5. Graze or cut leucaena to keep it within the reach of animals and minimize seed set. 6. Chemically manage leucaena escapees with Access® (currently the only registered herbicide for use on leucaena). 7. Establish and manage vigorous grass in the inter-rows to: a. provide competition to minimize establishment of volunteer leucaena seedlings; b. minimize the risk of seed being transported Figure 3. Leucaena irrigated under centre pivot at Theodore, during heavy rain; Central Queensland. c. productively utilize fixed nitrogen the system produces; and The Code of Practice d. maintain ground cover and prevent soil erosion. 8. Maintain the practice of: The key message of The Leucaena Code of Practice for a. regularly monitoring creeks and major producers is to plant leucaena ONLY if you intend to watercourses to detect any escaped leucaena manage it and are prepared to accept responsibility to seedlings and plants; and control leucaena that establishes outside the planted area b. controlling all plants detected adjacent to on your property, including watercourses. property boundaries on creek banks and other Producers are advised that this can be achieved by adjoining areas where cattle do not normally have adopting the following practices: access, and on public roadsides (after first 1. Do not plant leucaena in areas where rivers, creeks obtaining a permit from Main Roads Department and flood channels can disperse seed pods/seed. If or Shire Council). leucaena becomes a restricted or regulated plant 9. Comply with local laws (weed declarations etc.) and under a Wild Rivers declaration, growers must assist Local Government agencies to identify any comply with the relevant Wild Rivers Code. escaped leucaena so that action can be taken to 2. Keep leucaena at least 20 m away from external fence control it. lines. 10. Promote the responsible management of leucaena in 3. Maintain a buffer strip of strong grass pasture accordance with this Code. between leucaena plantings and creeks or boundary 11. Keep abreast of best-practice developments in the fences. management of leucaena. (Accepted 22 February 2019 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):333–335 333 DOI: 10.17138/TGFT(7)333-335 ILC2018 Poster and Producer paper* Evaluating leucaena in timbered northern basalt country in Queensland, Australia Evaluando leucaena bajo cobertura arbórea en el norte de Queensland, Australia JOE ROLFE1, MARK KEATING2, CRAIG LEMIN1, BERNIE ENGLISH1, ROBERT CAIRD1, EMMA BLACK3, LINDSEY PERRY4, GREG BROWN5, TOM & CHRISTINE SAUNDERS6 AND DARCY & LYNDA O’BRIEN7 1Queensland Department of Agriculture and Fisheries, Mareeba, QLD, Australia. daf.qld.gov.au 2Formerly Queensland Department of Agriculture and Fisheries, Mareeba, QLD, Australia. daf.qld.gov.au 3Queensland Department of Agriculture and Fisheries, South Johnstone, QLD, Australia. daf.qld.gov.au 4Queensland Department of Agriculture and Fisheries, Cloncurry, QLD, Australia. daf.qld.gov.au 5Tolga, QLD, Australia 6Whitewater Station, Mt Surprise, QLD, Australia 7The Brook, Charters Towers, QLD, Australia Keywords: Grazing, Queensland Gulf Country, tree legumes, Wondergraze. Introduction Materials and Methods Introduction and successful establishment of leucaena Whitewater Station (Leucaena leucocephela) has the potential to increase annual liveweight gains of grazing cattle and improve A Producer Demonstration Site was established at enterprise gross margins by up to 25% in a sustainable Whitewater Station (18.1467º S, 144.3183º E; 600‒700 way (Buck et al. 2019). However, there has been low masl), which covers an area of 25,200 ha. The land types adoption of leucaena in northern Queensland (<2,500 ha on Whitewater are broadly red duplex-based soils; red established) despite well-established protocols in central basalt (60%), granite (35%) and black basalt (5%) soils. and southern Queensland. Impediments to leucaena Average annual long-term rainfall is 796 mm with 70% adoption include: reduced productivity following psyllid falling between December and March. The enterprise infestations; high establishment costs; lack of existing supplies Brahman cross (Bos indicus × Bos taurus) and cleared sites; and low producer confidence and Droughtmaster (stabilized Bos indicus × Bos taurus) cattle experience with plant establishment in the region. The to live export (280‒350 kg) and local store markets. fertile, free-draining basalt soils in northern Queensland Typical stocking rates are one Adult Equivalent (AE = 450 (~2 M ha between Charters Towers and Mt. Garnet) are kg dry animal at maintenance) to 7 ha with opportunistic well suited to leucaena production. Two demonstration rotational spelling. sites were established to evaluate the establishment, Site. A 33 ha lightly timbered site was selected on well productivity and performance of leucaena on lightly drained, red basalt soils with high P and low S concentrations. timbered basalt sites located at Whitewater and The Predominant pasture species included naturalized Indian Brook Stations in far north Queensland. An additional couch (Bothriochloa pertusa), Stylosanthes spp. and native aim of these demonstrations was to increase producer grasses. Strips were ripped in November 2013, nominally at awareness and adoption of leucaena-based pastures in the 10 m spacings, following a ‘line of least resistance’ through region. the standing trees and rock outcrops to prepare a seedbed. ___________ Correspondence: Joe Rolfe, Queensland Department of Agriculture *Poster presented at the International Leucaena Conference, and Fisheries, Mareeba, QLD 4880, Australia. 1‒3 November 2018, Brisbane, Queensland, Australia. Email: joe.rolfe@daf.qld.gov.au Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 334 J. Rolfe, M. Keating, C. Lemin, B. English, R. Caird, E. Black, L. Perry, G. Brown, T. & C. Saunders and D. & L. O’Brien Due to insufficient rainfall in the 2013/14 wet season, The Brook planting was deferred until the following wet season (2014/15). Wondergraze leucaena was planted (1.5 kg/ha) in The breeding, backgrounding (molasses production single rows in January 2015. Gran-am® (24% S, 20% N) feeding), agistment and trading enterprises on The Brook fertilizer was applied (30 kg/ha) either side of the row at the cover 21,000 ha and include a mix of red (85%) and black same time. All rows were sprayed with glyphosate herbicide (15%) basalt country. Average annual rainfall is 650 mm. (570 g/L; 2 L/ha) before planting and Verdict® (haloxyfop at The Brahman breeder herd on The Brook is crossed with 520 g/L) was applied at 100 mL/ha after sowing for grass Brangus (Brahman × Angus), Angus and Brahman bulls. control. Low rainfall following sowing resulted in a failed Infrastructure development is advanced with 62 paddocks establishment and planting strips were re-ripped in October and greatest grazing distances to water of approximately 2015. Re-planting occurred in January 2016 at a seeding rate 2 km. Salt and sulphur supplements are fed in the wet of 1.5 kg/ha but no additional fertilizer was applied. A mix of season, while a water medication unit delivers dry season glyphosate and Spinnaker® (active ingredient 700 g/kg urea supplementation to animals in some paddocks. A walk- imazetaphyr applied at 140 g/ha) was applied immediately over weighing unit is also used to monitor cattle weight gains after planting. Granulated sulphur (90% S) was applied in and assist with the trading enterprise and marketing September 2016 (50 kg/ha) and again in August 2017 (140 decisions. kg/ha). Adequate follow-up rainfall ensured there was Site. A 400 ha site on The Brook was deep-ripped using a favorable leucaena emergence and establishment (Figure 1). bulldozer in October 2017. In order to establish a legume- grass pasture in the wide inter-rows, seed of Seca stylo (Stylosanthes scabra at 1 kg/ha) and granulated sulphur (90% S at 60 kg/ha) were aerially applied across the whole paddock in November 2017. Following early season storm rains, strips were sprayed with glyphosate (570 g/L; 2 L/ha) in December 2017. Both Redlands (350 ha) and Wondergraze (50 ha) were planted (twin rows 1.8 m apart; 12‒15 m inter-row spacing) at a seeding rate of 1 kg/ha during January and February 2018 using a custom-made planter (Figure 3). A glyphosate (1.5 L/ha) and Vezir® (700 g/kg imazethapyr; 140 g/ha) mix was applied at planting for knockdown and pre-emergent weed control. Figure 1. Tom Saunders (Whitewater) inspecting young leucaena seedlings (top) in February 2016 and mature leucaena in the standing timber in 2018 (bottom). Grazing. Grazing of the site (leucaena) began during the 2017 dry season (July‒October). Initial grazing was at a Figure 3. Single-pass twin-row planting (with custom-built heavy stocking rate and cattle were removed prior to the planter) and herbicide application at The Brook. 2017/18 wet season. No weight gain data were recorded. The paddock was spelled up to July 2018, when 18 Results weaner steers (average 228 kg) were introduced for comparison with similar animals (average 231 kg) Whitewater grazing on pastures in a neighboring paddock. Stocking rates between the 2 paddocks were identical and cattle in At Whitewater, leucaena was successfully established both paddocks had access to a weaner supplement. over approximately 75% of the site by the end of the Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena in northern basalt country in Queensland 335 2016/17 wet season. Average daily weight gain of steers Discussion and Conclusions grazing pasture only at Whitewater during the 2018 dry season was 0.06 kg/d versus a gain of 0.48 kg/hd/d for Results at the Whitewater site have demonstrated that the steers in the leucaena paddock at the same stocking rate challenges of establishing leucaena in lightly timbered but (Table 1). A corn-based weaner supplement was fed in fertile basalt country can be overcome. This indicates that it both paddocks (10.5 MJ ME/kg; crude protein 14%; crude is feasible to establish leucaena on the large areas of basalt protein equivalent 11%); intakes (as fed) in the leucaena country in north Queensland. While paddocks were not paddock were 0.57 kg/hd/d compared with 0.93 kg/hd/d replicated, the marked differences in initial animal in the pasture paddock. Without the daily intakes of productivity data confirm the anticipated benefits of leucaena weaner supplement some weight loss would have been over existing native pastures even at relatively low levels in expected in weaners in the pasture paddock. the diet. Further work is required to determine the long-term productivity and economics of leucaena in such situations, Table 1. Comparison of live weights (LW; kg) and average including overcoming practical constraints imposed by the daily gains (ADG; kg/hd/d ± s.d.) over 63 dry season days of standing timber (e.g. competition for moisture and on-going weaner steers grazing either pasture only or leucaena + pasture fertilizer requirements in fully mature leucaena). at Whitewater station. In contrast with the results at Whitewater, the poor leucaena establishment at The Brook highlights the inherent LW LW ADG risks with establishing leucaena in northern environments. 20.07.2018 21.09.2018 Particular issues are the need for adequate seedbed Pasture 231 ±19 237 ±20 0.06 ±0.08 preparation and planting techniques and the problems only Leucaena 228 ±20 258 ±21 0.48 ±0.13 associated with keeping leucaena seedlings free from grazing + pasture during establishment in the north, where cleared areas are relatively few compared with central Queensland and there is The Brook a long dry period coupled with variable soils and rainfall. At The Brook, observations will continue to determine how well Planting conditions, particularly in January 2018, were hot the legumes persist and produce in a range of seasons and and dry and establishment success was limited with leucaena how this is reflected in terms of animal production. sparsely established across 300 ha. However the establishment of Seca stylo has been very encouraging. Acknowledgments Controlling access by kangaroos, deer and cattle to the The Whitewater project was partially funded by MLA as a leucaena paddocks was challenging. Overall seedbed Producer Demonstration Site. The Brook planting was co- preparation was not ideal and planting depth could have been funded by MLA and the Producer Initiated Fast Track reduced. Planting such a large area when embarking on a program. leucaena development program is problematic. In future plantings the O’Brien family would plant a smaller area and References implement a pest management plan, combined with complete repair of electric fence and traditional fencing, to limit access Buck SR; Rolfe JW; Lemin CD; English BH. 2019. Adoption, by marsupials, deer and cattle. An additional 100 ha of profitability and future of leucaena feeding systems in Redlands will be planted in the 2018/19 wet season using a Australia. Tropical Grasslands-Forrajes Tropicales 7:303– similar twin-row configuration and inter-row spacing. 314. doi: 10.17138/TGFT(7)303-314 (Accepted 23 December 2018 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):336–338 336 DOI: 10.17138/TGFT(7)336-338 ILC2018 Poster and Producer paper* Pioneer of leucaena development in Queensland, Australia: Nyanda, Carnarvon Gorge Pionero en el desarrollo de leucaena en Queensland, Australia: Nyanda, Carnarvon Gorge JOHN & DEL O'NEILL Nyanda Station, Rewan, QLD 4702, Australia Keywords: Establishment, management, tree legumes. Background and history of leucaena production We (John and Del O’Neill; Figure 1) first planted leucaena (Leucaena leucocephala) on our property ‘Nyanda’ in 1982 and these original paddocks still look green and lush after summer rain, with no sign of nutrient deficiency (Figure 2). We were part of a small group of original innovative graziers supported by Department of Primary Industries extension champion John Wildin. The group were the pioneers of commercial use of leucaena in Australia. Figure 2. 30-year-old leucaena, recovered from burning, now Nyanda is 15,200 ha, much of it mountainous. A total under-grazed and about to be frosted. of 600 ha on the more arable areas was planted with variety Peru. We would plant more if we had suitable Environment areas and intend to plant 20 ha of Redlands when seed becomes available. Some graziers in the Carnarvon area The Carnarvon location is excellent for leucaena with have planted Tarramba but it is not popular as it grows too deep soils, especially on the creek flats, where soil tall. To date we have not tried Wondergraze. phosphorus levels can reach 120 ppm. No leucaena has ever been fertilized on Nyanda. Frost is an issue and most paddocks are frosted every year. The degree of damage varies from leaf fall to stems being frosted to ground level, which has a major influence on the amount of available leucaena in spring. With severe frosting it can take a few months for a significant amount of regrowth to occur from the base of the plants. After 25‒30 years of frosting the leucaena plantations are still productive. Establishment and management We have observed that, to ensure establishment success, it is best to plant into fully cultivated paddocks in December- Figure 1. John and Del O'Neill with Max Shelton in 2017. January. ___________ Correspondence: John O’Neill, Nyanda Station, Rewan Rd, Rewan, *Poster presented at the International Leucaena Conference, QLD 4702, Australia. Email: nyanda1@antmail.com.au 1‒3 November 2018, Brisbane, Queensland, Australia. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena pioneer in Queensland 337 We tried planting directly into a grass paddock but the the first 15 years after planting, infestations of psyllids resulting leucaena growth and production were very poor. were severe every year, but recently infestations have been We plant leucaena in single rows only and inter-row greatly reduced owing to a succession of dry years. cultivate during the first summer. Initial plantings were at a row spacing of 4.5 m but later we increased the spacing to Weed leucaena 6 m. We spray a 1 m wide band of a mixture of herbicides [Basagran® (bentazone) and Fusilade® (fluazifop-P) at 2 kg Leucaena plants have spread between rows but we control a.i./ha for each herbicide], directly over young leucaena them by blade-ploughing. Some spread has also occurred rows for control of broad-leaf weeds and grass. This was to lane ways, as well as to Consuelo creek, where green effective on both emerging leucaena, where young weeds panic and leucaena protect creek banks. were killed, and on older leucaena (up to 75 cm tall), where weeds were not fully controlled, but their growth was Animal management and marketing arrested, allowing the leucaena plants to gain advantage in uptake of water. If leucaena plants are sufficiently advanced Plants in most paddocks have been frosted every year, but at the end of autumn, we feed the area off before winter as not over-grazed, and are still productive after 25 years leaf will be lost from frosting anyway. (Figure 3). We recognize the need to spell leucaena each year to allow recovery after heavy grazing or frosting. One paddock has deteriorated dramatically as a result Height management of overstocking at 2.5 animals per ha almost all year I, John, consider that leucaena should be cut while still at a combined with annual frosting. Plants in this paddock manageable height when the contractor’s machines can have woody bases with leafy regrowth coming out like a travel through at a reasonable speed. These contractors bonsai plant, but have lost vigor (Figure 4). were not around when we started and the leucaena became virtually out of control in some areas. In those cases, excess height of leucaena was controlled by driving along the rows with a bulldozer every 5 years. A neighbor of ours pulled a heavy scrub chain over some of his leucaena paddocks to reduce the height and in subsequent years followed up with mechanical cutting. Burning Some paddocks have been burnt accidently with varying outcomes. While most recovered quickly, one paddock, which carried a large amount of tall frosted grass and lots of old dead branches, received a very hot burn. The bases of the leucaena plants were burnt to 2‒3 cm below ground Figure 3. Well-grazed 30-year-old leucaena. level and plants took about 3 years to recover. Inter-row grasses For the initial plantings we planted green panic and buffel between leucaena rows. However, competition from the highly vigorous growth of leucaena and the heavy stocking rates employed have weakened the grass. Psyllids In some years infestations of the leucaena psyllid (Heteropsylla cubana) are quite bad and their sticky secretions reduce the palatability of the plant to cattle. For Figure 4. Heavily-grazed 30-year-old ‘bonsai’ leucaena. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 338 J. & D. O’Neill We use a rotational grazing system (one block having leucaena, when it is often frosted and therefore not so 5 cells and others 2 cells), which gives all paddocks 6‒8 much leucaena leaf is available. weeks of recovery. The original leucaena is still in good condition, but perhaps not quite as good as in the Target markets beginning. Water points are fenced off and spear traps are used to muster cattle. We target the ‘Jap Ox’ market with steers at 30‒33 months old, usually ranging from 340 to 360 kg dressed Toxicity weight, often closer to 360 kg, with 70% of animals having a maximum of 2 permanent incisor teeth. Leucaena toxicity was an issue initially but the frequency However, in 2017 and 2018, average dressed weight was of occurrence seems to have lessened. In the past, when 375–380 kg with 70% of animals showing milk or steers first grazed leucaena in December, they would all 2 permanent teeth. Some are down-graded at the abattoir lose hair from their tail and sheath, prior to being sent for for having more than the optimal subcutaneous fat cover slaughter. At that time, there was only a small area of on the rump (P8 fat maximum 22 mm). leucaena, which was quite lush. However, no cases of hair For the past 9 years, we have developed a small-scale loss have been seen since cattle were first inoculated with Droughtmaster stud (a stabilized Brahman × Shorthorn Synergistes jonesii in 1984-85. cross). While leucaena pastures can be used for all classes On more than one occasion young maiden heifers were of cattle, we consider that leucaena is best used for joined with bulls while grazing on fresh leucaena and fattening, although we put our weaner heifers onto conception rates were very low. A neighbor also leucaena before moving them onto grass prior to joining. experienced low calving percentages in heifers. Our current policy is to grow heifers on leucaena after Concluding statement weaning followed by grazing in a grass paddock for 6 months prior to joining. We keep bulls on leucaena right Leucaena has been a major factor in the viability of up to mating with no observed negative effects on their Nyanda and we would be delighted to have more areas fertility. Calves are weaned in May and grazed on suitable to plant more leucaena! (Accepted 1 April 2019 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):339–341 339 DOI: 10.17138/TGFT(7)339-341 ILC2018 Poster and Producer paper* Leucaena production in the Fitzroy River catchment, central Queensland, Australia Producción de leucaena en la cuenca del río Fitzroy, Queensland central, Australia PAUL & CLARE HARRIS Sunland Cattle Company Pty. Ltd., Rockhampton, QLD, Australia. sunlandcattleco.com.au Keywords: Cattle, establishment, grazing, liveweight gain, management, tree legumes, Wagyu. Background planted a small area of leucaena on a 900 ha property north of Rockhampton. While the leucaena established My wife and I own Sunland Cattle Co. Pty. Ltd., which and grew, it was not impressive owing to the infertile soil operates 2 central Queensland cattle properties, Old type and frost incidence. Bombandy and Ten Mile Stations. Old Bombandy is situated on the Isaac River near Middlemount (11,308 ha) and Ten Mile is positioned on the Mackenzie River near Duaringa (6,868 ha). We are first-generation primary producers operating a Wagyu Stud and selling many fullblood Wagyu bulls. From our Wagyu breeding operation, we sell steers (400–450 kg) to feedlots and retain females to upgrade our herd (more than 10,000 fullblood and purebred Wagyu). We carry out numerous embryo transfer (over 1,150 embryos this year) and artificial insemination programs each year. Currently, we have a surplus of Wagyu females as we have reached our required breeding number. Another property was leased recently to increase cattle numbers. Our aim is to continue to improve our herd genetics. An area of 6,000 ha of Figure 1. Leucaena at Sunland Cattle Co. leucaena spread over the 2 properties has proven to be an integral part of our beef business (Figure 1). In the early 1990s we planted cultivar Tarramba leucaena at Old Bombandy and later at Ten Mile using Our leucaena history seed treated with boiling water to improve germination (today all seed is mechanically scarified). A good plant We became interested in leucaena in the early 1960s when population was achieved but the seedlings gradually died we observed cattle near our home town of Rockhampton off and disappeared. This was due to wireworms and false doing well on leucaena that was growing wild. We wireworms chewing the roots underground, while other collected some seeds, planted them and this developed insects attacked the seedlings above the ground. into a small patch. While the stand grew thickly but not Establishment success improved after a row of navy beans very tall, a couple of isolated leucaena plants grew to (white Phaseolus vulgaris) was planted each side of the about 8 m high. Our observations had shown that plants leucaena rows as a decoy crop for the insects and worms. growing wild along roadways or creeks usually do not Beetle baits are now routinely used at planting to kill reach that height, potentially due to high plant populations worms and insects that attack the small plants. Initially, and competition for moisture. By the late 1970s we had we ploughed strips in the paddocks and planted single ___________ Correspondence: P. Harris, Sunland Cattle Company Pty. Ltd., PO *Poster presented at the International Leucaena Conference, Box 1411, Rockhampton, QLD 4700, Australia. 1‒3 November 2018, Brisbane, Queensland, Australia. Email: paulharris@sunlandcattleco.com.au Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 340 P. & C. Harris rows of leucaena, but subsequently switched to ploughing Leucaena in our business whole paddocks and planting leucaena in twin rows (1 m apart; 6 m inter-row). While we are satisfied with this We aim to manage the leucaena by matching cattle inter-row spacing, opinions vary on the optimal spacing numbers to carrying capacity of paddocks to consume the for varying conditions. In a dry climate, we consider leucaena rather than having to use mulching to control it. wider inter-row spacing is preferable so leucaena can In very good seasons around 1,300 steers from Old obtain sufficient moisture for maximum growth. Bombandy (in addition to the current cattle grazing the leucaena paddocks) have been introduced on to Ten Mile Establishment ‘best bets’ to manage leucaena height. When significant areas of our leucaena reached heights and stem diameters above those Overall, while planting leucaena in summer with good soil which private contractors could successfully mulch to the moisture has proved successful, with good seed germination, desired height with their machines, we designed and heat wave conditions at this time can burn off seedlings. employed engineers to build a large mulcher (Figure 3) to Spring planting is preferred so seedlings can grow and reduce the height to what we desired. This has been quite become established, being less affected by summer heat successful. We also purchased a small leucaena cutter to waves. Frost is common in the area and a couple of bad frosts mulch our smaller leucaena. Our current aim is to manage followed one planting in early July. We expected the the height of leucaena so cattle can access all of it and planting to be a failure, but fortunately the seeds had not prevent it from seeding. My philosophy is: ‘When cattle germinated before the frosts and warmer weather which eat the leucaena, we make money but when we have to followed resulted in good germination and establishment. mulch it, it costs us money’. If our cattle eat 100% of the We spray with Spinnaker® (700 g/kg imazethapyr) as per leucaena produced during times of high growth and grow label across a 3 m strip (leucaena and 1 m either side of the well, it can eliminate mulching. grass) when planting to suppress grass growth in the leucaena strips and treat seed with chemical to deter insects. Grass is not sown in the inter-row spacing as grass seed germinates naturally when the effects of Spinnaker® decline. The grass varieties grown are: buffel (Cenchrus ciliaris), green panic (Megathyrsus maximus; syn. Panicum maximum var. trichoglume), Bambatsi panic (Panicum coloratum var. makarikariense), Urochloa (Urochloa mosambicensis) and Rhodes Grass (Chloris gayana) (Figure 2). To determine if soil phosphorus levels were adequate, we applied superphosphate fertilizer at 250 kg/ha to a couple of rows and observed no production benefit in the leucaena. Soil tests have been conducted since then, which revealed that there was considerable variation in fertility between Figure 3. The mulcher we designed and had built for mulching paddocks, and fertilizer will be applied to more paddocks to Tarramba. test possible further production responses. At Old Bombandy an area of about 5,000 ha is fenced and managed using ‘cell grazing’ (high intensity-short duration grazing) including the leucaena paddocks. We consider that cell grazing is an effective management strategy which provides a rest or spell for pastures so that lush feed is available when cattle next return to a paddock. We plan to extend this management system to more areas on both properties. Leucaena has boosted cattle weight gains and increased the carrying capacity of our operation. Wagyu cattle assessment and price rely on a high marbling score and weight; our Wagyu cattle grown on leucaena are sought after for these characteristics. All categories of cattle graze leucaena pastures on our properties but sale cattle have Figure 2. Grass inter-row between the leucaena rows. priority to enable earlier turnoff. We graze our steers on Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena in the Fitzroy River catchment 341 leucaena pastures to reach target weights quickly and reduce Limitations age of turnoff (Figure 4). Similarly, young heifers graze leucaena pastures to reach 300 kg (the desired mating There is potential on our property to more than double the weight) so they reach puberty and breed early, preventing area of leucaena planted. However, we are limited by our them being carried over to the following breeding season. capacity to manage it in accordance with The Leucaena Cull females, bulls, cows and calves all benefit from time Network Code of Practice. While we possess the mulching spent grazing leucaena. equipment required to prevent the plant from flowering and setting seed, it is preferable to control it through grazing pressure rather than mulching. We have experienced 2 psyllid (Heteropsylla cubana) infestations since we began growing leucaena. Aerial spraying was considered to control the infestations but after a period of cold weather the insects disappeared. Climatic conditions on our properties are normally sufficiently dry to prevent psyllid infestations being a significant problem. Future leucaena development options We are satisfied with the economics of planting and grazing leucaena as it is profitable and greatly increases our carrying capacity and rate of turnoff. While it has been planted on our Figure 4. Wagyu cattle at Sunland Cattle Co. property for only a limited time, we intend to plant more at Old Bombandy Station. With increased cattle numbers and The results achieved have been impressive and appropriate machines we can control the plants effectively leucaena is now an integral part of our production system. and intend to plant more areas to leucaena. Almost all of our Initially, some cattle on leucaena did display symptoms of leucaena is cultivar Tarramba as this was the latest and best mimosine toxicity but after dosing animals with the variety at the time of planting. However, Tarramba has a ‘rumen bug’ (Synergistes jonesii) the problem was tendency to grow tall, which presents management issues, so resolved and cattle grew well. Since then we have dosed future plantings will involve a different cultivar. We have the only a small number of cattle with rumen inoculum. soils, climate, equipment, staff and the know-how to Subsequent tests have shown that cattle do carry establish much more leucaena but will not proceed until we mimosine-degrading organisms in their rumens naturally are confident we can contain the plant. Leucaena is essential but we continue to sample animals periodically to confirm for our operation and we are interested only in new that this situation continues. properties that have suitable soils for leucaena production. (Accepted 6 December 2018 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):342–344 342 DOI: 10.17138/TGFT(7)342-344 ILC2018 Poster and Producer paper* Leucaena in southern Queensland, Australia Leucaena en el sur de Queensland, Australia CRAIG ANTONIO ‘Borambil’, Milmerran, QLD, Australia Keywords: Animal performance, establishment, fattening, management, tree legumes. Background Trialing leucaena Our 4 properties are located 250 km west of Brisbane and Our leucaena journey began in 2003. Although many 100 km north of the Queensland-New South Wales pasture advisors deemed leucaena unsuitable in southern border. Soil types range from undulating fertile Brigalow Queensland, due to the impact of cold temperatures and clay soils to infertile sandy forest loams of ironbark, pine frost on growth and overall profitability, we made the and box country. Average annual rainfall is 625 mm, decision to trial the plant. Owing to the favorable spread between winter and summer with the heavier falls elevation (higher) and north-facing slopes on some of in summer. our country, we were confident of being able to establish Three of the properties are used for breeding Angus and grow leucaena for 6‒7 months of the year. As land cattle, while steer and cull heifer progeny are carried on prices increased, we decided that improving what we the remaining property until they reach their respective already had was preferable to purchasing more land. The target weights. Our target markets include feeder steers first planting in March 2003 (twin rows at 30 cm apart; for feedlots (400‒500 kg live weight), cull heifers for 4 m inter-row spacing) was with a broad-acre planter slaughter (500 kg live weight) and milk and two tooth with a narrow point and press wheel following directly cattle (260–280 kg dressed) aimed at either Meat behind. Establishment was only partially successful with Standards Australia (MSA) Grassfed or Angus grids approximately 2 plants/m of row growing to around 50 (depending on price), if the season allows. cm high by late May, when the first frosts for the year were experienced. Good rainfall (100–150 mm; 95th Cropping history percentile for that time of year) and mild temperatures (25–35 C) in late August and early September (late- Historically this region was composed of small farms for winter and early spring) provided good growing dairying and over time, most landholders diversified into conditions. The leucaena plants competed successfully dryland (grain) cropping and small-scale beef production with weeds and poor soil fertility and we were surprised enterprises. As with all farming areas in Australia, with how they recovered and finally flourished. limited and unreliable rainfall plus marginal soil fertility for cropping, continuous cropping has resulted in Refining leucaena establishment practice rundown of soil nutrients. Subsequently, there has been a progressive shift from cropping to beef production on With the promising performance of leucaena in this sown pastures with this nutritional rundown. Sown initial trial, we decided to continue with further sowings, pasture establishment primarily involved tropical grasses but sought additional information for refining our as attempts to establish legumes were generally un- establishment techniques. After attending a University successful due to poor soils, variable rainfall and of Queensland leucaena course I proceeded to build a unsuitable legume varieties. Sown grass pastures would planter, which proved to be a bad decision. After a remain productive for 2‒3 years then slowly decline couple of unsuccessful attempted plantings with that leaving the land devoid of ground cover and susceptible planter, we eventually purchased a twin-disc vacuum to erosion and weeds. planter for $12,000. Acquiring this purpose-built planter ___________ Correspondence: Craig Antonio, ´Borambil´, Milmerran, QLD 4357, *Poster presented at the International Leucaena Conference, Australia. Email: craigandlex@bigpond.com 1‒3 November 2018, Brisbane, Queensland, Australia. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena in southern Queensland 343 coupled with meticulous seedbed preparation and phosphorus, sulphur and zinc. MAP Starter (22% P, 10% serious post-planting weed control regimes were all key N) is applied pre-planting at 25 kg/ha across the total area, factors in achieving successful leucaena establishment or closer to 100 kg/ha if applied directly under the twin on our properties. Problems with weed control are rows of leucaena. We plant a mixture of leucaena common and from experience we found that higher varieties, i.e. Cunningham, Wondergraze and Tarramba, application rates of Spinnaker® (Imazethapyr 700 g/kg) with no specific preference, although adjacent to creeks are required on lighter soils (160 g/ha) in comparison where frosts are more prevalent, Tarramba is well suited. with clay soils (120 g/ha). Spinnaker® is applied in a Infestations of psyllids have been a problem on only rare single pass pre-planting. Depending on the weeds in a occasions and we do not spray to control psyllids. given season, we spray across the leucaena strip (approx. 3 m) and cultivate the remainder (sometimes across the whole paddock; Figure 1). We use Verdict™ (520 g/L haloxyfop) to control grass in leucaena, and, if weed problems persist, we use conventional inter-row tillage. On our property, land that was used previously to grow grain does not require seedbed preparation but intensive cultivation is required on land developed from tree regrowth. Figure 2. Cattle grazing winter oats. Figure 1. Leucaena rows at Borambil. Our best recipe for success is September planting (twin rows 1 m apart; at 8 m inter-row centers spacing) with effective weed control and fertilizer application. Seeding rate is a seed every 3 cm, which is the equivalent of 1.4 kg/ha. If soil moisture is adequate and well distributed down the profile and adequate summer rainfall is Figure 3. Leucaena with fully established inter-row pasture. received, we can graze leucaena in the following March (6 months after sowing). By sowing grass or forage oats Paddock and business benefits for winter feed (Figure 2) in the inter-row space, the leucaena-grass pasture can be in full production by As our land use changed we noticed how our country October-November with adequate spring rain (Figure 3). improved. Since soil nutrient rundown had occurred Good soil fertility is paramount for leucaena prior to planting leucaena, cattle preferentially grazed establishment and productivity. Fertilizer must be added the leucaena, leaving grass on areas after the available to our soils as soil phosphorus levels range from 8 to 20 leucaena had been eaten. We were able to subdivide mg/kg (Colwell). Our fertilizer regime focuses on paddocks into 40‒60 ha blocks and to implement Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 344 C. Antonio rotational grazing, which maintained good ground cover time spent grazing in the rotations. The nature of the in each paddock after the edible leucaena had been eaten. leucaena taproot has provided a much-needed This reduced runoff and rates of soil loss, while improvement in our ability to manage drought and target improving soil organic matter and nutrient status. appropriate markets, as well as predict daily weight gains Our establishment costs are lower than those for most even over long dry spells. growers as we own the necessary machinery and our paddocks are already cleared. We have cleared regrowth Summary in some paddocks to plant leucaena, which increased costs. Regrowth control must be thorough prior to To date we have established approximately 400 ha of planting, as controlling suckers is problematic in leucaena. Unfortunately efforts to expand leucaena established leucaena stands. Depending on variety, plantings across our fattening block have been hampered leucaena seed can cost $10–50/kg and, taking into account by a series of below-average summer rainfall years. costs of using our own machinery, we estimate that Future development plans include expansion of leucaena establishment costs are $200–250/ha on country plantings across both our fattening block (500–600 ha) previously farmed and greater than $300/ha on country and breeder country (approx. 1,000 ha). Planting where regrowth must be cleared first. leucaena on the breeder country will increase protein Leucaena-grass pastures will increase annual live- supply and assist with drought mitigation. We propose weight gains and carrying capacities over those on grass to use wider row spacings (12 m) on this area. In the pastures but are profitable only if correct establishment future we intend to trial inter-row winter forage cropping procedures are followed. With occasional planting (Figure 2) to improve paddock productivity over the failures taken into account, establishment lags of 2–3 winter-spring period and extend production to 12 months years are common, which results in significant of the year. ‘opportunity costs’ or income foregone. While there are many challenges with leucaena Our best daily gain results from this leucaena program establishment and productivity in the southern regions of were 1.6 kg/hd/d (2 month period) averaging out over the Queensland, the positive outcomes for our business far summer (7 months) at 1.3 and 1.4 kg/hd/d (heifers and outweigh the negatives. Once the ‘upfront’ costs are steers, respectively). Gains at this level could have been covered, leucaena pasture systems are relatively cost-free maintained for longer if the stocking rate was decreased. (with the exception of fertilizer applications in some We focus on kg live weight produced per ha and have circumstances). When we look at the methane emissions achieved up to 250 kg/ha in the best years. Our stocking reduction potential, carbon sequestration attributes and rates have almost doubled in the leucaena paddocks (to 1 drought mitigation qualities (which in the future may beast/ha). In conventional grass paddocks, the long-term provide additional income opportunities), as well as carrying capacity deteriorates over time and there is more increased carrying capacity and profitability, the decision longevity in leucaena as it is a perennial legume and to plant leucaena on our property is not one that I regret reduces grazing pressure in the inter-row pastures. It and I cannot envisage any change to that situation in the enables us to look after the grass better due to decreased future. (Accepted 17 December 2018 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):345–347 345 DOI: 10.17138/TGFT(7)345-347 ILC2018 Poster and Producer paper* Irrigated leucaena in the Burdekin catchment produces high quality cattle for premium markets Leucaena bajo riego en la cuenca del río Burdekin, norte de Queensland, produce carne para mercados premium DON HEATLEY Byrne Valley, Home Hill, QLD, Australia Keywords: Grazing, irrigation, north Queensland, tree legumes. Background We are fifth-generation, north Queensland cattle producers. Between our 2 stations, Byrne Valley and Rangemore, we run around 8,000 head of cattle. The business focuses on producing beef for highly specialized markets in Korea, Japan and the USA. Byrne Valley (12,000 ha) is 90 km south of Townsville on the lower Burdekin River and is operated as a back- grounding and leucaena finishing property. Rangemore (15,000 ha) is operated primarily as a breeding property with a 2,000 head Bos indicus-based breeding herd. In recent years, we have been infusing Angus genetics and aim to stabilize the herd at approximately 40% Angus content. Leucaena in our program Figure 1. Peter Heatley (left) and Bruce Mayne (right) inspecting the leucaena. Initially we were hesitant about planting leucaena, due to a fear of farming, as we were cattle producers not farmers. We planted our first leucaena at Byrne Valley in 1998, after several visits to Kununurra on the Ord River in Western Australia. We currently have 500 ha of leucaena under irrigation in an industrial-type farming operation (Figure 1). Paddocks have been laser-levelled (2,000 m long × 400 m wide with a 2 m fall). We plant leucaena on double raised- bed rows with 4 m inter-row spacing and deep inter-rows to speed water flow. Two centrifugal pumps deliver 150 L/sec to flood irrigate the pastures, with every second inter-row being watered on an alternating basis with a fast flush of water (Figure 2). Water and power usage have been halved using this method down a V-shaped inter-row compared with slow watering that soaks into a level inter-row. Leucaena is fertilized every 4‒5 years with 500 kg/ha of Figure 2. Alternately irrigated inter-rows in the leucaena at superphosphate (8% P, 11% S). Byrne Valley. ___________ Correspondence: D. Heatley, Byrne Valley, Home Hill, QLD 4806, *Poster presented at the International Leucaena Conference, Australia. Email: byrnevalley@bigpond.com 1‒3 November 2018, Brisbane, Queensland, Australia. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 346 D. Heatley Key learnings with an irrigated system: weights of 630‒670 kg at 24–26 months of age with carcass  Never plant prior to a wet season hoping for a free weights of 340‒360 kg (54% dressing percentage). In rainfall advantage as failed seed strike due to heavy rain association with Prof. Luciano Gonzalez at the University of events is a major loss. Sydney, we have introduced automatic walk-over weighing  Initially lack of understanding about the importance of units and automated drafting of finished cattle. With our depth of planting (planting too deep) led to electronic identification system for animals, this has allowed establishment failures after heavy rainfall events. These us to monitor performance of all animals (identifying both issues with seed strike are significantly reduced if high and low performers) and has enabled us to monitor the planting occurs after the wet season. economics of the overall production system.  It is impossible to mechanically control weeds in a wet paddock.  Control of grass and weeds is limited to a maximum of 2 applications of herbicide.  Leucaena in an irrigated paddock is more important than roughage in the same paddock.  Maintain a consistent watering pattern. It is false economy to start late, hoping to save water. Psyllid infestations can be significant in this region but the new psyllid-resistant variety Redlands should help minimize this problem. Height management of leucaena is also a major issue in an irrigated system. We plan to address this in the future by decreasing our inter-row width from 4 m to 2 m, which will enable us to increase the stocking rate and allow cattle to have access to grazing height leucaena no matter where they are standing at all times. Figure 3. Crossbred steers (24 months) eating Rhodes grass hay and molasses in association with the leucaena. Animal production Future operations We operate a rotational grazing system and move cattle to a new paddock every 14 days, removing all cattle from the We are currently developing an additional 700 ha for leucaena during the wet season. Average daily gain (ADG) planting with leucaena and the planned decrease in inter-row ranges between 0.9 and 1.4 kg/hd/d and by continued spacing from 4 m to 2 m, to increase stocking rate and reduce emphasis on genetic improvement we aim to increase these maintenance trimming costs, as well as to change from figures over time. Molasses is fed at 2 kg/hd/d to supply fluming (Figure 4) to multiple fixed outlets in the additional energy and we cut and bale (600 kg square bales) underground pipelines. Callide Rhodes grass hay on the property as a source of roughage (Figure 3). The hay is provided on an ad lib basis and consumed by cattle at approximately 5 kg/hd/d. We bale approximately 700 tonnes hay per year and recoup about 30% of the production costs by selling surplus hay. By using this system, we have halved age of turnoff compared with cattle grazing a grass pasture-only diet and have the flexibility of marketing cattle at a time of year when prices are favorable, as opposed to having to sell as seasonal conditions decline when the majority of producers are also selling. Irrigated leucaena has eliminated many risks and variables in our steer production system, largely removing the influence of seasonal conditions, and we can calculate guaranteed kilos of beef which equals greater income and profit security. We sell direct to meat processors who supply Figure 4. The current fluming irrigation system in operation at markets in Japan, Korea and USA and our steers reach live Byrne Valley. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Irrigated leucaena in north Queensland 347 Our goal is to have every male weaner grazing leucaena (to capitalize on superior feed conversion efficiency) and the as soon as possible after weaning. We are considering the economics of cubing or pelleting leucaena to supplement cost-benefits of both selling slightly lighter younger steers breeders. (Accepted 14 December 2018 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):348–349 348 DOI: 10.17138/TGFT(7)348-349 ILC2018 Poster and Producer paper* Leucaena production in central Queensland, Australia Producción de leucaena en Queensland central, Australia BILLY-JOE REA, AMELIA REA AND WALLY REA Falcon Downs, Lotus Creek, QLD, Australia Keywords: Animal performance, buffel grass, cultivars, establishment, Wondergraze, tree legumes. Overview straddling the leucaena twin rows at planting as per manufacturer’s instructions to control weeds, and We operate a 100% Wagyu business across 3 central Spinnaker™ and Verdict™ (520 g/L haloxyfop) are Queensland cattle properties: Falcon Downs, Yaraandoo applied post planting (timing dependent on weed growth). and Overflow, with an additional block at Glen Innes, New South Wales to grow out cattle prior to entering feedlots. The operation includes breeding, growing and feedlot finishing. Finished cattle are contract-slaughtered and marketed both domestically and overseas. The central Queensland properties are made up of largely cracking-clay Brigalow soils with box flats, which are highly suitable for leucaena. Dryland leucaena was established on Falcon Downs and Yaraandoo beginning in 2009. It took 5 years to plant 3,700 ha and we aim to plant 400–800 ha/year on all suitable land. There is some irrigated leucaena on Overflow (Table 1) which we also aim to expand. Table 1. Areas of Falcon Downs, Yaraandoo and Overflow properties and areas planted with leucaena. Figure 1. Six-row leucaena planter used across our operation. Property Total area (ha) Leucaena (ha) Dryland Irrigated The first grazing occurs about 12 months after Falcon Downs 3,645 3,645 planting. The main variety used in our operation has been Yaraandoo 3,645 243 Wondergraze, with some areas of Cunningham, Tarramba Overflow 8,100 1,112 182 and Redlands. Wondergraze appears to be the most palatable. We harvest about 1‒2 tonnes per year of Establishment Wondergraze seed for home use, clean the seed and scarify it before planting. Usually, 2-year-old stands of The entire paddock is cross-cultivated before planting. Wondergraze are the best for seed production but some- Initially, we used a single-row planter, before moving to a times first-year crop is also used. Inter-row pasture is twin-row planter. Now we use a much larger unit to plant buffel grass (Cenchrus ciliaris; Figure 2). No fertilizer 6 rows at a time, 3 sets of twin rows (1 m apart) with 6 m has been used to date on our leucaena-buffel pasture. spacing between centers (Figure 1). In the 6 m inter-row While 182 ha of irrigated leucaena is currently established space, we leave the center 2 m untreated to allow pasture at Overflow, we aim to expand this area to 2,000 ha. to re-establish. Spinnaker™ (700 g/L imazethapyr) and Trickle tape irrigation is used, with irrigation lines being Round Up™ (glyphosate) are applied on a 2 m wide strip fed by an electric bore and a solar bore. We aim to plant ___________ Correspondence: Billy-Joe Rea, Falcon Downs Station, Lotus *Poster presented at the International Leucaena Conference, Creek, QLD 4705, Australia. Email: falcon.downs@bigpond.com 1‒3 November 2018, Brisbane, Queensland, Australia. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena production in central Queensland, Australia 349 all of the newly purchased property Yaraandoo to Animal performance leucaena eventually. Leucaena has doubled the carrying capacity across our operation to about 1 adult beast to 2‒3 ha. The leucaena rumen bug (Synergistes jonesii) was introduced to our herd by purchasing cattle from an existing leucaena producer. We run approximately 4,500 cows and progeny under a rotational grazing system. The system we have adopted in Queensland is to grow out weaners to over 300 kg LW, and transport them to Glen Innes, where they gain another 100 kg LW on improved temperate pastures, before entering feedlots at over 400 kg LW for a 400-day finishing period. We aim for a final carcass weight of 420‒450 kg with high marbling. In addition we sell 100‒200 (depending on demand) Wagyu bulls each year. Leucaena has made a significant contribution to our successful business model and we expect this impact to Figure 2. Typical leucaena-buffel grass pasture. increase as we expand the area under the legume. (Accepted 06 December 2018 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):350–352 350 DOI: 10.17138/TGFT(7)350-352 ILC2018 Poster and Producer paper* Ingelara Grazing: Leucaena in speargrass country, Queensland, Australia Ingelara Grazing: Leucaena en pasturas nativas de Heteropogon contortus en Queensland central, Australia STUART & SHEREE OGG ‘Ingelara’, Rolleston, QLD, Australia Keywords: Animal performance, establishment, fattening, management, oats, tree legumes. Background adapted our existing machinery for use in planting leucaena and performing cultivation to control these costs. Leucaena Ingelara is a 7,280 ha property located 20 km from the was planted straight into the oat stubble from a previous crop Carnarvon National Park in central Queensland. It was using a seeding rate of 2.5 kg/ha at a depth of 2–3 cm. We originally operated as a breeding block, selling store cattle, consider the optimal sowing time is October–December but as there was no capacity to fatten. The establishment of have planted as late as the end of February. For weed control leucaena on Ingelara has allowed us to change to a breeding at the planting stage, we used Fusilade® (250 g/kg fluazifop- and fattening operation. Ingelara receives an average annual p-butyl; for grasses) and Basagran® (broad-leaf) on the strip rainfall of 750 mm and consists of loamy creek flats, leading rows and, once leucaena was established, have not needed to into narrow-leaf ironbark ridges. Cunningham and Peru control weeds. We estimate establishment costs of cultivars of leucaena have been established across 445 ha, approximately $200–250/ha, on land that was already and the oldest plantings are 30 years old. Forage oats is also cultivated for oats. grown on 240 ha. Our crossbred steers (combinations of Simmental, Brahman and Angus; Figure 1) are sold to Teys Abattoir, Biloela and we target premium EU and PCAS markets. By grazing leucaena, these steers reach market weights at under 24 months of age, averaging 300 kg dressed weight and are graded into Meat Standards Australia (MSA) boning groups 1 to 8 (Figure 1). Leucaena in speargrass country In the early 1990s we started clearing creek flats to grow forage crops including oats, lablab and Sugargraze forage sorghum. When we observed the benefits achieved on the neighboring property ‘Nyanda’ from planting leucaena, we Figure 1. Crossbred steer on Ingelara in 2018. realized that black speargrass (Heteropogon contortus) flats could be transformed into sustainable, prime fattening Leucaena management country. We started planting leucaena at 6–8 m inter-row spacing on our farming country. Aside from some weed Leucaena is managed in a 3-stage cycle at Ingelara. pressure, leucaena established easily on our soil types, particularly the deep (>6 m) well drained loamy creek flats. Stage 1 Paddock production losses (opportunity cost losses) were kept to a minimum during the establishment stage as forage We manage leucaena under a rotational grazing system oats was grown between rows in the establishment year. We using a 4-paddock system and a 200-day cattle rotation. ___________ Correspondence: S. Ogg, ‘Ingelara’, Rolleston, QLD 4702, *Poster presented at the International Leucaena Conference, Australia. Email: ingelara@antmail.com.au 1‒3 November 2018, Brisbane, Queensland, Australia. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Ingelara Grazing: Leucaena in speargrass 351 In the wet season, when leucaena is green (Figure 2), our steers run in one mob and are moved when the paddock has been optimally grazed and needs a rest. Approximately 450 steers, with a start weight of 300–350 kg, enter the system in November (depending on rainfall) and achieve average daily liveweight gains (ADG) of 1–1.2 kg/head or 200–220 kg/head over the 200-day grazing period. Forage oats are also planted in other paddocks for grazing during the winter. Figure 4. Oats paddock to which steers are moved after frosting of leucaena (Stage 2). Stage 3 The leucaena is spelled in spring for 6–8 weeks to allow adequate regrowth (Figure 5). Rumen inoculum (Synergistes jonesii) was introduced on one occasion approximately 10 years ago. We could not detect any noticeable benefit from the drenching and consider Figure 2. Leucaena has regrown and is ready for the first that these organisms must be widespread across our grazing rotation. environment. Stage 2 With the onset of frosts (Figure 3) around June, our cattle are moved from the leucaena pasture to the oats paddocks (Figure 4) at weights ranging from 500 to 550 kg. Steers graze on the oats until they reach target slaughter live weights of 560–600 kg. Ninety percent of leucaena plants are frosted to ground level in winter (July) which controls leucaena height. For leucaena which is not frosted, height is controlled by cutting or pushing with a bulldozer. Weaner steers are moved on a rotation through frosted leucaena paddocks and graze on inter-row Callide Rhodes grass until spring. Figure 5. Leucaena re-shooting in spring following frosting Figure 3. Frosted leucaena (Stage 2). and a 6–8 week spell (Stage 3). Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 352 S. & S. Ogg Limitations and challenges and where soil types were appropriate, establishment has always been successful. One of the biggest challenges is controlling the spread of leucaena from designated paddocks into creeks and Summary waterways. We have a poisoning program in place to control leucaena spread into riparian areas and manage We intend to expand areas sown to leucaena at Ingelara our grazing of leucaena stands to minimize seed-set. when seed of the Redlands variety becomes readily The most significant leucaena production losses are available. New plantings will be into cultivated strips and associated with leaf loss from psyllid attack in wet and we will not be ploughing whole paddocks. The aim is to use leucaena on areas that are inundated during the wet humid years. The last psyllid outbreak was in the mid- season, and on some hilly country to reduce the risk of 2000s and we estimate that weight gains were halved. erosion. The use of leucaena has transformed our business Aerial spraying of psyllids with Rogor (dimethoate) is the from one of breeding and selling store cattle, into only effective control method and suppresses psyllids for breeding and selling top quality prime finished cattle. The only 2–3 weeks. We consider it is undesirable to spray our value of our land has increased from $3,700 to paddocks regularly, although there is no withholding $12,000/ha. Growing leucaena is the single most period before slaughter on this chemical. important element in our system. In the future, we intend Establishment failures have been experienced only in to trial slashing leucaena to ground level in an endeavor wet areas or on clay soils (box or sandalwood country) to improve leaf volume in our non-frosted areas. (Accepted 16 December 2018 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):353–358 353 DOI: 10.17138/TGFT(7)353-358 ILC2018 Keynote Paper* Leucaena intensive silvopastoral system: The CIPAV experience in Colombia Sistema silvopastoril intensivo con leucaena: La experiencia de CIPAV en Colombia ALVARO ZAPATA CADAVID1, CARLOS MEJÍA1, LUIS SOLARTE1, JUAN F. SUÁREZ2, CARLOS H. MOLINA3, ENRIQUE J. MOLINA3, FERNANDO URIBE1, ENRIQUE MURGUEITIO1, CÉSAR NAVARRO4, JULIÁN CHARÁ1 AND LEONARDO MANZANO1 1Centro para la Investigación en Sistemas Sostenibles de Producción Agropecuaria, Cali, Colombia. cipav.org.co 2Hacienda Lucerna, Bugalagrande, Valle del Cauca, Colombia 3Reserva Natural El Hatico, El Cerrito, Valle del Cauca, Colombia 4Hacienda El Chaco, Piedras, Tolima, Colombia Abstract The Center for Research in Sustainable Systems of Agricultural Production (CIPAV) has worked since 1991 on the establishment and management of intensive silvopastoral systems (ISPS) involving leucaena (Leucaena leucocephala). The initial work was carried out in the Valle del Cauca department, and afterwards in other regions of Colombia and abroad. This document presents the main characteristics of the work carried out on various farms in the tropical lowlands of Colombia, located between 0 and 1,300 masl, with 22‒28 °C average annual temperature. The leucaena ISPS integrate this species with grasses, mainly Cynodon plectostachyus, C. nlemfuensis and Megathyrsus maximus, although other species have been used, such as Dichanthium annulatum, Urochloa humidicola (including cv. Llanero, formerly classified as Brachiaria dictyoneura) and Urochloa hybrids. Leucaena is planted at densities in excess of 10,000 plants per ha, in rows 1 to 1.5 m apart with 0.3‒ 0.6 m between plants within rows. These ISPS are grazed by Bos indicus and B. taurus cattle and their crosses, in beef, dairy (tropical lowlands) and dual-purpose systems. The proper management of an ISPS requires a rotational grazing strategy with each paddock grazed for 1‒3 days (ideally 1 day) followed by a 42‒46 day rest period. Stocking rates are 2.5‒4.5 head/ha. Average daily gains by beef cattle are 650‒800 g/head (2‒3 kg/ha/d). Production in dairy systems (tropical lowlands) fluctuates between 5 and 14 L milk/cow/d, depending on genetic makeup, season (dry or rainy) and supplementation, with up to 17,000 L milk/ha/yr. Information from various farms that use ISPS is presented including main ecological characteristics and animal performance. Keywords: Beef production, dairy production, dual-purpose production, establishment, management, stocking rate, tree legumes. Resumen El Centro para la Investigación en Sistemas Sostenibles de Producción Agropecuaria (CIPAV) ha trabajado desde 1991 en el establecimiento y manejo del sistema silvopastoril intensivo (SSPi) con leucaena (Leucaena leucocephala). El trabajo inicial se llevó a cabo en el Departamento del Valle del Cauca y posteriormente en otras regiones de Colombia y en el exterior. Este documento presenta las principales características del trabajo realizado en varias fincas del trópico bajo en Colombia, situadas entre 0 y 1,300 msnm, con temperatura promedio anual de 22‒28 °C. El SSPi con leucaena integra esta especie con gramíneas, principalmente Cynodon plectostachyus, C. nlemfuensis y Megathyrsus maximus, aunque otras especies han sido utilizadas, tales como Dichanthium annulatum, Urochloa humidicola (incluyendo el cv. Llanero, anteriormente clasificado como Brachiaria dictyoneura) e híbridos de Urochloa. La leucaena se establece en densidades superiores a 10.000 plantas por ha, ___________ Correspondence: Álvaro Zapata Cadavid, Centro para la Investigación *Keynote paper presented at the International Leucaena en Sistemas Sostenibles de Producción Agropecuaria (CIPAV), Cra. Conference, 1‒3 November 2018, Brisbane, Queensland, Australia. 25 # 6-62, Cali, Colombia. Email: alvarozapatacadavid@gmail.com Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 354 A. Zapata Cadavid et al. en surcos separados entre 1 y 1.5 m, con distancias entre plantas de 0.3‒0.6 m. Estos SSPi son pastoreados por ganado Bos indicus y B. taurus y sus cruces, en sistemas de producción de carne, leche (en trópico bajo) y doble propósito. El manejo adecuado de los SSPi requiere una estrategia de pastoreo rotacional con un período de pastoreo de cada potrero de 1‒3 días (idealmente 1) seguido de un período de descanso de 42‒46 días. Las cargas animal son 2.5‒4.5 animales/ha. Aumentos de peso diario de ganado de carne son 650‒800 g/animal (2‒3 kg/ha/día). La producción en sistemas lecheras (trópico bajo) varía entre 5 y 14 L de leche/vaca/día, según raza y genética, época del año (seca o lluvias) y suplementación, obteniéndose hasta 17,000 L de leche/ha/año. Se presenta información de varias fincas que usan SSPi, incluyendo sus principales características ecológicas y datos de producción animal. Palabras clave: Carga animal, establecimiento, ganado de doble propósito, manejo, producción de carne, producción de leche. Introduction main 2 valleys (Cauca and Magdalena Rivers) located amid the 3 Andean mountain ranges at elevations of 200‒ Since 1991 the CIPAV Foundation has worked on the 1,300 masl, in ecosystems originally supporting dry or establishment of Intensive Silvopastoral Systems (ISPS) wet tropical forest. incorporating leucaena (Leucaena leucocephala) and grasses, following preliminary research carried out by Systems of plantation CIAT and CENICAFE (Echeverri et al. 1987; Suárez et al. 1987). The initial work by CIPAV was carried out in Colombian leucaena ISPS have been planted in different the Valle del Cauca department. Subsequently, work was ways, briefly explained below according to availability of performed on the Hacienda El Chaco (Tolima labor and machinery, cost and topographical conditions. department), then beginning of 2002 in the Quindío The main features of the systems in Colombia are: department and since 2005 in other regions of Colombia ● Leucaena is planted at high density (>10,000 (Ramírez 1997; Molina et al. 2001; Espinel et al. 2004; shrubs/ha) in a single-row configuration with 1‒1.7 m Zapata Cadavid and Silva 2010, 2016; Murgueitio et al. between rows, and 0.3‒1.0 m between plants within 2016) and abroad (Zapata Cadavid et al. 2010; Solorio- rows, to give leucaena densities of 10,000‒20,000 Sánchez and Flores-Estrada 2011; Alves-Cangussu et al. shrubs/ha. 2012; Mahecha et al. 2012a). The system and the ● Leucaena is planted in combination with improved particular characteristics of the work carried out on grasses, mainly Cynodon plectostachyus, C. nlemfuensis various farms in different regions are described below. and Megathyrsus maximus (cvv. Tanzania, Mombasa, The CIPAV work with leucaena in Colombia and other Colonial and Massai), although other species have been countries has focused mainly on very high leucaena used, e.g. Dichanthium annulatum, Urochloa densities (above 10,000 shrubs per ha) in association with humidicola (including cv. Llanero, formerly classified as various tropical grasses under cattle grazing with Brachiaria dictyoneura) and Urochloa (formerly rotational grazing systems. These systems are called Brachiaria) hybrids. Intensive Silvopastoral Systems, different from other ● Before planting, leucaena seeds are scarified and silvopastoral arrays in which grasses are associated with inoculated with specific rhizobium at 50 g peat lower tree densities or leucaena is used as a fodder bank. powder/kg seed. ● Improved grasses are established just after leucaena ISPS in Colombia where leucaena has been planted planting or up to 45 days later. ● After planting, weed control is carried out using In Colombia leucaena ISPS have been planted in several chemicals, mechanical control, manual weeding or a geographical regions, between 3°30' N and 10°58' N, at combination of these operations (Uribe et al. 2011). elevations up to 1,300 masl, with average temperatures ● Leucaena toxicity has not been a limitation and ranging from 22 to 26 °C, and an average annual rainfall animal inoculation with rumen bacteria (Synergistes range between 700 and 2,500 mm, in areas which jonesii) is not practiced. originally were tropical forest (ranging from dry to humid tropical forest). Manual planting of nursery seedlings The farms, where leucaena has been planted in Colombia, are located in the Caribe region (0‒200 masl), This system has been used mainly in the central coffee including areas of low (Dry Caribe) and higher (Wet production area of the country, in the Andean foothills Caribe) precipitation, and in the Andean region in the (Espinel et al. 2004; Zapata Cadavid and Silva 2010, 2016). Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Experiences with leucaena ISPS in Colombia 355 In this case, seedlings are produced in a nursery for Management and utilization subsequent transplanting into the field. Plastic bags, such as those normally used for coffee seedlings (13 cm × 23 Leucaena is first grazed about 5‒7 months after planting, cm), are utilized. Good soil, preferably mixed with some when the plants are about 1.8 m tall. chicken or cattle manure, is used and 3 or 4 seeds are Recommended management of the leucaena ISPS deposited in each bag. The nursery phase lasts 6‒8 weeks, requires that the plots be divided into several paddocks, during which the plants reach a height of 25‒40 cm. thus allowing a rotational grazing system to be An advantage of this system is that it reduces implemented with: establishment risks because seedlings have reached an ● Grazing not exceeding 5 days — preferably 1 day acceptable height and stage of development before only; and transplanting. This ensures seedlings have a greater ● Rest periods of 45‒50 days. capacity to withstand unfavorable weather conditions and Applying these 2 strategies means that each cycle it facilitates the control of weeds, while the establishment requires a minimum of 9 paddocks and preferably more time for a field can be reduced by as much as 2 months than 15. To reduce establishment costs, plots are divided compared with direct seeding. Disadvantages are the with electric fencing, although permanent fencing or a nursery cost, which can be very high (10,000 or more combination of permanent fencing and mobile electric seedlings are required per hectare) for farmers with little wires is often used. experience in this type of activity, plus high labor costs In Colombia leucaena trees are normally pruned for transplanting the seedlings to the field. every 6‒12 months. The higher frequency is employed in the Caribe region where solar radiation is high and Direct planting with mechanical soil preparation leucaena grows very quickly during the rainy season. Trees are pruned at 1‒1.2 m from ground level with a Planting following mechanical land preparation is carried machete. out in situations where the topography (flat or of moderate Mimosine toxicity has not been observed to be a slope) allows this method to be implemented and where problem for cattle in Colombia so inoculation with rumen machinery is available (areas with a tradition of bacteria is not carried out. mechanized agriculture like the Caribe region). After land preparation, leucaena seed is planted either Animal performance with machinery or manually, in single rows 1.5‒1.7 m apart and with about 20 seeds/m of row. All seeds that In Colombia, leucaena is grazed by both dairy and beef germinate and establish are allowed to remain, so plant cattle, although dual-purpose cattle are most common. densities in excess of 20,000 shrubs per ha can be Both Bos taurus and B. indicus cattle are used, as well as obtained (Zapata Cadavid and Silva 2010, 2016; their crosses, but usually not 100% B. taurus, as in Murgueitio et al. 2016). Colombia 100% Bos taurus dairy or beef cattle are raised at elevations above 2,000 masl, which are unsuitable for Direct planting with manual soil preparation leucaena ISPS. Stocking rates in Colombia range from 2.5 to 4.5 adult In some cases leucaena has been seeded into plots by hand equivalents (AE; 450 kg dry animal)/ha. In the Caribe without mechanical preparation but using herbicides to region, where the dry season lasts for 4‒5 months, stocking eliminate the plant cover. A common layout has been single rates must be adjusted seasonally, i.e. 4‒6 AE/ha during the rows at 1‒1.5 m spacing with 50‒70 cm between planting rainy season and 2‒3 AE/ha during the dry season. sites within rows and 4 or 5 leucaena seeds per site. Animal performance and general characteristics of some farms, on which CIPAV has worked for several Grass establishment years, are presented in Table 1. Grasses have been planted either immediately after leucaena Beef production or about 45 days later (in order to allow leucaena to reach 30‒45 cm height). In the former case, rapid growth of the Hacienda El Chaco is devoted to dairy production but in grass can outstrip the growth of leucaena and compete for 2010 an experiment was carried out to investigate light, nutrients and water, thereby affecting development of fattening of young steers in the leucaena systems leucaena. Planting grasses about 45 days after leucaena (Mahecha et al. 2011; 2012a, 2012b). The results of this seeds are sown is the most commonly used system now. experiment are presented in Table 2. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 356 A. Zapata Cadavid et al. Table 1. Location, system characteristics and animal performance of some farms on which CIPAV has worked over a number of years. Farm, location Geographical conditions, leucaena ISPS Livestock breed composition and productive parameters characteristics Hacienda 1,000 masl; 1,400 mm rainfall/year (AAR); 24 Dual-purpose Lucerna breed2 (national breed); 142 Lucerna1, °C. Tropical dry forest; leucaena first established milking cows producing 10.7 L milk/cow/d and 17,000 Bugalagrande, in 1991, currently 49 ha, with C. plectostachyus L/ha/yr; stocking rate 4.3 cows/ha; calving interval 390 Valle del Cauca and M. maximus (cvv. Mombasa and Tanzania). days. El Hatico1, 1,000 masl; 750 mm AAR; 24 °C. Tropical dry Dual-purpose Lucerna breed; 220 milking cows El Cerrito, forest; leucaena first established in 1992, producing 10 L/cow/d and 15,000 L/ha/yr; stocking rate Valle del Cauca currently 64 ha, with C. plectostachyus and 4.3 cows/ha; milking cows fed 3.5 kg/d of an energy M. maximus (cvv. Mombasa and Tanzania). supplement (rice and wheat byproducts); calving interval 395 days. Hacienda 605 masl; 1,200 mm AAR. Tropical dry forest; Tropical lowland specialized dairy. Around 75% Bos El Chaco, leucaena first established in 1992, currently 42 taurus × 25% B. indicus cows; 70 milking cows Piedras, Tolima ha, with C. plectostachyus. producing 13 L/cow/d; lactation length 296 days; stocking rate 3.5 cows/ha; calving interval 380 days. Hacienda 1,300 masl; 1,800 mm AAR. Leucaena first 50–75% B. taurus × 25–50% B. indicus cows; 183 Asturias, planted in 2002 using seedlings, 1 m between milking cows producing 13 L/cow/d; stocking rate 4 La Tebaida, rows and 1 m between plants within rows with cows/ha; milking cows fed 2.7 kg concentrate/d. Quindío C. plectostachyus and M. maximus. Hacienda El 724 mm AAR. Caribe region; dry tropical forest; Steers 180–250 kg achieving liveweight gains of 524 Porvenir, San leucaena first established in 2006, currently 110 g/d; stocking rate 2.33 AE/ha. Diego, Cesar ha (60 ha associated with rows of Eucalyptus tereticornis and 50 ha with native trees). 1Lucerna and El Hatico farms have international organic certification and include livestock and sugar cane production. 2The Lucerna breed is a Colombian 100% B. taurus breed developed in Hacienda Lucerna as a product of a crossbreeding program started in 1937 with Holstein, Red Milking Shorthorn and Hartón del Valle (a red Criollo breed in the region, descended from cattle brought by Spanish conquerors about 500 years ago). Table 2. Fattening of steers in the leucaena ISPS of Hacienda Problems and constraints El Chaco1 (Mahecha et al. 2012a; 2012b). Cost of establishment LWG Stocking LWG (g/animal/d) rate (AE/ha) (kg/ha/yr) High cost of establishment has been a major constraint for Leucaena Group 1 896 3.5 1,145 scaling-up the area under the leucaena intensive Leucaena Group 2 811 3.5 1,036 silvopastoral system in Colombia and several factors 1Performance of steers was evaluated over a period of 8.8 contribute to these high costs. Difficult topography or lack months. Final weight was 451 kg (average). of available machinery means some farmers use manual LWG = liveweight gain; AE = adult equivalent. labor and this increases the costs of land preparation, planting and all subsequent activities required. Even where Leucaena and cow reproductive performance machinery is used, the machinery plus operating costs are usually high. Cost of establishment is about US $1,000 per Data from more than 20 years, hundreds of cows and ha, and to this must be added the infrastructure for intensive different farms show calving intervals for cows grazing rotational grazing (paddock divisions, electric fences and a leucaena that are considerably lower than those recorded system for permanent supply of water), if these have to be in Colombia for outstanding dual-purpose and specialized constructed. dairy farms (456 and 458 days, respectively, the national averages being 664‒700 days; Gómez 2013). For Proper management of grazing and rest periods example, calving rates recorded in the farms Lucerna, El Hatico and El Chaco are 390, 395 and 380 days, In rotational grazing systems, ranchers traditionally allow respectively (Table 1). a rest period of about 30 days for their grass-only pastures Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Experiences with leucaena ISPS in Colombia 357 and many find it difficult to understand or accept that a el Valle del Cauca, Colombia. Pasturas Tropicales 9(3):25– system which requires a 42‒50 day rest period can be 29. bit.ly/2YVHKP0 more productive than a set-stocked area, and must be Espinel R; Valencia LM; Uribe F; Molina CH; Molina EJ; managed accordingly. It has been observed that a rest Murgueitio E; Galindo W; Mejía CE; Zapata Cadavid A; Molina JP; Giraldo J. 2004. Sistemas silvopastoriles, period shorter than 42 days does not allow leucaena to establecimiento y manejo. Fundación CIPAV, Cali, recover properly and plants begin to progressively Colombia. weaken, which can lead to the death of plants and the Gómez M. 2013. Costos e indicadores de la productividad en la collapse of the whole system. ganadería colombiana. Federación Colombiana de Ganaderos, Bogotá, Colombia. bit.ly/33qIXNA Overgrazing Mahecha L; Murgueitio MM; Angulo Arizala J; Olivera Ángel M; Zapata Cadavid A; Cuartas CA; Naranjo JF; Murgueitio Although stocking rates achieved on ISPS are Restrepo E. 2011. Desempeño animal y características de la significantly higher than those under traditional grass- canal de dos grupos raciales de bovinos doble propósito only grazing (≥3 vs. ≤1 AE/ha), farmers often tend to pastoreando en Sistemas Silvopastoriles Intensivos. Resumen. Revista Colombiana de Ciencias Pecuarias increase the stocking rate beyond the capacity of the 24(3):470. bit.ly/2yRvjVN leucaena silvopastoral system they have established, and Mahecha L; Corral G; Murgueitio MM; Sánchez C; Angulo J; a progressive and steady process of leucaena weakening Olivera M; Solorio B; Zapata Cadavid A; Cuartas CA; and death begins. Fine-tuning of the management has Naranjo JF; Rodríguez-Muela C; Ramírez JA; Mejía A; proved difficult to achieve on many farms, and long-term Flores MX; Murgueitio E. 2012a. SSPi producen elevada and good-quality technical assistance is required. cantidad de carne de alta calidad en Colombia y México. Carta Fedegan 129. Federación Colombiana de Ganaderos, Leucaena is not invasive Bogotá, Colombia. p. 60–71. bit.ly/2OQFxk5 Mahecha L; Murgueitio MM; Angulo J; Olivera M; Zapata A; CIPAV has worked with leucaena for more than 25 years, Cuartas CA; Naranjo JF; Murgueitio E. 2012b. Ceba de bovinos doble propósito pastoreando en sistemas not only in Colombia but also in other countries like Brazil, silvopastoriles intensivos. Memoria IV Congreso Internacional Nicaragua (Zapata Cadavid et al. 2010) and Mexico sobre Sistemas Silvopastoriles Intensivos, Michoacán, (Mahecha et al. 2012a). No cases of leucaena weediness Morelia, México, 21–23 March 2012. p. 143–151. have been observed (Calle et al. 2011). While leucaena is Molina CH; Molina CH Jr; Molina EJ; Molina JP; Navas A. invasive in disturbed areas like degraded lands or roadsides, 2001. Advances in the implementation of high tree-density it has not been observed to invade undisturbed ecosystems. silvopastoral systems. Proceedings of the Second Congress This observation is in accordance with findings of Costa and on Agroforestry and Livestock Production in Latin Durigan (2010) in Brazil. America, San José, Costa Rica, 2–9 April 2001. Murgueitio E; Galindo WF; Chará J; Uribe F. 2016. References Establecimiento y manejo de sistemas silvopastoriles (Note of the editors: All hyperlinks were verified 11 August 2019.) intensivos con Leucaena. Editorial CIPAV, Cali, Colombia. bit.ly/2Y1b2Yf Alves-Cangussu M; Nacur-Cangussu L; Fernandes-Sousa L; Ramírez H. 1997. Evaluación de dos sistemas silvopastoriles Martins-Mauricio R; Cezar de Macedo A; Rocha e Silveira integrados por Cynodon plectostachyus, Leucaena S; Zapata-Cadavid A. 2012. Experiencias pioneras en leucocephala y Prosopis juliflora. B.Sc. Thesis. Universidad sistemas silvopastoriles intensivos en la Amazonia Oriental Nacional de Colombia, Bogotá, Colombia. brasileña. Memoria IV Congreso Internacional sobre Solorio-Sánchez B; Flores-Estrada MX. 2011. Ganadería Sistemas Silvopastoriles Intensivos, Michoacán, Morelia, sustentable en México. Establecimiento de sistemas Mexico, 21–23 March 2012. p. 59–63. silvopastoriles intensivos para la producción de leche y Calle Z; Murgueitio E; Giraldo C; Ospina SD; Zapata A; carne en el trópico de México. Fundación Produce Molina CH; Molina EJ; Chará JD; Uribe F; Reyes K. 2011. Michoacán, Morelia, México. La leucaena Leucaena leucocephala no se comporta como Suárez S; Rubio J; Franco C; Vera R; Pizarro EA; Amézquita una planta invasora en Colombia. Carta Fedegan 127. MC. 1987. Leucaena leucocephala: Produccción y Federación Colombiana de Ganaderos, Bogotá, Colombia. composición de leche y selección de ecotipos con animales p. 70–87. bit.ly/2yThqGo en pastoreo. Pasturas Tropicales 9(2):11–17. bit.ly/ Costa JNMN da; Durigan G. 2010. Leucaena leucocephala (Lam.) 33qBlup de Wit (Fabaceae): Invasora ou ruderal? Revista Árvore Uribe F; Zuluaga AF; Murgueitio E; Valencia LM; Zapata A; 34:825–833. doi: 10.1590/S0100-67622010000500008 Solarte LH; Cuartas CA; Naranjo JF; Galindo WF; Echeverri JD; Gómez-Carabalí A; Pizarro EA; Franco LH. González JG; Sinisterra JA; Gómez JC; Molina CH; Molina 1987. Evaluación agronómica de accesiones de Leucaena en EJ; Galindo A; Galindo VA; Soto R. 2011. Establecimiento Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 358 A. Zapata Cadavid et al. y manejo de sistemas silvopastoriles. Manual 1. Proyecto Zapata Cadavid A; Silva BE. 2010. Reconversión ganadera y Ganadería Colombiana Sostenible. GEF, Banco Mundial, sistemas silvopastoriles en el Departamento de Risaralda y Fedegan, CIPAV, Fondo Acción, TNC, Bogotá, Colombia. el Eje Cafetero de Colombia. Carder, CIPAV, Cali, goo.gl/DoKn6z Colombia. Zapata Cadavid A; Mejía CE; Bayardo JG. 2010. Reconversión Zapata Cadavid A; Silva BE. 2016. Sistemas silvopastoriles: ganadera y sistemas silvopastoriles en la Vía Láctea de Aspectos teóricos y prácticos. Carder, CIPAV, Cali, Nicaragua. Fondeagro, ORGUT, CIPAV, Matagalpa, Colombia. Nicaragua. (Accepted 29 May 2019 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):359–369 359 DOI: 10.17138/TGFT(7)359-369 ILC2018 Keynote Paper* The inclusion of Leucaena diversifolia in a Colombian beef cattle production system: An economic perspective Leucaena diversifolia en un sistema de producción ganadera en Colombia: Una perspectiva económica KAREN ENCISO, MAURICIO SOTELO, MICHAEL PETERS AND STEFAN BURKART Tropical Forages Program, International Center for Tropical Agriculture (CIAT), Cali, Colombia. ciat.cgiar.org Abstract Despite the great potential of legumes in cattle production, their adoption and use throughout the tropical world remain limited. While this is largely attributed to factors such as limited knowledge or access to credit, lack of information on the viability and profitability of the technology can influence the adoption decision. The objective of this study is to evaluate the profitability of including Leucaena diversifolia, accession ILRI 15551 in a Colombian beef cattle production system. For this purpose, we use data from a grazing experiment comparing a grass-legume association (Brachiaria hybrid cv. Cayman and L. diversifolia) with a grass monoculture (cv. Cayman) in the Valle del Cauca department, both with the purpose of beef production. We use a discounted cash flow model, developed with the simulation software @Risk, which considers inherent risk and uncertainty factors in these types of rural investment projects, under three different pasture degradation scenarios. The results indicate that the inclusion of L. diversifolia is financially profitable and substantially improves the associated risk and performance indicators. Profitability indicators increased in a range of 15‒110%, and the probability of suffering economic losses decreased from 72% to 0%. The results were directly related to the increases in animal productivity (49%) and efficiency resulting from including the legume. This work shows that L. diversifolia has significant potential to increase both animal production and profitability, which is conducive to the sustainable intensification of beef production in grazing systems. Keywords: Grass-legume systems, Monte Carlo simulation, risk analysis, shrub legumes, sustainable intensification. Resumen A pesar del gran potencial de las leguminosas para la producción ganadera, su adopción y uso siguen siendo limitados. Mientras que esto se atribuye en gran medida a factores como el conocimiento limitado o falta de acceso a crédito, también la información faltante sobre la viabilidad y rentabilidad de la tecnología puede influir en la decisión de adopción. Este estudio tiene como objeto evaluar la rentabilidad de la inclusión de Leucaena diversifolia accesión ILRI 15551, en un sistema de producción de ganado de carne, basado en el pasto Brachiaria híbrido cv. Cayman (Cayman), en el Departamento del Valle del Cauca, Colombia. Se usaron datos de un experimento de pastoreo para comparar la asociación Cayman-L. diversifolia con el monocultivo de Cayman. Se aplicó la metodología de flujo de caja libre descontado y un análisis de simulación Monte Carlo con el software de simulación @Risk, con el fin de incluir los factores de riesgo e incertidumbre en las variables identificadas como críticas, bajo tres escenarios de persistencia de las pasturas. Los resultados indican que la inclusión de L. diversifolia es financieramente rentable y permite mejorar sustancialmente todos los indicadores de riesgo y desempeño. Los indicadores de rentabilidad incrementaron en un rango del 15 al 110%, y la probabilidad de obtener pérdidas económicas pasó del 72.1 al 0%. Los resultados estuvieron directamente relacionados con el incremento en la productividad animal (49%) y eficiencia resultantes de la inclusión ___________ Correspondence: Stefan Burkart, International Center for Tropical *Keynote paper presented at the International Leucaena Conference, Agriculture (CIAT), Apartado Aéreo 6713, Cali, Colombia. 1‒3 November 2018, Brisbane, Queensland, Australia. Email: s.burkart@cgiar.org Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 360 K. Enciso, M. Sotelo, M. Peters and S. Burkart de la leguminosa. Este trabajo muestra que L. diversifolia tiene un potencial significativo para aumentar tanto la producción animal como la rentabilidad, lo cual es propicio para la intensificación sostenible de la producción de carne en sistemas bajo pastoreo. Palabras clave: Análisis de riesgo, intensificación sostenible, simulación Monte Carlo, sistemas gramínea-leguminosa. Introduction access to capital (e.g. size of the productive unit, access to credit); lack of knowledge and limited perceived The forage-based cattle sector plays a key role in tropical benefits by the producer (Thomas and Sumberg 1995; food production, food security and poverty alleviation Wortman and Kirungu 2000; Lapar and Ehui 2004); and (Peters et al. 2013; Capstaff and Miller 2018). However, aspects associated with risk aversion and uncertainty along with the benefits, negative consequences on the (Feder 1980; Marra et al. 2003). A key aspect for environment can occur. Globally, it has been estimated that successful adoption of an innovation is personal the sector contributes 14.5% of all anthropogenic sustainability, i.e. adoption will not occur unless the greenhouse gas (GHG) emissions, mainly as methane economic benefits of adopting exceed the costs for (CH4) from the enteric fermentation process (Gerber et al. technological investment (Carey and Zilberman 2002; 2013). In addition, the sector is being associated with Pannell et al. 2006). Although adoption levels of forage problems of land degradation, deforestation, water legumes are still low in the tropics, some successful pollution and depletion, and loss of biodiversity (Steinfeld examples from different continents were reported by et al. 2009). Under this perspective, and in the context of: Shelton et al. (2005), highlighting their profitability and scarce resources; increased global demand for food; and multipurpose benefits to farmers. However, this type of climate change (FAO 2017), governments, NGOs and information is often scarce, making the decision making other organizations have developed strategies to mitigate process difficult for the producer. Therefore, it is the sector’s environmental impacts, increase its efficiency important to perform economic evaluations to generate and improve its productivity. In this regard, improvements information about the viability and profitability of the in animal feeding and sustainable intensification are desired technology. considered to be among the most promising strategies to The objective of this study was to evaluate the date (Gerber et al. 2013; FAO 2017). profitability of including Leucaena diversifolia in a Given this panorama, the inclusion of forage legumes in Colombian cattle production system. For this purpose, we cattle production systems has the potential to achieve the compared a grass-legume association (L. diversifolia in a aforementioned objectives. Firstly, legumes can increase Brachiaria hybrid cv. Cayman pasture) with a grass both yield and nutritional value of the forage, and improve monoculture (Cayman) in the Valle del Cauca the efficiency in converting forage to animal protein department, Colombia, both with the purpose of beef (meat/milk) (Lüscher et al. 2014). Secondly, legumes can production. The methodology is based on a discounted reduce enteric CH4 emissions from ruminants (Harrison et cash flow model, developed with the simulation software al. 2015) and increase the levels of nitrogen (N) in the soil @Risk, and considers the inherent risk and uncertainty through biological N fixation (Dubeux et al. 2017). For factors in these types of rural investment projects. The example, studies show that, when Leucaena leucocephala results provide a mechanism for improving the quality of is sown into grass pasture, CH4 emissions per kg of the decision making process regarding adoption of consumed dry matter can be reduced by 15% (Molina et al. legumes for cattle production systems. 2016) and more than 75 kg N/ha/yr can be fixed (Shelton and Dalzell 2007). Other environmental benefits include: Materials and Methods the improvement of soil fertility and carbon accumulation (Rao et al. 2015); the potential for mitigation of and Data source and study area adaptation to climate change (Schultze-Kraft et al. 2018); and a contribution to rehabilitating degraded pastures The data used in this study were obtained from field (Plazas and Lascano 2006). evaluations of: a) Cayman as a monoculture; and b) a Despite the great potential of tropical legumes in cattle Cayman-L. diversifolia association, carried out by the production, their adoption and use by producers remain Tropical Forages Program at the facilities of the limited (Shelton et al. 2005). Among the limiting factors International Center for Tropical Agriculture (CIAT) in for widespread use are: economic factors that determine Palmira, Valle del Cauca, Colombia. The ecological Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Economics of a Leucaena diversifolia-grass association 361 classification of the study area, according to Holdridge Description of the treatments (1967), corresponds to a pre-montane wet forest (bh-P), located at 1,001 masl, with average temperature, relative The treatments were: T1) Cayman monoculture (100%); humidity and annual precipitation of 23.8 °C, 75% and 1,045 and T2) Cayman-L. diversifolia association (in a mm, respectively and a bimodal rainfall regime (March‒ proportion of 70:30 of DM at the beginning of the trial). April and October‒November). The experiment was Each treatment had an area of 9,900 m2, divided into 3 established on a fertile Mollisol with clayey texture (clay plots of 3,300 m2, under an experimental design of a content between 40 and 60%; Howeler 1986), good randomized complete block. Each plot was divided with drainage, pH (H2O) 7.54, organic matter 4.85%, CEC 16.4 electric fences into 3 sub-plots of 1,100 m2. The animals cmol/kg, P concentration 25 ppm and Ca, Mg and K grazed under a rotational system with 6 days of concentrations 7.87, 6.17 and 0.82 cmol/kg, respectively. occupation and 48 days of rest for each sub-plot. For T2, The pastures were established in August 2013 and until 2,000 L. diversifolia plants/ha had been established and grazing commencement were maintained by cutting at distributed in twin rows separated by a distance of 8 m. 6 week intervals. Grazing was between August 2014 and The twin rows were separated by a distance of 1.5 m, and August 2015, using 10 Colombian half-blood steers (zebu × distance between plants within rows was 1 m. The initial Holstein, zebu × Normande, zebu × Jersey); liveweight stocking rate (SR) for both treatments was 2.3 animal gains were measured monthly. The steers were 12 months units (AU = 450 kg) per hectare and by the end of the old and weighed 210±25 kg (±SD) at the start and 416 ±28 evaluation year SRs were 3.36 AU for T1 and 4.04 AU kg at the end of the evaluation. The data related to the costs for T2. It is important to point out that during the time of were compiled using economic information collected during the evaluation, observations on the selective behavior of the establishment of the trial, and adjusted with the help of the animals showed a high acceptance in the consumption Colombian forage and livestock experts to avoid of the legume. This explains, partly, the high liveweight overestimation for research reasons. The prices were later gains and animal production in T2 (Table 1). Other factors updated to 2018 levels, according to the price bulletins of the contributing to the generally high forage and livestock Colombian Price Information System for the Agricultural production values are high soil fertility and the fact that Sector (SIPSA) and the Colombian Cattle Federation’s the measurements refer to the initial 1‒2 years of this (FEDEGAN) databases. production systems comparison trial. Table 1. Forage dry matter production, nutritional quality and animal response data over 1 year for a Brachiaria hybrid cv. Cayman monoculture (T1) and a Cayman-L. diversifolia association (T2). Parameter Variable T1 T2 (Mean ± SD) CV (%) (Mean ± SD) CV (%) DM production Tonnes DM/ha/yr 22.5 32.2 Nutritional Protein (%) 6.7 8.25 (Cayman) quality 26.7 (L. diversifolia) IVDMD (%) 65.5 64.9 (Cayman) 58.6 (L. diversifolia) Animal Mean stocking rate (AU/ha) 3.36 4.04 response Weight gain (g/hd/d) 440 ± 41 9.3 657 ± 73 11.2 Liveweight production (kg/ha/yr) 723 ± 68 9.3 1,078 ± 1201 11.2 Time to reach sale weight (months)2 18 12 DM = Dry matter; IVDMD = In vitro dry matter digestibility; AU = 450 kg animal. 1Statistically different at P<0.01. 2Period of time required to bring a calf with an average weight of 200 kg to a sale weight of 450 kg. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 362 K. Enciso, M. Sotelo, M. Peters and S. Burkart Economic risk and sensitivity analyses Although it has been shown that L. leucocephala can remain productive for periods longer than 30 years in The economic evaluation is based on a discounted cash flow other regions of the tropics and subtropics (Jones and model for the estimation of financial profitability indicators Bunch 1995; 2000), we decided to maintain a capable of measuring the viability of the 2 treatments. The conservative scenario for T2, given the lack of data and evaluated indicators include the internal rate of return (IRR), information on the persistence of L. diversifolia in the net present value (NPV), cost:benefit ratio (C:B) and specific study area. Additionally, a discount rate of 12%, payback period. The evaluation was made based on the and constant prices and flows for each treatment principles established by Park (2007) for each indicator. In according to the respective release and fattening periods addition, the minimum profitable area required to generate 2 (T1: 18 months; T2: 12 months) were assumed for integral Colombian Basic Salaries (CBS) on a monthly basis constructing the cash flow. during the 10 year evaluation horizon (1 integral CBS = US$ In order to include risk and uncertainty levels in the 469/month in 2018) was estimated as an indicator for variables identified as critical for the model and to smallholder producers, who normally experience strong consider different scenarios, a quantitative risk analysis resource limitations. was carried out by running a Monte Carlo simulation in The model includes a systematic categorization of the the software @Risk (Paladise Corporation). In such a variable costs and the benefits associated with the 2 simulation, random input variables are identified and evaluated treatments. Specifically, the following represented by means of probability distributions, to later categories of costs per hectare were considered: total cost calculate the profitability indicators (outputs of the of establishment; costs of renewal and maintenance of model). This process is repeated numerous times to obtain each treatment; capital opportunity costs during the the probability distributions of these outputs (Park 2007). establishment period for both treatments (T1: 3 months, For this analysis 5,000 simulations were carried out for 3 T2: 8 months); and operational costs (e.g. purchase of pasture persistence scenarios and the following variables animals, animal health, mineral supplementation, labor were randomly combined: liveweight gain/animal/year; costs for permanent and occasional staff). The benefits investment costs; maintenance costs; sale price per kg live derived from beef production in a cattle raising and weight; and purchase price per kg live weight. For the fattening system, according to the animal response 2 price variables, a correlation coefficient of 0.89 was indicators, are presented in Table 1. The evaluation determined. The simulation used a confidence level of horizon for both treatments was 10 years, according to the 95%. Table 2 shows the probability distributions for the lifespan of the grass (Holmann and Estrada 1997). input variables. Table 2. Probability distributions for input variables, parameters and risk factors. Variable Treatment Distribution Parameters Distribution adjustment Randomness p1 p2 p3 Liveweight T1 Pert (a,b,c) 139 161 174 Judgment of the researcher according Interaction between decision (LW) gain to the availability of data and variables (e.g. type of feeding) (kg/hd/yr) T2 Pert (a,b,c) 205 239 268 behavior of the variable according to and non-controlled ones (e.g. literature (Gutiérrez et al. 2009). climatic conditions). Sale price T1 & T2 Lognormal (µ,σ) 1.64 0.33 Based on the best historical data Varies as a result of factors (US$/kg LW)1 adjustment, using the Akaike associated with the supply and Purchase price T1 & T2 Lognormal (µ,σ) 1.36 0.22 information criterion (AIC; Akaike demand of the market. (US$/kg LW)2 1974). Investment T1 Triangular (a,b,c) 586 689 794 This distribution is recommended to Vary depending on the costs (US$/ha) specify situations that involve costs specific place where the T2 Triangular (a,b,c) 941 1,106 1,272 and investments. establishment is made (e.g. the Maintenance T1 Triangular (a,b,c) 134 148 163 amount of tillage and level of costs (US$/ha) T2 Triangular (a,b,c) 102 114 123 fertilizer applied are determined by soil characteristics and rainfall regime) (Rincón and Caicedo 2010). a,b,c: minimum, most probable and maximum value, parameters of the Triangular and Pert distributions. 1Exchange rate used: 1 US$ = 2,800 Colombian Pesos (COP). 2Historical data taken from FEDEGAN (2018). Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Economics of a Leucaena diversifolia-grass association 363 In both treatments, application of maintenance mean value criterion is based on the law of large numbers, fertilizer and pasture renewal were assumed for Year 5 in which states that, if many repetitions of an experiment are T1 and Year 7 in T2, in order to maintain the level of made, the average result will tend toward the expected production during the defined evaluation horizon. value (Park 2007). On the other hand, sensitivity and However, animals can cause physical damage to the scenario analyses were carried out in order to identify legume or grass which can affect production. To include those variables with the strongest effects on the this factor in the model, 3 treatment persistence scenarios profitability indicators within the total set of variables were built. These were determined by considering 3 defined as critical. The variables identified in the previous annual degradation rates that decrease the total forage analyses were studied individually by means of a stress supply and therefore the carrying capacity. The rates were analysis, where the values of the distribution are restricted estimated according to criteria provided by several forage to the 10th percentile, and through which the changes in experts, under the assumption of adequate management in the NPV indicator were identified. terms of fertilizer application, rotation and rest of the pasture, as follows: for T1 at 1% (S1), 3% (S2) and 8% Results (S3); and for T2 at 1% (S4), 3% (S5) and 5% (S6). In T2, the maximum rate of degradation is assumed to be lower The two treatments were compared in terms of their than for T1, given the constant supply of N to the pasture economic performance, considering the uncertainty of contributed by the legume through the process of random variables identified for the estimation of atmospheric N fixation. It should be noted that both the profitability indicators. Table 3 shows the main results simulations and risk indicators do not capture effects associated with the costs and income for each treatment. of extreme (climatic) events or losses due to an The costs of establishing T2 are 60% higher than those for extraordinary incidence of pests and diseases. T1. However, the evidenced animal production indicators As decision criteria, the mean value and the variations for T2 allowed average annual increases per hectare of 66% of the obtained profitability indicators were used, as well in gross income and 119% in net profit, when compared as the probability of success (NPV<0). The use of the with T1. Table 3. Costs and income for fattening steers on Brachiaria hybrid cv. Cayman pasture (T1) and a Cayman-L. diversifolia association (T2). Parameter T 1 T 2 Investment costs Establishment of pasture (US$/ha)1 689 1,107 Pasture renewal (US$/ha)2 211 (Year 5) 153 (Year 7) Electric fence (US$/ha/yr)3 750 752 Purchase of animals (US$/ha/cycle) 1,071 1,253 Operational costs Pasture maintenance costs (US$/ha)4 148 209 Permanent labor (US$/ha/yr)5 623 622 Animal health (US$/ha/yr) 20 22 Supplementation (US$/ha/yr)6 87 86 Gross income (US$/ha/yr) 2,190 3,199 Unit cost of production (US$/kg)7 1.2 1.21 Net income (US$/ha/yr)8 356 695 1For establishment, herbicide application and mechanical soil tillage were carried out. The sowing rate of Cayman was 8 kg/ha with a level of fertilizer of N, P, K, Mg and S of 100, 22, 41.5, 20 and 20 kg/ha, respectively. Two thousand L. diversifolia plants were established per ha. 2Includes maintenance fertilizer, soil 2x plowing and replanting of Cayman at a sowing rate of 2 kg/ha. 3Electric fence for a rotational grazing system. 4Maintenance is carried out every 2 years and includes weed control, fertilizing with half the dose used for establishment (no N fertilizer in T2), and pruning of L. diversifolia. 5Estimated: 2.5 permanent jobs required for every 100 animals in a cattle raising and fattening system (FEDEGAN 2018), and a legal minimum wage in force plus benefits in 2018 of US$ 469/month. 6Supplementation with mineralized salt at a rate of 100 g/hd/d. 7Unit cost of production: dividing total cost of the product by total production. 8Net income: total income (sale price x yield) minus total costs. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 364 K. Enciso, M. Sotelo, M. Peters and S. Burkart The summary of the main financial results of the ha, as well as reducing the payback period from 6 to 4 simulation for both treatments is presented in Table 4. The years. T1 shows a higher NPV variability than T2. results suggest that the inclusion of L. diversifolia is With regard to the probability of finding that the financially profitable and would improve all risk and evaluated treatments were not financially feasible, Figure 1 performance indicators when compared with Cayman as shows the distributions for the NPV indicator, which monoculture. The model shows a positive mean NPV for reflects the amplitude of the variation for the NPV T2 that, according to the pasture degradation scenario, indicator. For T1, the indicator ranges from negative values varies between US$ 1,716 and US$ 2,055, and an internal close to US$ 1,506, to positive values close to US$ 948, rate of return (IRR) to own resources of around 21%. In with 72% probability of obtaining negative values. For T2, addition, the superior productive indicators for T2 allow the inclusion of L. diversifolia shifts the distribution curve reduction in the minimum profitable area required to to the right, reducing the probability of losses to 0%, with generate 2 Colombian basic salaries from 6.54 ha to 3.76 values ranging from -US$ 61 to US$ 4,145. Table 4. Summary of profitability indicators of the simulation model for fattening steers on Brachiaria hybrid cv. Cayman pasture (T1) and a Cayman-L. diversifolia association (T2). Decision Indicator T1 T2 criterion Scenario 1 Scenario 2 Scenario 3 Scenario 4 Scenario 5 Scenario 6 NPV (US$) Mean1 (288) (342) (473) 2,055 1,881 1,716 SD2 447 434 404 697 673 651 CV 1.55 1.26 0.85 0.34 0.36 0.38 CI (95%)3 (1,135)–558 (1,165)–481 (1,239)–292 743–3,389 610–3,172 484–2,965 IRR (%) Mean 11 11 10 22 21 21 CI (95%) 4–15 4–15 4–14 16–28 15–28 15–27 Benefit:Cost4 Mean 0.98 0.97 0.96 1.13 1.12 1.12 CI (95%) 0.9–1.05 0.9–1.04 0.89–1.03 1.05–1.22 1.04–1.21 1.03–1.20 Payback period Mean 6 6 6 4 4 4 (years) CI (95%) 3–8 3–8 3–8 3–5 3–5 3–5 Minimum area Mean 6.54 3.76 (ha)5 1Mean value of the NPV obtained in the simulation (5,000 iterations). 2SD: Standard deviation of the NPV with respect to the mean value. 3CI: Minimum and maximum values with a 95% confidence interval. 4Quotient between benefits and discounted costs. 5Minimum area (in ha) required for generating 2 basic Colombian salaries. Figure 1. Probability and cumulative density distributions for NPV for fattening steers on Brachiaria hybrid cv. Cayman pasture (T1) and a Cayman-L. diversifolia association (T2). Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Economics of a Leucaena diversifolia-grass association 365 Figure 2. Contributions of random input variables to the variance of the NPV for fattening steers on Brachiaria hybrid cv. Cayman pasture (T1) and a Cayman-L. diversifolia association (T2). The contribution of the input variables to the variance et al. 2015). For example, in northern Colombia, of the NPV is shown in Figure 2. The calculated associations of L. leucocephala with grass have been correlation coefficients show that profitability is shown to increase animal production per hectare by affected primarily by 2 variables: sale price per kg of live 110%, a result of increased liveweight gain per animal weight; and animal production. Increases in these (56.6%) and carrying capacity (43.4%), when compared variables have an effect on the variability in the forecast with improved grass monoculture (Gaviria et al. 2012). In of the indicator as follows: Changes in sale price per kg Queensland, Australia, liveweight gains on buffel grass of live weight lead to changes in the variance of 64.2% (Cenchrus ciliaris)-L. leucocephala pastures were 38% for T1 and 55.2% for T2. Similarly, changes in animal higher than on buffel grass alone (Walton 2003). production modify the variance of the indicator by However, these studies have been carried out mainly 29.7% for T1 and 39.6% for T2. When conducting a with different accessions of the species L. leucocephala, stress analysis in the 10th percentile for the 2 variables which has been widely acknowledged as having excellent at the same time, negative changes with respect to the yield and high forage quality leading to high liveweight mean value of the NPV indicator can be observed for T1 gains in cattle, compared with other species of Leucaena (335%) and T2 (57%). (Lefroy 2002). For example, evaluations at Lansdown, north Queensland, Australia found differences in daily Discussion and Conclusions animal liveweight gains between L. diversifolia (532 g) and L. leucocephala (694 g), which were associated with The inclusion of L. diversifolia in a grazing system for greater in vitro dry matter digestibility and lower levels of beef production improved the productive and economic condensed tannins in L. leucocephala (Jones et al. 1998). performance indicators under different scenarios of However, L. diversifolia has shown a greater range of animal production and market conditions. In productive adaptation to different edaphoclimatic conditions than terms, the association of Cayman and L. diversifolia L. leucocephala, in particular to higher soil acidity and increased animal production by 49%, compared with a cooler temperatures (Peters et al. 2011), allowing a wider Cayman monoculture. The results are consistent with use in tropical and subtropical regions. various experimental studies in a wide range of In terms of animal response indicators, T2 showed environments, which demonstrate the ability of Leucaena superior performance to T1, which translates into better spp. to improve production and profitability in the tropics financial performance in all 3 evaluated degradation (Kennedy and Charmley 2012; Peck et al. 2012; Harrison scenarios. The profitability of the system is improved when Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 366 K. Enciso, M. Sotelo, M. Peters and S. Burkart L. diversifolia is associated with Cayman. These results are strategies and price premiums and therefore promote the comparable with values reported in other studies, which adoption of legumes. We recommend that these additional have identified the potential of legumes to improve cattle benefits be included in the evaluation of legume-based profitability, livelihoods and resource use efficiency (Muir cattle fattening systems. As mentioned in this paper, the et al. 2017). In Queensland, L. leucocephala has been inclusion of legumes also leads to important environmental identified as the most productive and profitable legume, benefits in the cattle system, such as the reduction of enteric increasing liveweight production (both per hectare and per methane emissions (Campbell et al. 2014) and overall animal) by 2.5 times and doubling the gross margin/ha, greenhouse gas emissions (Kennedy and Charmley 2012; when compared with perennial grasses (Bowen et al. Harrison et al. 2015). These, among others, represent 2016). At the regional level in Queensland, economic significant environmental benefits with economic and benefits from the adoption of L. leucocephala have been welfare impact at society level. We recommend that estimated to be more than US$ 69 million/yr for 2006 in a environmental benefits be included in future economic planted area of 150,000 ha (Shelton and Dalzell 2007). evaluation studies. Profitability evaluations in Costa Rica, Michoacán The authors of this research are aware that the data (Mexico) and the Colombian Caribbean region report an reported were obtained in an experiment under controlled IRR that oscillates around 33% for a L. leucocephala-grass conditions both in terms of animal and pasture association (Jimenez-Trujillo et al. 2011; González 2013; management, following expert recommendations and Murgueitio et al. 2015). The productive and economic constant monitoring schemes. This has to be taken into indicators of sowing L. diversifolia presented in this study account when replicating the trial. Alterations to the are a fundamental input to the discussion on how to reduce reported values might occur under different settings and the need for expansion of land area required for agricultural more so under real farming conditions, depending on the production (FAO 2017), and show that L. diversifolia can region, climate or soil conditions, animal breeds, or animal become a potential option for sustainable intensification and pasture management, among others. and for reducing the pressure on natural resources. In conclusion, this study indicates that investing in the Improvements in the profitability indicators when establishment of legumes in grass-legume associations, such including L. diversifolia in the system demonstrate a as L. diversifolia, turns out to be a valuable option for reduction in the risk of economic loss and less variance in improving both efficiency and profitability of the production changes in critical variables. In particular, the results of the system, and thus can contribute in a positive way to producer sensitivity analysis showed that changes in the sale price of welfare. Providing livestock producers with such meat have stronger impacts on the profitability indicators information is a first step towards overcoming barriers to for the Cayman monoculture, which suggests increased technology adoption, i.e. towards decreasing the risk with respect to market conditions that cause price misconception by producers that there are limited benefits decreases. Although the price risk is also present after from planting pasture legumes (Shelton et al. 2005). including L. diversifolia, it is much lower and this might be However, for broader adoption to occur, providing this type a key factor in encouraging adoption, since farmers, being of information on its own is not sufficient; improvements in naturally rather risk-averse (Marra et al. 2003), will most the framework conditions are also needed. The likely favor technologies with a relatively lower variance. establishment of such systems should be accompanied by In addition, its higher stability over the years in terms of specific training and extension programs, which in many forage production and the higher protein concentration, cases would need to be developed (e.g. in the Colombian especially in dry seasons, compared with a grass context), to overcome the lack of knowledge and experience monoculture (Tedonkeng Pamo et al. 2007), allow for in the use of tropical forage legumes. This should reduce stronger persistence and result in less variability when it uncertainties associated with technology adoption and comes to indicators of production. increase adoption rates. At the same time, the access to and In addition to the increased production and profitability structure of necessary financial resources (e.g. credits), as highlighted in this research, several other studies have well as the availability and access to seed or vegetative shown improvements in meat quality when Leucaena is material, need to be improved in order to provide the being used. For example, Montoya et al. (2015) found that necessary resources for technology adoption. This holds true animals from systems incorporating L. leucocephala especially for Colombia, where credit schemes do not produced meat with superior tenderness, better pH and respond to the producer reality (i.e. no credits available for color, as well as higher carcass weights, when compared pasture improvement, too short grace periods in livestock with animals from traditional grazing systems. Such credits) and where a well-functioning legume seed system is quality attributes could contribute to product differentiation non-existent. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Economics of a Leucaena diversifolia-grass association 367 Acknowledgments cambio climático a través de la ganadería – Una evaluación global de las emisiones y oportunidades de mitigación. This work was conducted as part of the CGIAR Research Organización de las Naciones Unidas para la Alimentación y la Agricultura (FAO), Roma, Italia. goo.gl/1Y6vz6 Program on Livestock. We thank all donors who globally González JM. 2013. Costos y beneficios de un sistema support our work through their contributions to the silvopastoril intensivo (SSPi), con base en Leucaena CGIAR system. The views expressed in this document leucocephala (Estudio de caso en el municipio de may not be taken as the official views of these Tepalcatepec, Michoacán, México). Avances En organizations. CGIAR is a global research partnership for Investigación Agropecuaria 17:35–50. goo.gl/fqiY9z a food-secure future. Its science is carried out by 15 Gutiérrez CD; Wingching-Jones R; Rodríguez RR. 2009. Research Centers in close collaboration with hundreds of Factibilidad del establecimiento de un sistema de partners across the globe (www.cgiar.org). producción de engorde de búfalos en pastoreo. Agronomia Costarricense 33:183–191. goo.gl/YcJifc Harrison MT; McSweeney C; Tomkins NW; Eckard RJ. 2015. 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Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):370–374 370 DOI: 10.17138/TGFT(7)370-374 ILC2018 Keynote Paper* Feeding leucaena to dairy cows in intensive silvopastoral systems in Colombia and Mexico Leucaena como alimento para vacas lecheras en sistemas silvopastoriles intensivos en Colombia y México JULIÁN ESTEBAN RIVERA1, JULIAN CHARÁ1, ENRIQUE MURGUEITIO1, JUAN JOSÉ MOLINA2 AND ROLANDO BARAHONA3 1Centro para la Investigación en Sistemas Sostenibles de Producción Agropecuaria, Cali, Colombia. cipav.org.co 2Reserva Natural El Hatico, El Cerrito, Valle del Cauca, Colombia 3Universidad Nacional de Colombia, Medellín, Colombia. medellin.unal.edu.co Abstract The demand for milk and dairy products globally is expected to grow in future decades, leading to an increase in the global dairy cattle population. Therefore it is important to identify production options that both improve efficiency and help reduce negative effects on the environment. Intensive silvopastoral systems have been proposed as a sustainable strategy in the tropics to increase the availability and quality of forage throughout the year for milk production from cattle. This paper reports the effects of silvopastoral systems that include leucaena at the farm level on milk production and on the environment in both Colombia and Mexico. Evaluation of different milk production systems has shown that the leucaena-based systems increased milk production both per cow and per hectare, increased the production of milk solids, improved the fatty acid profile in the milk and resulted in environmental benefits when compared with conventional systems. Keywords: Cattle, environmental benefits, grazing, milk solids, profit, tree legumes. Resumen Se espera que la demanda de leche y productos lácteos a nivel mundial crezca en las próximas décadas, lo que llevará a un aumento de la población de ganado lechero en todo el mundo. Debido a esto, es importante identificar opciones de producción ganadera que mejoren la eficiencia y ayuden a reducir los efectos negativos sobre el medio ambiente. En las últimas décadas, se han propuesto los sistemas silvopastoriles intensivos como una estrategia sostenible en el trópico para aumentar la disponibilidad y la calidad del forraje durante todo el año para la producción de leche bovina. Este documento informa sobre los efectos de los sistemas silvopastoriles con leucaena a nivel de finca sobre la producción de leche y cómo estos pueden ser más amigables con el medio ambiente en Colombia y México. La evaluación de diferentes sistemas de producción de leche ha demostrado que los sistemas basados en leucaena aumentan la productividad tanto por unidad animal como por unidad de área, aumentando de igual forma la producción de sólidos lácteos, mejoran el perfil de ácidos grasos en la leche y aportan beneficios ambientales en comparación con los sistemas convencionales. Palabras clave: Beneficios ambientales, ganado bovino, leguminosas arbóreas, pastoreo, rentabilidad, sólidos en leche. Introduction percentage of people living in urban areas (Alexandratos and Bruinsma 2012). In particular the demand for milk It is projected that the world’s demand for animal protein and dairy products is expected to grow by 58% between will continue to grow during future decades as a result of 2010 and 2030, and world milk production is projected to increases in global population, income per capita and the increase by 177 Mt (23%) by 2025 compared with the ___________ Correspondence: J.E. Rivera, Centro para la Investigación en Sistemas *Keynote paper presented at the International Leucaena Sostenibles de Producción Agropecuaria (CIPAV), Carrera 25 # 6-62, Conference, 1‒3 November 2018, Brisbane, Queensland, Australia. Cali, Colombia. Email: jerivera@fun.cipav.org.co Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena for dairy cows 371 base years (2013‒15), corresponding to an average (Megathyrsus maximus and Cynodon plectostachyus), growth rate of 1.8% per annum (OECD/FAO 2017). native multipurpose trees and palms (25–100 trees/ha) To achieve these production levels an increase in have been evaluated for many years (Figure 3). world milk production of 35% or 300 Mt will be required. Therefore, it is important to identify livestock production systems that improve efficiency and reduce negative effects on the environment while fulfilling the demand for good quality food in an economically efficient manner (Thornton and Herrero 2010). Intensive silvopastoral systems (ISPS) have been advanced as sustainable strategies in the tropics to increase the availability and quality of forage throughout the year for milk production from cattle (Chará et al. 2017). In addition, these systems are claimed to reduce or reverse the negative environmental impacts of cattle ranching, while increasing animal production and economic performance. With these systems it is also possible to certify milk and cheese as organic products (Nahed-Toral et al. 2013), thereby Figure 1. ISPS with leucaena, Cynodon plectostachyus and Megathyrsus maximus grazed by Brahman breed animals in a justifying improved prices (Solís-Méndez et al. 2013). For dual-purpose system. El Porvenir, Cesar, Colombia. (Photo: example, some leucaena-based systems in Colombia have Claudia Córdoba) been certified organic for more than 20 years, with milk products such as long-life milk without additives in either the milk or the animal diet. This paper reports the effects of ISPS with leucaena (Leucaena leucocephala) on milk production and environmental outcomes at the farm level. For more than 20 years in Colombia, different systems of milk production have been evaluated. The leucaena-based systems have increased milk production per cow and per hectare, increased the production of milk solids and improved the fatty acid profile of milk, when compared with conventional systems (Rivera et al. 2009; Prieto- Manrique et al. 2018). ISPS are a type of silvopastoral system that combines Figure 2. ISPS with leucaena with more than 20 years of high-density cultivation of fodder shrubs (4,000‒40,000 continuous production. El Chaco, Tolima, Colombia. (Photo: plants/ha) with: (i) improved tropical grasses; and (ii) tree Julián Rivera) or palm species at densities of 100–600 trees/ha. These systems are rotationally grazed for periods of 12‒24 hours followed by 40‒50 day resting periods (Chará et al. 2017) (Figures 1 and 2). On the other hand, typical traditional systems in Colombia are characterized by: low stocking rates (fewer than 0.6 AU/ha; AU = 450 kg dry animal), the use of grass monocultures, low biomass and animal production, low fodder quality and low animal reproductive performance (González et al. 2015). Intensive silvopastoral systems with Leucaena leucocephala for milk production In the Valle del Cauca department in Colombia for Figure 3. ISPS with leucaena and Megathyrsus maximus example (El Hatico farm), ISPS with L. leucocephala grazed by Lucerna breed animals in a tropical dairy system. El interspersed with highly productive improved pastures Hatico, Valle del Cauca, Colombia. (Photo: M. Kohut) Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 372 J.E. Rivera, J. Chará, E. Murgueitio, J.J. Molina and R. Barahona After establishing the silvopastoral system, there was With the higher milk solids from ISPS, the an increase in both quantity and quality of forage. Forage characteristics of the milk produced allow for increased dry matter (DM) production increased by an average of yields of dairy products and improved efficiency in the 17% compared with the initial situation (a grass transformation of milk to cheese, when compared with monoculture with fertilizer application and irrigation, milk produced by animals fed grass plus sorghum grain concentrate feed use and high production costs). Although (Mohammed et al. 2016). In spite of using lower leucaena shrubs planted at high density directly produced supplementation, the ISPS did not differ from the only 20% of the total DM/yr, through their N contribution, conventional system regarding production, according to total DM production in the ISPS increased from 24 to 36 Mohammed et al. (2016), who also indicated higher t/ha/yr. Thus, this system can produce up to 47% more profitability in the system with leucaena. González (2013) biomass than treeless pastures (Calle et al. 2013; Gaviria estimated internal rates of return (IRR) of 13% in systems et al. 2015). By incorporating leucaena and scattered trees involving leucaena and only 0.7% in conventional on El Hatico farm, the use of chemical fertilizers was systems in Mexico and Colombia. In World Animal eliminated from the grazing system, which once relied on Protection et al. (2014), it is reported that once the system the application of 400 kg urea/ha/year (equivalent to 184 is established, maintenance costs are lowered due to the kg N). Average milk production was maintained at 12,000 reduction in external inputs such as fertilizers, L/ha/yr for more than 20 years without relying on the use mineralized salts and concentrate feeds. After the initial of concentrate feeds (Calle et al. 2013). investment and a stabilization period, the higher Another example is Lucerna farm, where in the 1990s productivity per hectare generates returns that ensure the African star grass (Cynodon plectostachyus) mono- economic viability of ISPS. Analyzing financial data cultures supported a stocking rate of 3.5 cows/ha and identified that, after the 4th year, income exceeds costs produced 9,000 L milk/ha/yr, but required N fertilizer resulting in a positive balance in cash flow, achieving application (450–500 kg urea/ha/yr). Since converting to situations of economic surplus. For this study, farm ISPS with 10,000 L. leucocephala shrubs/ha, the same income and profitability were 56 and 72% higher, farm now supports up to 4.5 cows per hectare, produces respectively, than those of the traditional system (grass 15,000 L milk/ha/yr and requires no fertilizer or monoculture with high concentrate feed use) (Reyes et al. concentrate feeds on areas that have had 28 years of 2016). continuous production (Chará et al. 2017; Rivera-Herrera Finally, with respect to environmental issues, Rivera et al. 2017). et al. (2016) found lower emissions of greenhouse gases In the Colombian dry Caribe region, Rivera et al. (GHG) from ISPS involving leucaena and (2009) reported production of 5,551 L milk/ha/yr in ISPS C. plectostachyus rotationally grazed (1 day grazing and with leucaena (10,000 shrubs/ha), C. plectostachyus and 28 days rest) than from a conventional system. To M. maximus (Figure 1) but only 1,150 L milk/ha/yr produce one kg of fat-and-protein-corrected milk in a conventional grass pasture without trees. In Brazil, (FPCM), the ISPS emitted 12.3% less GHG (2.05 vs. 2.34 Paciullo et al. (2014) reported that incorporating leucaena kg CO2-eq). Regarding the use of non-renewable energy, in Urochloa decumbens pasture increased milk the ISPS required only 63% of the energy used in the production from 9.5 to 10.4 L/cow/d (P<0.05). conventional system to produce one kg FPCM (3.64 vs. The concentrations of protein, fat and total solids in the 5.81 MJ/kg). In the context of climate change, systems milk from ISPS were significantly higher (P<0.05) than with leucaena can produce milk more consistently in from pure grass pastures with yields of 0.15 vs. 0.13 times of severe drought, e.g. during periods of El Niño. kg/cow/day, 0.22 vs. 0.17 kg/cow/day and 0.59 vs. 0.51 The shade provided by the trees reduces soil moisture kg/cow/day for the ISPS and conventional system, losses and soil biological activity is increased, especially respectively (Rivera et al. 2009). Another benefit leucaena dung beetle activity, allowing the resilience of the system offers is the modification of the fatty acid profile of the through periods of drought (Chará et al. 2017). milk. Prieto-Manrique et al. (2018) observed that cows in The mechanisms that explain the productive responses ISPS produced higher amounts of polyunsaturated fatty from the ISPS include an increase in forage supply, acids than cows in conventional systems fed grass plus greater intake of dry matter and improved nutritive value concentrates. Unsaturated fatty acids such as c9t11 of the pastures. Animals grazing in ISPS including conjugated linoleic acid, t11 transvaccenic acid and some leucaena have DM intakes up to 30% higher than those long-chain n-3 fatty acids in bovine milk are associated grazing in conventional systems (Cuartas et al. 2015). with human health benefits, e.g. reduced incidence of heart This could be a function of higher forage on offer in the disease (Livingstone et al. 2012). ISPS, which can be up to 330% higher than that of Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena for dairy cows 373 conventional systems based only on tropical grass References monocultures, allowing higher selectivity for the animals (Note of the editors: All hyperlinks were verified 11 August 2019.) (Broom et al. 2013; Gaviria et al. 2015). According to Gaviria et al. (2015) and Cuartas et al. Alexandratos N; Bruinsma J. 2012. World agriculture towards (2015), including leucaena at 25% of the diet with 2030/2050: The 2012 revision. ESA Working paper No. 12-03. FAO (Food and Agriculture Organization of the M. maximus and C. plectostachyus could lower neutral United Nations), Rome, Italy. goo.gl/xn9ijA detergent fiber (NDF) concentration in the total ration by Barahona R; Sánchez S. 2005. Limitaciones físicas y químicas 15%, while the acid detergent fiber (ADF) concentration de la digestibilidad de pastos tropicales y estrategias para could be reduced by 20%. The low fiber concentration in aumentarla. Revista Corpoica 6(1):69‒82. doi: 10.21930/ the diet improves intake by allowing higher passage rates rcta.vol6_num1_art:39 (Boval and Dixon 2012). In addition, legume particles are Boval M; Dixon RM. 2012. The importance of grasslands for animal production and other functions: A review on cubic, while grass particles are long and thin, which management and methodological progress in the tropics. implies higher passage rates in such species as Animal 6:748‒762. doi: 10.1017/S1751731112000304 L. leucocephala (Barahona and Sánchez 2005). An added Broom DM; Galindo FA; Murgueitio E. 2013. Sustainable benefit is that ISPS with L. leucocephala provide higher efficient livestock production with high biodiversity and thermal comfort for the animals, so they can dedicate good welfare for animals. Proceedings of the Royal Society more time to browsing and grazing, because they have B 280:20132025. doi: 10.1098/rspb.2013.2025 possibilities of ingesting a higher biomass quantity Calle Z; Murgueitio E; Chará J; Molina CH; Zuluaga AF; Calle A. 2013. A strategy for scaling-up Intensive Silvopastoral (Broom et al. 2013). Molina et al. (2016) reported that Systems in Colombia. Journal of Sustainable Forestry including L. leucocephala at 24% of the diet of growing 32:677‒693. doi: 10.1080/10549811.2013.817338 heifers increased DM intake from 2.02 to 2.47% of the Chará J; Rivera JE; Barahona R; Murgueitio E; Deblitz C; animal live weight (P=0.01). Reyes E; Mauricio RM; Molina JJ; Flores M; Zuluaga A. From a nutritional point of view, an aspect to be 2017. Intensive silvopastoral systems: Economics and considered is the digestibility of the legume, which contribution to climate change mitigation and public describes the quantity of truly available nutrients for the policies. In: Montagnini F, ed. Integrating landscapes: Agroforestry for biodiversity conservation and food animal. Although leucaena has a lower digestibility than sovereignty. Advances in Agroforestry 12. Springer, some forage species due to the presence of secondary Dordrecht, The Netherlands. p. 395–416. doi: 10.1007/978- metabolites such as condensed tannins, its combination 3-319-69371-2_16 with lower quality grasses increases the degradability of Cuartas C; Naranjo JF; Tarazona AM; Correa GA; Barahona R. the total forage, which increases the availability of 2015. Dry matter and nutrient intake and diet composition nutrients to be used by rumen microflora and by the in Leucaena leucocephala-based intensive silvopastoral animal itself. Other desirable attributes are the high systems. Tropical and Subtropical Agroecosystems 18:303– 311. bit.ly/2ZVToq4 protein concentration, low fiber percentages and Gaviria X; Naranjo JF; Bolívar DM; Barahona R. 2015. acceptable non-structural carbohydrate values (rapidly Consumo y digestibilidad en novillos cebuínos en un soluble carbohydrates). sistema silvopastoril intensivo. Archivos de Zootecnia 64:21‒27. doi: 10.21071/az.v64i245.370 Final considerations González JM. 2013. Costos y beneficios de un sistema silvopastoril intensivo (SSPi), con base en Leucaena Intensive silvopastoral systems incorporating leucaena leucocephala (Estudio de caso en el municipio de Tepalcatepec, Michoacán, México). Avances en constitute a sustainable strategy to increase the Investigación Agropecuaria 17:35‒50. bit.ly/2MeNddu availability and quality of forage throughout the year for González R; Sánchez MS; Chirinda N; Arango J; Bolívar DM; milk production from cattle in the tropics. Relative to Escobar D; Tapasco J; Barahona R. 2015. Limitaciones para grass monocultures ISPS can: produce more edible dry la implementación de acciones de mitigación de emisiones matter and nutrients per hectare (more crude protein and de gases de efecto de invernadero (GEI) en sistemas less fiber); increase milk production due to higher diet ganaderos en Latinoamérica. Livestock Research for Rural quality while reducing the need for chemical fertilizers Development 27, Article#249. bit.ly/2YRFGHJ Livingstone KM; Lovegrove JA; Givens DI. 2012. The impact and concentrate feeds; improve farm profitability; of substituting SFA in dairy products with MUFA or PUFA increase carbon sequestration and reduce methane on CVD risk: Evidence from human intervention studies. emissions from enteric fermentation; and contribute to Nutrition Research Reviews 25:193‒206. doi:10.1017/S095 improved animal welfare and biodiversity. 442241200011X Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 374 J.E. Rivera, J. Chará, E. Murgueitio, J.J. 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Proceedings of the National leucaena in an intensive silvopastoral system. Animal Feed Academy of Sciences USA 107:19667–19672. doi: Science and Technology 239:55‒65. doi: 10.1016/j. 10.1073/pnas.0912890107 anifeedsci.2018.03.003 World Animal Protection; Fedegan; CIPAV; agri benchmark. Reyes E; Chará J; Deblitz C; Molina J; Gómez M; Mitchell L; 2014. A case study of triple wins in beef and milk Romanowicz B. 2016. Impact of intensive silvopastoral production in Colombia. World Animal Protection, London, systems on economics, diversity and animal welfare in UK. bit.ly/2Mcuhwd (Accepted 30 May 2019 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):375–380 375 DOI: 10.17138/TGFT(7)375-380 ILC2018 Keynote Paper* Leucaena leucocephala feeding systems for cattle production in Mexico Sistemas de alimentación con Leucaena leucocephala para la producción bovina en México LUIS RAMÍREZ-AVILÉS, FRANCISCO J. SOLORIO-SÁNCHEZ, CARLOS F. AGUILAR-PÉREZ, ARMIN J. AYALA-BURGOS AND JUAN C. KU-VERA Facultad de Medicina Veterinaria y Ganadería, Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico. uady.mx Abstract The impacts of leucaena (Leucaena leucocephala) feeding systems on cattle production, environmental services and animal welfare in Mexico are discussed. A total of about 12,000 ha of leucaena have been established in the tropical regions of México, where most of the information for the current review was obtained. Incorporating leucaena in a grass pasture increases dry matter intake of grazing cattle and reduces the level of methane produced. This results in improved liveweight gains and milk yields as well as a reduction in the level of greenhouse gas released. Additional benefits are increases in soil carbon and nitrogen levels and less stress on animals as the leucaena plants provide shade and reduce environmental temperatures. While these benefits are substantial, the area developed to leucaena represents less than 0.1% of the area which could potentially be developed. Strategies to increase adoption of these grass-legume systems by farmers need to be developed to make effective use of the systems for increasing beef and milk production while reducing the undesirable environmental outcomes normally associated with ruminant production. Keywords: Environmental services, liveweight gain, mitigation of methane emissions, tree legumes. Resumen Se discuten los impactos de los sistemas de alimentación con leucaena (Leucaena leucocephala) sobre la producción bovina, los servicios ambientales y el bienestar animal en México. En las regiones tropicales de México se han establecido cerca de 12,000 ha de leucaena, de donde se obtuvo la mayor parte de la información para la presente revisión. La incorporación de leucaena en las pasturas de gramíneas incrementa el consumo de materia seca de bovinos en pastoreo y reduce el nivel de metano producido. Esto resulta en incrementos en la ganancia de peso y rendimientos de leche, así como reducción del nivel de gas de efecto invernadero emitido. Beneficios adicionales de este sistema son los incrementos en los niveles de carbono y nitrógeno almacenados en el suelo y la reducción del estrés animal asociada con la sombra y la mitigación de las temperaturas ambientales aportada por la leucaena. A pesar de estos beneficios substanciales, el área establecida con leucaena representa únicamente el 0.1% del área potencial total que podría desarrollarse. Se requiere diseñar estrategias para incrementar la adopción de estos sistemas de gramíneas-leguminosas por los ganaderos para hacer un uso efectivo de los sistemas para incrementar la producción de carne y leche al mismo tiempo que se reducen los efectos indeseables en el ambiente usualmente asociados con la producción de rumiantes. Palabras clave: Ganancia de peso vivo, leguminosas arbóreas, mitigación de emisiones de metano, servicios ambientales. ___________ Correspondence: Luis Ramírez-Avilés, Facultad de Medicina *Keynote paper presented at the International Leucaena Veterinaria y Ganadería, Universidad Autónoma de Yucatán, km 15.5 Conference, 1‒3 November 2018, Brisbane, Queensland, Australia. carretera Mérida‒Xmatkuil, Mérida, Yucatán 97100, Mexico. Email: luis.ramirez@correo.uady.mx Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 376 L. Ramírez-Avilés, F.J. Solorio-Sánchez, C.F. Aguilar-Pérez, A.J. Ayala-Burgos and J.C. Ku-Vera Introduction In Mexico, animal production systems which utilize leucaena (Leucaena leucocephala) can increase productivity, improve animal welfare and mitigate environmental impacts relative to grass-only systems (Figure 1), but adoption of these systems by commercial farmers is limited. In this review, we discuss the Mexican experience in terms of animal productivity, energy supplementation and environmental services. This analysis provides an understanding of the achievements that have been made and challenges facing the system. Figure 2. Leucaena-grass-trees systems have the potential to improve animal comfort. Materials and Methods Information analyzed in the current review was generated from several regions of the Mexican tropics, particularly the states of Michoacán and Yucatán. In those regions, leucaena has been established by 615 livestock owners (mainly cattle producers) located in 10 different states (Campeche, Chiapas, Guerrero, Jalisco, Michoacán, Quintana Roo, San Luis Potosí, Tamaulipas, Veracruz and Yucatán), with a total livestock production area of 27,307,096 ha (Sagarpa 2014) of which about 14,906,331 Figure 1. Gyroland cattle in a leucaena-grass system for milk ha are appropriate for leucaena establishment. This production. indicates the enormous potential to expand the planting of this legume, since only about 0.08% (12,000 ha) has been Leucaena-grass systems can provide a wide range of successfully established to date. ecosystem services. These include: reduction of Animal performance and energy supplementation greenhouse gas emissions through both mitigation of trials have been carried out using crossbred (Bos taurus × methane (CH4) emissions and increased carbon (C) B. indicus) cattle. Levels of C storage, N fixation and storage; improved nutrient cycling; increased soil organic nutrient cycling were quantified in commercial grass-only matter; and improved atmospheric nitrogen (N) fixation. pastures and leucaena-grass associations under grazing. Considerable effort has been made in various countries to improve our understanding of mechanisms of enteric Environmental services of leucaena feeding systems CH4 mitigation in cattle fed rations containing foliage of leucaena, notably in Australia (Harrison et al. 2015) and Methane mitigation in crossbred cattle fed rations Colombia (Molina-Botero et al. 2016). In Mexico, containing leucaena respiration chamber methodology (Canul-Solis et al. 2017) has been used to measure enteric CH4 emissions in Trials carried out in open-circuit respiration chambers cattle fed leucaena. revealed that, as the level of chopped fresh foliage of In the tropical regions of Mexico, environmental leucaena was increased in a basal ration of a low-quality temperatures and relative humidity are high, and at certain grass (Cenchrus purpureus syn. Pennisetum purpureum), times of the day (during summer), above the enteric CH4 emissions of cattle decreased linearly physiological capacity of livestock to dissipate body heat. (Piñeiro-Vázquez et al. 2018) (Table 1). This confirmed This condition leads to low animal productivity due to previous results by Harrison et al. (2015) in Australia. It elevated body temperature and respiratory rate, leading to is possible that condensed tannins contained in leucaena reduced voluntary feed intake. A strategy to improve foliage induced changes in the microbial population of the animal comfort is the inclusion of woody species in rumen, thus affecting methanogenic Archaea and monocrop-grass systems (Figure 2). decreasing CH4 emissions. Energy loss through CH4 Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena feeding systems in Mexico 377 Table 1. Effects of increasing levels of incorporation of leucaena forage in a basal ration of low-quality Cenchrus purpureus (syn. Pennisetum purpureum) grass for cattle on emissions of enteric methane and dry matter digestibility (Piñeiro-Vázquez et al. 2018). Parameter Leucaena level in the ration (% DM) s.e. Linear 0 20 40 60 80 Cattle LW (kg) 293 298 289 298 295 6.8 Intake (kg DM/hd/d) 7.0 7.2 7.1 7.0 7.0 0.6 NS Methane (L/hd/d) 137.3 101.2 87.4 74.9 53.5 14.8 ** Methane (L/kg DMI) 20.1 14.7 12.1 10.5 7.7 2.1 ** Digestibility (% DM) 54.2 50.5 47.8 46.9 46.6 4.0 NS LW = live weight; DMI = Dry matter intake. production, as percentage of gross energy intake (Ym), fell Animal performance from 5.2% for the grass-only ration, to 3.6%, when leucaena was fed at 20% of ration dry matter (DM), and it continued Intake and productivity of animals grazing leucaena to fall as legume levels were increased. DM digestibility also decreased as leucaena percentage in the ration increased, but Farmers are interested in knowing the amount of leucaena differences were not significant. These findings suggest that forage consumed under practical grazing conditions in a incorporating leucaena at 20% of ration DM would reduce leucaena-grass system to achieve maximum benefit. In CH4 emissions by around 25%, relative to a grass-only diet. south-east Mexico, Bottini-Luzardo et al. (2016) measured This represents an important outcome from both an the intakes of both grass and leucaena under grazing environmental point of view (reduction of CH4 production conditions (n-alkane technique) and observed that dual- and emission) and animal performance (improvement purpose lactating cows were able to browse 34% of their diet through reduced energy loss). as leucaena. That level of leucaena DM intake will probably correspond with a reduction in CH4 emissions of around Carbon storage and N cycling increased 30%, which is a substantial decrease on environmental grounds. Piñeiro-Vázquez et al. (2018) demonstrated in a Carbon storage and N cycling increased by 38 and 47%, respiration chamber experiment with heifers that feeding respectively, in leucaena-grass systems compared with 20% (of ration DM) leucaena (in a basal ration of tropical pure grass pastures. The legume fixed more than 200 kg grass) induced a reduction of 26% in CH4 emission while N/ha/yr and soil organic matter increased by about 200% 40% leucaena gave a reduction of 36%. It is reasonable to in the legume association compared with the grass-only assume that 34% of ration DM (Bottini-Luzardo et al. 2016) system. Environmental temperature was reduced by would probably lead to a reduction of around 30% in CH4 almost 13% in the legume tree-grass system (Table 2). emissions. This guesstimate agrees, in general, with results obtained at other laboratories. Intakes of leucaena reported Table 2. Environmental factors in leucaena-grass and grass- by Bottini-Luzardo et al. (2016) agreed with results reported only systems recorded in Michoacán, Mexico (Solorio Sánchez by Sierra-Montoya et al. (2017), who found a leucaena et al. 2009; Sarabia 2013; López-Santiago et al. 2019). intake (DM) of around 28% of the diet in dual-purpose lactating cows grazing in a silvopastoral system in Environmental factor Grass only Leucaena-grass Colombia. Steers in silvopastoral systems with leucaena Total C storage 78 120 (without supplementation) gained 770 g/hd/d (Mayo- (t/ha/yr)1 Eusebio et al. 2013), with associated benefits of Temperature (ºC)2 34‒38 30‒34 Nutrient recycling 1‒15 (N), 6 22‒30 (N), 4 (P), improvement in carcass yield and lean meat production, (kg/ha/yr) (P), 17 (K) 2 (K) made possible through desired fatty acid composition and Soil organic matter 320 1,005 high concentration of unsaturated fatty acids (Rodríguez- (kg/ha)3 Echevarria et al. 2013). Atmospheric N 0 200‒300 fixation (kg/ha/yr) Energy supplementation to increase efficiency of nitrogen 1Above- and below-ground (0‒0.30 m soil depth) carbon. (N) utilization 2Measured at 0.80 m above ground in the grass-monocrop and in the tree shade in the leucaena-grass system. Range recorded during April- May (dry season) and June (early rainy season) at 12:00 h. Intake of crude protein (CP) by cattle grazing in paddocks 3Measured from 0 to 0.60 m soil depth. with high leucaena plant densities (about 35,000 plants/ha), Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 378 L. Ramírez-Avilés, F.J. Solorio-Sánchez, C.F. Aguilar-Pérez, A.J. Ayala-Burgos and J.C. Ku-Vera as currently used in Mexico, could be high, resulting in and affiliative behavior, such as social licking, head leaning excessive losses of N in the urine (Bottini-Luzardo et al. and social rubbing (Améndola et al. 2015). 2015). This may increase energy requirements for maintenance of cattle (Jennings et al. 2018) and increase Leucaena-grass system adoption N2O emissions from the urine (Bao et al. 2018). There may also be an imbalance in the protein:energy ratio in the rumen From 2012 to 2017, leucaena-grass systems have been leading to inefficient microbial protein synthesis established over almost 12,000 ha (615 farms), which (Calsamiglia et al. 2010; Barros-Rodríguez et al. 2013). represents about 0.08% of the total livestock area suitable Blood urea nitrogen (BUN) is a good indicator of nutritional for leucaena establishment (14,906,331 ha) in 10 states of balance in ruminants and the protein:energy ratio in total the tropical region in Mexico. Although this area is dietary intake is the most important factor related to significant, the rate of adoption has been slow and limited, fluctuations in BUN (Hess et al. 1999). In south-east as there are more than 350,000 cattle farms in the tropical Mexico, Ruiz-González (2013) found that both BUN and region (PGN 2018). Possible contributing factors are: a) urinary N excretion in cows increased linearly with uncertainty in livestock markets; b) lack of state laws that increasing levels of leucaena in the diet, suggesting give long-term support to this initiative; c) lack of long- inefficient use of N in the rumen. In addition, Arjona (2015) term extension services for cattle producers; d) high labor compared cane molasses, sorghum grain, citrus peel and demand for leucaena-based systems, which means farmer rice polishing as energy supplements for lactating Holstein leaders must have confidence in the system; e) lack of × Zebu cows fed a diet containing 45% leucaena foliage, availability of good quality farm inputs and services and relative to a control treatment without energy supplemen- the need for an appropriate market-chain for distribution; tation. Both BUN and urinary excretion of N were higher for f) inefficient support from state policies; and g) high costs the control group than for the supplemented treatments, and limited access to credit. suggesting that energy supplementation improved the utilization of N in the rumen. Total feed intake was 25% Conclusions higher and milk yield was increased by 30% with energy supplementation, with no differences due to the particular Leucaena feeding systems could be an important strategy energy sources. It was concluded that energy supplemen- in the tropical regions of Mexico to improve animal tation, regardless of the source used, will improve the productivity and welfare, and to reduce greenhouse gas efficiency of microbial protein synthesis in the rumen, as emissions to the environment. well as increase consumption of DM and animal Silvopastoral systems with leucaena have proved performance, in cattle fed rations incorporating leucaena highly productive in Mexico. However, these systems (Castillo et al. 2000). have not been adopted widely by farmers, mainly due to lack of readily available technical support, several socio- Animal welfare economic and political constraints and appropriate strategies to make effective use of the systems for cattle In the central part of Mexico, growing bullocks grazing production with minimal impact on the environment. leucaena associated with Megathyrsus maximus had lower body temperature (measured with an infrared thermometer) Acknowledgments and respiratory rates in the morning (36 vs. 38 °C and 42 vs. 65 breaths per minute) and in the afternoon (38 vs. 39.5 °C We thank Fundación Produce Michoacán AC, the Yucatán and 59 vs. 80 breaths per minute) than in a feedlot (Utrilla- Initiative (SIIDETEY, State Government of Yucatán), García 2013). This suggests that the feedlot system, which is SAGARPA-CONACYT, Universidad Nacional Autónoma becoming a common practice in Mexico, can have negative de México and Molina Center for Energy and the impacts on animal welfare and productivity, if shade is not Environment (San Diego, USA) for financial support to provided, since it could reduce feed intake and liveweight carry out the studies described above. gain and therefore general productivity. In another study, undertaken in southeast Mexico, to evaluate animal welfare References of dairy cattle grazing leucaena-grass systems with trees, (Note of the editors: All hyperlinks were verified 11 August 2019.) improved microclimate conditions allowed animals to cope better with heat stress. In addition to increased biodiversity Améndola L; Solorio FJ; Ku-Vera JC; Améndola-Massiotti there were advantages for animal welfare in terms of social RD; Zarza H; Galindo F. 2015. 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Nitrous oxide emissions from Mayo-Eusebio R; Utrilla-García MP; Aguilar-Pérez CF; the urine of beef cattle as regulated by dietary crude protein Solorio-Sánchez FJ; Ayala-Burgos AJ; Briceño-Poot EG; and gallic acid. Journal of Animal Science 96:3699‒3711. Ramírez-Avilés L; Ku-Vera JC. 2013. Productive doi: 10.1093/jas/sky252 performance of growing cattle grazing a silvopastoral Barros-Rodríguez M; Solorio-Sánchez J; Sandoval-Castro C; system with Leucaena leucocephala. In: Proceedings of the Klieve AV; Briceño-Poot E; Ramírez-Avilés L; Rojas- 22nd International Grassland Congress, Sydney, Australia, Herrera R. 2013. Effects of two intake levels of Leucaena 15‒19 September 2013. p. 1013‒1014. leucocephala on rumen function of sheep. Tropical Molina-Botero IC; Angarita EA; Mayorga OL; Chará J; Grasslands-Forrajes Tropicales 1:55‒57. doi: 10.17138/ Barahona-Rosales R. 2016. Effect of Leucaena TGFT(1)55-57 leucocephala on methane production of Lucerna heifers fed Bottini-Luzardo M; Aguilar-Pérez C; Centurión-Castro F; a diet based on Cynodon plectostachyus. Livestock Science Solorio-Sánchez FJ; Ayala-Burgos A; Montes-Pérez R; 185:24‒29. doi: 10.1016/j.livsci.2016.01.009 Muñoz-Rodriguez D; Ku-Vera J. 2015. Ovarian activity and PGN (Padrón Ganadero Nacional). 2018. Estadística Pecuaria, estrus behavior in early postpartum cows grazing Leucaena PGN Bovinos. bit.ly/2Mfg9lM leucocephala in the tropics. Tropical Animal Health and Piñeiro-Vázquez AT; Canul-Solís JR; Jiménez-Ferrer GO; Production 47:1481‒1486. doi: 10.1007/s11250-015-0887-3 Alayón-Gamboa JA; Chay-Canul AJ; Ayala-Burgos AJ; Bottini-Luzardo MB; Aguilar-Pérez CF; Centurión-Castro FG; Aguilar-Pérez CF; Ku-Vera JC. 2018. Effect of condensed Solorio-Sánchez FJ; Ku-Vera JC. 2016. Milk yield and tannins from Leucaena leucocephala on rumen blood urea nitrogen in crossbred cows grazing Leucaena fermentation, methane production and population of rumen leucocephala in a silvopastoral system in the Mexican protozoa in heifers fed low-quality forage. Asian tropics. Tropical Grasslands-Forrajes Tropicales 4:159‒ Australasian Journal of Animal Sciences 31:1738–1746. 167. doi: 10.17138/TGFT(4)159-167 doi: 10.5713/ajas.17.0192 Calsamiglia S; Ferret A; Reynolds CK; Kristensen NB; van Rodríguez Echevarria ME; Corral-Flores G; Solorio Sánchez B; Vuuren AM. 2010. Strategies for optimizing nitrogen use by Alarcón Rojo AD; Grado-Ahuir JA; Rodríguez-Muela C; ruminants. Animal 4:1184–1196. doi: 10.1017/S1751731 Cortés Palacios L; Segovia Beltrán VE; Solorio Sánchez FJ. 110000911 2013. Meat quality from cattle fattened in intensive Canul Solís JR; Piñeiro Vázquez AT; Arceo Castillo JI; Alayón silvopastoril system in two seasons of the year. 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Universidad and Feed Science 9:1‒32. doi: 10.22358/jafs/68025/2000 Autónoma de Yucatán, Mérida, Yucatán, Mexico. Harrison MT; McSweeney C; Tomkins NW; Eckard RJ. 2015. Sagarpa (Secretaría de Agricultura, Ganadería, Desarrollo Improving greenhouse gas emissions intensities of Rural, Pesca y Alimentación). 2014. Comisión Técnico subtropical and tropical beef farming systems using Consultiva de Índices de Agostadero (Cotecoca). Leucaena leucocephala. Agricultural Systems 136:138‒ bit.ly/2MXkXMi 146. doi: 10.1016/j.agsy.2015.03.003 Sierra-Montoya E; Chará JD; Barahona-Rosales R. 2017. The Hess HD; Flórez H; González E; Ávila M. 1999. Efecto del nutritional balance of early lactation dairy cows grazing nivel de nitrógeno amoniacal en el rumen sobre el consumo intensive silvopastoral systems. Ciência Animal Brasileira, voluntario y la digestibilidad in situ de forrajes tropicales. Goiânia 18:1‒12. doi: 10.1590/1089-6891v18e-40419 Pasturas Tropicales 21(1):43‒49. bit.ly/2ToM0B4 Solorio Sánchez FJ; Bacab Pérez H; Castillo Caamal JB; Jennings JS; Meyer BE; Guiroy PJ; Cole NA. 2018. Energy Ramírez Avilés L; Casanova Lugo F. 2009. Potencial de los costs of feeding excess protein from corn-based by-products sistemas silvopastoriles en México. Proceedings of the II Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 380 L. Ramírez-Avilés, F.J. Solorio-Sánchez, C.F. Aguilar-Pérez, A.J. Ayala-Burgos and J.C. Ku-Vera Congreso en Sistemas Silvopastoriles, Morelia, Mexico, silvopastoril con Leucaena leucocephala asociado con 3–5 November 2009. p. 21–30. Panicum maximum. M.Sc. Thesis. Universidad Autónoma Utrilla-García MP. 2013. Conducta ingestiva e indicadores de Yucatán, Mérida, Yucatán, Mexico. fisiológicos de toros en crecimiento en un sistema (Accepted 24 January 2019 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):381–388 381 DOI: 10.17138/TGFT(7)381-388 ILC2018 Keynote Paper* Leucaena feeding systems in Argentina. I. Five decades of research and limitations for adoption Sistemas de alimentación con leucaena en Argentina: I. Cinco décadas de investigación y limitantes para su adopción ALEJANDRO RADRIZZANI1, NAHUEL A. PACHAS2,3, LUIS GÁNDARA1, CRISTINA GOLDFARB2, ALEJANDRO PERTICARI1, SANTIAGO LACORTE2 AND DANTE PUEYO1 1Instituto de Investigación Animal del Chaco Semiárido, Instituto Nacional de Tecnología Agropecuaria (INTA), Leales, Tucumán, Argentina. inta.gob.ar 2Former staff member of INTA, Leales, Tucumán, Argentina. inta.gob.ar 3School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD, Australia. agriculture.uq.edu.au Abstract This review describes the history of research in Leucaena leucocephala (leucaena) feeding systems carried out by the National Institute of Agricultural Technology (INTA) over the last 5 decades and discusses the main limitations resulting in poor adoption in Argentina. Leucaena was introduced in the subtropical region of the north of the country in the late 1960s and early 1970s. Since then, INTA has conducted research to evaluate forage and animal productivity, leucaena accessions, rhizobial strains, contribution to soil carbon and total nitrogen and density effects on competition and other ecosystem interactions in silvopastoral systems. In spite of the convincing research results showing the excellent potential of leucaena to increase forage quality and animal production in suitable areas, there has been poor adoption of this forage tree legume on a broad scale. Keywords: Beef cattle, Chaco region, forage tree legumes, protein banks, silvopastoral systems. Resumen Esta revisión describe la historia de investigación conducida por el Instituto Nacional de Tecnología Agropecuaria (INTA) en la utilización de Leucaena leucocephala (leucaena) en sistemas ganaderos en las últimas 5 décadas, y analiza las principales limitantes que resultaron en su escasa adopción en Argentina. Leucaena fue introducida en la región subtropical del norte de Argentina a finales de la década de 1960 y comienzos de los 70s. Desde entonces, INTA ha conducido investigaciones para evaluar la productividad forrajera y ganadera, accesiones de leucaena, cepas de rizobio, contribución de carbono y nitrógeno al suelo, y efectos de la densidad de leucaena sobre competencia y otras interacciones ecosistémicas en sistemas silvopastoriles. A pesar de los alentadores resultados de dichas investigaciones, que mostraron el excelente potencial de leucaena para incrementar la producción forrajera y ganadera en áreas aptas para su crecimiento, se observa escasa adopción de esta leguminosa forrajera arbórea en gran escala. Palabras clave: Bancos de proteína, Chaco, ganado de carne, leguminosas arbóreas, sistemas silvopastoriles. Introduction Leucaena leucocephala (leucaena) has excellent potential to increase forage quality and animal production in suitable In the subtropical region of the north of Argentina, livestock areas for its growth (Goldfarb et al. 2005; Radrizzani and feed mainly on pastures and grasslands dominated by Nasca 2014). In the late 1960s and early 1970s the National grasses, which are deficient in protein for most of the year. Institute of Agricultural Technology (INTA) investigated ___________ Correspondence: Alejandro Radrizzani, Instituto de Investigación *Keynote paper presented at the International Leucaena Animal del Chaco Semiárido, INTA, Chañar Pozo s/n, CP 4113, Conference, 1‒3 November 2018, Brisbane, Queensland, Australia. Leales, Tucumán, Argentina. Email: radrizzani.alejandro@inta.gob.ar Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 382 A. Radrizzani, N.A. Pachas, L. Gándara, C. Goldfarb, A. Perticari, S. Lacorte and D. Pueyo the role of leucaena in feeding systems for this region by Leucaena protein bank, INTA Mercedes Research evaluating its persistence in different environments and Station. On the Experimental Farm located in the center farming systems. This paper reviews the history of research of Corrientes province (29º22'18.88" S, 57º40'36.48" W; carried out by INTA on leucaena feeding systems over the 95 masl) with a mean annual rainfall (MAR) of 1,380 last 5 decades and discusses the main limitations affecting mm, more than 1,000 accessions of forage legumes were adoption of leucaena by farmers. introduced in 1965 and their adaptation and forage characteristics were evaluated. Leucaena stood out for History of research its yield, quality and persistence (Royo Pallarés and Fernández 1978). Two decades later leucaena was still Although several tropical forage legumes have been vigorous and productive, so Pizzio et al. (1989) tested as possible solutions to the protein deficiencies of evaluated forage and animal productivity of native grasslands and pastures, only leucaena has stood out grasslands with and without access to leucaena protein against other perennial legumes in terms of forage banks comparing the effect of 0, 10 and 20% of the production and persistence (Royo Pallarés and Fernández grassland area sown to leucaena cv. Peru. Grazing 1978; Goldfarb et al. 1986; Goldfarb and Casco 1994). periods were 288 days/year (June‒March) over 3 years. During the last 5 decades, leucaena has been evaluated in Mean annual LWGs with 20% leucaena protein banks terms of forage and animal productivity, performance of were 38% higher than on pure grassland (Table 1a). various accessions, nodulation, contribution to soil carbon Annual LWGs with 20% leucaena were 143 kg/head and (C) and total nitrogen (N) and density effects on 190 kg/ha compared with 103 kg/head and 137 kg/ha for competition and synergistic effects. grassland only. Since large steers lost little weight (-8%) during winter and small steers gained weight (+4%) with Forage and animal productivity 20% leucaena, an increased proportion (30%) of leucaena was recommended. Steers 32 months old with Since the early 1980s, experiments have been conducted to access to 20% leucaena could be finished at heavier test forage and animal production of pastures incorporating weights (476 kg) than steers grazing pure native leucaena. Cattle liveweight gains (LWGs) with and without grassland (410 kg). Animals grazing leucaena showed leucaena in the diet were compared in the following 7 no symptoms of mimosine toxicity under these experiments, that are summarized in Table 1. conditions. Table 1. Cattle liveweight gains (LWGs) on treatments with and without leucaena in 7 experimental trials in Argentina. Experiment and treatments LWG (kg/hd/d) Increment due to leucaena Toxicity Reference a. Protein bank, INTA Mercedes Pizzio et al. 1989 - Leucaena, 20% of available area 0.497a1 38% No - Native grassland 0.358b b. Protein bank, INTA Corrientes Gándara et al. 1986 - Leucaena, 18% of available area 0.385a 75% No - Native grassland (winter) 0.220b c. Silvop. syst., INTA Corrientes Gándara and Casco 1993 - Leucaena 0.436a 35% (70%)2 No - Native grassland 0.322b d. Protein bank, INTA Cerro Azul Lacorte et al. 1987 - Leucaena, 20% of available area 0.408a 57% No - Cynodon plectostachyus pasture 0.259b e. Supplement, INTA Cerro Azul Lacorte 2001 - Leucaena supplementation 0.657a No difference No - Comercial protein supplement 0.586a f. Protein bank INTA El Colorado Roig 1992 - Leucaena, 10% of available area 0.454a 22% No - Pangola pasture 0.373b g. Silvop. system, INTA Leales Radrizzani and Nasca 2014 - Leucaena, 40% of available area 1.070a 65% (195%) Yes - Brachiaria pasture 0.650b 1Values within experiments followed by different letters differ at P<0.05. 2Values within parentheses indicate the increase in production per hectare. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena in Argentina. I. Research and adoption 383 Leucaena protein bank, INTA Corrientes. During 3 protein banks in winter when the difference in LWG was consecutive winters (May‒September 1981, 1982 and greatest, viz. 0.7 kg LWG/d for protein banks vs. a loss of 1983) on a cattle farm located in ‘Empedrado’, Corrientes 0.4 kg/d for pure grass pastures. However, to maintain province (27º54'41.25" S, 58º44'47.81" W; 71 masl; leucaena green leaf in winter, protein banks must be MAR 1,350 mm), Gándara et al. (1986) compared LWGs established in elevated areas protected by tree windbreaks to of heifers and cows grazing native grasslands with access reduce damage from frosts and cold winds. to protein banks of leucaena cv. Peru for 4 h/d with those Leucaena supplementation, INTA Cerro Azul. Lacorte of heifers and cows grazing only native grassland. (2001) used fresh leucaena to replace commercial protein LWGs/head of animals with daily access to leucaena were supplements for heifers and showed that weight gains in 44, 130 and 110% greater in 1981, 1982 and 1983, the leucaena and protein supplement treatments were respectively, than on native pasture alone (mean increase similar (Table 1e). The author recommended leucaena 75%, 0.39 vs. 0.22 kg/hd/d; Table 1b). The improved cut-and-carry for reducing feeding costs in small farming gains were directly related to the additional quantity and systems. Furthermore, Pachas et al. (2011; 2012) carried quality of forage provided by leucaena. In this trial, out collaborative experiments with dairy producers using animals grazing leucaena also showed no symptoms of ‘intensive silvopastoral system’ configurations with mimosine toxicity leucaena planted at high densities (10,000‒20,000 Leucaena silvopastoral system, INTA Corrientes. In the plants/ha) in single rows spaced 1.6 m apart with same area as the previous experiment, Gándara and Casco companion grass between rows and high-quality timbers (1993) conducted an exploratory trial to assess the LWGs of planted in alleys 10‒20 m apart. These collaborative trials steers in a silvopastoral system with leucaena in hedgerows helped to involve smallholders in leucaena utilization to in comparison with steers on straight grassland over 2 years improve the quantity and quality of forage produced and (August 1989‒August 1990 and November 1990‒ increase dairy cattle productivity. November 1991). Leucaena (cv. Cunningham) had been Leucaena protein bank, INTA El Colorado Research established in spring 1987 in hedgerows 5 m apart with Station. On the Experimental Farm located in the Digitaria eriantha (syn. D. decumbens, Pangola grass) as a southeast of Formosa province (MAR 1,150 mm) in the companion grass in the inter-rows. LWGs of steers grazing years 1980, 1981, 1983, 1987, 1988 and 1989, Roig the leucaena silvopastoral system were 34 and 36% greater (1992) studied LWGs of weaner and yearling steers in 1989‒90 and 1990‒91, respectively, than those on grass grazing Pangola grass pastures or Pangola grass with 10% only (Table 1c). Animal production per hectare from of area as a leucaena protein bank. Pangola grass pastures leucaena-Pangola grass was 170% greater than on grass only were continuously grazed, while pastures with leucaena as a result of a doubling of stocking rate (2 vs. 1 head/ha). were rotationally grazed with access to protein banks for Between 1992 and 1996, Goldfarb et al. (2005) explored 2‒3 h/d. Mean daily LWGs were higher in steers with different cutting regimes to maintain a dense leafy canopy access to leucaena during the first, second and fourth within the browse height (<2 m) and improve forage quality. years (Table 1f), but not in the other years. Both age This work, also conducted at the Corrientes Research groups responded, but the effect was stronger in younger Station, showed that cutting regime did not affect forage animals that require forage with higher nutritive value. quality (protein and phosphorus concentrations). The absence of responses in LWG in the other years was Leucaena protein bank, INTA Cerro Azul Research Station. attributed to the abundance of native and naturalized In the ‘Cuartel Río Victoria’ Experimental Farm, located in legumes, e.g. Desmodium incanum, annual Vicia spp. and the center of Misiones province (MAR 1,650 mm), Lacorte Melilotus sp., in the Pangola grass pastures. et al. (1987) evaluated LWGs of steers grazing protein bank Leucaena silvopastoral system, INTA Animal Research systems in comparison with a pure grass control pasture Institute of the Semi-arid Chaco region. On the during 1984‒85 and 1985‒86. Leucaena protein banks had Experimental Farm located in Leales, Tucumán, with a been planted in September 1981 in 20% of the area of a subtropical subhumid climate and MAR of 880 mm, Cynodon dactylon pasture, which was sown in summer Radrizzani and Nasca (2014) conducted a trial in the 1980/81. The pure grass pasture was dominated by Cynodon 2009/10 summer to evaluate the effects on beef plectostachyus (‘pasto estrella’). Steer LWGs were 57% productivity and its toxicity of planting leucaena in a higher in the leucaena protein bank systems than in pure Urochloa brizantha (syn. Brachiaria brizantha) cv. grass pastures (Table 1d). Recommendations from this study Marandú (brachiaria) pasture established in 1995. were to reduce the proportional area of the protein banks Leucaena cv. K636 was zero till-planted into the pasture since there was an oversupply of leucaena forage, and to use in hedgerows (single or twin rows) with 5 m inter-row Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 384 A. Radrizzani, N.A. Pachas, L. Gándara, C. Goldfarb, A. Perticari, S. Lacorte and D. Pueyo spacings in December 2009 to form 3 treatments with Leucaena spp. that persisted and are still under evaluation different proportions of the total area planted to leucaena are: L. collinsii, L. glabrata, L. esculenta, L. pulverulenta, (0, 20 and 40%). For the first 45 days, mean LWGs were L. stenocarpa (CIAT 17268), L. diversifolia (CIAT 0.65, 1.00 and 1.07 kg/hd/d for straight brachiaria, 17461, CIAT 17264, 11677 Lot 5 Zwai 1989 and 11676 brachiaria with 20% leucaena and brachiaria with 40% Lot 7 Zwai 1989), L. pallida (CPI 84581), L. retusa leucaena, respectively, with corresponding gains per unit (CIAT 17267), L. macrophylla (CIAT 17481, CIAT area of 1.33, 3.08 and 4.32 kg/ha/d (Table 1g). At this 17245 and 55/58 ILCA Kenya), L. gregii (CPI 91198), point animal LWGs on pastures containing leucaena L. lanceolata var. lanceolata (CPI 95571). The hybrids began to decline significantly, maintaining this trend until that persisted until 2018 and are still under evaluation are: the end of the trial. This coincided with signs of mimosine L. leucocephala × L. diversifolia (Line 7, Line 18, Batch toxicity, despite high yields of available leucaena. This 283-050-10). study suggested that, before putting animals on a pasture In another study Acosta (2008) selected 19 accessions containing a high proportion of leucaena (e.g. 40%) in the (L. leucocephala, L. diversifolia and their hybrids) from Chaco region, the value of ruminal inoculation with the INTA Corrientes collection to evaluate forage yield in mimosine- and DHP-degrading bacteria (as used in other acid soils; results showed good yields for most of these tropical and subtropical areas) must be assessed. accessions, with the top 5 producing between 4,238 and 5,685 kg DM/ha/year. Leucaena accessions In 2011, 57 accessions of Leucaena species and hybrids from the INTA Corrientes collection were established at the Temperatures in the subtropical region of Argentina are Animal Research Institute of the Semi-arid Chaco region, favorable for leucaena growth during most of the year INTA, Leales, Tucumán, to preserve and allow evaluation (7‒9 months) but frost can significantly slow or stop its of these genetic resources in another environment. growth in winter when leucaena forage is needed most to supplement ruminant diets. To identify tolerance to low Rhizobial strains and nodulation temperature while maintaining adequate forage yield and quality, Goldfarb and Casco (1998) selected 56 Effective nodulation is essential for vigorous leucaena accessions of Leucaena species and hybrids. The study growth and it is known that the presence of inadequate or was conducted in 2 phases: in Phase 1, 3-month-old ineffective rhizobial strains may limit both biological N seedlings were subjected to temperature treatments of fixation and forage yield in many subtropical soils. In the either -8 or -3 °C for 14 h. After the -8 °C treatment, only year 2000, farmers from northeast Argentina sought 1 plant of a single accession (L. leucocephala × inoculum to establish leucaena, given the absence of L. diversifolia SF 9043) survived. After -3 °C treatment, effective nodulation due to a lack of specific rhizobia in 17 plants retained 50% of their leaves. In Phase 2, these these soils (A. Perticari unpublished data). Facing this 17 plants were planted out in the field to measure demand, Bryant (2007) evaluated nodulation capacity and agronomic features. Eight plants, representing 4 cultivars leucaena biomass production under controlled conditions of and accessions of L. leucocephala and 4 plants of 40 strains stored in the collection of the Institute of different L. leucocephala × L. diversifolia hybrids, Microbiology and Agricultural Zoology (IMYZA-INTA) in showed good agronomic adaptation and chilling tolerance comparison with a control strain (CB81, Bradyrhizobium sp. but only a single plant of L. leucocephala K72 (SF8073) introduced from CSIRO, Australia and recommended since maintained green stem and meristematic tissue after a the first introductions of leucaena in the 1960s). The 40 frost event of -8.8 °C. strains were collected either from leucaena nodules from In 2000, other field trials evaluated the sensitivity of other countries or from Phaseolus vulgaris nodules. Four Leucaena species to low temperatures in winter and strains were preselected for their symbiotic effectiveness leucaena production in hedgerow silvopastoral systems (100% of plants nodulated with more than 3 nodules per (Goldfarb and Altuve 2002; Goldfarb 2005; Goldfarb et plant and plants had a dark green color): CB81, C215 al. 2005; Rolhaiser 2013). All Leucaena spp. survived the (Bradyrhizobium sp. from soils cropped with P. vulgaris in frost, reshooting vigorously from the stem base as Salta province, northwest Argentina) plus C191 temperatures rose. Accessions of L. leucocephala that (Bradyrhizobium sp. from the Central University of persisted until 2018 and have continued under evaluation Venezuela) and CIAT899 (Rhizobium tropici, from CIAT, are: 368 (Lot 2 Zwai 1985), Cunningham P13, Colombia that had been recommended for inoculation of P. Cunningham P14, CIAT 17481, CIAT 17479, Hawaiian vulgaris). The effectiveness study was carried out with cvv. Giant and ecotypes ‘Piquete’ and ‘Colorado’. Other Cunningham and K636 in a growth chamber over 50 days, Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena in Argentina. I. Research and adoption 385 using 2 control treatments: uninoculated and N-fertilized deepest horizon (50‒100 cm). This was attributed to a leucaena plants. Strains CIAT899 and C215 were the most greater abundance of leucaena roots than of grass roots effective in terms of total shoot biomass accumulated and deeper in the profile. Leucaena also enhanced N nodule size, while nodule number was highest with strains concentration by 7.6% (0.13 vs. 0.14%) in the topsoil (0‒20 CB81 and C191. Rhizobium tropici (strain CIAT899) cm) associated with an increment in the labile form showed the fastest growth rate compared with (particulate organic N), due to leaf deposition, recycling of Bradyrhizobium spp., known as having slow to moderate animal feces and nodule-N turnover from N fixation. growth. The shorter generation time of CIAT899 facilitates Introduction of leucaena into tropical grass pastures has the the production of inoculum by reducing fermentation time, potential to improve soil fertility and hence N availability for costs and contamination risks. From this study, 2 new companion grass growth. strains, CIAT899 and C215, were recommended for inoculating leucaena in northeast Argentina in preference to Density effects on competition and facilitation the CB81 strain (these 3 strains are currently available in IMYZA-INTA). Strains CIAT899 and C215 continue to be The effect of leucaena density on forage biomass was evaluated in field trials showing excellent nodulation and studied by Gándara et al. (2019) in a silvopastoral system at plant growth (A. Perticari unpublished data). INTA Corrientes Research Station. Leucaena hedgerows In another study to evaluate the effectiveness of consisting of twin rows 1 m apart with inter-row spacings of naturalized rhizobia, Eöry et al. (2010) collected soil 8, 4 and 2 m (22,222, 40,444 and 66,666 trees/ha, samples from 28 sites in northeast Argentina (Corrientes, respectively) were planted in October 2016. The companion Chaco and Formosa provinces), where leucaena had been grass, Urochloa brizantha (syn. Brachiaria brizantha) cv. growing for up to 50 years since establishment. They found Marandú, was sown in October 2017. Tree density was little or no presence of nodulating rhizobia in these soils, positively and linearly related to total leucaena biomass and though some of the naturalized rhizobia were more effective inversely related to grass yield (R2 = 0.99). Maximum total than the control strain CB81 (Eöry et al. 2010). This biomass was obtained in hedgerows with inter-row spacing collection was added to the IMYZA-INTA collection for of 2 m (leucaena 11 t DM/ha and grass 2.5 t DM/ha) but future studies. In these regions a high and persistent response maximum grass yield was obtained with 8 m inter-row to inoculation of leucaena is expected. spacing (6.7 t DM/ha). Apart from leucaena density, the By contrast, in northwest Argentina (Salta, Jujuy, decline in grass yield was directly related to the increase in Tucumán and Santiago del Estero provinces), rhizobia degree of shading with higher leucaena density. Level of strains that nodulate leucaena have been detected and the shade was estimated from the luminous intensity measured nodules are assumed to be formed by native Rhizobium etli by a ceptometer. Edible leucaena biomass was linearly and or other species of rhizobia associated with cultivated P. directly related to leucaena density (R2 = 0.99) and it was vulgaris and other native wild beans. According to highest with 2 m inter-row spacing (6.2 t DM/ha), but the Martínez-Romero (2009) these species of rhizobia have the percentage of edible biomass was not significantly different ability to nodulate several legumes, particularly at the 3 leucaena densities. Substantial changes in forage P. vulgaris and L. leucocephala. Nevertheless, even in production arise from diverse leucaena densities, i.e. northwest Argentina, field trials are warranted to ensure that combinations of single or twin rows and different inter-row apparently effective strains are competitive in leucaena spacings, in silvopastoral systems. The low radiation feeding systems. available under high density (2 m inter-row spacing) limits grass growth but moderate density (4 m inter-row spacing, Contribution to soil organic carbon and total nitrogen levels 40,444 plants/ha) allows an efficient combination with grasses that produces an adequate fiber:protein balance in Banegas et al. (2019) determined concentrations and vertical available forage. distribution of organic C (OC) and total N (TN) and their fractions (particulate and associate forms) in the profiles (0‒ Limitations to adoption 100 cm) of a 4-year-old leucaena-grass pasture and an adjacent grass-only pasture at the Animal Research Institute In spite of the convincing research results showing that of the Semi-arid Chaco region, INTA, Leales, Tucumán leucaena introduction in tropical pastures or grasslands (27º11' S, 65º14' W; 335 masl), in the west of the Chaco improves forage and animal production, there has been poor region, northwest Argentina. Leucaena introduction adoption of this forage tree legume on a wide and intensive increased OC concentration in the subsoil (20‒100 cm) by scale in Argentina. Based on our experience, we identify 8 45%, particularly the stable form (associate OC) in the main reasons for the slow adoption over the last 5 decades: Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 386 A. Radrizzani, N.A. Pachas, L. Gándara, C. Goldfarb, A. Perticari, S. Lacorte and D. Pueyo The contradiction of planting trees on cleared land stand must be long to ensure sufficient time for cost recovery to be complete. Most cropping land in north Argentina, a region dominated by forest vegetation, was developed by clearing trees. Inexperience in managing silvopastoral systems Therefore, it is contradictory for farmers to plant trees in a paddock where trees and shrubs have been systematically Livestock farmers are unfamiliar with managing controlled and removed. Moreover, some farmers have shrubs/trees as forage plants, an uncommon practice among concerns accepting that a pasture formed with trees can be cattle farmers in Argentina. Even farmers from the Pampa as productive as a cleared pasture, as with a silvopastoral region (dominated by grasslands) with experience in system. Traditionally for a cattle farmer, a pasture is formed establishing and grazing herbaceous legumes in mixed by pure grass only and all shrubs and trees have to be cleared. pastures, e.g. clover-grass pastures, have to gain new knowledge to manage hedgerow trees with companion Rigidity of land uses grasses in silvopastoral systems. Although it is known that leucaena plants need time to recover carbohydrate reserves Some farmers have issues about the loss of flexibility during the regrowth phase before they are grazed again (Stür associated with conversion of land suitable for dryland et al. 1994), some farmers are unaware that successive cropping into long-term leucaena silvopastoral systems severe grazings combined with frost damage can seriously (soils suitable for leucaena are generally also suitable for affect leucaena survival. cropping). The expected life of leucaena hedgerows (>30 years) makes it difficult to conduct a rotational management Excessive leucaena height program in which crops and pastures are alternated over time in the same paddock. Moreover, in mixed farming systems, To ensure stock can access leucaena forage in direct grazing leucaena establishment reduces the possibility of allocating systems, animal pressure should be managed to maintain more or less land for crops or animal production, according leucaena hedgerows at up to 2‒3 m tall with a dense leafy to the expected net returns of cropping and livestock (a canopy within the browse height (Dalzell et al. 2006). relationship that has been changing frequently in recent However, tall-growing leucaena cultivars, e.g. K636 or years). Tarramba, can easily grow beyond the browse height, making forage inaccessible to stock, even in frost-prone Slow establishment of leucaena areas where frost can help to control plant height. Consequently, farmers must develop skills to control The slow early growth of leucaena seedlings makes them leucaena height through heavy grazing pressure and/or vulnerable to ant attacks, weed and grass competition and cutting back plants by trimming machines, e.g. predatory wildlife, e.g. rabbits. Consequently, leucaena must slashers/mulchers, tree pruners or roller-choppers. be planted as a crop using current cropping techniques, e.g. zero-till for sowing leucaena into grass pastures, selective Misinformation regarding mimosine toxicity herbicides for weed control and appropriate insecticides for ant control. Further, some cattle farmers have insufficient Farmers in Argentina have a poor understanding and experience and machinery, e.g. sowing and spraying awareness of the occurrence and significance of leucaena machines. Moreover, erratic leucaena establishment owing toxicity. They are uncertain if their animals are suffering to the unreliable summer rain of the semi-arid Chaco region from chronic toxicity since animals may still be performing demands a careful approach to successful establishment. better in systems with leucaena than in those without it, but rarely use urine tests to diagnose if a problem exists. Leucaena-grass pastures are more expensive to establish Research and extension programs to inform farmers of than pure grass pastures upgraded inoculation protocols and improved management practices are needed urgently (Halliday et al. 2018). The establishment costs of leucaena hedgerows and the companion grass, plus costs of seed scarification, and control Scarce funding for research and development programs of ants, weeds and rabbits is higher (about double that for a pure-grass pasture). Therefore, the higher initial investment There have been no well-supported research and extension in establishing leucaena means the payback period is programs to promote the utilization of tropical legumes in extended unless returns from leucaena are much higher than Argentina in recent decades. Nowadays, there is a lack of from grass only. Alternatively, the lifespan of a leucaena technical information on leucaena feeding systems in a form Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena in Argentina. I. Research and adoption 387 accessible to both technicians and farmers. Effective Universidad del Salvador, Gobernador Virasoro, Corrientes, research programs and extension services are urgently Argentina. needed to improve establishment methods, management Banegas N; Corbella R; Viruel E; Plasencia A; Roig B; practices and grazing systems. Utilizing successful leucaena Radrizzani A. 2019. Leucaena leucocephala introduction into a tropical pasture in the Chaco region of Argentina. farmers as ‘champions’ to promote the practice and Effects on soil carbon and total nitrogen. Tropical demonstrate it on commercial farms seems a promising Grasslands-Forrajes Tropicales 7:295–302. doi: 10.17138/ approach. Greater involvement of experienced and TGFT(7)295-302 successful leucaena growers in the technology transfer Bryant ME. 2007. Selección de cepas de rizobios efectivas para process is essential to improve the future uptake and success la fijación biológica de nitrógeno en Leucaena of leucaena feeding systems. leucocephala. Trabajo Final de Aplicación. Universidad Nacional de Luján, Luján, Buenos Aires, Argentina. Conclusion Dalzell SA; Shelton HM; Mullen BF; Larsen PH; McLaughlin KG. 2006. Leucaena: A guide to establishment and Experiments involving forage and animal productivity have management. Meat & Livestock Australia, Sydney, Australia. bit.ly/2YHs66P shown that leucaena has excellent potential to increase Eöry CA; Iglesias MC; Goldfarb MC; Perticari A. 2010. animal production in areas suitable for leucaena in the Aislamientos eficientes de rizobios para inocular leucaena en el subtropical region of northern Argentina. However, when nordeste argentino. Comunicación. Revista Argentina de leucaena was introduced to fill the winter forage gap, this Producción Animal 30(Supl. 1):204‒205. bit.ly/2yUgG3O expectation was not always fulfilled and will be difficult (if Gándara FR; Goldfarb MC; Arias Mañotti AA; Ramírez WM. not impossible) to achieve in frost-prone areas without new 1986. Leucaena leucocephala (Lam) de Wit como banco de cold-tolerant leucaena varieties. Moreover, to avoid toxicity proteína invernal en un campo natural de la provincia de associated with a high proportion of leucaena in the diet, e.g. Corrientes. Revista Argentina de Producción Animal 6:562‒ 40%, appropriate management practices are needed. Studies 572. to assess the effectiveness of rhizobial strains and soil C and Gándara FR; Casco JF. 1993. Valor alimenticio de una asociación Pangola (Digitaria decumbens) y leucaena N contributions have revealed the potential of leucaena to fix (Leucaena leucocephala). Revista Argentina de Producción N and to improve soil fertility and C storage. However, there Animal 13:41‒42. bit.ly/2KKVp1Y is still a gap in knowledge about how much N leucaena can Gándara L; Pereira MM; Stup M. 2019. A preliminary study of fix associated with different rhizobial strains under different spatial distribution and plant density in a leucaena-grass environmental conditions and management practices. With planting in north Corrientes, Argentina. Tropical regard to competition studies and the effective integration of Grasslands-Forrajes Tropicales 7:143–145. doi: 10.17138/ leucaena and grass, there is still limited information on how TGFT(7)143-145 to optimize planting layout and management of leucaena, Goldfarb MC. 2005. Experiencias con leucaena en Corrientes y grass and animals in grazing systems. In spite of the Misiones, Argentina. In: Glatzle A; Klassen P; Klassen N, convincing research results showing that leucaena eds. Leucaena y otras leguminosas con potencial para el Chaco. Congreso internacional. Iniciativa para la introduction in tropical pastures and grasslands can improve Investigación y Transferencia de Tecnología Agraria forage and animal production, the limited adoption of this Sostenible (INTTAS), Loma Plata, Paraguay, 9–11 March technology is a major concern. It has been attributed to a mix 2005. p. 89‒92. of social, economic and agronomic constraints and Goldfarb MC; Gándara FR; Casco JF. 1986. Introducción de education and extension programs are needed to address this gramíneas y leguminosas forrajeras de distintos suelos del issue. NO de la provincia de Corrientes, Argentina. XII Congreso Argentino de Producción Animal. Revista Argentina de Acknowledgments Producción Animal 6:68. Goldfarb MC; Casco JF. 1994. Leucaena in the northwest region of Corrientes province, Argentina. In: Shelton HM; Piggin CM; This work was supported by the National Institute of Brewbaker JL, eds. Leucaena - opportunities and limitations. Agricultural Technology (INTA). Proceedings of a Workshop held in Bogor, Indonesia, 24‒29 January 1994. ACIAR Proceedings No. 57. ACIAR, Canberra, References ACT, Australia. p. 159‒162. bit.ly/2UphJVM (Note of the editors: All hyperlinks were verified 11 August 2019.) Goldfarb MC; Casco JF. 1998. Selection and agronomic characterisation of Leucaena genotypes for cold tolerance. In: Acosta RD. 2008. Evaluación agronómica de 19 orígenes de Shelton HM; Gutteridge RC; Mullen BF; Bray RA, eds. Leucaena leucocephala, L. diversifolia e híbridos entre Leucaena - adaptation, quality and farming systems. ambas en suelos ácidos del sur de Misiones. B.Sc. Thesis. Proceedings of a Workshop held in Hanoi, Vietnam, 9‒14 Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 388 A. Radrizzani, N.A. Pachas, L. Gándara, C. Goldfarb, A. Perticari, S. Lacorte and D. Pueyo February 1998. ACIAR Proceedings No. 86. ACIAR, Morelia y Tepalcatepec, Michoacán, Mexico, 2–3 March Canberra, ACT, Australia. p. 172‒173. purl.umn.edu/135197 2011. bit.ly/2KHUOOx Goldfarb MC; Altuve SM. 2002. Estado actual y futuro de Pachas AN; Dehle R; Esquivel JI; Fleitas F; Colcombet L. leguminosas forrajeras en la zona campos. In: Memorias, 2012. Sistemas silvopastoriles intensivos en Misiones. In: XIX Reunión del Grupo Técnico en Forrajeras del Cono Actas del Segundo Congreso Nacional de Sistemas Sur. Zona campos, Argentina-Brasil-Uruguay. INTA, Silvopastoriles, Santiago del Estero, Argentina. p. 191. Mercedes, Corrientes, Argentina. p. 91‒95. Pizzio RM; Benítez CA; Fernández JG; Royo Pallarés O. 1989. Goldfarb MC; Giménez LI; Casco JF; Núñez F. 2005. Leucaena. Banco de proteínas para novillos pastoreando Utilización de Leucaena leucocephala cv. Cunningham. campo natural. Noticias y Comentarios 246. Estación Avances de la producción vegetal y animal en el NOA Experimental Agropecuaria INTA, Mercedes, Corrientes, 2003‒2005, Tucumán, Argentina. Argentina. Halliday MJ; Hayley EG; Padmanabha J; McSweeney CS; Dalzell Radrizzani A; Nasca JA. 2014. The effect of Leucaena SA; Shelton HM. 2018. The efficacy of a cultured Synergistes leucocephala on beef production and its toxicity in the jonesii inoculum to control hydroxypyridone toxicity in Bos Chaco Region of Argentina. Tropical Grasslands-Forrajes indicus steers fed leucaena/grass diets. Animal Production Tropicales 2:127‒129. doi: 10.17138/TGFT(2)127-129 Science 59:696–708. doi: 10.1071/AN17853 Roig CA. 1992. Efecto de la Leucaena leucocephala (Lam.) de Lacorte SM. 2001. Engorde de vaquillonas a corral con leucaena Wit. combinada con pasto Pangola y pasturas naturales en como fuente protéica. Boletín técnico 1. Estación Experimental la producción de carne. Informe final del plan de trabajo 59. Agropecuaria INTA, Cerro Azul, Misiones, Argentina. Estación Experimental Agropecuaria INTA, El Colorado, Lacorte SM; Martínez PE; Fernández FL. 1987. Uso de Formosa, Argentina. leucaena como banco de proteínas en Misiones. Nota Rolhaiser M. 2013. Desempeño invernal de líneas de Leucaena Técnica 38. Estación Experimental Agropecuaria INTA, spp. implantadas desde 1993 en jardines de introducción. Cerro Azul, Misiones, Argentina. B.Sc. Thesis. Universidad Nacional del Nordeste, Martínez-Romero E. 2009. Coevolution in Rhizobium-legume Corrientes, Argentina. symbiosis? DNA and Cell Biology 28:361‒370. doi: Royo Pallarés O; Fernández JG. 1978. Exploración, 10.1089/dna.2009.0863 introducción y evaluación de forrajeras subtropicales en el Pachas AN; Colcombet L; Fassola HE. 2011. Los sistemas NEA. Serie Técnica 15. Estación Experimental silvopastoriles en Argentina. Oportunidades para pequeños Agropecuaria INTA, Mercedes, Corrientes, Argentina. productores de producción de leche en sistemas Stür WW; Shelton HM; Gutteridge RC. 1994. Defoliation silvopastoriles en la provincia de Misiones, Argentina. In: management of forage tree legumes. In: Gutteridge RC; Memorias, III Congreso sobre Sistemas Silvopastoriles Shelton HM, eds. Forage tree legumes in tropical agriculture. Intensivos para la ganadería sostenible del siglo XXI, CABI, Wallingford, UK. p. 158‒167. bit.ly/2MXg3yA (Accepted 13 April 2019 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):389–396 389 DOI: 10.17138/TGFT(7)389-396 ILC2018 Keynote Paper* Leucaena feeding systems in Argentina. II. Current uses and future research priorities Sistemas de alimentación con leucaena en Argentina: II. Situación actual y prioridades de investigación futura ALEJANDRO RADRIZZANI1, NAHUEL A. PACHAS2,3, LUIS GÁNDARA1, FERNANDO NENNING1 AND DANTE PUEYO1 1Instituto de Investigación Animal del Chaco Semiárido, Instituto Nacional de Tecnología Agropecuaria (INTA), Leales, Tucumán, Argentina. inta.gob.ar 2Former staff member of INTA, Leales, Tucumán, Argentina. inta.gob.ar 3School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD, Australia. agriculture.uq.edu.au Abstract This paper presents the current status of Leucaena leucocephala (leucaena) feeding systems and proposes research priorities for leucaena development in Argentina. Although research on leucaena as forage for cattle production began in the late 1960s, it was not widely adopted until 2010 (5 decades later). The recent adoption is related to the incorporation of the ‘Australian technology package’, previously adapted for use by farmers in the neighboring region of the Paraguayan Chaco. In June 2018, we surveyed 8 properties with about 2,400 ha of leucaena in silvopastoral systems for beef cattle production in the Argentinean Chaco region, as well as 10 smallholder farms with about 10 ha of leucaena protein banks for dairy cattle in the northeast of Argentina. In the silvopastoral systems, leucaena condition was excellent on most properties in the 750‒1,350 mm/year rainfall zone and low/poor on only 1 farm due to low rainfall (600 mm/year). In protein banks, leucaena condition was excellent or good on 6 of the properties and low/poor on the remaining 4, attributed to ingress of weeds and/or overgrazing. Grass condition was good in most of the systems but was low/poor in 2 silvopastoral systems due to very high stocking rates imposed to restrict leucaena height. Although there is high potential for leucaena development in Argentina, expansion should take place carefully with leucaena planted only on areas suitable for successful establishment, and using appropriate management practices to reduce establishment failures and costs, restrict leucaena height, enhance grass persistence, improve grazing strategies and manage mimosine toxicity problems. Keywords: Beef cattle, Chaco region, forage tree legumes, protein banks, silvopastoral systems. Resumen Este trabajo presenta la situación actual de sistemas de producción ganadera que utilizan Leucaena leucocephala (leucaena) en Argentina. Aunque la investigación en leucaena como forrajera para la producción ganadera comenzó a fines de los 60s, la especie fue adoptada en mayor escala recién a partir del 2010 (5 décadas después). Esta reciente adopción se relaciona con la incorporación del ‘paquete tecnológico australiano’, también adoptado y adaptado por productores de la región vecina del Chaco paraguayo. En junio de 2018 identificamos y avaluamos unas 2,400 ha (8 propiedades) de leucaena en sistemas silvopastoriles de bovinos de carne en la región del Chaco argentino. Al mismo tiempo, evaluamos unas 10 ha (10 pequeños productores) con leucaena como bancos de proteína para vacas lecheras en el noreste argentino. En los sistemas silvopastoriles, la condición de leucaena fue calificada como excelente en la mayoría de los campos ubicados en áreas con precipitación anual de 750 a 1,350 mm/año, a excepción de una propiedad con mala condición de leucaena asociada a la baja precipitación (600 mm/año). En los bancos de proteína, la condición de leucaena fue valorada como excelente y buena en el 60% de los campos ___________ Correspondence: Alejandro Radrizzani, Instituto de Investigación *Keynote paper presented at the International Leucaena Animal del Chaco Semiárido, INTA, Chañar Pozo s/n, CP 4113, Conference, 1‒3 November 2018, Brisbane, Queensland, Australia. Leales, Tucumán, Argentina. Email: radrizzani.alejandro@inta.gob.ar Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 390 A. Radrizzani, N.A. Pachas, L. Gándara, F. Nenning and D. Pueyo. y fue mala en el 40% restante, atribuida a la falta de control de malezas y/o sobrepastoreo. La condición de las gramíneas fue buena en la mayoría de los sistemas, pero fue mala en 2 de los sistemas silvopastoriles donde se aplicó alta presión de pastoreo para evitar el crecimiento excesivo de leucaena. Si bien existe un gran potencial para el desarrollo de leucaena en Argentina, la expansión debe hacerse cuidadosamente, seleccionando solo aquellos sitios apropiados para su crecimiento, y aplicando prácticas de manejo adecuadas para reducir riesgos y costos de implantación, restringir la altura excesiva, aumentar la persistencia de las gramíneas, mejorar las estrategias de pastoreo y manejar los problemas de toxicidad por mimosina. Palabras clave: Bancos de proteína, ganado de carne, leguminosas forrajeras arbóreas, región del Chaco, sistemas silvopastoriles. Introduction leucaena was planted in twin rows with 5‒10 m inter-row spacing using scarified seed of cv. Tarramba (improved Leucaena (Leucaena leucocephala) is grown as forage for K636) imported from Paraguay (previously imported to grazing cattle in the subtropical region of the north of Paraguay from Australia). On one property (ID 4 in Table 1) Argentina, where livestock graze mainly on pastures and leucaena cv. Cunningham was sown on part of the farm and grasslands that are deficient in protein for much of the cv. Tarramba on the other part. On 5 properties (63%) seed year. Both research and extension staff recognize that the was inoculated with specific rhizobium provided by INTA’s introduction of leucaena into grass pastures as hedgerows Institute of Microbiology and Agricultural Zoology (silvopastoral systems) and as blocks of high leucaena (IMYZA-INTA), while seed was sown without rhizobia on density (protein banks) has excellent potential to increase the other 3 properties. The most common grass species sown both forage quality and animal production in areas in the inter-row spaces were Megathyrsus maximus (4 suitable for its growth. This paper presents the current pastures with cv. Gatton panic and 1 with cv. Tanzania) and status of use of leucaena in livestock feeding systems in Urochloa brizantha (syn. Brachiaria brizantha) cv. Argentina and proposes research priorities for future Marandu, while other species were Dichanthium aristatum development. and native grasses. All leucaena silvopastoral systems were rotationally grazed, 6 at high grazing pressure and the Usage of leucaena feeding systems remaining 2 at very high grazing pressure based on 4 possible ratings (low, moderate, high and very high). Cattle In May-June 2018, we surveyed leucaena growers in were inoculated with the mimosine-degrading rumen Argentina to gather information regarding property location, bacterium Synergistes jonesii imported from Paraguay area of established leucaena, its intended use, planting (previously imported from Australia to Paraguay) on methods employed, grazing management, condition of grass 5 properties, while no inoculum was applied on the other and leucaena and any concerns about leucaena introduction 3 properties. into their feeding systems. We might not have included all Current leucaena condition, based on 4 possible levels growers, as adoption of leucaena feeding systems in the (low/poor, moderate, good and excellent), was excellent on region has not previously been documented. 7 farms, while the other property, where growth was rated as low/poor, was located in a dry zone (600 mm AAR) and Hedgerow silvopastoral systems 2 years after planting (February 2013) only 50% of the plants had survived. The farmer attributed leucaena mortality to Eight properties with leucaena established in hedgerow low rainfall on this property (ID 2 in Table 1), since the silvopastoral systems were surveyed and were located in the surviving plants have persisted in depressions where soil 600‒1,350 mm average annual rainfall (AAR) zone of the water content was highest. The same farmer is successfully Chaco region (Salta, Chaco and Formosa provinces) (Figure grazing 588 ha of leucaena in the northeast of Salta province 1; Table 1). These silvopastoral systems were established (ID 1 in Table 1), where AAR is 750 mm. Current grass between December 2011 and January 2018 and covered a condition (same condition scale) was good on 6 of the total area of 2,379 ha (average 297 ha/property, range 4‒950 properties and low/poor on 2 farms, where very high ha). Physical and chemical properties of prevailing soils on stocking rates were employed. These 2 farmers reported that the farms did not present any major obstacles to the growth leucaena had been heavily grazed to restrict the height of leucaena. The main purpose for introducing leucaena into growth of leucaena plants, causing overgrazing of the inter- the grazing systems was to improve forage and beef row grass. The main concerns about leucaena silvopastoral production and to enhance soil nitrogen (N) concentration systems were poor grass persistence and excessive leucaena and hence sustainability of the system. On all properties, height. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena in Argentina. II. Uses and research priorities 391 Figure 1. Leucaena feeding systems recognized and surveyed in Argentina in 2018: 8 hedgerow silvopastoral systems (SPS), 10 protein banks (PB) and 4 experimental trials (ET). The hatched area represents the Dry Chaco region. Table 1. Characteristics of the leucaena hedgerow silvopastoral systems surveyed. ID AAR Leucaena Establishment Inter-row Seed Companion Cattle Grazing Current Current (mm/yr) area (ha) (month and year) spacing (m) inoculation grass1 inoculation pressure leucaena grass condition condition 1 750 588 Dec. 11‒Mar. 14 5.5 (twin) Yes Mm Yes Very high Excellent Low/poor 2 600 104 Feb. 13 6 (twin) Yes Mm Yes High Low/poor Good 3 950 50 Oct. 17 6 (twin) No Ub No High Excellent Good 4 1,100 28 Mar. 14 5 (twin) Yes Nat - Mm Yes Very high Excellent Low/poor 5 1,350 650 Jan. 17‒18 8‒10 (twin) Yes Mm - Ub Yes High Excellent Good 6 1,150 950 Jan. 15‒16 10 (twin) Yes Mm Yes High Excellent Good 7 1,000 4 Dec. 11 5 (twin) No Ub - Da No High Excellent Good 8 900 5 Dec. 17 6 (twin) No Ub No High Excellent Good 1Mm: Megathyrsus maximus; Ub: Urochloa brizantha; Nat: Native grass; Da: Dichanthium aristatum. The survey indicated that recent adoption of leucaena in in the neighboring central Chaco region of Paraguay, where Argentina was based on technology developed over the last the area sown increased from 20 ha in 2001 to about 10,000 2 decades in northern Australia, including mechanical seed ha in 2018 (Glatzle et al. 2019). A contributing factor in this scarification, improved agronomic practices, especially expansion was the introduction of cv. Tarramba and the weed control during establishment, appropriate animal rumen bacterium from Australia, with the support of the management and solving of the mimosine toxicity problem Central Chaco Research Station (EECC) and the Initiative (Dalzell et al. 2006; Radrizzani et al. 2010). This ‘Australian for Sustainable Agricultural Technology Research and technology package’ was adopted initially by cattle farmers Transfer (INTTAS) (Klassen 2005). Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 392 A. Radrizzani, N.A. Pachas, L. Gándara, F. Nenning and D. Pueyo Protein banks grazing and height control. Poor establishment and overgrazing were observed on farms that received less Ten properties with leucaena protein banks for dairy cattle technical support. Farmers were not familiar with production were surveyed in the 1,650 mm AAR zone managing leguminous trees in their feeding systems and of the Misiones province, in the humid Mesopotamia need ongoing technical support to optimize the region of northeast Argentina (Figure 1; Table 2). These establishment and persistence of their protein banks. protein banks occupied a total area of 10 ha (average 1 While dairy farmers are still interested in growing ha/property, range 0.25‒3 ha). Physical and chemical leucaena in the Misiones and Corrientes provinces, based properties of prevailing soils on the farms did not present on the assessment of research and extension personnel, any major obstacles to the growth of leucaena. The main adoption remains low, probably due to a lack of purpose of introducing leucaena to these grazing systems promotion and information about how to utilize leucaena was to improve forage quantity and quality for increased for feeding dairy and beef cattle. milk production, and to enhance soil fertility from atmospheric nitrogen fixed by leucaena. Most of the Experimental trials farmers established leucaena between December 2010 and October 2011, while one planted it in October 2006. Four experiments were identified and surveyed. Their main In contrast with hedgerow silvopastoral systems, all purposes were: to evaluate leucaena persistence under protein banks were planted in single rows 1.5‒2.5 m apart different environmental conditions, agronomic practices and using cvv. Cunningham and Peru. Seed was inoculated grazing systems; to determine the potential of leucaena with rhizobia on 9 properties with specific rhizobium introduction to improve forage and animal production; and provided by IMYZA-INTA. The most common grass to enrich soil fertility and C sequestration in the soil. The 4 species sown between leucaena hedgerows was Axonopus experiments occupied a total area of 5.2 ha (average 1.3 catarinensis (‘Jesuita gigante’), while other species were ha/experiment, range 0.2‒4 ha) and were located on U. brizantha and Cynodon nlemfluensis (‘pasto estrella’). Experimental Farms operated by INTA (Figure 1; Table 3). All protein banks were rotationally grazed, 8 at high ‘Cerro Azul’ Agricultural Research Station, ‘Cuartel Río grazing pressure and the remaining 2 at very high grazing Victoria’ farm. This farm (ID 1 in Table 3) is located in pressure. Cattle were not inoculated with the mimosine- the center of Misiones province where AAR is 1,650 mm. degrading rumen bacterium on any property. The soils in the experimental area are Ultisols and Oxisols Current leucaena condition was excellent on 2 farms, (Rhodic Kandiult and Rhodic Hapludox, respectively, in good on 4 farms and poor on the remaining 4, owing to an the US Soil Taxonomy System), deep, well-drained, ingress of weeds and/or overgrazing. Grass condition was strongly acidic and of low fertility (including high good on 9 properties with only a single farm classed as aluminum concentration). Leucaena cvv. Cunningham moderate, associated with a very high stocking rate. The and Peru were planted in October 1985 as a protein bank main concerns about leucaena protein banks were how to for dairy cattle production, in single rows 2 m apart. manage leucaena in relation to intensity and frequency of Cynodon nlemfuensis was planted between the rows. Table 2. Characteristics of the leucaena protein bank systems surveyed. ID AAR Leucaena Establishment Inter-row Seed Companion Cattle Grazing Current Current (mm/year) area (ha) (month and year) spacing (m) inoculation grass1 inoculation pressure leucaena grass condition condition 1 1,650 0.9 Dec. 10 1.5 (single) Yes Ac No High Good Good 2 1,650 0.8 Jun. 11 1.5 (single) Yes Ac No Very High Good Moderate 3 1,650 3.0 Sep. 11 1.5 (single) Yes Ub No Very High Poor Good 4 1,650 1.0 Oct. 11 1.5 (single) Yes Ac No High Poor Good 5 1,650 0.5 Sep. 11 1.5 (single) Yes Ac No High Good Good 6 1,650 0.5 Sep. 11 1.5 (single) Yes Ac No High Poor Good 7 1,650 1.0 Sep. 11 1.5 (single) Yes Ac No High Good Good 8 1,650 0.3 Oct. 11 1.5 (single) Yes Ac No High Excellent Good 9 1,650 0.8 Sep. 11 2.5 (single) Yes Ac No High Poor Good 10 1,650 1.0 Oct. 06 1.0 (single) No Cn No High Excellent Good 1Ac: Axonopus catarinensis; Ub: Urochloa brizantha; Cn: Cynodon nlemfuensis. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena in Argentina. II. Uses and research priorities 393 Table 3. Characteristics of the experimental trials surveyed (1. INTA Cerro Azul; 2. INTA El Colorado; 3. INTA Leales; and 4. INTA Corrientes). ID AAR Leucaena Establishment Inter-row Seed Companion Cattle Grazing Current Current (mm/year) area (ha) (month and year) spacing (m) inoculation grass1 inoculation pressure leucaena grass condition condition 1 1,650 2.0 Oct. 85 2 (single) No Cn No High Good Good 2 1,150 0.8 Oct. 01 8 (single) No Cp - Ub No Very high Excellent Low/poor 3 880 4.0 Dec. 09 5 (double) Yes Ub - Cg No Very high Excellent Low/poor 4 1,350 0.2 Oct. 16 2‒8 (double) No Ub No High Excellent Good 1Cn: Cynodon nlemfuensis; Cp: Cenchrus purpureus; Ub: Urochloa brizantha; Cg: Chloris gayana. ‘El Colorado’ Agricultural Research Station. This site Apart from the 4 experiments, germplasm is preserved (ID 2 in Table 3) is located in the southeast of Formosa in 2 leucaena collections in Argentina. The first was province with AAR of 1150 mm. The soil in the established at INTA Corrientes in September 1994 and experimental area is a Mollisol (Oxic Haplustoll in the US the second, a replica of the first, at the Animal Research Soil Taxonomy System), clayey but well-drained, acidic. Institute of the semi-arid Chaco region in Leales, Leucaena cv. Cunningham was sown in a hedgerow Tucumán in September 2011. The 57 accessions of pastoral system (single rows 8 m apart) in October 2001 Leucaena spp. and hybrids in each collection were with Urochloa brizantha and Cenchrus purpureus (syn. selected by Goldfarb and Casco (1998) for low- Pennisetum purpureum, ‘pasto elefante’) in the inter-row temperature tolerance and for forage yield and quality. spaces. The pasture was rotationally grazed at very high stocking rates. Future research and development priorities Animal Research Institute of the semi-arid Chaco region in Leales. Located in the southeast of Tucumán province, The potential for further adoption of leucaena in this site (ID 3 in Table 3) has AAR of 880 mm. The soils subtropical Argentina, particularly in the Chaco region, is in the experimental area are Mollisols (Fluventic huge. Areas suitable for leucaena are mostly in the subhumid part of the Chaco region (AAR 700‒1,200 Haplustoll and Typic Haplustoll in the US Soil Taxonomy mm), where large and medium size farms for breeding System), both well-drained with slow to good and finishing beef cattle predominate. Both domestic and permeability, slightly basic reaction. Leucaena cv. K636 export markets require tender beef that usually is was sown as a hedgerow silvopastoral system in double produced in farming systems where cattle gain weight rows 5 m apart after inoculation with specific rhizobium throughout the whole year, which is difficult for farmers provided by IMYZA-INTA in December 2009. Urochloa to achieve on native pastures in the north of Argentina brizantha was sown in the inter-row spaces in association without significant protein and energy supplementation. with Chloris gayana (‘grama Rhodes’). The pasture was Leucaena is an excellent protein source with potential to rotationally grazed at very high stocking rates. increase daily liveweight gains in the Chaco region Corrientes Agricultural Research Station. The research (Radrizzani and Nasca 2014) and can contribute to station (ID 4 in Table 3) is located in the northwest of reducing reliance on expensive protein supplements for Corrientes province with AAR of 1,350 mm. The soil in growing and finishing cattle. the experimental area is a Mollisol (Aquic Argiudoll in Other benefits from leucaena demonstrated in the the US Soil Taxonomy System), clayey, with low Chaco region are its contribution to deep C storage/ phosphorus, slightly acidic. Cultivar Cunningham was sequestration in the subsoil and to increased availability sown as a hedgerow silvopastoral system in October 2016 of soil N in the topsoil (Banegas et al. 2019). Moreover, in double rows at different row spacings (2‒8 m apart) there is substantial potential for dairy cattle farmers in the with U. brizantha in the inter-rows. humid Mesopotamia region of northeast Argentina to Cattle were not inoculated with the mimosine- establish leucaena to supply protein-rich forage and degrading rumen bacteria in any experimental trial. improve digestibility of native grasslands and improved Leucaena condition was good to excellent at all sites, grass pastures (Pachas et al. 2011; 2012). Nitrogen is the while grass condition was low/poor at El Colorado and key element for sustaining grazing systems and there is a Leales, associated with very high grazing pressure and great opportunity for increasing usage of tropical forage overgrazing. legumes as cattle farming systems are intensified. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 394 A. Radrizzani, N.A. Pachas, L. Gándara, F. Nenning and D. Pueyo However, many issues still need to be clarified if pruners and roller-choppers). This operation incurs maximum benefit is to be obtained from this ‘new’ unnecessary costs. Development of appropriate technology, namely: machinery and management practices to control  High establishment risks and costs. Since leucaena leucaena height is necessary. seedlings are susceptible to ant attacks, weed and grass  Low grass persistence. This problem is closely linked competition and predatory wildlife (rabbits), leucaena to excessive leucaena height since, when grazing has to be planted as a crop using current cropping pressure is increased to control the height of leucaena techniques (e.g. zero till for sowing leucaena into grass hedgerows, overgrazing of the inter-row grass can pastures, selective herbicides for weed control and result. Grass persistence and productivity over time appropriate insecticides for ant control). Furthermore, need to be evaluated under different management the erratic leucaena establishment associated with the practices and grazing regimes. Grass management in unreliable summer rain of the semiarid Chaco region relation to leucaena density (inter-row spacing, demands careful approach to establishment. The double or twin rows, plant numbers/ha) and plant establishment cost of leucaena hedgerows, plus the height also must be evaluated to properly understand establishment cost of the grass, plus seed scarification, the interaction between leucaena and grass plus ant, weeds and rabbit control, is higher (about (competition and ecosystem benefits). double) than that of a pure-grass pasture. Consequently,  Interactions between leucaena and grasses. A a long productive life of leucaena is essential to achieve better understanding of above- and below-ground high returns and allow repayment of the initial interactions between leucaena and grasses is required investment in establishment. to optimize the design and management of leucaena  Inoculation with an effective rhizobial strain. This is silvopastoral systems given the highly variable required to promote vigorous leucaena growth. rainfall and severe dry seasons in the Chaco region. Native rhizobia in the soil in northeast Argentina are Studies on root distribution of both leucaena and unlikely to form effective nodules with leucaena and grass, together with better knowledge of soil water will fix little, if any, N (Radrizzani et al. 2019). usage and the resulting water use efficiencies under However, no commercial leucaena inoculant is diverse leucaena densities (e.g. combinations of readily available and only IMYZA-INTA supplies single or twin rows with varying inter-row spacings) specific rhizobial strains to leucaena growers. To and different environmental conditions, management maintain the availability of inoculant, it is vital to practices and grazing systems, would provide preserve the IMYZA-INTA strain collection. This information to promote efficient use and long-term collection could also provide strains to assess stability of leucaena feeding systems. rhizobial effectiveness and competitiveness in both  Improved winter growth of leucaena. This is needed as the northeast and northwest regions. Moreover, since in many areas of northern Argentina growth is farmers expect to enhance soil N concentration using constrained by cold temperatures and frost (Radrizzani leucaena in their pastures, further research is needed unpublished data), which occur at a time when leucaena to determine soil organic carbon and total N stocks, is most needed to supply protein to ruminant diets. and to quantify actual biological N fixation by There are promising cold-tolerant accessions in the leucaena in association with different rhizobial strains INTA collection which could increase forage under a range of environmental conditions, availability in winter (Radrizzani et al. 2019). Research management practices and grazing systems. to evaluate these accessions under different  Excessive leucaena height. Large animals (big steers, environmental conditions, agronomic management and bulls and cows) control leucaena height better than grazing systems needs to be continued. Furthermore, small animals, since they can break down tall stems development of new leucaena varieties, cultivars and (4–5 m) to reach leaf at the tips. However, most cattle even interspecific hybrids, e.g. combining the frost in Argentinean herds are small animals, such as resistance of L. retusa and L. greggii with the vigor calves, heifers and even fattening steers (mean live and cool-season growth of L. pallida, L. diversifolia weight at slaughter is 280‒300 kg for the domestic and L. trichandra and the superior forage quality of market), and only a few animals in the herds are large L. leucocephala, could help fill the winter forage gap (cows, bulls and steers finished for export). When and extend the environmental adaptation of Leucaena leucaena plants grow to beyond browse height, spp. in Argentina. material above the desirable height must be removed  Mimosine toxicity. Concern about mimosine toxicity by trimming machines (e.g. slashers/mulchers, tree and its management has contributed to restrict Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena in Argentina. II. Uses and research priorities 395 adoption of leucaena as a forage for ruminants in contributions in the survey. This work was supported by Argentina (Radrizzani et al. 2019). Farmers are the National Institute of Agricultural Technology (INTA). uncertain if their animals are suffering from toxicity since animals may still be performing better in References systems with leucaena than in those without it. (Note of the editors: All hyperlinks were verified 14 August 2019.) Research is needed to clarify the effects of feeding high leucaena diets on cattle performance (Shelton et Banegas NR; Corbella R; Virual E; Plasencia A; Roig B; al. 2019) and to improve management practices Radrizzani A. 2019. Leucaena leucocephala introduction into a tropical pasture in the Chaco region of Argentina: (Halliday et al. 2018), along with extension activities Effects on soil carbon and total nitrogen. Tropical for future success of leucaena feeding systems. Grasslands-Forrajes Tropicales 7:295‒302. doi: 10.17138/  Scarce research and development programs. For TGFT(7)295-302 successful leucaena adoption, farmers must increase Dalzell SA; Shelton HM; Mullen BF; Larsen PH; McLaughlin their skills and become involved in the process of testing KG. 2006. Leucaena: A guide to establishment and manage- and validating the technology and even in establishing ment. Meat & Livestock Australia Ltd, Sydney, Australia. priorities for research. Research and extension Glatzle AF; Cabrera AN; Naegele The Late A; Klassen N. 2019. specialists must develop and provide to farmers all Leucaena feeding systems in Paraguay. Tropical necessary information for effective leucaena adoption, Grasslands-Forrajes Tropicales 7:397‒402. doi: 10.17138/ TGFT(7)397-402 if the species suits their farming system. Participatory Goldfarb MC; Casco JF. 1998. Selection and agronomic research and extension activities, including training characterisation of Leucaena spp. genotypes for cold tolerance. courses, on-farm demonstrations and field days, are In: Shelton HM; Gutteridge RC; Mullen BF; Bray RA, eds. valuable techniques to ensure that accurate and practical Leucaena – adaptation, quality and farming systems. information about the technology is readily available Proceedings of a Workshop held in Hanoi, Vietnam, 9‒14 and is transmitted to farmers using appropriate tools. February 1998. ACIAR Proceedings 86. ACIAR, Canberra, A flexible approach is necessary to allow farmer Australia. p. 172‒173. purl.umn.edu/135197 innovations to be included in the information base to Halliday MJ. 2018. Unravelling Leucaena leucocephala improve recommendations and for these to be passed toxicity: Ruminant studies in eastern Indonesia and on to other farmers in their locality (neighbors) and in Australia. Ph.D. Thesis. The University of Queensland, Brisbane, Australia. doi: 10.14264/uql.2018.382 other regions. Klassen N. 2005. Producción animal con Leucaena en el Chaco. In: Glatzle A; Klassen P; Klassen N, eds. 2005. Leucaena y Conclusion otras leguminosas con potencial para el Chaco. Congreso Internacional, Iniciativa para la Investigación y Leucaena as forage for cattle production was not widely Transferencia de Tecnología Agraria Sostenible (INTTAS), adopted in Argentina until 2010 and there is still a Loma Plata, Paraguay, 9‒11 March 2005. p. 4‒16. considerable potential for a broader adoption in the north Pachas AN; Colcombet L; Fassola HE. 2011. Los sistemas of the country. However, expansion should take place silvopastoriles en Argentina. Oportunidades para pequeños wisely, selecting only suitable areas for its establishment, productores de producción de leche en sistemas and using appropriate management practices to: reduce silvopastoriles en la provincia de Misiones, Argentina. In: Memorias, III Congreso sobre Sistemas Silvopastoriles establishment costs and risk of failure; restrict leucaena Intensivos para la ganadería sostenible del siglo XXI, height; enhance grass persistence; improve grazing Morelia y Tepalcatepec, Michoacán, Mexico, 2–3 marzo strategies; and manage mimosine toxicity problems. 2011. bit.ly/2KHUOOx Although some adoption can be achieved with relatively Pachas ANA; Dehle R; Colcombet L; Esquivel JI; Fleitas F. little intervention, for complex and new farming systems, 2012. Sistemas silvopastoriles intensivos en Misiones. In: such as leucaena silvopastoral systems, sustained support Actas del 2º Congreso Nacional de Sistemas Silvopastoriles, from the State and private sector is required in order to Santiago del Estero, Argentina, 9−11 May 2012. p. 191. reach maximum adoption with real impact for the Radrizzani A; Dalzell SA; Kravchuk O; Shelton HM. 2010. A economic, environmental and social well-being of grazier survey of the long-term productivity of leucaena farmers and rural communities. (Leucaena leucocephala)-grass pastures in Queensland. Animal Production Science 50:105‒113. doi: 10.1071/ AN09040 Acknowledgments Radrizzani A; Nasca JA. 2014. The effect of Leucaena leucocephala on beef production and its toxicity in the We are grateful to the leucaena growers Mauro Vanoli, Chaco Region of Argentina. Tropical Grasslands-Forrajes Martín Alonso and Lucas Martínez, for their valuable Tropicales 2:127‒129. doi: 10.17138/TGFT(2)127-129 Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 396 A. Radrizzani, N.A. Pachas, L. Gándara, F. Nenning and D. Pueyo Radrizzani A; Pachas ANA; Gándara L; Goldfarb C; Perticari Shelton HM; Graham LK; Dalzell SA. 2019. An update on A; Lacorte S; Pueyo D. 2019. Leucaena feeding systems in leucaena toxicity: Is inoculation with Synergistes jonesii Argentina. I. Five decades of research and limitations for necessary? Tropical Grasslands-Forrajes Tropicales 7:146– adoption. Tropical Grasslands-Forrajes Tropicales 7:381‒ 153. doi: 10.17138/tgft(7)146-153 388. doi: 10.17138/TGFT(7)381-388 (Accepted 19 June 2019 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):397–402 397 DOI: 10.17138/TGFT(7)397-402 ILC2018 Keynote Paper* Leucaena feeding systems in Paraguay Sistemas de alimentación con leucaena en Paraguay ALBRECHT F. GLATZLE1, ANTERO N. CABRERA2, THE LATE ALBERTO NAEGELE3 AND NORMAN KLASSEN1 1Iniciativa para la Investigación y Transferencia de Tecnología Agraria Sostenible, Fernheim, Paraguay. chaconet.com.py/inttas 2Facultad de Ciencias Agrarias, Universidad Nacional de Asunción (UNA), Asunción, Paraguay. agr.una.py 3Servicio Agropecuario (SAP), Loma Plata, Paraguay. chortitzer.com.py/ganaderia.php Abstract Leucaena leucocephala became naturalized in Paraguay long ago. However, due to cases of toxicity in horses and cattle, now identified as mimosine toxicity, leucaena was considered a weed until the beginning of this millennium. At this time the mimosine toxicity problem was overcome by the introduction of ruminal fluid from Australia containing the mimosine-degrading and -detoxifying bacterium Synergistes jonesii. As long as an internationally funded technical assistance project was operating (offering technical advice, provision of seed, seed scarification service and transmission of ruminal fluid containing Synergistes), the area sown to leucaena (either in twin rows into grass pastures or as fodder banks) increased rapidly in Paraguay, particularly in the Chaco area. However, the powdery fluvisols of the drier parts of the Chaco were not well suited to growth of leucaena, as persistence was restricted due to the impact of rodents, termites and also leaf-cutting ants, which prosper particularly well in this part of the Chaco. In more humid areas with usually heavier soils, currently leucaena represents an integral part of the feeding systems in hundreds of Paraguayan farms (large-scale as well as smallholders), mainly for steer fattening and dairy cow supplementation. After taking into account the above-mentioned setbacks, the total area of leucaena is currently estimated at about 10,000 ha. Keywords: Chaco, fodder bank, mimosine toxicity, row seeding, shrub legumes, steer fattening. Resumen Leucaena leucocephala ha sido naturalizada en Paraguay desde hace mucho tiempo. Sin embargo, debido a casos de intoxicación en caballos y bovinos, ahora identificada como toxicidad por mimosina, la leucaena fue considerada una maleza hasta principios de este milenio. El problema de la intoxicación se ha podido solucionar mediante la introducción, en 2003 desde Australia, de fluido ruminal con la bacteria Synergistes jonesii que degrada y desintoxica la mimosina, Mientras estuvo en funcionamiento un proyecto de asistencia técnica financiado con fondos internacionales, el cual ofrecía asesoría técnica, suministro de semilla, servicio de escarificación de semilla y provisión de fluido ruminal con Synergistes, el área sembrada con leucaena (ya sea en forma de doble-hileras en pasturas o como bancos de forraje) aumentó rápidamente en Paraguay, particularmente en la región del Chaco. Sin embargo, los fluvisoles de las partes más secas del Chaco resultaron no ser aptos para el cultivo de la leucaena, ya que su persistencia estuvo afectada por roedores, termitas y también hormigas cortadoras de hojas. Estas plagas prosperan particularmente bien en esta parte del Chaco. En áreas más húmedas, con suelos generalmente más pesados, la leucaena representa actualmente una parte integral de los sistemas de alimentación animal en centenares de granjas paraguayas (tanto propiedades grandes como pequeñas fincas), principalmente para novillos de engorde y suplementación de vacas lecheras, abarcando una superficie de aproximadamente 10,000 ha. Palabras clave: Bancos de forraje, ceba de novillos, Chaco, hileras dobles, leguminosas arbustivas, toxicidad por mimosina. ___________ Correspondence: A.F. Glatzle, Iniciativa para la Investigación y *Keynote paper presented at the International Leucaena Conference, Transferencia de Tecnología Agraria Sostenible (INTTAS), Filadelfia- 1‒3 November 2018, Brisbane, Queensland, Australia. 317, 9300 Fernheim, Paraguay. Email: albrecht.glatzle@gmail.com Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 398 A.F. Glatzle, A.N. Cabrera, the Late A. Naegele and N. Klassen Introduction Davies Laboratory in Townsville, Australia and invited him to Paraguay. After extended zoo-sanitary clearing The leguminous forage shrub Leucaena leucocephala is procedures in Australia and Paraguay, Dr Jones managed not native to Paraguay; having been introduced a long to bring a thermos of ruminal fluid from Australian steers time ago it has been partly naturalized. Anecdotally, there grazing leucaena, which contained the appropriate was a major effort during the 1970s to grow leucaena on bacteria. Immediately on arrival at the Central Chaco a broad scale for grazing and feeding purposes and to Research Station (it was after midnight) we inoculated 2 integrate this excellent forage, also named ´tropical rumen-fistulated steers with this fluid, about 72 hours alfalfa´, into local feeding systems. Clearly, these efforts after it had been extracted from steers in Queensland. The failed and farmers had a generally poor image of recipient animals had been prepared by feeding abundant leucaena. Although it was used occasionally by small- leucaena for several days. By 5 days after inoculation a holders as a source of forage, it was considered primarily urine coloration test demonstrated that these steers were a weed, as cases of hair loss, particularly among horses, effectively degrading mimosine in their rumens (Jones were observed. and Megarrity 1986). In the 1990s, a German-financed agricultural R&D After some animal-to-animal transmission tests of the project commenced in the Paraguayan Chaco. Initial mimosine-degrading capability of the rumen fluid we small-scale, short-term grazing trials demonstrated offered a service for ruminal fluid transmission to farm leucaena´s high potential to increase growth of steers, animals grazing on leucaena. This service was soon taken even when both grass and leucaena leaves were dry over by a local agricultural extension program that but abundant after being frosted in winter (Glatzle 1999; maintained fistulated steers on leucaena as rumen fluid Cabrera et al. 1999). In studies over longer grazing donors. Between 2003 and 2017 an estimated 800 farmers periods, however, monthly bodyweight gains in were provided with the mimosine-degrading microflora in steers decreased progressively, with weight losses being order to prevent mimosine toxicity from developing in experienced after animals grazed leucaena for stock grazing leucaena. Even leucaena growers from approximately 6 months (Klassen 2005) (Figure 1). The neighboring Argentina came to collect a thermos of cause of this phenomenon was identified as mimosine rumen fluid for dosing their animals. toxicity. It became obvious that a solution to this problem Initially the ruminal fluid (10 mL/animal) was injected was crucial if wider acceptance of leucaena as a forage with a rumen injection gun to about 20% of the animals crop at farm level was to be achieved. in the target herds grazing leucaena. The ruminal fluid was transported in a flexible rubber bottle (Figure 2) to avoid suction of air into the container as the fluid volume was reduced with each injection. Oxygen is lethal for the obligate anaerobic Synergistes bacterium. When injection into the rumen was not properly executed, isolated cases of infections happened (resulting in subsequent animal mortality in one case). Therefore we changed to an oral application system (Figure 3), and doubled the dose to 20 mL/animal. This method has proven quite effective. When considering some basic rules, it is necessary to inoculate only a single group of animals per farm, as the ruminal bugs are readily transmitted from one animal to another within the same herd. Jones (1986) suggested that, Figure 1. Monthly liveweight gains (LWG) of steers (without mimosine-degrading bacteria) as a function of the time spent as Synergistes needs mimosine (or its metabolite 2,3-DHP) grazing on leucaena. as its major carbon and energy source, these organisms are lost from the rumen within 6‒9 months, after the Dealing with the mimosine toxicity problem delivery of substrate ceases when animals are no longer fed on leucaena. However, we observed mimosine toxicity In early 2003, INTTAS (Iniciativa para la Investigación symptoms in a group of dairy cows when they re-entered a y Transferencia de Tecnología Agraria Sostenible) leucaena fodder bank after a break of only 4 months contacted Dr Raymond Jones, the discoverer of the without access to leucaena. We assumed that the diet of the mimosine-degrading rumen bacterium Synergistes jonesii dairy cows, which was primarily silage and concentrate (Jones 1986), a retired senior scientist from the CSIRO feed, reduced the survival time of Synergistes in the rumen Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena in Paraguay 399 in the absence of mimosine. On commercial beef ranches ferralitic and slightly more acidic soils. This expansion some steers are usually kept as donor animals on leucaena was supported and driven by the active promotion of a pasture for most of the year. These animals are mixed with technology package for leucaena establishment and groups of ‘naïve’ steers to provide a source of inoculum management made public through numerous field days, when these groups enter leucaena for fattening. When active participation in agricultural expositions with fattened animals are sold, the lightest ones are usually held exhibition stands, pamphlets, extension videos (which back and mixed with the next group for fattening. were even broadcast on television) and a well-attended leucaena congress with international (including Australian) participation organized in the Chaco in 2005. The disseminated technology package covered all relevant aspects of leucaena establishment, including seedbed preparation, sowing methods, initial weed and pest (leaf-cutter ants) control and leucaena management under grazing. Acceptance of the technology was supported by the offer of a number of services provided by the R&D project INTTAS: general technical assistance to leucaena growers; provision of ruminal fluid containing Synergistes bacteria; and supply of leucaena seed, both the common Peru type and the new cultivar Tarramba (tree type, fast-growing and more frost- tolerant). By signing a contract with the Australian license holder, Leucseeds, INTTAS acquired the right to multiply and commercialize Tarramba seed in Paraguay (Figure 4) and was equipped with a prototype of a patented seed- Figure 2. Transmission of ruminal fluid with a rumen injection scarification device. Naegele (2005) summarized the gun supplied from a flexible rubber bottle to avoid suction of air. crucial points in leucaena management, while this information is also accessible on the INTTAS website [Glatzle et al. (2004, 2006, 2007); Klassen et al. (2007); Naegele et al. (2007)]. As a consequence of the active technology promotion, the area sown with leucaena in the Paraguayan Chaco increased rapidly to an estimated 10,000 ha within a few years, almost all of which (99%) was sown in twin rows at a distance of 5‒10 m into existing grass pastures (mostly Gatton panic). This was achieved after either total soil tillage or tillage of strips within the pasture (Figure 5), or, in more humid regions, sowing in combination with a crop (Figures 6 and 7). Animal production (finishing steers or bulls) per Figure 3. Oral application of ruminal fluid is less risky for the unit area and per head increased remarkably with the recipient animal but requires more restraint. incorporation of leucaena (Table 1; Figure 8). The responses in productivity to sowing of leucaena are generally smaller Large-scale adoption of leucaena feeding systems on in summer than in winter, when grass quality is low (Figure farms 9). About 5% of the total area sown with leucaena is represented by high density stands, used as fodder banks, The solution to the mimosine problem in 2003 was the mostly in smallholder dairy farms in the Chaco and in ‘launching pad’ for a rapid expansion of the area sown Eastern Paraguay. These are either directly grazed on an with leucaena in the semi-arid and subhumid Chaco hourly basis or used by cut-and-carry, partly offered as region (600‒1,200 mm of annual, summer-dominant chopped fodder while milking (Cabrera 2005). Dairy cows rainfall) with geologically young, mostly neutral to that had access to leucaena produced up to 2 liters more milk alkaline soils, as well as the more humid ecosystems in per day than those from the control group that grazed on Eastern Paraguay (1,200‒1,700 mm annual rainfall) with Gatton panic pasture only (Klassen et al. 2007). Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 400 A.F. Glatzle, A.N. Cabrera, the Late A. Naegele and N. Klassen Figure 6. Leucaena establishment in twin rows accompanied by a sorghum crop in the first year. Figure 4. Label of a bucket of Tarramba seed, harvested, processed and marketed in Paraguay under Australian license. Figure 7. Leucaena establishment with zero-tillage in strips in a soybean crop in humid Eastern Paraguay. Table 1. Carrying capacity and liveweight production per ha of steers grazing Gatton panic alone and Gatton panic with leucaena sown in twin rows (Glatzle and Klassen 2004). AU = Animal Unit = 450 kg live weight. Pasture Stocking density Liveweight gain (AU/ha) (kg/ha) Gatton panic 1.1 211 Gatton & 1.7 476 leucaena Figure 5. Leucaena sown in twin rows into Gatton panic Grazing period: 15.7.2003 to 15.4.2004, at Rio Verde, Chaco. pasture, previously tilled in strips. Steers had been inoculated with Synergistes ruminal microflora. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena in Paraguay 401 others, very common in the dryer parts of the Chaco), where termites and rodents (tuco tuco, Ctenomys spp.) killed increasing numbers of leucaena plants, thinning out the stands. This is certainly due to the fact that these rodents and certain species of termites prosper particularly well on these light-textured soils in the dryer areas of the Chaco. In more humid zones, however, on clay soils and coarse sands, leucaena has usually persisted very well for at least a decade, even when a high saline ground water table was present (which apparently does not affect deep-rooting leucaena). In some years with particularly heavy frosts, leucaena not only lost its leaves but also died back to the base, from where plants re- sprouted vigorously in the next spring. Today, we Figure 8. Brahman bulls grazing leucaena sown in twin rows consider that the total area sown to leucaena in Paraguay in Gatton panic pasture. has found an equilibrium slightly below the 10,000 ha level, with a balance between newly established leucaena pastures and those lost due to rodents and ants. However, particularly among smallholders, leucaena has been well adopted as a source of forage and firewood, and is very common in fodder banks in the home gardens of small-scale producers. Conclusions Leucaena is a highly productive and valued tropical/ subtropical forage legume, well adapted to most regions of Paraguay. While the mimosine toxicity problem prevented earlier integration into the country’s feeding Figure 9. The presence of leucaena in pastures boosts animal systems, introduction of the mimosine-degrading bacteria performance, particularly in winter, when grass is dry and of in 2003 removed this impediment. From that time, the low quality. area sown to leucaena (either in twin rows into grass pastures or as high-plant-density fodder banks) increased The present situation and leucaena persistence rapidly until it found a new equilibrium between new establishments and die-offs, mainly due to pests. Today, When external funding of the R&D project INTTAS on hundreds of Paraguayan farms (large-scale as well as ended in 2007, the services provided to farmers could no smallholders) leucaena represents an integral part of the longer be maintained. Seed production became virtually a feeding systems, mainly for steer fattening and dairy cow matter of farmers’ own initiatives (which presented supplementation. Although the initial dynamics of few concerns in Paraguay as labor costs are low and leucaena expansion have slowed down considerably, the minimal seed is required per hectare). Mechanical seed past decade can be considered as a consolidation phase, scarification is available nowadays from a private seed which allowed the documentation of where leucaena is grower, and ruminal fluid containing Synergistes from a well adapted and persistent. Hundreds of thousands of local cooperative in the Chaco. However, the absence of hectares of country in Paraguay are suitable for leucaena, active promotion and associated services offered from the respective technology packages are available and a single entity has considerably reduced the rate of improved animal performance has been demonstrated. If expansion of leucaena feeding systems during the past another promotional campaign (which would require 10 years. Furthermore, major areas of well-established some funding and considerable enthusiasm) could be leucaena pastures have been progressively lost, mounted, it might trigger renewed interest in leucaena particularly in zones with an average annual rainfall of with another increase in area sown and corresponding <800 mm and with silty, powdery soils (fluvisols and increases in animal production. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 402 A.F. Glatzle, A.N. Cabrera, the Late A. Naegele and N. Klassen References Duerksen T; Giesbrecht K. 2007. TARRAMBA: Nuevo (Note of the editors: All hyperlinks were verified 16 August 2019.) cultivar de leucaena, Leucaena leucocephala. Iniciativa para la Investigación y Transferencia Agraria Sostenible Cabrera AJN. 2005. Leucaena leucocephala [(Lam.) de Wit.], una (INTTAS), Loma Plata, Paraguay. goo.gl/mjRnpz opción forrajera para las pequeñas y medianas fincas ganaderas Jones RJ. 1986. The use of rumen bacteria to overcome Leucaena del Chaco. In: Glatzle A; Klassen P; Klassen N, eds. 2005. toxicity. Tropical Grasslands 20:88‒89. goo.gl/g51B3X Leucaena y otras leguminosas con potencial para el Chaco. Jones RJ; Megarrity RG. 1986. Successful transfer of DHP- Congreso internacional. Iniciativa para la Investigación y degrading bacteria from Hawaiian goats to Australian Transferencia de Tecnología Agraria Sostenible (INTTAS), ruminants to overcome the toxicity of Leucaena. Australian Loma Plata, Paraguay, 9‒11 March 2005. p. 19‒24. Veterinary Journal 63:259‒262. doi: 10.1111/j.1751-0813. Cabrera AJN; Idoyaga D; Martínez D; Lajarthe GJ. 1999. Uso 1986.tb02990.x de la Leucaena leucocephala como forraje invernal en el Klassen N. 2005. Producción animal con Leucaena en el Chaco. Chaco Paraguayo. In: Paniagua RJ, ed. 1999. El Ingeniero In: Glatzle A; Klassen P; Klassen N, eds. 2005. Leucaena y Agrónomo: La realidad agraria nacional y los desafíos del otras leguminosas con potencial para el Chaco. Congreso nuevo milenio. III Congreso Paraguayo de Agronomía, San internacional. Iniciativa para la Investigación y Lorenzo, Paraguay, 2‒3 December 1999. p. 6‒8. Transferencia de Tecnología Agraria Sostenible (INTTAS), goo.gl/5uYsoi Loma Plata, Paraguay, 9‒11 March 2005. p. 4‒16. Glatzle A. 1999. Compendio para el manejo de pasturas en el Klassen N; Knelsen E; Nägele A. 2007. Potencial de Leucaena Chaco. Editorial El Lector, Asunción, Paraguay. en la producción de leche en el Chaco. Iniciativa para la Glatzle A; Klassen N. 2004. Consorciación de gramíneas y Investigación y Transferencia Agraria Sostenible leguminosas inclusive Leucaena, y suplementación estra- (INTTAS), Loma Plata, Paraguay. goo.gl/nqWmmu tégica. Memorias XI Congreso Internacional del Consorcio Naegele A. 2005. Experiencia con la siembra de Leucaena en de Ganaderos para Experimentación Agropecuaria (CEA), pasturas chaqueñas. In: Glatzle A; Klassen P; Klassen N, Asunción, Paraguay, 1‒2 November 2004. p. 121‒137. eds. 2005. Leucaena y otras leguminosas con potencial para Glatzle A; Nägele A; Klassen N. 2004: Manejo de la Leucaena el Chaco. Congreso internacional. Iniciativa para la para la invernada. Iniciativa para la Investigación y Investigación y Transferencia de Tecnología Agraria Transferencia Agraria Sostenible (INTTAS), Loma Plata, Sostenible (INTTAS), Loma Plata, Paraguay, 9‒11 March Paraguay. goo.gl/gq7xLR 2005. p. 25‒29. Glatzle A; Cabrera A; Klassen N. 2006. ¿Cómo solucionar el Naegele A; Glatzle A; Neufeld B; Báez H; Reimer L; Harder S. problema de la Mimosina? Iniciativa para la Investigación y 2007. Recomendaciones referentes a la instalación de Transferencia Agraria Sostenible (INTTAS), Loma Plata, Leucaena. Iniciativa para la Investigación y Transferencia Paraguay. goo.gl/k1PHZY Agraria Sostenible (INTTAS), Loma Plata, Paraguay. Glatzle A; Nägele A; Hirsch R; Klassen N; Neufeld B; Fast A; goo.gl/EXjsP2 (Accepted 26 October 2018 by the ILC2018 Editorial Panel and the Journal editors; published 3 September2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):403–406 403 DOI: 10.17138/TGFT(7)403-406 ILC2018 Poster and Producer paper* Leucaena feeding systems in Cuba Sistemas de alimentación con leucaena en Cuba TOMÁS E. RUIZ1, GUSTAVO J. FEBLES1, EMILIO CASTILLO1, LEONEL SIMÓN2, LUIS LAMELA2, ISMAEL HERNÁNDEZ2, HUMBERTO JORDÁN1, JUANA L. GALINDO1, BERTHA B. CHONGO1, DENIA C. DELGADO1, GUSTAVO JACINTO CRESPO1, NURYS VALENCIAGA1, ORESTES LA O1, JATNEL ALONSO1, DELIA M. CINO1, SANDRA LOK1, FRANCISCO REYES2, MARCOS ESPERANCE2, JESÚS IGLESIAS2, MARTA HERNÁNDEZ2, TANIA SÁNCHEZ2, ARÍSTIDES PÉREZ2 AND MILDREY SOCA2 1Instituto de Ciencia Animal, Ministerio de Educación Superior, San José de las Lajas, Cuba. ica.edu.cu 2Estación Experimental de Pastos y Forrajes Indio Hatuey, Perico, Matanzas, Cuba. ihatuey.cu Keywords: Beef production, environmental benefits, grass-legume mixtures, milk production, profitability, protein banks, tree legumes. Introduction There were problems with weediness during the establishment phase, and with overgrazing and general The utilization of leucaena (Leucaena leucocephala) for management of the pastures, partly due to a lack of economic ruminant production by farmers in Cuba began during the resources. The first grazing after sowing occurred when a 1980s based on the concept of protein banks covering 100% plant height of 120‒140 cm was reached (Ruiz and Febles of the grazing area. In the last decade, a National Program to 2012). promote silvopastoral systems with leucaena in the livestock After 4 years of growth, plants were pruned to limit production sector was developed with the participation of woody growth and maximize edible biomass production. 1,543 cattle farms with an emphasis on milk production. The The height of pruning was 0.5 m with decumbent star grass cattle farms occupied 20,000 ha of which 7,000 ha was as and 1 m with the more erect guinea grass. Pruning occurred protein banks, while the remaining area was planted with from January to March to maximize availability of forage leucaena in association with grasses. Most of the work was during the dry season or from April to June when quicker carried out within the research agenda of the Instituto de regrowth was required. Ciencia Animal (ICA). The commercial varieties of leucaena used were mainly Physiology of the rumen cv. Peru and to a lesser extent cv. Cunningham. The area of each livestock farm ranged from 20 to 70 ha. The work was Ruminal bacteria capable of degrading mimosine and DHP developed with producers from both the State and non-State were isolated for the first time in Cuba (Galindo et al. 1995), sector. and their persistence in the rumen of animals under normal feeding conditions was confirmed. Other studies showed Establishment and plant management that there was no mimosine in the rumen of the cattle, sheep and goats consuming leucaena, and levels of DHP were non- Soil preparation for sowing was with strips when the existing toxic (Galindo et al. 2012). Hence, the inclusion of leucaena grass was retained (star grass – Cynodon nlemfuensis) or in the ration of animals even at levels up to 100% are with full cultivation when a new grass was introduced considered not to represent a potential danger for animal (guinea grass – Megathyrsus maximus). Following feeding in Cuba. inoculation of the seed planting occurred in double rows The effects of the inclusion of 4 levels of leucaena (0, 20, 0.70 m apart, with 3‒4 m inter-row spacing to achieve plant 40 and 60%) in a ration with star grass for rams was populations of 7,000‒8,000 trees/ha; fertilizer was not used. evaluated and it was shown that it was possible to include ___________ Correspondence: T.E. Ruiz, Instituto de Ciencia Animal, Carretera *Poster presented at the International Leucaena Conference, Central Km 47 1/2, San José de las Lajas, La Habana, CP 32700, 1‒3 November 2018, Brisbane, Queensland, Australia. Cuba. Email: teruizv@gmail.com Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 404 T.E. Ruiz et al. high levels of leucaena in the diet (Galindo 2001). The (5‒6 days occupancy) without fertilizer application or legume inclusion improved total digestibility of both fiber supplementation, and with a stocking rate of 2.0‒2.5 and dry matter consumed, and the nitrogenous fractions of animals/ha, gained 450 g/d (Mejías 2004; 2008). The results the rumen contents suggested that conditions for microbial were similar to those obtained by a second group under equal protein synthesis and by-pass protein availability for post- grazing conditions on a grass-only pasture but supplemented ruminal absorption were enhanced (Galindo et al. 2012). with 2 kg concentrate/animal/day. Bos taurus animals with Analysis of blood metabolites in fattening bulls with free an initial weight of 285‒300 kg reached puberty at 22 access to grazing of 100% leucaena showed normal values months with 77% first service conception rate. Calf birth of the thyroxine and tri-iodothyronine hormones (Castillo et weights were greater than 35 kg. In these systems more than al. 2012). 90% of the animals reached a body condition between 3.0 and 3.5 (Zarragoitia et al. 1992). As above, results were Animal production based on leucaena similar to those obtained by a group under equal grazing conditions on grass-only pastures but supplemented with 2 Dairy production kg concentrate/animal/day. With leucaena, associated with guinea grass, production per Beef production milking cow was 8‒9 L/day (Jordán 2001); annual production increased from 2,790 to 6,344 L/ha, and total Gains of 620 g/animal/day were recorded in a rotationally milk production from the project area rose from 53,056 to grazed leucaena-guinea grass pasture with a stocking rate of 119,136 L. The Holstein cows were supplemented with 2 animals/ha. These gains were 147% higher than on the 196 g concentrate/L of milk and stocking rate increased from grass-only paddocks (Castillo et al. 1989). 2 to 2.7 animals/ha. Milk production per cow in the When using natural grasses associated with leucaena at a leucaena-guinea grass system was similar to that of cows fed stocking rate of 2 animals/ha and rotationally grazing 4 N-fertilized guinea grass pasture and supplemented with paddocks, weight gains were 600 g/animal/day, when 588 g concentrate/L milk. The milk contained adequate supplemented during the dry period with sugarcane or levels of total solids (12‒13%), fat (3.5‒3.7%) and protein molasses and urea to 3%. Without leucaena, weight gains (3.2‒3.3%) (Jordán 2001). Likewise, with crossbred animals were 500 g/animal/day (Castillo et al. 1999). (more than 66% Holstein) production ranged between 8 and On a leucaena-star grass pasture, grazed at 3 animals/ha, 10 L/cow/d (Figure 1). There was a close link between the daily gains of 781 g/animal were achieved without increase in milk production and biomass of leucaena on offer supplementation (Castillo et al. 2012). Slaughter of the (Jordán 2012). animals occurred at 400 kg live weight and 26‒27 months of age with a hot carcass yield of 54% and 7‒8% of fat (Figure 2). The results obtained were similar to those obtained on star grass without leucaena but fertilized with 100 kg N/ha/year. Figure 1. Grazing of leucaena-star grass pasture by dairy animals. Performance of females F1 animals (10 months of age and 150 kg mean weight), in 6‒8 rotationally grazed leucaena-star grass paddocks Figure 2. Grazing of leucaena-star grass for beef production. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena feeding systems in Cuba 405 Improvement of the environment positive aspects were savings in the use of concentrates and a decrease in production costs. In a leucaena-guinea grass system, the initial plant The results obtained suggest that the present leucaena population of approximately 1,100 leucaena plants/ha technology is an economically viable option for livestock was adjusted to 400‒600 plants/ha after 4 years to avoid production in Cuba and other tropical countries. Further the negative effects of shade on the growth of the grass. research on its application and adoption is indicated. The chemical composition of the soil was improved by the recycling of nutrients, and there was an appreciable Dissemination of knowledge contribution of N from biological fixation and decomposition of the litter (Lok et al. 2005). The All personnel in the productive sector who participated in structural stability of the soil increased with time as soil the technology transfer process were systematically carbon storage was increased (Lok 2012), with the added trained. Particularly the need for systematic technical environmental benefit of reduced methane gas emissions assistance in the early stages of technology transfer (Galindo et al. 2012). became evident. Biodiversity increased when leucaena was present (Lok 2005), and earthworms reached highest frequency with References predominance of the species Polypheretima elongata, (Note of the editors: All hyperlinks were verified 11 August 2019.) Onychochaeta elegans and Diplotrema spp. Other indicators of biodiversity were the increased frequency of Arthropoda Castillo E; Ruiz TE; Puentes R; Lucas E. 1989. Produccion de followed by Annelida in the brown soils planted with a carne bovina en area marginal con guinea (Panicum maximum Jacq.) y leucaena (Leucaena leucocephala). I. mixture of guinea and star grasses and leucaena; and of Comportamiento animal. Revista Cubana de Ciencia Arthropoda, followed by Annelida, in red soils planted with Agrícola 23:137‒142. guinea grass and leucaena (Lok 2012). Castillo E; Ruiz TE; Febles G; Galindo J; Chongo B; Hernández J. With time, there was an increase in predatory 1999. Producción de carne bovina en pastos naturales Heteropsylla cubana, but the population did not reach asociados en el 100% del área de Leucaena leucocephala. harmful thresholds. The incidence and stability of the bio- Informe de etapa del Proyecto CITMA Territorial Habana. regulating Chilocorus cacti increased as well (Valenciaga Instituto de Ciencia Animal, La Habana, Cuba. 2003). Castillo E; Díaz A; Martín PC; Ruiz TE. 2012. Utilización de Leucaena leucocephala para la producción de carne bovina. Animal health In: Ruiz TE; Febles GJ; Lok S, eds. Experiencia en el manejo de Leucaena leucocephala para la producción animal en Cuba. Ediciones del Instituto de Ciencia Animal There was no harmful effect of mimosine or its derived (EDICA), Mayabeque, Cuba. p. 154‒164. product DHP (hydroxipyridone) on vital organs such as Cino DM; Castillo E; Hernández J. 2006. Alternativas de ceba the liver, thyroid, heart and thymus, and blood indicators vacuna en sistemas silvopastoriles con Leucaena leucocephala. were not affected when leucaena-star grass was fed Indicadores económicos y financieros. Revista Cubana de to livestock (Castillo et al. 2012). In comparison with Ciencia Agrícola 40:25‒29. bit.ly/2Kxk6jM grass-only diets, gastrointestinal nematode infestations Cino DM; Díaz A; Castillo E; Hernández JL. 2011. Ceba were reduced by 66% when leucaena was included. The vacuna en pastoreo con Leucaena leucocephala: Algunos indicadores económicos y financieros para la toma de main genera of parasites found were, in order of decisiones. Revista Cubana de Ciencia Agrícola 45:7‒10. importance, Haemonchus, Oesophagostomum, Cooperia bit.ly/2KH2MYo and Ostertagia (Soca et al. 2007). Body composition was Galindo J. 2001. Fermentación microbiana ruminal y pasaje also improved with a decrease of diarrhea and respiratory hacia las partes bajas del tracto gastro-intestinal de árboles diseases (Soca 2005). y arbustos de leguminosas. In: Ruiz TE; Febles G; Jordán H; Castillo E; Galindo J; Chongo B; Delgado D, eds. Economic impact on production systems Sistemas silvopastoriles: Una opción sustentable. Centro de Desarrollo Tecnológico Tantakin, Tzucacab, Yucatán, Mexico. p. 132‒151. In the livestock farms where this legume has been Galindo J; Geerken CM; Elias A; Aranda N; Piedra R; Chongo introduced, gross returns/ha/year ranged from 1,898 to B; Delgado D. 1995. Bacterias que degradan la mimosina, 4,056 Cuban pesos, and the benefit:cost ratio increased in el 2,3 dihidropiridona y 3 hidroxi-4 (1H) piridona en el the range of 2.5‒4.5. The economic analysis indicated that rumen. Revista Cubana de Ciencia Agrícola 29:53‒58. a lower proportion of income was needed to cover Galindo J; La O O; Delgado D; Marrero Y; González N; production expenses (Cino et al. 2006; 2011). Particularly Chongo B; Rodríguez R; Scull I. 2012. Efecto de Leucaena Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 406 T.E. Ruiz et al. leucocephala en la fisiología de rumiantes. In: Ruiz TE; Mejías R. 2004. Estudio de un ecosistema diversificado con Febles GJ; Lok S, eds. Experiencia en el manejo de gramíneas, leguminosas y árboles y su impacto en la Leucaena leucocephala para la producción animal en Cuba. producción de hembras bovinas para reposición. M.Sc. Ediciones del Instituto de Ciencia Animal (EDICA), Thesis. Instituto de Ciencia Animal, La Habana, Cuba. Mayabeque, Cuba. p. 47‒77. Mejías R. 2008. Sistema para la producción de hembras bovinas Jordán H. 2001. Los sistemas silvopastoriles para la producción de reposición con asociación de gramíneas-leguminosas. de leche en bovinos y caprinos. In: Ruiz TE; Febles G; Ph.D. Thesis. Instituto de Ciencia Animal, La Habana, Jordán H; Castillo E; Galindo J; Chongo B; Delgado D, eds. Cuba. Sistemas silvopastoriles: Una opción sustentable. Centro de Ruiz TE; Febles GJ. 2012. Establecimiento: Siembra, manejo Desarrollo Tecnológico Tantakin, Tzucacab, Yucatán, para el establecimiento y puesta en explotación. In: Ruiz TE; Mexico. p. 229‒254. Febles GJ; Lok S, eds. Experiencia en el manejo de Jordán H. 2012. Los sistemas silvopastoriles para la hembra de Leucaena leucocephala para la producción animal en Cuba. reemplazo y producción de leche en bovinos. In: Ruiz TE; Ediciones del Instituto de Ciencia Animal (EDICA), Febles GJ; Lok S, eds. Experiencia en el manejo de Mayabeque, Cuba. p. 31‒46. Leucaena leucocephala para la producción animal en Cuba. Soca M. 2005. Los nemátodos gastrointestinales de los bovinos Ediciones del Instituto de Ciencia Animal (EDICA), jóvenes. Comportamiento en los sistemas silvopastoriles Mayabeque, Cuba. p. 132‒153. cubanos. Ph.D. Thesis. Centro Nacional de Sanidad Lok S. 2005. Determinación y selección de indicadores del Agropecuaria (CENSA), La Habana, Cuba. sistema suelo-pasto en pastizales dedicados a la producción Soca M; Simón L; Roque E. 2007. Árboles y nemátodos de ganado vacuno. Ph.D. Thesis. Instituto de Ciencia gastrointestinales en bovinos jóvenes: Un nuevo enfoque de Animal, La Habana, Cuba. las investigaciones. Pastos y Forrajes 30(supl. 5):21‒33. Lok S. 2012. La fertilidad del suelo en sistemas ganaderos bit.ly/2N2pn4p donde se apliquen tecnologías basadas en Leucaena Valenciaga N. 2003. Biología, ecología y base teórica para leucocephala. In: Ruiz TE; Febles GJ; Lok S, eds. establecer las alternativas de manejo de Heteropsylla Experiencia en el manejo de Leucaena leucocephala para la cubana Crawford (Hemiptera: Psyllidae) en Leucaena producción animal en Cuba. Ediciones del Instituto de leucocephala (Lam.) de Wit. Ph.D. Thesis. Instituto de Ciencia Animal (EDICA), Mayabeque, Cuba. p. 103‒131. Ciencia Animal, La Habana, Cuba. Lok S; Crespo G; Frómeta S; Fraga S. 2005. Evaluación del Zarragoitia L; Elías A; Ruiz TE; Rodríguez J. 1992. Leucaena comportamiento de algunos indicadores agrofísicos, leucocephala y un concentrado de saccharina como biológicos y productivos en dos sistemas con utilización o suplemento para hembras bovinas en crecimiento en no de Leucaena leucocephala. Revista Cubana de Ciencia pastizales de gramíneas de secano. Revista Cubana de Agrícola 39:361‒366. bit.ly/2OVTAEW Ciencia Agrícola 32:263‒267. (Accepted 7 August 2019 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):407–409 407 DOI: 10.17138/TGFT(7)407-409 ILC2018 Poster and Producer paper* Use and performance of leucaena (Leucaena leucocephala) in Venezuelan animal production systems Uso de leucaena (Leucaena leucocephala) en sistemas de producción ganadera venezolanos EDUARDO E. ESCALANTE Formerly Universidad de Los Andes, Facultad de Ciencias Forestales y Ambientales, Mérida, Estado Mérida, Venezuela. forest.ula.ve Keywords: Alley hedgerow systems, protein banks, silvopastoral systems, tree legumes. Silvopastoral systems Use of leucaena One of the limitations for the efficient production of meat Livestock systems utilizing leucaena (Leucaena and milk in livestock systems of Venezuela is the scarcity leucocephala) were developed and promoted in the 1970s of high-protein forage from plants adapted to the acid and 1980s by various organizations, including the soils and prolonged droughts of the Llanos (savannas). National Center of Agricultural Research (CENIAP), the The Llanos cover an estimated area of 15‒20 M ha Venezuelan Central University (UCV) and Zulia predominantly in the southeast and southwest of the University (LUZ). Leucaena was used as a protein bank, country. They are mainly covered with native grasses alley/hedgerow grazing systems and living fences and (Trachypogon spp.), which have low carrying capacity more recently in intensive silvopastoral systems. The (0.10‒0.25 AU/ha; 1 AU = 450 kg bovine). uptake of leucaena as a strategic component for dairy In Venezuela silvopastoral systems are found mainly cattle has allowed farmers to increase the carrying in the tropical dry forest (1,000‒1,200 mm average annual capacity of their land as well as animal productivity. rainfall, AAR) of the savanna plains and the very dry In 2003 it was estimated that 800‒1,500 ha of leucaena tropical forest (800‒900 mm AAR) and semi-arid forage systems had been established in Venezuela, (700 mm AAR) environments of the country (Escalante distributed mainly in the states of the western central 1985). Other important production areas are south of Lake zone: states of Zulia, Falcón, Lara, Yaracuy, Táchira, Maracaibo in Zulia State and the intra-montane valleys in Trujillo, Barinas, Portuguesa, Cojedes and Aragua the central states of Aragua, Carabobo, Yaracuy, (Espinoza et al. 2003). At the present time it is estimated Portuguesa and Cojedes, as well as the highland dairy that the area planted with leucaena has significantly cattle ranch areas in the states of Táchira, Mérida and increased due to farmers’s interest. Trujillo. A significant limitation in the adoption of leucaena Despite the presence of some forage tree species that forage systems has been the limited availability and high are well adapted to savanna conditions, such as samán cost of planting material. This is particularly the case for (Samanea saman), matarratón (Gliricidia sepium) and protein banks where high densities of 10,000‒20,000 guácimo (Guazuma ulmifolia), their potential for plants/ha are required. Farmers have identified reduced intensive use in agroforestry systems has not been establishment costs, increased availability of high quality realized. Use of these species has been limited to living seed and of affordable good quality nursery seedling stock fences and providing shade for livestock. Only G. sepium as options for accelerating the adoption of leucaena planting. has been used in alley/hedgerow pastoral systems to a In an attempt to reduce cost of seed and improve its limited extent (Escalante 1985). availability, they often obtain seeds from neighbors and ___________ Correspondence: E.E. Escalante, Facultad de Ciencias Forestales y *Poster presented at the International Leucaena Conference, Ambientales, Universidad de Los Andes, Chorros de Milla, Mérida, 1‒3 November 2018, Brisbane, Queensland, Australia. Estado Mérida, Venezuela. Email: Escalan3e60@yahoo.com Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 408 E.E. Escalante establish their own nurseries to develop seedlings to grandis) and other valuable wood species were planted in transplant at the beginning of the wet season. Seeds are the borders around the plots as living fences (Figure 2). inoculated with Rhizobium spp. provided by either The system increased the carrying capacity from 1 AU/ha commercial companies or government agencies. Before to 3 AU/ha (Escalante et al. 2011) and daily milk yields planting, weed control is carried out and fertilizer is applied. by 1.5 L/cow. First grazing commences 4‒5 months after planting, when plants have reached a height of 150‒200 cm. Dairy producers who establish protein banks usually introduce the cattle for direct browsing of a small plot (e.g. 1,000 m2, depending on the size of the herd) for 2 hours after milking. After the plot has been browsed sufficiently the leucaena plants are pruned at a height of 90‒120 cm and allowed to regrow for 75‒90 days before they are grazed again. The alley/hedgerow system is also used in dairy production areas. Twin rows (100 cm apart) of leucaena plants are established, with 50‒100 cm between plants within rows. The twin hedgerows are usually separated by grass alleys (inter-row space) of 4 m wide. The estimated plant density of leucaena in these systems is 4,000‒8,000 plants/ha (Figure 1). Animals graze the grass and browse Figure 2. Intensive multi-stratified silvopastoral system of 5 the leucaena plants; after that the trees are pruned. leucaena rows in a guinea grass (Megathyrsus maximus syn. Panicum maximum) pasture with teak (Tectona grandis) planted around the border and samán (Samanea saman) in the middle of the grazing plot, established at the DANAC Foundation, Yaracuy State, Venezuela. Photo: E.E. Escalante. Selected scientific studies In studies conducted by FONAIAP (Fondo Nacional de Investigaciones Agropecuarias) in Zulia State, the agronomic performance of 90 leucaena accessions was evaluated (Faría-Mármol 1994). Dry matter (DM) yields of up to 10.4 t/ha were obtained for accessions CIAT 17129 and 10.9 t/ha for CIAT 17128, subjected to 9 harvests over a period of 315 days. CIAT 17129 produced Figure 1. Pasture alley/hedgerow system of African star grass almost 4 times as much edible DM in the rainy season as (Cynodon nlemfuensis) with twin hedgerow of Leucaena in the dry season (8.5 t/ha vs. 2.2 t/ha) and crude protein leucocephala at Fundación para el Desarrollo Agrícola, (CP) concentration was 27.3% in the wet and 21% in the DANAC Foundation, Yaracuy State, Venezuela. Photo: E.E. dry season. Escalante. A survey of 60 randomly selected dual-purpose farms In 2002, a diversified multi-stratified intensive in Trujillo State determined the level of adoption of silvopastoral system of 4.2 ha was established at the leucaena as a grassland improvement strategy (Osechas et DANAC Foundation, Yaracuy State. In plots 20 m wide al. 2008). Pastures on most of the farms were based upon a central row of leguminous trees, e.g. samán, cují either guinea grass or African star grass (Cynodon (Prosopis juliflora) and cañafistola (Cassia moschata), nlemfuensis). The survey found 21.1% of the farmers used was established to provide shade, comfort and edible L. leucocephala as a protein supplement for grazing pods. Five rows of leucaena were planted on each side of livestock. Leucaena pastures were intensively grazed for the central leguminous tree row, at a spacing of 1 × 1 m 2–4 days, then rested for 30–40 days. Mean milk yields of within a guinea grass (Megathyrsus maximus syn. cows and animal liveweight gains of beef cattle were 5.12 Panicum maximum) pasture. This system requires a L/cow/d and 389 g/hd/d, respectively during the rainy leucaena plant density of 5,000 plants/ha. Teak (Tectona season. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena in Venezuela 409 A study carried out by Torres et al. (2002) determined References the optimal distance of sowing configuration for leucaena (Note of the editors: All hyperlinks were verified 11 August 2019.) seed production. A planting configuration of 2 × 2 m increased seed yields and seed size and weight in Blanco C; Palma M; Machuca X; Castro K; Rodríguez H. 2015. comparison with 1 × 1 m. Seed quality (germination Bromatología de tres especies forrajeras en la zona sur del estado Anzoátegui, Venezuela. Revista Facultad de percentage) was not affected. Agronomía (UCV) 41(suplemento 1):49. bit.ly/2Tp8jGM The forage quality of leucaena, matarratón and casco Escalante EE. 1985. Promising agroforestry systems in Venezuela. de vaca (Bauhinia forficata) was compared in terms of Agroforestry Systems 3:209–221. doi: 10.1007/BF00122644 crude protein, ash and ether extract concentrations Escalante E; Guerra AJ; Martínez R; Alirio P. 2011. The (Blanco et al. 2015). Leucaena had the highest values for multispecies agroforestry system of the DANAC Foundation in crude protein (28.6%), ash (17.2%) and ether extract tropical dry forest landscapes of Yaracuy, Venezuela (a case (7.3%) concentrations. This demonstrates the excellent study). In: Montagnini F; Francesconi W; Rossi E, eds. nutritive value of leucaena as a protein supplement to Agroforestry as a tool for landscape restoration. Nova Science tropical grass forage. Publishers Inc., New York, USA. p. 69–81. Rodríguez et al. (2015) conducted a study to compare Espinoza F; Hernández RA; Folache L. 2003. Etología de vaquillas doble propósito en un sistema silvopastoril durante the agronomic performance of leucaena and mulberry el período seco en una sábana tropical. Zootecnia Tropical (Morus spp.). Leucaena grew taller than mulberry (124 26:429–437. bit.ly/2OQy5p2 vs. 94 cm; P<0.01) and produced higher DM yields (295 Faría-Mármol J. 1994. Evaluación de accesiones de Leucaena vs. 210 g/plant; P<0.01); it was most productive when en el bosque muy seco tropical del Estado Zulia, Venezuela. harvested at a cutting height of 50 cm. Revista Facultad de Agronomía (LUZ) 11:43–52. Osechas D; Becerra L; Rodríguez I. 2008. Uso de Leucaena Conclusions leucocephala como recurso forrajero en fincas doble propósito del estado Trujillo, Venezuela. Agricultura The review of literature and the author’s personal Andina 14:49–58. saber.ula.ve/handle/123456789/29370 experience suggest that there is still great potential for Rodríguez V; Benezra MA; Ríos de Álvarez L; Espinoza F; Beatriz B. 2015. Evaluación de variables estructurales en leucaena to improve the carrying capacity and plantas de Leucaena leucocephala (Lam.) de Wit y Morus productivity of beef and dairy systems in the Venezuelan sp. Revista Facultad de Agronomía (UCV) 41(suplemento savannas and other milk production areas. Additional 1):57. bit.ly/2Tp8jGM research effort is required to determine if leucaena Torres A; Alvarado A; Chacón E; Zerpa A; Romero R. 2002. systems are adapted to the acid infertile savanna soils, Producción de semilla de Leucaena leucocephala (Lam) de where a marked dry season combined with poor quality Wit en Venezuela. Memorias, XI Congreso Venezolano de grasses is a severe limitation for efficient livestock Producción e Industria Animal, Valera, ULA-Trujillo, production. Venezuela, 22‒26 Octubre 2002. (Accepted 16 May 2019 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):410–414 410 DOI: 10.17138/TGFT(7)410-414 ILC2018 Keynote Paper* Tarramba leucaena: A success story for smallholder bull fattening in eastern Indonesia Leucaena Tarramba: Un caso de éxito para el engorde de toros en el este de Indonesia JACOB NULIK1, DEBORA KANA HAU1, MICHAEL J. HALLIDAY2 AND H. MAX SHELTON3 1The East Nusa Tenggara Assessment Institute for Agriculture Technology, Kupang, Indonesia. ntt.litbang.pertanian.go.id 2The University of New England, Armidale, NSW, Australia. une.edu.au 3School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD, Australia. agriculture.uq.edu.au Abstract Leucaena (Leucaena leucocephala) cv. Tarramba was first introduced to eastern Indonesia (East and West Nusa Tenggara Provinces) as part of an ACIAR project in 2001‒2003. Its superior value was recognized immediately as it: was preferred by cattle over local leucaena; was less affected by psyllids; provided better dry season growth; and produced poles suitable for construction. In on-farm Bali bull feeding demonstrations, Tarramba leucaena doubled weight gains compared with traditional practices, enabling the most progressive farmers to win local bull-fattening competitions. Owing to strong demand for seed, the East Nusa Tenggara Assessment Institute for Agriculture Technology, in collaboration with the Provincial Livestock Department, assisted smallholders to establish seed orchards to ensure that professionally produced and packaged Tarramba seed was available for commercial sale. By the end of the ACIAR involvement, approximately 2,000 kg of Tarramba seed had been distributed to farmers, in addition to farmer-to-farmer seed sales. Approximately 800,000 ha of land in East Nusa Tenggara Province is suitable for Tarramba leucaena so the potential for this legume to contribute to beef production in the region is huge. Tarramba is now contributing to forage development in other parts of Indonesia as well as in Timor-Leste. Keywords: Liveweight gains, seed production, tree legumes. Resumen Leucaena (Leucaena leucocephala) cv. Tarramba se introdujo por primera vez en el este de Indonesia (provincias de Nusa Tenggara Oriental y Nusa Tenggara Occidental) como parte de un proyecto de ACIAR en 2001‒2003. Inmediatamente se reconoció el valor superior de este cultivar, debido a: fue preferido por el ganado en comparación con la leucaena local; fue menos afectada por psílidos (insectos de la familia Psyllidae); creció mejor en la época seca; y produjo postes de madera para la construcción. En demostraciones de engorde de toros de la raza Bali (Bos javanicus), se duplicaron las ganancias de peso vivo de los animales con el cv. Tarramba en comparación con las prácticas tradicionales, lo que les permitió a algunos agricultores innovadores ganar concursos locales de engorde de toros. Debido a la fuerte demanda de semilla, East Nusa Tenggara Assessment Institute for Agriculture Technology, en colaboración con Provincial Livestock Department, trabajó con pequeños agricultores para establecer semilleros con el fin de asegurar que la semilla de Tarramba sea producida y empacada profesionalmente, y estuviera disponible en el mercado. Finalizado el proyecto de ACIAR, se habían distribuido aproximadamente 2,000 kg de semilla de Tarramba, además de las ventas de semilla de agricultor a agricultor. Solo en la provincia Nusa Tenggara Oriental existen aproximadamente 800,000 ha de tierra apta para la leucaena cv. Tarramba; por tanto su potencial para contribuir a la producción de carne en la región es muy alto. El éxito de Tarramba en el este de Indonesia está ahora contribuyendo al desarrollo de leucaena en otras partes del país, así como en Timor-Leste. Palabras clave: Árboles leguminosos, ganancia de peso, producción de semilla. ___________ Correspondence: Jacob Nulik, East Nusa Tenggara Assessment *Keynote paper presented at the International Leucaena Conference, Institute for Agriculture Technology, Jl. Timor Raya Km 32, 1‒3 November 2018, Brisbane, Queensland, Australia. Kupang, NTT., Indonesia. Email: Jacob_nulik@yahoo.com Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tarramba leucaena in eastern Indonesia 411 Introduction Success with smallholder cattle fattening enterprises Leucaena leucocephala or ‘Lamtoro’ has been well Apart from the improved characteristics of the cultivar known for decades in eastern Indonesia. However, until outlined above, Tarramba leucaena demonstrated the early 2000s, apart from limited usage of what was excellent results in on-farm trials with smallholders termed ‘local’ leucaena for feeding cattle in Sumbawa and (Shelton 2017). Timor (Nulik 1998; Piggin and Nulik 2005; Panjaitan et A one-year feeding experiment to study growth of Bali al. 2014), there was minimal on-going interest in the cattle (Bos javanicus) from weaning to market weight species. This resulted from inadequate knowledge by during the first phase of the ACIAR project demonstrated many farmers of the value of the species as fodder for to farmers that feeding Tarramba leucaena to cattle cattle as well as to the availability of relatively large areas doubled weight gains compared with their traditional of native grassland for free grazing (Kana Hau et al. practices (Figure 1). In particular, a ration comprised of a 2014). Many farmers in Indonesia believed that the ‘local’ mixture of Tarramba leucaena with grasses and fresh variety of leucaena was unpalatable to cattle. Finally, the cassava tubers was among the most popular adopted by arrival of the psyllid insect (Heteropsylla cubana) in the collaborating farmers. Using this method of feeding, late 1980s devastated existing stands of leucaena and put yearling weaned calves increased weight from an initial an end to further plantings. average of 90‒100 kg to 250‒300 kg within 12 months. Conventionally, this market weight is achieved at 3 years The introduction of Tarramba leucaena to Indonesia of age after intensive stall feeding or at 4‒5 years of age from traditional free grazing on native grasslands. Leucaena leucocephala cv. Tarramba (syn. accession K636) was released for commercial use in 1995. It was described as more cold- and frost-tolerant than other varieties of L. leucocephala available at the time, but not competitive with other Leucaena spp., such as L. diversifolia and L. pallida, known for their cool tolerance at high elevations in Hawaii. However, it was known to display some tolerance of the leaf-sucking insect Heteropsylla cubana, largely due to its ability to continue growth through lateral branching while under psyllid pressure. Trials in Hawaii and Australia showed it to be superior in growth and yield to other accessions of L. leucocephala available at the time, when infested by the psyllid (Dalzell et al. 2006). It also displayed less branching than cv. Cunningham, being quite arboreal in growth habit. It was not until 2001‒2003 that cultivar Tarramba was Figure 1. Bali bulls fed Tarramba leucaena. introduced to eastern Indonesia (East and West Nusa Tenggara Provinces), as a component of the ACIAR The most efficient farmer participant in this feeding project ‘Leucaena management in West Timor and Cape demonstration won a beef cattle fattening competition York’. There was immediate recognition of the superior with his Bali bull that had reached 400 kg at 2 years value of Tarramba leucaena, which was found to be (Figure 2). The achievement was published in the local preferred by cattle over other available cultivars/varieties, newspaper with a statement from the farmer concerning less affected by psyllids, leafier and lasting longer into the the benefits of the feeding ration he had applied. Other dry season, thus providing better growth through to the participating farmers from the new areas developed with peak of the dry season, and to produce suitable poles for Tarramba in the Fatuleu Region of Kupang district also door and window frames, house construction and other started to win championship awards in the 2018 local beef uses (Kana Hau and Nulik 2012). Understanding the cattle competitions. barriers to adoption of leucaena (Kana Hau et al. 2014) There is now strong demand for seed of Tarramba was the major achievement of the ACIAR project, as cv. leucaena in these regions. Accordingly, much effort has Tarramba now has a huge reputation among Government been devoted to both the technical aspects of seed officials and farmers alike; it is widely accepted as vastly production and the logistics of establishing an on-going superior to ‘local’ varieties and cv. Cunningham. seed supply network. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 412 J. Nulik, D. Kana Hau, M.J. Halliday and H.M. Shelton Figure 2. Bali bull fed leucaena wins fattening competition. Figure 4. Tarramba leucaena seed produced by smallholders. How smallholders grow, manage and feed Tarramba leucaena The East Nusa Tenggara Assessment Institute for Agriculture Technology, in collaboration with the Provincial Livestock Department, worked with smallholders to increase the number of seed orchards of this cultivar. The village of Kuenheun in Timor was initially chosen due to lack of contamination with local naturalized leucaena and the enthusiastic support of the local authority. Procedures were introduced to ensure that a professionally produced and packaged product was available for commercial sale (Figures 3‒4). Figure 5. Seedlings grown in polybags ready for transplanting. Tarramba seed was distributed to farmers and propagated in a variety of ways to produce seedlings, Encouraged by the good price for seed due to the high including in polybags (Figure 5) and from bare-stem demand, in the second phase of the ACIAR project new gardens (Figure 6), for transplanting in the field when village areas were developed and contributed to the seedlings were >50 cm tall. They were protected from supply of seeds. grazing until they reached a height of >4 m. Figure 6. Bare-stem seedling showing where it is to be cut Figure 3. Mature seed of Tarramba leucaena. prior to transplanting. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tarramba leucaena in eastern Indonesia 413 Some farmers independently produced and sold The most acceptable seed production system resulted Tarramba seed, while others marketed Tarramba foliage when farmers grew their own trees on their own land, (Figure 7), as a secondary product, to other farmers in the as farmer group plantings encountered problems in nearby villages and to the nearby cattle market at Lili in effectively sharing the proceeds from sale of seed. West Timor. Farmers adopted a practice of preserving those branches that produced pods, while cutting branches Conclusions and Recommendations that did not produce seeds to feed to their animals or to sell to other farmers. Other farmers intercropped their Tarramba leucaena has been successfully introduced and Tarramba leucaena with horticultural crops (Figure 8). developed in eastern Indonesia, where it provides not only good quality forage for smallholder cattle fatteners, but also cash income from the sale of seed, which is in strong demand. The success of Tarramba is contributing to forage development in other parts of Indonesia (Sumatra, Kalimantan and Java) and in Timor-Leste. The demand for Tarramba seed continues to increase and is indicative of the interest in expanding the use of forage tree legumes for fattening cattle. Seed production is best conducted on individually owned land as profit-sharing from communal village plantings has created difficulties. In East Nusa Tenggara Province alone, there are >800,000 ha of suitable land available to grow Tarramba. Accordingly, there is a huge potential market for seed for the next 20 years. Ultimately, a private investor or investors Figure 7. Tarramba leucaena cut-and-carried for feeding. should be encouraged to organize the seed business to ensure a sustainable market supply as demand increases. The superiority of leucaena cv. Tarramba for the dry conditions of eastern Indonesia, especially for marginal lands (coral limestone Mollisols and Alfisol soils) of eastern Indonesia (West Timor, East Nusa Tenggara and Sumbawa, West Nusa Tenggara), and its multiple uses will ensure expanding demand for seed to supply the increasing demand for beef from other parts of Indonesia. References (Note of the editors: All hyperlinks were verified 20 August 2019.) Dalzell SA; Shelton HM; Mullen BF; Larsen PH; McLaughlin Figure 8. Regrowth of Tarramba leucaena after cutting inter- KG. 2006. Leucaena: A guide to establishment and cropped with dragon fruit. management. Meat & Livestock Australia, Sydney, Australia. bit.ly/2YHs66P Farmers obtained excellent prices for good quality Kana Hau D; Nulik J. 2012. Potency of re-promoting use of Tarramba seed, e.g. farmers from Oebola Dalam received Leucaena in supporting cattle production and land conser- up to A$ 4,500 for 600 kg of Tarramba seed in 2015. vation in East Nusa Tenggara. Proceedings of International During the life of the project, almost 3,000 kg of Tarramba Conference on Livestock Production and Veterinary seed were collected and approximately 2,000 kg seed were Technology, Bogor, Indonesia, 2012. p. 234–251. Kana Hau D; Panjaitan T; Nulik J; Dahlanuddin; van de Fliert re-distributed to various locations within and outside the E. 2014. Barriers to and opportunities for the use of forage Provinces of East and West Nusa Tenggara. Seed tree legumes in smallholder cattle fattening systems in production has continued to increase and by November Eastern Indonesia. Tropical Grasslands-Forrajes Tropicales 2018, almost 5,000 kg of seed were sold for distribution to 2:79–81. doi: 10.17138/tgft(2)79-81 various places in Indonesia and to Timor-Leste (Kana Hau Nulik J. 1998. The use of Leucaena leucocephala in farming and Nulik unpublished data). systems in Nusa Tenggara, Eastern Indonesia. Proceedings Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 414 J. Nulik, D. Kana Hau, M.J. Halliday and H.M. Shelton of the Third Regional Meeting of the Forages for Piggin C; Nulik J. 2005. Leucaena: Sustainable crop and Smallholders Project, Samarinda, East Kalimantan, livestock production systems in Nusa Tenggara Timur Indonesia, 23–26 March 1998. p. 178–182. hdl.handle.net/ Province, Indonesia. Tropical Grasslands 39:218. goo.gl/ 10568/56538 BgDmbh Panjaitan T; Fauzan M; Dahlanuddin; Halliday MJ; Shelton Shelton HM. 2017. Improving smallholder cattle fattening HM. 2014. Growth of Bali bulls fattened with Leucaena systems based on forage tree legume diets in eastern leucocephala in Sumbawa, Eastern Indonesia. Tropical Indonesia and northern Australia. Final report. Australian Grasslands-Forrajes Tropicales 2:116–118. doi: 10.17138/ Centre for International Agricultural Research (ACIAR), tgft(2)116-118 Canberra, ACT, Australia. goo.gl/b9RX5N (Accepted 16 December 2018 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):415–419 415 DOI: 10.17138/TGFT(7)415-419 ILC2018 Keynote Paper* Leucaena feeding systems in India Sistemas de alimentación con leucaena en la India NANDINI NIMBKAR Nimbkar Agricultural Research Institute (NARI), Phaltan, Maharashtra, India. nariphaltan.org Abstract Since its introduction to India in 1976 Leucaena leucocephala ssp. glabrata has spread rapidly, especially in the last couple of decades, mainly due to its use as either firewood or pulpwood. Use of its foliage for feeding livestock has been mainly a by-product of this activity. The foliage is highly nutritious because it has high protein concentration and good palatability, and the tree can withstand repeated defoliation. Research carried out by Indian scientists on leucaena has focused on mainly agronomic management, agroforestry studies of mixed cropping systems, mimosine toxicity, germplasm testing and economic evaluation. Feeding leucaena has had a positive impact on the dairy industry in particular. It is rarely purchased for fodder and is usually poached by smallholders from existing plantations, most of which are established by animal rearers for their own purposes. More widespread use of leucaena for fodder could be achieved in India by introducing varieties with either reduced seed production or sterile ones, which can be easily propagated vegetatively. In addition, psyllid resistance, suitable mechanized harvesting methods and training livestock owners in proper management of leucaena trees should help in making this high quality fodder more popular in India. Keywords: Fuelwood, leguminous tree fodders, pulpwood, silvopastoral systems. Resumen Desde su introducción a la India en 1976, Leucaena leucocephala ssp. glabrata se ha dispersado rápidamente, especialmente en las últimas dos décadas, sobre todo debido a su uso como leña o pulpa para papel. El uso de su follaje para la alimentación de ganado ha sido más bien un subproducto de esta actividad. El follaje es de alto valor nutritivo debido a su alta concentración de proteína y buena palatabilidad; a su vez esta especie arbustiva puede soportar defoliaciones frecuentes. Investigaciones llevadas a cabo en la India se han centrado en el manejo agronómico, estudios agroforestales en sistemas de cultivos mixtos, toxicidad de mimosina, evaluación de germoplasma y análisis económicos. La alimentación de ganado con leucaena ha tenido un impacto positivo sobre todo en la producción de leche. La leucaena es rara vez comprada para la utilización como forraje; generalmente los productores extraen su follaje de plantaciones existentes que en su mayoría son establecidas por criadores de ganado para sus propios fines. Un mayor uso de leucaena como forraje en la India se puede lograr mediante la introducción de variedades con escasa producción de semillas o hasta estériles, que se puedan propagar fácilmente en forma vegetativa. Además, variedades resistentes a los psilidos, métodos de cosecha mecanizada adecuados y capacitación de los propietarios de ganado en el manejo adecuado de los árboles de leucaena deberían contribuir a que este forraje de alta calidad se vuelva más popular en la India. Palabras clave: Árboles forrajeros leguminosos, leña, pulpa para papel, sistemas silvopastoriles. Introduction India from Mexico more than a century ago as a fast- growing species for afforestation. It spread rapidly into Leucaena leucocephala ssp. leucocephala (shrubby various habitats (Ghate 1991) and became naturalized. ‘common’ type) is supposed to have been introduced into After Dr J.L. Brewbaker (University of Hawaii) supplied ___________ Correspondence: Nandini Nimbkar, Nimbkar Agricultural Research *Keynote paper presented at the International Leucaena Institute (NARI), Tambmal, Phaltan-Lonand Road, P.O. Box 44, Conference, 1‒3 November 2018, Brisbane, Queensland, Australia. Phaltan – 415523, Maharashtra, India. Email: nnimbkar@gmail.com Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 416 N. Nimbkar seeds of L. leucocephala ssp. glabrata (arboreal Their rumen microflora have an ability to fully degrade ‘Hawaiian giant’ or ‘Salvador’ type) in 1976, the mimosine in high (>50%) leucaena diets within 2 weeks popularity of leucaena rapidly increased, mainly through from initial introduction (Ghosh et al. 2007). the efforts of the Bharatiya Agro Industries Foundation (BAIF), Pune. Adoption Leucaena leaf and small stems are a nutritious feed for all kinds of animals because they contain high protein Adoption of improved pasture systems such as those with concentration and are highly palatable, while the plants leucaena is very low owing to limited land availability, can withstand repeated defoliation. low producer confidence, establishment issues and costs The semi-arid climate in many parts of India and the and psyllid attack on existing varieties. pressure on land use have increased the importance of tree The pattern of adoption of leucaena in the and shrub fodders as components of feeds for ruminants M. Nidamanuru village of Andhra Pradesh state (Saigal compared with grasses or grass-herbaceous legume and Kashyap 2002) is representative of the situation in pastures. Many fodder trees are not cultivated and the most parts of India. The farmer who originally brought landless population, which owns small herds of sheep and leucaena to the area placed advertisements in the local goats, depends on accessing shrubs and tree feed papers and sold seeds from his plantations to farmers. resources growing near the villages, on roadsides and Over the next few years, leucaena planting spread rapidly community lands (Raghavan 1990). Although most trees in the village and in 2000, most farmers had some part of and shrubs used for animal feed are self-sown, in some their land planted to leucaena. Timber from stems was traditional farming systems in India, trees are planted with initially sold as firewood for tobacco curing barns but crops to provide sources of fuel and feed (Chen et al. subsequently the pulpwood market developed and 1991). Therefore, though the arboreal type of leucaena is farmers began growing leucaena to sell to the pulpwood a relatively new introduction to India, the farming system industry. Leucaena plantations had a positive impact on in which it is used is generally a traditional one. the dairy industry with village milk production increasing from 50‒60 L/day to 900‒1,000 L/day, due to the Research and development increased availability of nutritious fodder in the form of leucaena leaf. Fat content of the milk also reportedly Five areas of research have been the focus of concerted increased. Landless and marginal farmers were efforts by Indian scientists: agronomic management to apparently the main beneficiaries, as expenditure on optimize sustained yields; agroforestry studies of mixed buying fodder from the market was reduced by more than cropping systems; mimosine toxicity; germplasm testing; a third. Leucaena foliage was obviously poached from the and economic evaluation (Hegde and Gupta 1994). plantations and not purchased from their owners. While Some of the more extensive data on the effects of damage caused to the plantations through lopping and varietal or spacing differences on forage yields of grazing was significant, surprisingly, according to the leucaena in India are from BAIF Research Development authors of the report, plantation owners did not perceive Foundation (Relwani et al. 1983). The Indian Grassland this as a major problem and most did not object to it. In and Fodder Research Institute (IGFRI) at Jhansi the experimental plantations of cvv. Tarramba and conducted a series of leucaena alley farming trials with Wondergraze on Nimbkar Agricultural Research Institute crops such as maize, sorghum, buffel grass, millet and (NARI) lands leafy branches are also often seen broken napier grass with generally beneficial outcomes (Gill et and taken away by the surrounding livestock owners. al. 1982, 1983; Gill and Patil 1983, 1984, 1985). To illustrate adoption by a specific farmer, an From a survey of leucaena toxicity status based on interview was conducted with Mr Vikram Dattatray assays of urinary DHP excretions, it was concluded that Yadav on 16 May 2018 (Figures 1‒3). His farm is located India is one of the 8 countries protected from toxicity by at Yadav Wasti, Kala Odha, Shiravli, Tal. Baramati. He the presence of Synergistes jonesii (Jones 1994). had planted 0.4 ha of leucaena in 2016 using seed of However, more recently Pattanaik et al. (2007) reported variety K8 bought from BAIF for INR 225/kg (1 USD = that mimosine was rapidly converted to 3,4- 68 INR). He planted rows 120 cm apart with 30 cm dihydroxypyridine (3,4-DHP) post-ingestion resulting in spacing within rows, and supplied drip irrigation every 4 poor animal performance on otherwise high-quality days. He fertilizes with goat manure and cuts 4 times per pasture. While mimosine toxicity can be potentially year. Rogor (dimethoate 30 EC at 30 mL/15 L water) or severe, it is relatively short-term and is manifest only Nuvan (dichlorvos 76 EC at 40 mL/15 L water) is sprayed when animals are first introduced to high leucaena diets. for psyllid control during winter. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena feeding systems in India 417 than any other fodder, his fodder supply from the 0.4 ha was insufficient for the 74 goats year-round. There is currently no ready market for the wood produced. Profitability Under rainfed conditions, leucaena variety K636 (marketed in Australia as cv. Tarramba), either as a pure stand or in intercropping systems, recorded higher gross and net returns than arable cropping in Andhra Pradesh (Prasad et al. 2011). The main product was wood for industrial use. At our institute (NARI), in 5 plantations with a total area of 3.5 ha, we have planted cvv. Wondergraze and Figure 1. Mr Yadav’s leucaena plantation. Tarramba, which we intend to use for fodder and seed production, at a density of 2,644 plants/ha. During the first year, estimated fresh edible biomass production from cutting every 4 months was about 4,000 kg/ha per harvest. The expenditure including establishment and cutting costs came to INR 30,000/ha/yr, giving a cost of about INR 2.50/kg fresh edible biomass produced. Therefore the sale price of fresh fodder should be at least INR 3/kg. Since leucaena fodder can be easily harvested from naturalized areas at no cost, there is a limited market for the sale of leucaena forage. However, the main problem was that there were no buyers for the wood of small size (3‒5 cm diameter), as in the last 2‒3 years, availability of liquid petroleum gas for cooking, even in rural areas, has increased tremendously. Such a venture has a chance of becoming profitable only if the wood can be used for Figure 2. Re-sprouting leucaena in Mr Yadav’s plantation. industrial purposes such as production of paper pulp. Future relevance Some of the main reasons why leucaena was shunned by many farmers in India were its prolific seeding and resultant weediness. Moreover, being an aggressive species it was seen to adversely affect the growth of other species in agroforestry systems. Varieties such as K8 were also very susceptible to the psyllid pest (Heteropsylla cubana), which is especially damaging during the coldest 4 months (winter). While the trees do recover and there is rarely any mortality, growth and fodder yield suffer. In spite of high protein deficits in ruminant nutrition, leucaena is still underutilized in states like Kerala, owing to limited land availability for Figure 3. Mr Yadav’s goats feeding on leucaena. planting, low biomass yields and difficulty in harvesting (Raj et al. 2016). Mr Yadav has 74 Osmanabadi goats that he feeds To overcome the problems of weediness and psyllids, either leucaena or lucerne twice a day – the amount the outstanding hybrid KX2 shows promise as it is offered is not weighed. While he observed that his goats psyllid-resistant as well as practically seedless. However, gained weight at a relatively faster rate when fed leucaena since its saplings have to be produced by vegetative Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 418 N. Nimbkar propagation, supplying the quantity of planting material Mr Hari Shankar for getting the data and photographs of desired by farmers at an affordable price has proved Mr Vikram Yadav’s leucaena plantation. difficult. The new variety, cv. Redlands, recently released in Australia, may offer a partial solution, as it is psyllid- References resistant and easy to propagate from seed, although the (Note of the editors: All hyperlinks were verified 13 August 2019.) weediness potential remains. However, under a pasture- based model, ease of propagation from seed is definitely Chen CP; Halim RA; Chin FY. 1992. Fodder trees and fodder a major advantage for any fodder species. shrubs in range and farming systems of the Asian and Pacific region. In: Speedy A; Pugliese P-L, eds. Legume trees and Many farmers contacted by us reported ‘difficulty in other fodder trees as protein source for livestock. Proceedings harvesting’ as the main reason for leucaena not being used of the FAO Expert Consultation, Kuala Lumpur, Malaysia, 14‒ as widely as it should. They need to be made aware of 18 October 1991. p. 11‒22. bit.ly/31xNZpK planting patterns whereby double-row hedges of leucaena Ghate VS. 1991. Noteworthy plant invasions in the flora of can be formed, which can be trimmed every 3‒4 months Western Ghats of Maharashtra. Journal of the Bombay Natural by cutting at 1 m height from the ground. Depending on History Society 88:390‒394. biostor.org/reference/152965 the spacing between the hedges, grasses such as buffel Ghosh MK; Atreja PP; Buragohain R; Bandyopadhyay S. 2007. (Cenchrus ciliaris) or Chrysopogon fulvus can be planted Influence of short-term Leucaena leucocephala feeding on once leucaena is established. Mechanized harvesting milk yield and its composition, thyroid hormones, enzyme using small tractor-mounted machines may be another activity, and secretion of mimosine and its metabolites in milk of cattle. The Journal of Agricultural Science 145:407‒ solution to the problem. 414. doi: 10.1017/S0021859607007113 Companies like J.K. Paper Ltd. have established clonal Gill AS; Patil BD. 1983. Mixed cropping studies in leucaena seed orchards by first identifying Candidate Plus Trees under intensive forage production system. Leucaena from the existing plantations and then rooting the Research Reports 4:20. coppiced cuttings from these trees in mist chambers. The Gill AS; Patil BD; Yadav CL. 1982. Intercropping studies in saplings so developed are either utilized for setting up leucaena. Leucaena Research Reports 3:30. clonal seed orchards or establishing mother plants in Gill AS; Patil BD; Yadav CL. 1983. Intercropping studies in raised beds filled with sand as a source of juvenile coppice hybrid napier varieties associating leucaena and other cuttings for mass production. Thus farmers are supplied leguminous fodder shrubs. Leucaena Research Reports 4:21. with either seeds or rooted cuttings. Similarly, leucaena Gill AS; Patil BD. 1984. Crop association studies in leucaena under rainfed conditions. Leucaena Research Reports 5:24‒25. clones have also been developed by ITC Limited with Gill AS; Patil BD. 1985. Intercropping studies with leucaena their current planting level of about 3,000 ha/year under an intensive fodder production programme. Leucaena (Kulkarni 2013 pers. comm.). Research Reports 6:36‒37. Hegde NG; Gupta VK. 1994. Leucaena in India. In: Shelton Conclusions HM; Piggin CM; Brewbaker JL, eds. Leucaena ‒ opportunities and limitations. Proceedings of a workshop At present, large-scale plantations of leucaena like those held in Bogor, Indonesia, 24‒29 January 1994. ACIAR in Queensland, Australia are rarely seen in India, but Proceedings No. 57. ACIAR, Canberra, ACT, Australia. p. leucaena is quite commonly utilized as a fodder by 182‒185. bit.ly/2UphJVM Jones RJ. 1994. Management of anti-nutritive factors with livestock farmers. The source is leucaena trees from special reference to leucaena. In: Gutteridge RC; Shelton industrial plantations (such as for paper pulp), roadside HM, eds. Forage tree legumes in tropical agriculture. CAB trees and trees on field boundaries. International, Wallingford, UK. p. 216‒231. Availability of psyllid-tolerant cultivars which are Pattanaik AK; Khan SA; Goswami TK. 2007. Influence of sterile or seedless, but can be easily and cheaply iodine on nutritional, metabolic and immunological propagated via cuttings, will go a long way in response of goats fed Leucaena leucocephala leaf meal diet. popularizing leucaena fodder in India. Small tractor- The Journal of Agricultural Science 145:395‒405. doi: mounted or stand-alone harvesting machines, if available, 10.1017/S0021859607007058 should lead to more widespread use of this highly Prasad JVNS; Korwar GR; Rao KV; Srinivas K; Srinivasarao C; Pedababu B; Venkateswarlu B; Rao SN; Kulkarni HD. palatable, high-protein feed in India. 2011. On-farm evaluation of two fast growing trees for biomass production for industrial use in Andhra Pradesh, Acknowledgments Southern India. New Forests 42:51‒61. doi: 10.1007/ s11056-010-9236-6 I thank Mr Sharad Choudhari for making available the Raghavan GV. 1990. Availability and use of shrubs and tree data from NARI farms and Mr Prashant Salgude and fodder in India. In: Devendra C, ed. 1990. Shrubs and tree Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena feeding systems in India 419 fodders for farm animals. Proceedings of a workshop, Relwani LL; Mohatkar LC; Bhavsar GK; Nakat RV. 1983. Denpasar, Indonesia, 24‒29 July 1989. p. 196‒210. Effect of spacings and stubble heights on forage yields of hdl.handle.net/10625/20020 K-8 and Cunningham. Leucaena Research Reports 4:41. Raj RM; Raj AK; Kunhamu TK; Jammaludheen V; Prakash A. Saigal S; Kashyap D. 2002. The second green revolution: 2016. Fodder yield and nutritive value of subabul (Leucaena Analysis of farm forestry experience in Western Terai leucocephala Lam.) under diverse management regimes in region of Uttar Pradesh and coastal Andhra Pradesh. coconut garden. Indian Journal of Agroforestry 18:79‒85. Ecotech Services Private Limited, New Delhi, India. bit.ly/2KG7ZQa pubs.iied.org/pdfs/9185IIED.pdf (Accepted 9 January 2019 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):420–422 420 DOI: 10.17138/TGFT(7)420-422 ILC2018 Poster and Producer Paper* Leucaena as basal feed for meat goats in Prachuapkhirikhan Province, Thailand Leucaena como alimento base para cabras de carne en la provincia de Prachuapkhirikhan, Tailandia G. NAKAMANEE1, S. POATHONG2, T. CHANWARIN3 AND S. HARRISON4 1Nakhonratchasima Animal Nutrition Research and Development Center, Pakchong, Nakhonratchasima, Thailand 2Bureau of Animal Nutrition, Department of Livestock Development, Bangkok, Thailand. www.dld.go.th 3Prachuapkhirikhan Animal Nutrition Research and Development Center, Kuiburi, Prachuapkhirikhan, Thailand 4Srakaew Animal Nutrition Research and Development Center, Klonghad, Srakaew, Thailand Keywords: Cut-and-carry feeding, small ruminants, tree legumes. Introduction Table 1. Numbers of goats and farmers in Thailand and Prachuapkhirikhan Province in 2017 (DLD 2018b). Goat rearing for meat and milk has long been practiced in Thailand, mostly associated with the Thai Muslim Meat goats community. The Department of Livestock Development Male Female Farmers (DLD 2018a) estimated the total number of goats in All of Thailand 182,645 442,745 50,758 Prachuapkhirikhan 15,163 23,852 918 Thailand in 2017 at 653,000 with 34.3% located in the Dairy goats south. The productivity of goats depends largely on Male Female Farmers availability of pasture and other sources of feed, All of Thailand 8,586 18,988 1,780 which vary with site. This paper reports on the use of Prachuapkhirikhan 99 145 13 leucaena (Leucaena leucocephala) for goat feeding in Total Prachuapkhirikhan Province, which covers 6,368 km2 in Goats Farmers the central part of Thailand. All of Thailand 652,964 51,851 Prachuapkhirikhan 39,259 925 Goat population and number of farmers in Prachuapkhirikhan Province Production systems and feeding Prachuapkhirikhan Province is ranked 4th in terms of goat Breeding of kids for meat goat production numbers in Thailand with 39,260 goats or 6% of the country’s total. Most are meat goats with 50% Boer goat There are 2 production systems in this group: infusion (Table 1). While some male goats are castrated, a. A semi-intensive system in which breeding goats are most are left entire and fattened. grazed for 4‒6 hours per day (Figure 1) on naturally Based on recent statistics of the Department of occurring plants such as leucaena, desmanthus, Livestock Development (DLD 2018b), 36% of goat Pithecellobium dulce and native grasses. Fresh farmers in Prachuapkhirikhan keep 1‒20 head, 29% keep leucaena is fed as a supplement in pens in the evening 21‒40, 19% keep 41‒60, 11% keep 61‒100 and only 5% at a rate of 3‒5 kg/hd/d. The pens are in either elevated keep more than 100 animals. houses with slatted flooring or on the ground. ___________ Correspondence: G. Nakamanee, Nakhonratchasima Animal *Poster paper presented at the International Leucaena Conference, Nutrition Research and Development Center, Pakchong, 1‒3 November 2018, Brisbane, Queensland, Australia. Nakhonratchasima 30130, Thailand. Email: ganda.nak@gmail.com Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Goat feeding with leucaena 421 b. An intensive system (zero grazing) practiced mostly as a part-time activity and generally on a small scale with approximately 30‒40 head per farm. After finishing their main activity as a contingent worker in other agricultural activities, farmers cut leucaena, which is available naturally along the roadsides or in a public area, to feed their goats (Figure 2). While the basal feed is leucaena, napier grass (Cenchrus purpureus; syn. Pennisetum purpureum), pangola grass (Digitaria eriantha), ruzi grass (Brachiaria ruziziensis) and native grasses may be added. Farmers feed fresh Figure 3. Goats consuming leucaena leaf. leucaena at 7‒10 kg/hd/d, in the morning and in the evening. Goats consume leucaena leaf, young stems, pods and bark (Figures 3 and 4). The chemical composition of the leucaena varies with plant part. Unpublished data from Prachuapkhirikhan Animal Nutrition Research and Development Center indicate that leucaena leaf contains about 23% crude protein (CP), 19% crude fiber, 9% fat and 44% nitrogen-free extract. Bark contains 12% CP at 50 cm height and 15% CP at the tip of the stem; young pods contain 23% CP and pods with seeds contain 21% CP. In both systems, does kid twice per year and produce 2‒3 kids/year. Farmers sell weaned kids at about 15 kg Figure 4. Non-edible leucaena stem residue after feeding. (3‒4 months of age) or continue feeding them for 4‒5 months before selling them at about 25‒30 kg live Meat goat producers weight. Farmers generally buy weaned kids at 15 kg live weight and feed for 4‒5 months to about 25‒30 kg live weight achieving weight gains of 100‒150 g/d. Goats are sold by weight. In general, goat management is a confined intensive system. Other than grasses, leucaena has gained wide acceptance among goat farmers as a suitable basal feed due to its wide availability naturally and its high crude protein concentration. Goats are fed with combinations of feed sources, which vary among farms and seasons, including: a. Chopped leucaena (Figure 5) or chopped leucaena Figure 1. Free grazing. mixed with napier grass 1:1 supplemented with 300 g of pelleted concentrate feed with a total of 16% CP (e.g. 50% maize grain or broken rice, 10% rice bran, 26.5% coconut meal, 10% leucaena leaf meal, 1.5% urea, 1% dicalcium phosphate, 0.9% salt and 0.1% sulphur), half being fed in the morning and half in the afternoon. b. Chopped leucaena mixed with corn silage 1:1 (Figures 6 and 7). c. In the dry season, when production of leucaena is low, farmers feed leucaena and pineapple waste from Figure 2. Leucaena collected along roadside. pineapple jam factories. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 422 G. Nakamanee, S. Poathong, T. Chanwarin and S. Harrison There are no reports of toxicity symptoms due to mimosine and the main constraint that goat farmers face is low production of leucaena in the dry season. Figure 7. Leucaena and corn silage fed to goats. Acknowledgments Figure 5. Chopping leucaena. We thank Associate Professor Max Shelton and Dr Chaisang Phaikaew for their encouragement and advice. Secondly we send special thanks to farmers for their time and for sharing their information with us. References (Note of the editors: All hyperlinks were verified 20 August 2019.) DLD (Department of Livestock Development). 2018a. Information on livestock number in Thailand year 2017. DLD, Bangkok, Thailand. (in Thai) goo.gl/yL5of4 DLD (Department of Livestock Development). 2018b. Number of goats and farmers by province. DLD, Bangkok, Thailand. Figure 6. Leucaena and corn silage. (in Thai) goo.gl/NNjoPB (Accepted 25 October 2018 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in cooperation with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):423–427 423 DOI: 10.17138/TGFT(7)423-427 ILC2018 Keynote Paper* Leucaena feeding systems in Myanmar Sistemas de alimentación de ganado con leucaena en Myanmar A. AUNG Department of Physiology and Biochemistry, University of Veterinary Science, Yezin, Nay Pyi Taw, Myanmar. uvsyezin.edu.mm Abstract Agriculture and livestock provide the main source of income for farmers in Myanmar. As feeds with low nutritive value and digestibility are traditionally used for animal feed, alternative feed sources of better quality are needed to improve production levels. While concentrates can be used to improve the quality of diets, this leads to high feed costs. To solve this problem, researchers in Myanmar conducted trials to replace some concentrates with leucaena. The nutritive value of leucaena in Myanmar is relatively the same as found in other countries. Control of leucaena toxicity was also studied in Myanmar by isolating mimosine-degrading bacteria and managing the feeding of leucaena. While farmers in Myanmar are aware that leucaena can be fed to livestock and can be toxic to animals, they have limited knowledge of the real benefits of leucaena as a feed for animals. Research to demonstrate the potential of leucaena feeding to animals in Myanmar and efforts to promote establishment of leucaena stands are urgently needed. Keywords: Feeds, nutritive value, tree legumes, tropical pastures. Resumen La agricultura y la ganadería constituyen la principal fuente de ingresos para los agricultores de Myanmar. En vista de que tradicionalmente se usan forrajes de bajo valor nutritivo y digestibilidad para la alimentación animal, se necesitan fuentes de alimentación alternativas de mayor calidad para mejorar los niveles de producción. Si bien se podrían usar concentrados para mejorar la calidad de las dietas, esto conduce a altos costos de alimentación. Para resolver este problema, investigadores en Myanmar realizaron experimentos para reemplazar algunos concentrados con leucaena. El valor nutritivo de la leucaena en Myanmar es similar al que se encuentra en otros países. En Myanmar también se estudiaron el control de la toxicidad de la leucaena mediante el aislamiento de bacterias que degradan la mimosina, y el manejo de la leguminosa para la alimentación animal. Si bien los agricultores en Myanmar saben que la leucaena puede ser usada como alimento para el ganado, su conocimiento sobre los beneficios actuales de esta especie para la alimentación animal es aún limitado. En Myanmar se necesitan con urgencia tanto trabajos de investigación para demostrar el potencial de leucaena como alimento para los animales como apoyo para promover la siembra de leucaena. Palabras clave: Forrajes, leguminosas arbóreas, pasturas tropicales, semilla, valor nutritivo. Introduction development of productive and intensive livestock and agricultural systems (Aung Aung 2007). Livestock Increasing human population densities highlight the production contributes a large portion of household priority that must be placed on efficient land use for the income in developing countries. The economy of production of food and plantation crops. Globally, this Myanmar is largely based on agriculture and livestock are demographic pressure leads to increased emphasis on the a vital component of the nation’s economy; livestock and ___________ Correspondence: A. Aung, Department of Physiology and *Keynote paper presented at the International Leucaena Biochemistry, University of Veterinary Science, Yezin 05282, Nay Pyi Conference, 1‒3 November 2018, Brisbane, Queensland, Australia. Taw, Myanmar. Email: aung.aaung@gmail.com Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 424 A. Aung fisheries contribute about 9% of total GDP with the that leucaena leaves contained 4.39 ± 0.8 MJ/kg DM and private sector contributing 99% of livestock production seeds contained 4.19 ± 1.8 MJ/kg DM. In Myanmar, (Hla Hla Thein 2017). leucaena is used as a protein source in urea-molasses Seventy percent of the population of Myanmar reside multi-nutrient blocks for ruminants (Ni Ni Maw et al. in rural areas and 64% of the population are farmers, who 2002) and is a potential feed for animals in the dry season derive their main income from agriculture. Livestock (Aung Aung 2018). However, there is still limited production is closely linked with agriculture as farmers information on leucaena in Myanmar. This paper use cattle as draught animals and utilize agricultural by- describes the research carried out and feeding systems products as feed. Some farmers raise pigs and village involving leucaena in Myanmar. chickens as a small-scale backyard system. Smallholder livestock farmers obtain draught power, local transport Nutritive value of leucaena in Myanmar and manure as fertilizer from their draught animals. Eggs, milk, meat and hides are products/by-products which As in other countries, research workers in Myanmar have contribute to household income (Hla Hla Thein 2017). conducted research on the nutritive value of leucaena Crop residues are the main source of animal feed, (called Bawzagaing in Myanmar) as an animal feed especially during the dry period, with rice straw being the (Mehm Ko Ko Gyi 2002). most abundant and widely used feed in many Asian Concentrations of various nutrients in leucaena leaves countries including Myanmar (Trung 1987). These are as follows: crude protein (22.2‒30.1%), neutral agricultural fibrous residues have severe nutritional detergent fiber (8.2‒28.6%), acid detergent fiber (6.6‒ limitations, being low in digestibility and crude protein, 20.0%) and ether extract (5.3‒8.2%) (Ni Ni Maw et al. and high in fiber and anti-nutritional factors such as 2002; Khin Htay Myint 2005; Wink Phyo Thu 2010; Moe lignin, silica, gossypol, etc. To achieve satisfactory Thida Htun 2012; Dezin Soe Lwin 2014). animal performance, supplementation with concentrates, Nutritive value of leucaena reported from different which are expensive, is needed to overcome the regions and seasons showed little variation and was nutritional limitations of the feeds. similar to results from other countries. Farmers in Myanmar currently use commercial feeds for monogastric animals, resulting in high inputs and Experiments on feeding leucaena to animals costs. The other concern with monogastric animals is that they often compete with humans for food. Ruminants To solve these problems with ruminants and monogastrics, supplementation with fodder tree legume Many researchers in Myanmar have conducted feeding leaves was studied as leguminous forages are high in protein trials involving leucaena diets for ruminants. In the and soluble carbohydrates. experiment of Khin Htay Myint (2005), diets for goats Leucaena (Leucaena leucocephala) is a palatable, based on rice straw with leucaena at 25 and 50% of the digestible and nutritious forage for cattle, buffalo, sheep, diet showed similar nutrient digestibilities to diets goats, chickens and other animals (ter Meulen et al. 1979) containing rice straw and sesame cake (all diets as it provides a valuable source of protein, energy, isonitrogenous at 18% crude protein). However, in the vitamins and minerals for rumen bacteria (van Tol 2004) experiment of Aung Aung (2007), sheep fed a diet and is quite versatile. It can function: (a) as a source of containing 40% leucaena showed toxic symptoms and firewood and timber; (b) in controlling soil erosion lower digestibilities of nutrients than sheep fed a diet (Dijkmann 1950); (c) in providing shade for other plants; without leucaena. In this experiment, it was also (d) in maintaining the fertility of the soil; (e) as a possible discovered that sheep could be fed leucaena at 30% of bio-herbicide (Xuan et al. 2006); (f) in reducing cattle the diet without adverse effects as was reported by Jones methane emissions (Shelton and Dalzell 2007); and (f) as (1979), while Moe Thida Htun (2012) reported similar nutritious forage for animals (NRC 1977). Leucaena findings to those of Aung Aung (2007). However in foliage and young branches supply both nutrients and contrast, another experiment reported no adverse effects roughage, forming an almost complete ruminant feed and in sheep fed a diet containing 50% leucaena (Wink Phyo being widely used as forage for cattle in tropical Thu 2010) with the same digestibility as for sheep fed on agriculture (Shelton 1998). It can also be utilized for a diet without leucaena. Recently, goat kids fed a diet monogastrics. D’Mello and Thomas (1978) demonstrated containing 30% leucaena increased liveweight at a rate of that the N-corrected metabolizable energy (ME) for 80 g/d (Khin Ngu Wah Htun 2018); fecal worm egg poultry is 8.3 ± 0.74 MJ/kg DM. Gieseke (1984) stated counts were reduced by 70%. Yin Moe Aung (2018) also Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena in Myanmar 425 showed that including leucaena at 30% in a diet for calves 50% leucaena. Moe Thida Htun (2012) conducted a study reduced fecal worm egg counts, while Han Zin Maung with sheep being fed gradually increasing amounts of (2018) showed that calves fed a diet containing 30% leucaena leaves. For the first week, the sheep were fed leucaena had comparable weight gains with calves fed a leucaena at 10% of the diet and the level was increased by conventional feed without leucaena. Feed cost was lower 10% each week until it reached 50% of the diet, which in the calves fed diets containing leucaena. was thought to be a toxic level for sheep. However, the sheep showed no toxic symptoms and Bacillus cereus was Poultry isolated and identified from the rumen liquor of those sheep. The mimosine-degrading Bacillus cereus microbes Small-holders use leucaena as a green feed for poultry to were then transferred to goats (Dezin Soe Lwin 2014), aid in the prevention of cannibalism. Aye Kyi (2003) which consumed a diet containing 50% leucaena without compared different levels of leucaena leaf meal (0, 2, 4 or showing clinical symptoms of mimosine toxicity. In 6%) included in a conventional concentrate ration for contrast, the control goats without inoculation continued layer hens for 15 weeks. Hens fed on the diet containing to display toxic symptoms. 4% leucaena showed higher egg production (88%) Niang Htun Aung et al. (2015) found that chicks than hens fed the other diets (85.1, 84.7 and 84.8%, showed leucaena toxicosis when fed a diet containing 6% respectively). A similar experiment with broiler chickens leucaena but not after 21 days of age. Other reports (0, 1, 3 and 4% of leucaena in the diet) was conducted suggest that chicks can tolerate 4–6% leucaena in the diet by Aye Aye Maw (2004). In her experiment, feed (NRC 1977) without developing symptoms of toxicity. It conversion ratio (FCR) of chickens fed on the diet may be that at low levels of leucaena in the diet, toxic containing 4% leucaena also showed the highest value. In levels for chickens are not reached. both experiments, supplementation with leucaena showed lower feed costs for the poultry. Although mild symptoms Feeding of leucaena to animals in the field of leucaena toxicosis such as goitre and weakness of bones were observed, there was a tendency for FCR for Farmers in Myanmar have very limited knowledge of the broiler chicks fed on diets containing 6% leucaena seed to benefits of feeding leucaena to animals. A case study in be better than for those on a conventional diet (Khin Thida 10 townships from Yangon Region (75 farmers), Nay Pyi Win 2014). In another experiment, Naing Htun Aung et Taw Council (50 farmers) and Mandalay Region (125 al. (2015) recommended that 4% of leucaena leaf meal farmers) in 2016 revealed that, while 80% were aware that should be included in the diet of chicks from 21 days of leucaena could be used as animal feed, only 30.5% age (because economic returns in the broilers were better actually fed it to stock. There was wide variation between and there were no serious adverse effects). regions. In Yangon Region 65% of farmers rarely used leucaena as an animal feed. However, those in Nay Pyi Leucaena toxicity and attempts to overcome this Taw Council regularly fed leucaena to cattle and goats, problem in Myanmar collecting leucaena branches from the roadsides to feed their goats at home, often hanging the branches to Researchers in Myanmar offered leucaena to animals as the minimize wastage. No information is available on sole diet but encountered problems. Sheep fed a diet amounts of leucaena offered to goats and cattle. Farmers containing 50% leucaena showed symptoms of toxicity such consider that feeding leucaena reduces costs of as decreased feed intake, alopecia and emaciation (Aung production and also increases weight gains in ruminants Aung 2007) plus regurgitation of green digesta (Moe Thida and pigs. Htun 2012). When goats were fed leucaena at 50% of the In Mandalay Region, leucaena is abundant on diet, symptoms similar to those in the previous experiment roadsides and as fences for estates and cropping lands. were observed (Dezin Soe Lwin 2014). In poultry, Farmers allow cattle to graze communal lands, where osteoporosis and bone ossification were observed with leucaena grows, and consume leucaena. With the aid of leucaena feeding (Khin Thida Win 2014), but there is little the Australian Centre for International Agricultural information on leucaena toxicosis on-farm. Research (ACIAR), leucaena trees were provided to Aung Aung (2007) developed and isolated a farmers to grow along fence lines of houses for feeding subspecies of Klebsiella pneumoniae from steers in goats during the rainy season. Most farmers from Germany, which was transferred to sheep in Myanmar. Mandalay Region and Nay Pyi Taw area consider Sheep inoculated with those microbes showed no clinical leucaena has potential to provide foliage for feeding signs of leucaena toxicosis when fed a diet containing animals in the dry season. There is a need to collect data Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 426 A. Aung on the amount of leucaena being fed to the animals and conference. I also thank ACIAR for their support to visit on the effects of leucaena on daily liveweight gains of the Australia for this event. I am most grateful to Dr Khyne animals, and any possible toxic side-effects. U Mar, who provided partial support to make the Table 1 summarizes the knowledge situation of the presentation at ILC2018. The staff from the Department farmers regarding leucaena and Figure 2 depicts of Physiology and Biochemistry from the University of collecting of leucaena foliage. Veterinary Science, Myanmar are the engine of my work. Therefore, it is important to convey my thanks to them. Table 1. Knowledge of farmers regarding leucaena feeding and toxicity in various regions of Myanmar. References (Note of the editors: All hyperlinks were verified 15 August 2019.) Description No. of Answer (%) farmers Yes No Unsure Aung Aung. 2007. Feeding of leucaena mimosine to small ruminants: Investigation on the control of its toxicity in Know that leucaena 250 80.4 19.6 - small ruminants. Ph.D. Thesis. Georg-August University, can be fed to stock Goettingen, Germany. bit.ly/2YQzksH Actually feed 250 30.5 69.5 - Aung Aung. 2018. Livestock production systems, status on leucaena national feed resource availability and future developments, Know of leucaena 250 20.8 60.9 18.3 challenges and opportunities to efficiently utilize locally toxicity available feed resources and to enhance feed use efficiency Want to plant 250 55.0 40.0 5.0 in Myanmar. Proceedings of a Workshop on Technological leucaena Innovation and Education Training in Animal Production with a Focus on Feeding and Feed Production, Nanjing, P.R. China, 10‒13 May 2018. p. 27‒32. bit.ly/33DxCJV Aye Aye Maw. 2004. The effect of feeding leucaena leaf meal (LLM) on the performance of broilers. M.V.Sc. Thesis. University of Veterinary Science, Yezin, Myanmar. Aye Kyi. 2003. Effect of leucaena leaf meal (LLM) in poultry ration on the performance of CP Brown layers. M.V.Sc. Thesis. University of Veterinary Science, Yezin, Myanmar. D’Mello JPF; Thomas D. 1978. The nutritive value of dried leucaena leaf meal from Malawi. Studies with young chicks. Tropical Agriculture (Trinidad) 55:45‒50. bit.ly/31KqEBp Dezin Soe Lwin. 2014. Effect of transinoculation of mimosine degrading bacteria from sheep to goats fed on toxic level of leucaena leaves. M.V.Sc. Thesis. University of Veterinary Figure 1. Farmers collecting leucaena to feed their animals. Science, Yezin, Myanmar. Dijkmann MJ. 1950. Leucaena – A promising soil-erosion- Conclusion control plant. Economic Botany 4:337‒349. doi: 10.1007/ BF02985092 Information on the distribution and genetic diversity of Gieseke A. 1984. Untersuchungen zur Verdaulichkeit und umsetzbaren Energie von Leucaena leucocephala an leucaena in Myanmar is limited, but farmers indicate there is Kaninchen. M.Sc. Thesis. Georg-August University, insufficient leucaena available for animal feeding. Further Goettingen, Germany. research is recommended to investigate why farmers in Han Zin Maung. 2018. Comparative effects of two different some areas rarely feed leucaena, so that extension programs creep feeds on digestibility and growth performance of the to increase adoption can be mounted. Further programs to pre-weaned calves. M.V.Sc. Thesis. University of promote the establishment of leucaena plantations for Veterinary Science, Yezin, Myanmar. feeding animals in close collaboration with rural Hla Hla Thein. 2017. Myanmar livestock industry overview. communities in Myanmar are warranted. Myanmar Livestock Federation, Yangon, Myanmar. bit.ly/ 2YRhjdW Acknowledgments Jones RJ. 1979. The value of Leucaena leucocephala as feed for ruminants in the tropics. World Animal Review 31:13‒23. Khin Htay Myint. 2005. Evaluation of Leucaena leucocephala I am indebted to the Organizing Committee of ILC2018 and Ziziphus mauritiana of tannin and their interference to for giving me the chance to present my experience at the the nitrogen utilization in goat. M.V.Sc. Thesis. University research conference and for partial support to attend this of Veterinary Science, Yezin, Myanmar. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena in Myanmar 427 Khin Ngu Wah Htun. 2018. Effects of two different creep food HM; Gutteridge RC; Mullen BF; Bray RA, eds. Leucaena - on haematological parameters, parasitic oocyst/egg counts adaptation, quality, and farming systems. Proceedings of a and live-weight gain in goat kids. M.V.Sc. Thesis. workshop held in Hanoi, Vietnam, 9‒14 February 1998. University of Veterinary Science, Yezin, Myanmar. ACIAR Proceedings 86. ACIAR, Canberra, Australia. p. Khin Thida Win. 2014. Effects of different levels of leucaena 15‒24. purl.umn.edu/135197 seed as a source on growth performance and nutrient Shelton M; Dalzell S. 2007. Production, economic and retention of broilers. M.V.Sc. Thesis. University of environmental benefits of leucaena pastures. Tropical Veterinary Science, Yezin, Myanmar. Grasslands 41:174‒190. goo.gl/nAHLzN Mehm Ko Ko Gyi. 2002. Species trial for fuelwood production. ter Meulen U; Struck S; Schulke E; El-Harith EA. 1979. A Journal of Agricultural Forestry, Livestock and Fishery review on the nutritive value and toxic aspect of Leucaena Sciences (Myanmar Academy of Agricultural Forestry, leucocephala. Tropical Animal Production 4:113‒126. Livestock and Fishery Sciences) 3:43‒52. bit.ly/2NngjY1 bit.ly/2H8N7jv Moe Thida Htun. 2012. Development and isolation of leucaena Trung LT. 1987. Appropriate feeding strategy involving mimosine degrading bacteria from the rumen of sheep. Ph.D. untapped feed resources: The key to accelerate meat and Thesis. University of Veterinary Science, Yezin, Myanmar. milk production in the tropics. Transactions of the National Naing Htun Aung; Aung Aung; Moe Thida Htun; Lwin Naing Oo; Academy of Science and Technology (Philippines) 9:333– Pyae Phyo Aung; Kyaw Yan Naing Htun; Khin San Mu. 2015. 346. bit.ly/2OUpBwV Effect of different levels of leucaena leaf meal supplementation van Tol A. 2004. Fodder trees. Agrobrief series. Agromisa, on performances and apparent digestibility in male broilers. Wageningen, The Netherlands. bit.ly/2YZrlcn Proceedings of First International Conference and Annual Wink Phyo Thu. 2010. Study on the effect of silage making on Meeting of Myanmar Veterinary Association, Yangon, the content of tannin and mimosine in Leucaena Myanmar, 2‒3 February 2014. p. 189‒198. leucocephala. M.V.Sc. Thesis. University of Veterinary Ni Ni Maw; Khin San Mu; Aung Aung; Moe Thida Htun. 2002. Science, Yezin, Myanmar. Preliminary report on nutritive value of tree foliages available Xuan TD; Elzaawely AA; Deba F; Fukuta F; Tawata S. 2006. in Yezin area. Proceedings of the Annual Research Conference, Mimosine in Leucaena as potent bioherbicide. Agronomy Yangon, Myanmar, 28–30 June 2002. p. 128‒134. and Sustainable Development 26:89‒97. doi: 10.1051/ NRC (National Research Council). 1977. Leucaena: Promising agro:2006001 forage and tree crop for the tropics. The National Academy Yin Moe Aung. 2018. Effects of creep feeds and anthelmintics Press, Washington, DC, USA. doi: 10.17226/21315 on haematological parameters, growth performance, faecal Shelton HM. 1998. The Leucaena genus, new opportunities for egg and oocyst counts of pre-weaned calves. M.V.Sc. agriculture (a review of workshop outcomes). In: Shelton Thesis. University of Veterinary Science, Yezin, Myanmar. (Accepted 19 March 2019 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):428–436 428 DOI: 10.17138/TGFT(7)428-436 ILC2018 Keynote Paper* Adoption of leucaena-based feeding systems in Sumbawa, eastern Indonesia and its impact on cattle productivity and farm profitability Adopción de sistemas de producción basados en leucaena en Sumbawa, Indonesia Oriental, y su impacto en la productividad bovina y rentabilidad del sistema de producción DAHLANUDDIN1, TANDA PANJAITAN2, SCOTT WALDRON3, MICHAEL J. HALLIDAY3, ANDREW ASH4 , STEVE T. MORRIS5 AND H. MAX SHELTON3 1University of Mataram, Mataram, Lombok, Indonesia. unram.ac.id 2Assessment Institute for Agricultural Technology – West Nusa Tenggara, Narmada, Lombok, Indonesia 3School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD, Australia. agriculture.uq.edu.au 4Commonwealth Scientific and Industrial Research Organization (CSIRO), Canberra, ACT, Australia. csiro.au 5School of Agriculture and Environment, Massey University, Palmerston North, New Zealand. massey.ac.nz Abstract Leucaena has been fed to cattle by the Balinese community in Sumbawa and West Sumbawa districts on Sumbawa Island since the 1980s. However, prior to 2011, this practice was not adopted by the local Sumbawanese farmers. Since then, a model leucaena-based cattle fattening system was developed in Sumbawa and West Sumbawa districts in a collaborative research project between the Assessment Institute for Agricultural Technology (BPTP), University of Mataram and The University of Queensland (UQ) funded by the Australian Centre for International Agricultural Research (ACIAR), followed by a scaling- out project involving collaboration between the University of Mataram and CSIRO (Applied Research and Innovation Systems in Agriculture - ARISA project) funded by DFAT (Department of Foreign Affairs and Trade) promoting public- private partnerships. Further promotion of leucaena-based fattening systems occurred in Dompu, Sumbawa, through a project with the University of Mataram and Massey University funded by the New Zealand Ministry of Foreign Affairs and Trade (MFAT). By the end of October 2018, more than 2,500 farmers on Sumbawa Island were practicing leucaena-based cattle fattening. The main drivers of adoption of cattle fattening with leucaena were: (1) The high growth rates achieved (0.4–0.6 kg/d for bulls fed 100% leucaena and 0.66 kg/d when maize grain was added to the leucaena basal diet) compared with 0.16 kg/d for the traditional system, combined with high profitability; (2) the needs of farmers being met in terms of relevance and cultural appropriateness; (3) field extension staff being well trained and mentored, and respected by the farmers; (4) the local government being highly supportive of leucaena-based cattle fattening; and (5) additional benefits being increased dressing percentage and high carcass quality. The rapid increase in the use of leucaena for cattle fattening in eastern Indonesia is expected to have a significant positive impact on household incomes as well as on regional economic growth. Keywords: Cattle fattening, farmer income, growth rate, tree legumes. Resumen Leucaena ha sido usada, desde la década de 1980, para la alimentación de bovinos por la comunidad balinesa en los distritos de Sumbawa y Sumbawa Oriental pertenecientes a la isla de Sumbawa. Sin embargo, previo al 2011 esta práctica no fue ___________ Correspondence: Dahlanuddin, Faculty of Animal Science, University *Keynote paper presented at the International Leucaena of Mataram, Jl. Majapahit No.62, Gomong, Kec. Selaparang, Kota Conference, 1‒3 November 2018, Brisbane, Queensland, Australia. Mataram, NTB 83115, Indonesia. Email: dahlan.unram@gmail.com Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Impact of leucaena in Sumbawa 429 adoptada masivamente por los agricultores locales. Desde esa fecha en adelante, se desarrolló un sistema modelo de engorde de bovinos basado en leucaena en dichos distritos en un proyecto de investigación colaborativa entre el Assessment Institute for Agricultural Technology (BPTP), la universidad de Mataram y la universidad de Queensland (Australia), financiado por el Centro Australiano para la Investigación Agrícola Internacional (ACIAR), y seguido de un proyecto de ampliación de escala con la colaboración entre la universidad de Mataram y la Organización de Investigación Científica e Industrial del Commonwealth (CSIRO; Proyecto ARISA: Applied Research and Innovation Systems in Agriculture), financiado por el Departmento de Relaciones Exteriores y Comercio de Australia, el cual promueve las asociaciones público-privadas. Los sistemas de engorde basados en leucaena se promovieron también en Dompu, Sumbawa, mediante un proyecto con la universidad de Mataram y la universidad de Massey (Nueva Zelanda), financiado por el Ministerio de Relaciones Exteriores y Comercio de Nueva Zelanda. A fines de octubre de 2018, más de 2,500 productores en la isla de Sumbawa adoptaron el engorde de bovinos a base de leucaena. Los principales impulsores de la adopción de esta tecnología fueron: (1) las altas ganancias de peso de los toretes (0.4–0.6 kg/d cuando la ración fue 100% leucaena y 0.66 kg/d cuando se añadió grano de maíz a la dieta basal de leucaena), en comparación con 0.16 kg/d en el sistema tradicional, además de una alta rentabilidad; (2) tecnología adaptada a las necesidades de los agricultores en términos de relevancia e idoneidad cultural; (3) extensionistas bien capacitados y orientados, además de respetados por los agricultores; (4) fuerte apoyo por parte del gobierno local de la tecnología de engorde de bovinos a base de leucaena; y (5), como beneficio adicional, mayor porcentaje y alta calidad de la carcasa. Se espera que el rápido aumento en el uso de leucaena para el engorde de ganado en el este de Indonesia tenga un significativo impacto positivo en los ingresos de los productores, así como en el crecimiento económico regional. Palabras clave: Engorde de ganado; ingresos, leguminosas arbóreas, tasa de crecimiento. Introduction The Indonesian Government has initiated programs to boost domestic beef production in an endeavor to achieve Beef consumption per capita in Indonesia is low at 1.5 self-sufficiency. The majority of cattle in Indonesia are kg/person/yr in 2000 and 2.5 kg/person/yr in 2015. kept by about 6.5 M smallholder farmers, supplemented However, local supply plus imports, mainly from Australia, by a small number of much larger cattle ranches and are limited and the tight supply-and-demand relationship is larger feedlots, especially in Java and Sumatra. reflected in the retail price of beef, which has quadrupled Lifting the productivity of smallholder-fattened from 2000 to 2015 (Waldron et al. 2015; Shelton and the cattle to meet the increasing demands of the Indonesian Project Team 2017). This has led to changes in policy in population for beef has been nominated by provincial recent years, with large amounts of frozen buffalo meat and agencies as one of the most important ways to improve beef being imported from India. A projection by the the incomes of the rural poor. The Indonesian provinces Australian Bureau of Agricultural and Resource Economics of West Nusa Tenggara (NTB) and East Nusa Tenggara and Sciences (ABARES) suggested that the value of (NTT) (Figure 1) have been identified as areas with national beef consumption in Indonesia will increase 13-fold high potential for expansion of smallholder beef from 2009 to 2050 (Gunning-Trant et al. 2015). production. Figure 1. Map of Indonesia showing West Nusa Tenggara, with the islands of Sumbawa and Lombok, and East Nusa Tenggara provinces. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 430 Dahlanuddin, T. Panjaitan, S. Waldron, M.J. Halliday, A. Ash, S.T. Morris and H.M. Shelton Currently, smallholder fattening systems in these In 2011, a 5-year collaborative research project regions are characterized by irregular, slow turn-off and between the Assessment Institute for Agricultural poor carcass quality, largely resulting from very poor Technology (BPTP), University of Mataram and The nutrition of cattle fattened under traditional feeding University of Queensland (UQ), funded by the systems, which comprise cattle free-grazing on native Australian Centre for International Agricultural rangeland or on rice stubble after crop harvest (Figure 2). Research (ACIAR), was initiated to improve small- This has negative consequences for the overall cattle holder cattle fattening systems based on promoting the population in Indonesia because too many young females use of forage tree legumes entitled ‘Improving are slaughtered to meet the growing demand for beef smallholder cattle fattening systems based on forage tree rather than being retained for breeding. legume diets in eastern Indonesia and northern Prospects for expansion of the smallholder sector are Australia’ (LPS-2008-054). The project focused on the constrained by: most viable option to improve diet quality in eastern 1. Low production efficiency due to: low growth rates Indonesia, which was to feed cattle with the foliage of (0.15–0.25 kg/d); low calving rates (~65%); high calf high-quality forage tree legumes (FTL). The successful mortality (10–20%); low sale live weights (averaging cattle fattening model was then scaled-out by a 250 kg); low carcass dressing percentages (48%); low CSIRO/DFAT (Department of Foreign Affairs and genetic potential of local breeds; and poor Trade)-funded project promoting public-private partner- management of the herd. ships, and further supported by a New Zealand Ministry 2. Socio-economic limitations due to: poor under- of Foreign Affairs and Trade (MFAT)-funded project standing of opportunities for improvement of based in Dompu, Sumbawa. smallholder cattle fattening enterprises; lack of Examples of such systems, in which cattle were fattened knowledge and experience in forage improvement; on FTL, already existed in Indonesia. Sesbania (Sesbania problems with supply of credit; limited availability of grandiflora; known locally as turi) was fed in south-central land; and poor extension services and training. Lombok in NTB, and leucaena (Leucaena leucocephala; a. Limited wet season communal grazing (Island of Sumbawa). b(a. )L a ck of quality forage in dry season. c. Lack of forage in dry season. d(b. )H i gh calf mortality due to inadequate nutrition. Figure 2. Lack of adequate forage severely limits nutrition of beef cattle in eastern Indonesia. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Impact of leucaena in Sumbawa 431 known locally as lamtoro) was fed in Sumbawa District in fattening cattle. One of these Balinese villages (Jatisari) NTB and in Amarasi District of NTT. Both species were became a demonstration site for the new ACIAR project capable of greatly improving the protein nutrition of cattle. to describe and promote leucaena-based cattle fattening to These systems were locally successful, but were not widely other farmers in these districts. adopted outside these regions despite similar physical and socio-economic conditions. Methods This paper reports findings from the ACIAR and other projects in terms of: the history of cattle fattening in The ACIAR project commenced by conducting a survey Sumbawa; the impact of leucaena-based fattening on of 21 farmers and collecting data from 276 Bali bulls cattle productivity and quality and farm profitability; and between 2011 and 2016 to determine the characteristics the progress made with an extension strategy designed to of the leucaena-based cattle fattening used by the Balinese promote the uptake of leucaena planting and feeding for in the hamlet of Jatisari in Sumbawa district on Sumbawa fattening cattle by smallholder farmers. Island. Parameters measured included area of land planted to leucaena, length of fattening period and the growth of Early history of cattle fattening in Sumbawa the Bali bulls (Bos javanicus) including bull live weight, average daily gain (ADG), feed offered including amount The use of leucaena for cattle feeding in eastern Indonesia of leucaena in the diet and purchase and sale weights was originally thought to occur mainly in the Amarasi (Panjaitan et al. 2014; Shelton and the Project Team 2017). District of West Timor (Piggin and Nulik 2005). In concurrent controlled animal trials, Dahlanuddin et However, in August 2010, as the ACIAR project got al. (2014) studied the growth rate of Bali bulls and underway, we discovered that leucaena feeding was lactating cows fed leucaena hay compared with native or common practice for Balinese communities in Sumbawa introduced grass, and the effect of supplementing with and West Sumbawa districts. These Balinese maize grain, maize stover and mineral mix. communities had been using leucaena to fatten cattle since the 1980s with very little input from government Results agencies, or adoption by the local Sumbawanese farmers. The Balinese communities had very little cropping land Survey of cattle production, profitability, carcass and grew leucaena to fatten cattle on the steeper slopes percentage and meat quality behind their villages as their main source of income. In contrast, the Sumbawanese farmers had greater areas of The survey revealed that: land and spent most of their labor and time on cropping 1. Farmers had an average of 2.8 ha of land with 0.8 ha activities in the wet season, while raising cattle (0.1‒5.0 ha) of planted leucaena. They purchased bulls traditionally on communal grazing lands. with an average live weight of 191 ± 41 kg at 18 ± 7 Balinese settlers first came to Sumbawa in the 1970s months of age and fattened them for periods averaging to work in the shrimp nursery. However, incomes from 127 ± 58 days (Panjaitan et al. 2014). the shrimp nursery were not sufficient to support their 2. The average percentage of leucaena in diets throughout families, so they acquired low-value steeper dryland the year was 80% with 13% maize stover and 7% native nearby and planted crops, especially maize. In the 1980s, grass. The percentage of leucaena was highest (100%) a Government scheme provided a couple of cows to some in the wet season, and lowest (approximately 50%) in households and they managed to breed and grow a small October, when limited availability of leucaena meant herd. With previous experience from Bali that leucaena farmers supplemented diets with crop residues. could be fed to cattle, they began growing leucaena to 3. Based on more than 3 years of monitoring (Figure 3) feed cattle and it became a common practice within this daily liveweight gains of Bali bulls ranged from 0.4 to community. The leucaena was planted with support from 0.6 kg/d (Dahlanuddin et al. 2014; Panjaitan et al. 2014) an International Fund for Agricultural Development on these rations. This was at least double the ADG of (IFAD) program. Initially the leucaena variety used was Bali bulls (0.2 kg/d) achieved in the traditional rearing brought from Bali but was of unknown origin. Later, a system. ADGs peaked (0.56–0.61 kg/d) in the months variety called ‘Lamtoro Gung’ was used; it was found to of May, June and January, when feed supply and be L. leucocephala cv. Cunningham, originally imported percentage leucaena in diets were highest (close to from Australia. By 2010, there were more than 100 100%), and the most efficient individual farmers Balinese households in the Sumbawa and West Sumbawa achieved monthly maximum weight gains ≥0.8 kg/d, districts, who were feeding leucaena as the sole diet for which is close to the genetic potential of Bali bulls. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 432 Dahlanuddin, T. Panjaitan, S. Waldron, M.J. Halliday, A. Ash, S.T. Morris and H.M. Shelton Figure 3. Liveweight gains and number of cattle fattened in Jatisari village, Sumbawa. Pen-feeding trials and 45% gliricidia mix ad libitum + 5 g rice bran/kg LW/d (all diets supplemented with mineral mix at 3% of rice In controlled animal trials, Dahlanuddin et al. (2014) bran). Bulls in all treatments grew at 0.4–0.5 kg/d with no reported that the growth rate of Bali bulls fed 100% significant differences in growth rate between diets. leucaena hay was 0.47 kg/d, more than double the growth rate of Bali bulls fed native grass. When leucaena hay was Meat quality supplemented with 10 g maize grain (DM)/kg LW, growth rates increased to 0.66 kg/d (Dahlanuddin et al. In response to anecdotal evidence that leucaena feeding 2018). In another experiment, Bali bulls fed 100% fresh results in dark meat and yellow fat, 5 bulls from the leucaena ad libitum gained 0.50 kg/d; this growth rate Dompu trial (fed fresh leucaena ad libitum plus 5 g rice reduced to 0.46 and 0.39 kg/d when maize stover was bran/kg LW/d and mineral mix supplement) were substituted for fresh leucaena at 25 and 50% of the diet, slaughtered to measure carcass dressing percentages and respectively (Soares et al. 2018). meat quality. Carcass dressing percentages exceeded the Feeding high levels of leucaena hay (leaf and thin average carcass dressing percentage of Bali bulls grazed branches) to lactating cows increased milk production and traditionally and slaughtered at an abattoir in Sumbawa calf growth. The milk production of cows fed leucaena (52.4% vs. 48%). Meat quality tests (O. Yanuarianto pers. hay ad libitum and 10 g maize grain DM/kg LW was 2.1 comm.) demonstrated that meat color of leucaena-fed kg/d, double the milk production of cows fed 8-week-old bulls was cherry red and fat color was white. These regrowth of king grass ad libitum. Consequently, pre- parameters plus tenderness and marbling scores were weaning calf growth was significantly higher when cows similar to those from local beef animals considered as were fed leucaena plus maize grain (0.37 kg/d) than when ‘grade one’ beef by Indonesian standards (W. Yulianto cows were fed king grass (0.16 kg/d) (Dahlanuddin et al. pers. comm.). Marbling score was low (mean of 2.4 on a 2016). 0–9 scale), which was mostly genotype-related. As part of the IFSCA (Innovative Farming System and Capability for Agribusiness) project, a collaborative Profitability of leucaena-based feeding systems program between Massey University, New Zealand and University of Mataram, a feeding trial was conducted in Based on the production parameters above, an economic Dompu district of Sumbawa using 20 growing Bali bulls analysis was conducted on cattle fattening on a leucaena- fed: 100% leucaena ad libitum + 5 g rice bran DM/kg based diet in Jatisari (for details see Waldron et al. 2015). LW/d; 85% leucaena and 15% gliricidia mix ad libitum + Production regimes are quite variable and speculative in 5 g rice bran/kg LW/d; 70% leucaena and 30% gliricidia the village, as knowledgeable and entrepreneurial farmers mix ad libitum + 5 g rice bran/kg LW/d; or 55% leucaena have become skilled at estimating weights and the Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Impact of leucaena in Sumbawa 433 fattening potential of feeder cattle, and adjusting fattening based cattle fattening system increased net income by 60% numbers according to periods for seasonal feed over the base case where leucaena was not fed. availability and prices. While this variability should be taken into account, this section reports values for a Adoption of leucaena-based cattle fattening system in ‘representative (typical) household’, with scenarios West Nusa Tenggara Province explored in Waldron et al. (2015). Compared with other areas of eastern Indonesia, bull The ACIAR project was also designed to test the fattening on leucaena in Jatisari was highly profitable, hypothesis that: “FTL feeding practices can be especially in the wet season, primarily because of the high successfully transferred to neighboring districts provided growth rates (0.5 kg/d) achieved. As a result, households the constraints for diverse groups of farmers were can grow and turn-off cattle relatively quickly (e.g. identified and effectively tackled through participatory growing from 130 kg to 200 kg in 140 days). adaptive research and ‘Roll-Out’ efforts, and provided With these high growth rates farmers have expanded pen specific technical issues that might limit their use were operations to an average of 10 head on leucaena during the resolved”. wet season. There are large ‘upfront’ land, labor and capital An extension strategy was developed with the costs in developing this capacity (IDR 6.5 million for pens following key components: and IDR 1.7 million for 3,000 leucaena trees; USD 1 = IDR 1. Awareness-raising regarding the use and benefits of 14,000). However, if house-holds can meet these costs (as a FTLs in cattle farming; household, community or with external support), costs are 2. Adaptive on-farm trials and demonstration of FTL low when spread over 20 years and hundreds of cattle. management systems; Variable costs ‒ transport and veterinary ‒ are also low. 3. Capacity building on the management and use of Transport costs are not significant as households source FTLs; feeder cattle from their own herds, a nearby trading area or 4. Facilitation of access to inputs and services related to traders, and cattle are sold at the farm gate. FTL management; With regard to revenue, cattle prices (about IDR 5. Support for FTL/cattle farmer groups; and 37,000/kg live weight in 2015) were lower on Sumbawa 6. Establishment and fostering of inter-institutional than for Lombok (because of the transport and permit relationships. costs), but markets were competitive and buoyant. As We found that there was a lack of understanding of the mentioned, farmers seek favorable alignments between nutritional needs of animals, and especially of fattening the input (feeder cattle) and output (finished cattle) prices. bulls, and the comparative nutritive values of the various While farmers use some of the manure from pens on feeds available to smallholder farmers. Many farmers did nearby fields and leucaena trees for firewood, cattle sales not understand the large differences in nutritional value make up 99% of revenue. among various forage resources, especially the After accounting for these costs and revenues, farmers superiority of leucaena compared with rice straw, crop earn gross profits of up to IDR 160,000 per day from cattle residues, grasses or banana stems. Another reason for not fattening. However, a typical household also incurs adopting leucaena was concern about leucaena toxicity, significant capital costs (for expensive cattle) and, more which proved to be a short-term problem, as cattle quickly importantly, significant labor costs (for 10 cattle on adapted even when on 100% leucaena diets. leucaena). A typical household spends 5.7 person hours per The establishment of on-farm demonstration sites was day doing cattle work, the majority of which is for forage a critical component of this work (Figure 4). These sites collection, followed by pen work and buying/selling cattle. allowed for the assessment and refinement of practices However, even after taking these costs into account, the and the development of extension materials, and were ‘returns to labor day’ (i.e. the amount made per 8 hours of used for cross-visits to promote good management work) was IDR 185,000. This is far higher than off-farm practices to other farmer groups. An integrated package work (IDR 50,000 per day). It is important to note, however, was developed comprising recommendations for the that the returns per person day are far lower in the dry season establishment, management and feeding of leucaena, and (IDR 31,000) when weight gains are lower (0.35 kg/d) and included recommendations for provision of water, accordingly households reduce the number of cattle on feed hygiene and health. The project also recommended a basic (to 3 head). model fattening shed (kandang) which could be easily Based on the results of the Applied Research and replicated by farmers or farmer groups, in single or Innovation Systems in Agriculture (ARISA) project impact multiple units, either exactly as recommended or assessment study (R. Caudwell pers. comm.), the leucaena- modified to suit local construction materials. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 434 Dahlanuddin, T. Panjaitan, S. Waldron, M.J. Halliday, A. Ash, S.T. Morris and H.M. Shelton a. Leucaena seedling nursery b. Leucaena bare stems ready for planting c. Leucaena rows inter-planted with maize d. Leucaena ready for harvest e. Freshly harvested leucaena f. Fresh leucaena being fed to Bali bulls Figure 4. Establishing, harvesting and feeding of leucaena for cattle fattening in Sumbawa. Barriers to and opportunities for adoption leucaena, cv. Tarramba, and began fattening some young bulls. They soon found the system to be very profitable and Initially, there was very slow adoption by local Sumbawanese became trainers for other farmers. Since then, the adoption farmers even after they were taken to the Balinese village to rate has increased, driven by these local examples and by the observe the system in operation (Figure 4). high cattle prices obtained for fattened bulls. By the end of The project team then approached some local innovative 2015, 535 farmers were involved in the leucaena-based farmers, rather than farmer groups, who had started to plant fattening system in West Sumbawa and Sumbawa districts and use leucaena. This included a radio technician, who was at various stages of adoption (Shelton and the Project Team interested in planting forages on his own land to feed goats. 2017). After several visits by the project team, these individual The barriers to and opportunities for adoption of FTL in farmers became convinced to plant the new variety of Indonesia are now well understood. Our findings were first Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Impact of leucaena in Sumbawa 435 presented in the paper by Kana Hau et al. (2014), and an Innovative Farming System and Capability for updated list of barriers and opportunities for adoption was Agribusiness (IFSCA). described in the final report to ACIAR on Project LPS/2008/054 (Shelton and the Project Team 2017) under The number of newly planted leucaena areas continued to the principal categories: Nature of the innovation; technical increase rapidly and the practice was scaled-out to the constraints; project leadership and staffing; engagement neighboring district of Dompu through the IFSCA project, a with farmers; socio-economic and agribusiness issues; and collaborative program between Massey University, New Government policy and involvement. Zealand and University of Mataram. The aim of this project was to increase income from cattle-crop (especially maize) Applied Research and Innovation Systems in Agriculture integration by improving capacity of all participants in the (ARISA) project value chain. One of the interventions was to scale-out proven innovations in cattle production, one of which was the Commencing in 2016, a collaborative research project leucaena-based cattle fattening system. Through this project, was initiated between the University of Mataram and more than 200 farmers have been involved in cattle fattening Commonwealth Scientific and Industrial Research using leucaena as the main component of the diet. The Organisation (CSIRO), Australia as part of the Applied number is increasing rapidly and is expected to at least Research and Innovation Systems in Agriculture double in the next financial year. (ARISA) project funded by the Australian Department of Foreign Affairs and Trade (DFAT). While this new Conclusions initiative was aimed at improving incomes by developing partnerships between the private sector and farmers, the Having one community, e.g. the Balinese community in most successful activity was a continuation of scale-out Sumbawa and West Sumbawa districts, feeding leucaena of the intervention to improve supply of high quality successfully to cattle for decades does not necessarily mean forages using leucaena. that another community, e.g. the local Sumbawanese By October 2018, 2,500 farmers (direct adoption from farmers, would adopt the strategy, partly due to cultural and other farmers) in Sumbawa and West Sumbawa districts communication barriers. had adopted leucaena fattening. These farmers initially It took a combined research effort between BPTP, the used a local leucaena variety, which they had harvested University of Mataram and The University of Queensland, from wild leucaena growing on roadsides or forest supported by ACIAR, DFAT and MFAT, to develop a margins, which had survived the psyllid infestations in the model leucaena-based cattle fattening system, which was 1980s. Based on survey figures from June 2018, 733 new then introduced to the Sumbawanese farmers to dramatically farmers on Sumbawa and West Sumbawa had planted the change the situation. This, combined with a well-planned improved more psyllid-tolerant cultivar Tarramba and extension strategy including on-farm demonstrations, 133 of them were already fattening their cattle with this resulted in more than 2,500 Sumbawanese farmers (1,050 new cultivar (Figure 5). The total area planted to cv. directly influenced by the project plus more than 1,000 Tarramba was 567 ha. copying farmers) on Sumbawa Island adopting cattle fattening based on leucaena by October 2018, 7 years after 400 the study commenced. 350 The main drivers of adoption of fattening with leucaena 300 were: 250 1. The high growth rates achieved compared with the 200 traditional system, combined with the high cattle price 150 (up to IDR 50,000/kg live weight) that resulted in high 100 profitability; 50 2. The needs of farmers being met in terms of relevance 0 and cultural appropriateness to local cattle production Fattening cattle Just planted Planted Tarramba Fattening cattle using local Tarramba, no but still fattening using own systems, land being available for planting leucaena and leucaena fattening using local Tarramba leucaena input costs being low; leucaena 3. Field extension staff being well trained and mentored, Figure 5. Numbers of farmers directly adopting leucaena- so they gained the respect of the farmers; based cattle fattening in Sumbawa and West Sumbawa districts 4. The local government being highly supportive of at various levels of adoption. leucaena-based cattle fattening, and actively supporting Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 436 Dahlanuddin, T. Panjaitan, S. Waldron, M.J. Halliday, A. Ash, S.T. Morris and H.M. Shelton adoption by farmers. With the improved availability of Dahlanuddin; Panjaitan TS; Sofyan; Poppi DP; Quigley SP. leucaena, local government was successful in attracting 2018. Bali × Hissar cattle fed Leucaena leucocephala additional central government funding for cattle supplemented with maize grain grew faster than Bali cattle. development on the island; Poster presented at the10th International Symposium on the 5. Increased carcass dressing percentage compared with Nutrition of Herbivores, Clermont-Ferrand, France, 2‒6 September 2018. doi: 10.1017/S2040470018000146 traditionally fattened Bali bulls and meat characteristics Gunning-Trant C; Sheng Y; Hamshere P; Gleeson T; Moir B. being of high quality; and 2015. What Indonesia wants: Analysis of Indonesia's food 6. Observing farmers of their own ethnic community demand to 2050. ABARES Research Report No. 15.9. successfully practicing the system of feeding. Australian Bureau of Agricultural Research Economics, The adoption of leucaena-based cattle fattening has Canberra, ACT, Australia. bit.ly/2MrM4zq proven to be a very effective forage improvement strategy in Kana Hau D; Panjaitan T; Nulik J; Dahlanuddin; Van De Fliert the dry areas of eastern Indonesia. Using similar strategies to E. 2014. Barriers to and opportunities for the use of forage those employed should improve uptake of new technology tree legumes in smallholder cattle fattening systems in in similar situations in the region. Rapid increase in the use Eastern Indonesia. Tropical Grasslands-Forrajes Tropicales of this cattle-fattening strategy in eastern Indonesia is 2:79−81. doi: 10.17138/TGFT(2)79-81 Panjaitan T; Fauzan M; Dahlanuddin; Halliday MJ; Shelton expected to have a significant positive impact on household HM. 2014. Growth of Bali bulls fattened with Leucaena incomes as well as on regional economic growth. leucocephala in Sumbawa, Eastern Indonesia. Tropical Grasslands-Forrajes Tropicales 2:116−118. doi: 10.17138/ Acknowledgments TGFT(2)116-118 Piggin C; Nulik J. 2005. Leucaena: Sustainable crop and livestock Data presented in this paper are from results of ACIAR production systems in Nusa Tenggara Timur Province, LPS/2008/054, CSIRO - University of Mataram ARISA and Indonesia. Tropical Grasslands 39:218. goo.gl/BgDmbh Massey University - University of Mataram IFSCA projects. Shelton HM and the Project Team. 2017. Improving We thank ACIAR, DFAT and MFAT for funding support smallholder cattle fattening systems based on forage tree for these projects. legume diets in eastern Indonesia and northern Australia. Final report. Australian Centre for International Agricultural Research (ACIAR), Canberra, Australia. goo.gl/b9RX5N References Soares OW; Ekaputra Gunartha IG; Mullik ML; Sutaryono YA; (Note of the editors: All hyperlinks were verified 20 August 2019.) Dahlanuddin. 2018. Feed intake, feed digestibility and live weight gain of male Bali cattle fed different combinations Dahlanuddin; Yanuarianto O; Poppi DP; McLennan SR; of Leucaena leucocephala and maize stover under farm Quigley SP. 2014. Liveweight gain and feed intake of conditions in Timor Leste. Livestock Research for Rural weaned Bali cattle fed grass and tree legumes in West Nusa Development 30, Article #124. bit.ly/2zb4kVb Tenggara, Indonesia. Animal Production Science 54:915– Waldron S; Halliday M; Shelton HM; Ngongo J; Nulik J; Nulik 921. doi: 10.1071/AN13276 D; Kusuma Putri Utami S; Panjaitan T; Baiq Tutik Y; Dahlanuddin; Supriyadi M; Panjaitan TS; Poppi DP; Quigley Dahlanuddin. 2015. Economic analysis of cattle fattening SP. 2016. Increased body condition during lactation systems based on forage tree legume diets in Eastern increases milk production and pre-weaning growth of Bali Indonesia. Final Report. Australian Centre for International cattle. Journal of Animal Science 94:399–400. doi: Agricultural Research (ACIAR), Canberra, Australia. 10.2527/jam2016-0830 bit.ly/33JxicJ (Accepted 17 January 2019 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):437–444 437 DOI: 10.17138/TGFT(7)437-444 ILC2018 Keynote Paper* Economic analysis of cattle fattening systems based on forage tree legume diets in eastern Indonesia Análisis económico de sistemas de engorde de ganado basados en árboles leguminosos forrajeros en Indonesia Oriental SCOTT WALDRON1, JOHANIS NGONGO2, SILVIA KUSUMA PUTRI UTAMI3, MICHAEL J. HALLIDAY1, TANDA PANJAITAN3, BAIQ TUTIK YULIANA3, DAHLANUDDIN4, JACOB NULIK2, DEBORA KANA HAU2 AND H. MAX SHELTON1 1School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD, Australia. agriculture.uq.edu.au 2Assessment Institute for Agricultural Technology – East Nusa Tenggara, Naibonat, Kupang, Indonesia. ntt.litbang.pertanian.go.id 3Assessment Institute for Agricultural Technology – West Nusa Tenggara, Mataram, Lombok, Indonesia. ntb.litbang.pertanian.go.id 4Faculty of Animal Science, University of Mataram, Mataram, Lombok, Indonesia. unram.ac.id Abstract Research and government agencies in eastern Indonesia have identified 2 systems with potential to increase productivity and incomes of small-holder cattle producers: improved cattle feeding practices through forage tree legumes (FTL); and the development of more efficient and specialized cattle-fattening systems. Extensive research has been conducted on production and technical aspects of FTL-fattening systems, but there is a gap in research on economic incentives for households to adopt the systems. This paper provides an economic analysis of a leucaena-fattening system in a village in West Timor. It draws on trial data from associated technical research projects and detailed semi-structured interviews with farmers and other stakeholders to populate a bio-economic model built for the research. Under all measures of profitability, leucaena-fattening systems in representative households are profitable in the wet season. Importantly, ’returns to person days’ are higher than off-farm incomes. The activity generates cash income, increasingly required to meet cash expenses in modern rural Indonesian society. However, returns vary considerably between households, are considerably lower in the dry season and, as would be expected, are sensitive to relative prices of feeder and finished cattle. Keywords: Household budgeting, leucaena, profitability, small-holders, West Timor. Resumen Instituciones de investigación y desarrollo en Indonesia Oriental han identificado dos sistemas con potencial para aumentar tanto la productividad bovina como los ingresos de pequeños productores de ganado en la región: prácticas de alimentación mejorada de los animales mediante forraje de árboles leguminosos; y el desarrollo de sistemas de engorde de ganado más eficientes y especializados. A pesar de amplias investigaciones sobre aspectos técnicos y de producción de los sistemas de engorde basados en árboles leguminosos forrajeros, aún existe una brecha en la investigación sobre incentivos económicos para que los productores adopten los sistemas. Este trabajo presenta un análisis económico de un sistema de engorde de ganado basado en leucaena en una aldea en Timor Occidental, Indonesia. Basado en datos de experimentos de proyectos de investigación técnica y entrevistas semiestructuradas con agricultores y otras partes interesadas, se desarrolló un modelo bioeconómico específico para esta investigación. Bajo todas las medidas de ___________ Correspondence: Scott Waldron, School of Agriculture and Food *Keynote paper presented at the International Leucaena Sciences, The University of Queensland, Brisbane, QLD 4072, Conference, 1‒3 November 2018, Brisbane, Queensland, Australia. Australia. Email: Scott.Waldron@uq.edu.au Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 438 S. Waldron et al. rentabilidad, los sistemas de engorde con leucaena en fincas representativas son rentables en la estación lluviosa. Es importante destacar que los retornos a la mano de obra empleada son más altos que eventuales ingresos provenientes de actividades no agrícolas. El sistema estudiado genera ingresos que son cada vez más requeridos para cubrir los gastos pertinentes a la moderna sociedad rural en Indonesia. Sin embargo, los retornos varían considerablemente entre las fincas, son considerablemente más bajos en la estación seca y, como es de esperar, son sensibles a la relación del precio de compra de animales para engorde y el de venta de los animales para el matadero. Palabras clave: Leucaena, pequeños productores, presupuesto familiar, rentabilidad, Timor Occidental. Introduction However, there has been a dearth of studies to verify the economic incentives for households to take up and sustain The province of Nusa Tenggara Timur (NTT) in eastern the systems, which is the focus of this paper. Indonesia faces substantial development challenges. The province is one of the least developed in Indonesia, with Methods a per capita GDP one-quarter of the national average. In 2017 incomes of 25% of the rural population of NTT were Sites below the poverty line (Rp 329,136 or AU$ 32 per month), compared with the national average of 13% (BPS The economic analysis on which this paper draws was 2018). Agriculture is a central economic activity in NTT, conducted across 3 sites in the provinces of NTT and and livestock production makes up 16% of agricultural NTB, which have differing characteristics. This paper GDP. There are 60,000 livestock producers in NTT, the focuses on the West Timor village site of Oebola, where majority of whom own cattle (DGLAHS 2013), three- Bali bulls are fattened in pens on a leucaena-based diet. quarters of which are small-holders with 1‒10 head Leucaena is strip-planted with corn. The system is widely (Mullik 2012). In particular parts of NTT, cattle sales can applicable to other areas of West Timor including Kupang represent more than 80% of the family’s cash income and Amarasi, which are the largest cattle-producing areas (Nimmo-Bell and ICASEPS 2007). Cattle also play a in NTT. Results for the Sumbawa site of Jati Sari are social role for ceremonies and as a source of ’savings’ that reported in this issue (Dahlanuddin et al. 2019), including can be cashed-in to meet large cash outlays including cattle systems, history, adoption, productivity, economics housing, school fees, health and transport. and meat output from the village. In response to high beef prices over a sustained period, cattle numbers have almost doubled in the past decade from The model 555,000 in 2007 to more than one million in 2017 (BPS 2018). However, productivity is low as indicated by annual To assess household structures and incentives for FTL- turnoff rates of just 13%, due to low weaning rates and long based fattening, a bio-economic model was developed for periods of slow growth to reach sale weight, for either a representative cattle-fattening household in Oebola. It is slaughter or live cattle export (Waldron et al. 2012). Cow- a partial budget, insofar as it focuses on the activity of calf production is conducted mainly in extensive grazing leucaena production and cattle fattening. It is also a systems in NTT and various measures have been taken to steady-state budget, with production and returns assessed improve reproduction and reduce calf mortality (Copland et over a specified fattening period, which is almost always al. 2011). The emergence of a cattle-fattening sector has less than 365 days. The focus on leucaena-fattening potential to increase growth rates to reach sale weights at an means that the model accounts for virtually all direct cost earlier age and to create demand for feeder cattle (from the and revenue items. However, the budget does not account cow-calf sector). Of particular interest in relation to this for environmental externalities including soil enrichment paper, cattle-fattening has the potential to generate positive and reduction in over-grazing. cash flows that are increasingly required in a society It is problematic to conduct a ‘with and without’ transitioning from a subsistence to a cash economy. economic analysis of leucaena-fattening systems. Small- Forage tree legumes, particularly leucaena, have been holders did not fatten cattle as a specialized activity prior identified as a central feed source for the development of to the extension of the systems. As elaborated in the the small-holder cattle-fattening sector. This has given ‘scenarios’ section of the paper, it is economically rise to a body of literature on the impacts on cattle growth unviable to fatten cattle on a diet of crop residues and of feeding tree legume forage (e.g. Dahlanuddin et al. grasses, and grain is prohibitively expensive. Thus this 2014, 2019; Shelton and the Project Team 2017). analysis begins with a detailed discussion of a single Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Cattle fattening economics in eastern Indonesia 439 scenario of fattening with leucaena, namely a households fattened only 1 or 2 head at a time, with a representative (typical) household in Oebola fattening maximum of 8. 4 cattle in the wet season, with average prices over the period. Alternative scenarios – based on season, weight Cattle fattening in Oebola gains and prices – are then examined to test production and income effects. The model reports on various The budget results are summarized in Table 1 and detailed measures of profitability, the most relevant being ’returns throughout the rest of the paper. Based on average to labor’. All budget items and formulae are explicitly results of monitored households (Pakereng 2015) the stated in Excel spreadsheets that are publically available representative household sourced 4 bulls from its own on request. All values are expressed in Rupiah and the herd or bought them in, with a starting live weight of exchange rate adopted is Rp 10,000 to AU$ 1 in 2014 189 kg. Feeding periods were variable but averaged 170 when the research and fieldwork was conducted. days. There was a large difference in feed regimes and weight gains between seasons. In the wet season, bulls Data were fed a diet amounting to 2.5% of their body weight, comprised of 80% FTL (60% leucaena, 20% gliricidia), Production data for the research were drawn from ACIAR 17.5% native grasses and leaves and 2.5% corn silage. project LPS/2008/054, which monitored 8 households in Average daily weight gain (ADWG) was 0.4 kg/d and Oebola during 2013 and 2014 with a total of 30 head of bulls were sold at 257 kg live weight. In the dry season cattle between them (Pakereng 2015). Price data collected bulls were fed only 40% FTL (30% leucaena, 10% from the monitored households were cross-referenced gliricidia) plus 60% native grasses and leaves and ADWG with meetings with traders and butchers and with weekly was only 0.2 kg/d, with bulls sold at 223 kg live weight. beef price data (MoA, various years). Costs and sales data were collected through focus groups and semi-structured Revenues interviews with 5 farmers. Village-level data were used to place the farmers in context and to establish a Cattle sales accounted for 98% of all cattle revenues for ‘representative’ or ‘typical’ fattening household, which is the household. Prices for both feeder and finished cattle reported in this paper. Fieldwork was undertaken in were Rp 29,000/kg live weight in July 2015 (with price August 2012, May 2014 and July 2015. variations discussed in scenarios below). The model also accounted for revenue from manure and timber. While Results these were only 2% of total revenues, they were significant as a percentage of value added from fattening Background on Oebola village (finished cattle cost minus feeder cattle cost) at 7 and 12%, respectively. Of the manure produced (35% of DM The budgeting for NTT focuses on Oebola village, Fatuleu intake), 10% was sold (Rp 250/kg dry), 20% was used for Sub-District, Kupang District, West Timor. The system is fertilizer (valued based on the substitution of urea and based on corn cropping with strip-planting of leucaena and NPK fertilizers) and 50% was unused (which can have the fattening of Bali bulls in pens owned by individual negative environmental impacts). The remainder (20%) households, all of which immigrated from other parts of was used for biogas which was valued based on reduction Indonesia. In 2015 village statistics reported 276 households in household labor spent collecting firewood (1 hour per with an average of 4.2 household members. Household day) and kerosene usage for cooking and light in the cropland sizes were 0.5‒1 ha per household but some household. The branches of leucaena trees were used for households had up to 2 ha split into parcels. Cattle were firewood. If 2 branches were used per cut (every 120 grazed collectively on village land and sometimes days) then 3,600 branches were collected over the government forest land. Ninety-five percent of households fattening period with a value of Rp 100,000. earned a living from agriculture for both own consumption and sales. The main crops were corn (a single crop in the wet Capital investments season), pumpkins and beans. Livestock included cattle, pigs and chickens. There were 1,453 cattle in the village, i.e. an The representative household made capital investments average of 5.3 head per household. Cow-calf production in in items used for multiple household activities over grazing systems predominated and calves were usually taken extended periods. The cost (both cash and labor) was through to slaughter age. Many households bought-in feeder amortized over the economic life of the asset and cattle to use in specialized feeding operations and most attributed to cattle fattening over the fattening period. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 440 S. Waldron et al. Table 1. Revenues, costs and returns (in Indonesian rupiah; 1 AU$ = 10,000 Rp) on leucaena-based cattle fattening for a representative household in Oebola village, West Timor, and weight gain and price scenarios. Highlighted cells refer to the scenarios analyzed in the paper and the key indicator of ‘returns to labor’. Source: Author calculations; all values are expressed for a fattening period for the number of cattle specified, except ‘returns to labor’, which are expressed on a per day basis. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Cattle fattening economics in eastern Indonesia 441 To meet dietary requirements of the 4 bulls, the sold to traders at the farm gate and so incurred negligible household required a total of 1,200 trees with a 120-day sale costs. interval between harvests, strip-planted on the land of the After leucaena has been established there are no household. Planting costs included fencing, purchase of additional cash costs but there are significant labor costs for seeds, nursery (poly bags, bedding, shade cloth) and collection and transport. In the wet season all members of transplanting (labor and transport). The modest up-front the household traveled an average of 1 km (range of 0.5‒5 costs (Rp 308,000 in cash and 13 person days labor) were km) to collect forage twice per day, taking 1.5 hours. negligible when depreciated over 40 years. Motorbike fuel was Rp 700 per day. The collection of native The costs of constructing a pen (nails, wire, timber, grasses and leaves in the wet season was less time- cement, sand, gravel, reinforcing, troughs, roof and other consuming because it comprised the smaller part of the diet items) were higher than for trees (Rp 1.35 million) but but was more labor-intensive to collect from scattered trees also low when depreciated, given a lifespan of over 20 and bending over to cut grass. Labor costs to collect native years and fattening 160 cattle. The ‘design capacity’ of grasses and leaves in the dry season were high (2 hours per the pen was 5 head. Given the actual number (4 head) and day). Corn stalks were fed after harvest (at the end of the wet time not on feed (26 days) capacity utilization was 72%, season), which required labor for cutting, transport and which increased overhead costs per head. storage over a few days but little after that. The cost of a motorbike (used to transport feed and Several households in the group paid Rp 240,000 per marketing of cattle) was high but the machine was used year for access to group water supplies (access, pipe for fattening for only 20% of the time and was depreciated maintenance, fuel for pump) of which about 30% was over a life-span of 15 years. Most households had a well used for cattle fattening. The household spent 30 minutes that lasts 15 years at a cost of Rp 1,500,000 plus the costs per day collecting and distributing water to the troughs in of meals for workers that dig it. Biogas facilities (pits and the pen. The household spent another hour per day in converters) are commonly installed in West Timor to use cleaning pens and cattle management. effluent from the pens. Equipment is free (as part of a Veterinary costs included vaccination (for anthrax and government program) but costs are incurred for meals for haemorrhagic septicaemia to allow for live export), one installers and household labor, especially to dig the pit medical check (from local vet), a vitamin supplement and and for maintenance (cleaning out pits and lines). a small amount of salt. The total veterinary treatment When costs of all capital items were amortized, costs (Rp 364,000 over a fattening period) were the depreciation costs totaled Rp 186,000 per fattening second highest cash outlay. period. Together, these made up <1% of total costs and Crop shading and moisture competition were included were eclipsed by other costs, so appear to be small. as additional costs of production. When 1 ha of corn is However, it is important to note that these are up-front planted in the wet season and strip-cropped with leucaena, costs (in land, labor and capital) that can be significant it is assumed that the grain yield (2,400 kg/ha) is reduced for households when first investing and can be a barrier by 10%. Valued at Rp 3,000/kg, the forgone revenue is to adoption. While loans are available through formal Rp 720,000 or Rp 335,000, when allocated over a and informal channels including banks with subsidized fattening period. loans, traders and profit-sharing arrangements with other households (Waldron et al. 2012), households usually Returns to cattle fattening use their own limited savings for these infrastructure items. The returns (or profits) were estimated in different ways to provide different measures of profitability. Subtraction Production costs of costs from revenues provided ‘Gross profit’, which was positive in the wet season (at more than Rp 7 million over Production costs are incurred specifically for cattle the fattening period) but declined to less than half of this fattening on a daily basis or within the fattening cycle and in the dry season. Capital costs were deducted from gross are directly linked to production volumes. Feeder cattle profits to give ‘Net profit’. Few households took out purchase costs accounted for 94% of total costs. Self- loans, but an opportunity cost was applied to the money produced bulls were valued as an opportunity cost (that invested in cattle that could otherwise be invested. The could otherwise be sold) or as a cash cost when bought in. interest rate on a deposit in a savings account was used to Costs of cattle purchases, mainly from a nearby live cattle value the opportunity cost of capital (8%). For large and market, included search costs (telephone, fuel and expensive inputs like feeder cattle, the opportunity costs household labor), trucking and broker fees. Cattle were of capital were significant. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 442 S. Waldron et al. The next section on family labor reports the labor to returns to labor of Rp 61,463 in the wet season more inputs into cattle fattening. The majority of labor was than 5 times the returns in the dry season (Rp 12,097). used on feed collection and watering, followed by work Households in the group with highest gains in the in pens, then by cattle marketing. Labor input into wet season (0.8 kg/d) recorded very high returns (Rp infrastructure was allocated over the fattening period and 153,788), while those with lowest weight changes (-0.2 was small. The total labor inputs were converted into kg/d) operated at a heavy loss (Rp -77,024). hours per day in cattle fattening (i.e. 4 hours for 4 cattle Prices. Profitability is also sensitive to market trends and in the wet season), then converted into an 8-hour working especially the relative prices of feeder and finished cattle, day (i.e. half a day). which are a function of market conditions, weather, ‘Net returns’ were divided by total labor input to household conditions, the skills of buyers and sellers in derive ‘Returns to labor’, which provided the most useful appraising cattle (visually) and timing (ceremonies, the indicator of profitability. This provided an indication of issue of export permits or when school fees are due). If the profits from cattle production that a household was finished cattle prices are 15% higher than feeder cattle making from their own labor and management, and prices, returns increase strongly by 86%, but if they are allowed comparison with other farm and off-farm work. 15% lower than feeder prices, cattle fattening is barely a Results for the representative household suggested that break-even activity (Rp 9,170). returns to cattle fattening in the wet season were positive Returns without FTL. It is also useful to examine returns (Rp 61,463), which compared favorably with average off- to fattening without leucaena. This is done in the farm work (Rp 45,000). Comparisons were not so modelling by assuming a diet of improved grasses (80%) favorable in the dry season. At Rp 12,097 per day, income and corn stover (20%). However, this would not be was at or below the poverty line. However, it must be possible throughout the wet season because corn is considered that cattle can be produced all-year-round harvested at the end of the wet season, unless corn stover compared with off-farm work, which can be seasonal or was carried over from the previous season or was inconsistent. Farmers may also be attracted to the customs purchased in. While the stover could be stored and used and pride of running their own enterprise. in the dry season, quantities of grass available would be Budget results from 1 ha of corn in Oebola using (low) insufficient or very time-consuming to collect. Weight yields from 2015 and 2016 suggested that returns to gains are reduced to 0.15 kg/d, which is a generous person days were comparable with cattle fattening in the assumption given comparisons in various feed systems wet season. Because of its central role in household and locations (Quigley et al. 2009; Panjaitan 2012; consumption and cash sales and its agro-climatic Dahlanuddin et al. 2014). Time to chop stover increases suitability, farmers in Oebola continue to grow corn. from 0.1 to 0.5 hours, and to collect grass and leaves from While strip planting of leucaena reduces corn yields (by 1 to 2.5 hours. In this case, ‘Returns to person days’ are 10%), it is integrated into the corn cropping, and not a very low at Rp 4,821, indicating that cattle fattening is not substitute activity. biologically or commercially viable without leucaena. Scenarios Conclusions While the discussion above examined an average household Analyses reported in this paper confirm the intuitive in 2 seasons, there is large variation between households and understanding that cattle fattening on a leucaena-based natural and market conditions. A range of scenarios are diet is biologically and economically viable for most reported in Waldron et al. (2015) including changes to small-holders in West Timor under most conditions. rations, weight gains, fattening period, price, capital Leucaena is a low-cost input, provides feed through the investment, labor cost and sales channels. This paper dry season (albeit at a lower yield) and generates examines just the major variables – weight gain and price. reasonable weight gains. Cattle fattening is capital- Weight gain. Profitability of feeding in the wet season was intensive, but allows for rapid turnover of both cattle and far greater than in the dry season for the representative capital. Cattle fattening is not land-intensive, can be done household. By far the most important determinant was the under various ownership (owner-keeper) arrangements, difference in ADWG (0.4 vs. 0.2 kg/d) due to diet and and is relevant for a wide range of households. These compensatory weight gain early in the wet season. The factors explain the growth of leucaena-fattening systems labor cost in collecting native grasses and leaves in the in NTT. dry season was also slightly higher than collecting FTL Growth in the sector could be disrupted if circum- leaves in the wet season. The differences in ADWGs lead stances differed. Beef prices were buoyant for most of the Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Cattle fattening economics in eastern Indonesia 443 2010s and market fundamentals remained strong, but Dahlanuddin; Panjaitan T; Waldron S; Halliday M; Ash A; prices have fluctuated in recent years (for policy reasons, Morris S; Shelton HM. 2019. Adoption of leucaena-based including trade policy and domestic support), which may feeding systems in Sumbawa, eastern Indonesia and its affect incentives. Cattle fattening with leucaena is impact on cattle productivity and farm profitability. Tropical Grasslands-Forrajes Tropicales 7:428–436. doi: relatively labor-intensive. In countries and regions where 10.17138/TGFT(7)428-436 there are good alternative opportunities for work and MoA (Ministry of Agriculture). Various years. Buletin Analisis wages, small-holders can be drawn out of cattle Perkembangan Harga Komoditas Pertanian. Kementerian production (Waldron et al. 2018). While cattle fattening Pertanian Republik Indonesia, Jakarta, Indonesia. bit.ly/ may provide reasonable returns for small-scale farmers 2z9vGet (such as the representative household in this study), Mullik M. 2012. Pembangunan Pertanian Yang Selaras profits of AU$ 6 per day will not make them Wilayah Lahan Kering Iklim Kering di Indonesia: Potensi, rich. Future growth in the sector may see the emergence tantangan, dan strategi pengembangan. Presentation for of more large, skilled and entrepreneurial fattening- Pertemuan Alumni SMKPPN, Kupang, Indonesia, 27 trading households, which could utilize leucaena October 2012. sometimes through land and cattle-/land and labor- Nimmo-Bell and Company Ltd; ICASEPS (Indonesian Center for Agriculture Socio-Economic and Policy Studies). 2007. sharing arrangements. Value chain analysis for SADI agri sectors: The NTT beef industry. IFC SADI Agri Sectors, Jakarta, Indonesia. Acknowledgments bit.ly/2zdszCk Pakereng C. 2015. Progress in adoption of bull fattening with This research was funded under ACIAR Project LPS- FTL in new (and existing) locations and the keys to success. 2014-034 ‘Economic analysis of cattle fattening systems Villages: Oebola Dalam, Naunu, Camplong I, Nunsaen, based on forage tree legume diets in Eastern Indonesia’. Ekateta, Uel, and Raknamo, West Timor, Kupang District. It draws on data and technical expertise from ACIAR Presentation at project workshop LPS/2008/054, Carnarvon Project LPS/2008/054 ‘Improving smallholder cattle Gorge, QLD, Australia, December 8‒9, 2015. fattening systems based on forage tree legume diets in Panjaitan T. 2012. Performance of male Bali cattle in village Eastern Indonesia and Northern Australia’. The support system of Lombok. In: Koonawootrittriron S; Suwanasopee T; Jattawa D; Boonyanuwat K; Skunmun P, eds. Improving from ACIAR, research colleagues and from interviewees smallholder and industrial livestock production for in Indonesia is greatly appreciated, including Charles enhancing food security, environment and human welfare. Pakereng, the junior scientist working in Oebola. Thanks Proceedings of the 15th AAAP Animal Science Congress, are due to Fred Chudleigh and Steve Harrison for Bangkok, Thailand, 26−30 November 2012. p. 956−959. comments and edits. bit.ly/2KJOrvj Quigley SP; Poppi DP; Budisantoso E; Dahlanuddin; References Marsetyo; McLennan SR; Pamungkas D; Panjaitan T; (Note of the editors: All hyperlinks were verified 21 August 2019.) Priyanti A. 2009. Strategies to increase growth of weaned Bali calves. Final Report LPS/2004/023. Australian Centre BPS (Biro Pusat Statistik). 2018. Statistical Yearbook of for International Agricultural Research (ACIAR), Indonesia. BPS, Jakarta, Indonesia. bit.ly/2ZcbPKf Canberra, ACT, Australia. goo.gl/yMDCnB Copland R; Jelantik G; Mullik M; Belli HLL; Soigen J; Nalley Shelton HM and the Project Team. 2017. Improving smallholder A; Benu F. 2011. Evaluating strategies to improve calf cattle fattening systems based on forage tree legume diets in survival in West Timor villages. Final project. Australian eastern Indonesia and northern Australia. Final report. Centre for International Agricultural Research (ACIAR), Australian Centre for International Agricultural Research Canberra, ACT, Australia. bit.ly/30w1u9v (ACIAR), Canberra, ACT, Australia. goo.gl/b9RX5N DGLAHS (Directorate General for Livestock and Animal Waldron S; Dahlanuddin; Mayberry D; Mulik M; Quigley S; Health Statistics). 2013. Statistik Peternakan dan Kesehatan Poppi D. 2012. Eastern Indonesia agribusiness development Hewan (Livestock and Animal Health Statistics). Direktorat opportunities - analysis of beef value chains. Final report. Jenderal Peternakan dan Kesehatan Hewan, Jakarta, Australian Centre for International Agricultural Research Indonesia. (ACIAR), Canberra, ACT, Australia. espace.library.uq.edu. Dahlanuddin; Yanuarianto O; Poppi DP; McLennan SR; au/view/UQ:326414 Quigley SP. 2014. Liveweight gain and feed intake of Waldron S; Halliday M; Shelton HM; Ngongo J; Nulik J; Nulik D; weaned Bali cattle fed grass and tree legumes in West Nusa Kusuma Putri Utami S; Panjaitan T; Baiq Tutik Y; Tenggara, Indonesia. Animal Production Science 54:915– Dahlanuddin. 2015. Economic analysis of cattle fattening 921. doi: 10.1071/AN13276 systems based on forage tree legume diets in eastern Indonesia. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 444 S. Waldron et al. Final Report. Australian Centre for International Agricultural 2018. Macro developments in the China and Southeast Asia Research (ACIAR), Canberra, ACT, Australia. bit.ly/33JxicJ beef sector. Animal Production Science 59:1001–1015. doi: Waldron S; Pham L; Smith D; Hieu PS; Dong XX; Brown C. 10.1071/AN17434 (Accepted 7 March 2019 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):445–448 445 DOI: 10.17138/TGFT(7)445-448 ILC2018 Poster and Producer Paper* Preliminary assessment of rearing male buffalo calves on Leucaena leucocephala-buffel grass pasture in Maharashtra State, India Valoración preliminar de cría de terneros bubalinos en una pastura de Leucaena leucocephala-Cenchrus ciliaris en el estado de Maharashtra, India NANDINI NIMBKAR, SHARAD CHOUDHARI AND BON NIMBKAR Nimbkar Agricultural Research Institute, Phaltan, Maharashtra, India. nariphaltan.org Keywords: Animal growth rates, Bubalus bubalis, pasture, tree legumes. Introduction by Gupta (1995). ALT and AST are serum biochemical variables whose activities are considered as biomarkers for India’s US$4 billion buffalo meat export industry relies liver function, and synthesis of protein, albumin and globulin mainly on the slaughter and processing of females that have largely depends on the liver function status. T4 and T3 levels stopped lactating. The potential for fattening of male buffalo are considered valuable indicators of thyroid function in calves (MBCs) for quality meat production was identified in animals. 1995 in a report of the National Dairy Research Institute Given the contrasting results from previous (Sharma et al. 1995): “Underfed MBCs after weaning are experiments in India, the objective of this study was to either starved to death or pushed to the slaughterhouse. Such conduct a preliminary assessment of rearing MBCs on malnourished calves, weighing 60 to 80 kg, yield only 30 to leucaena-buffel grass pasture in a semi-arid part of the 35 kg carcasses of inferior quality. These calves, if reared on state of Maharashtra in India. high energy diets up to a live body weight of 350 kg, may yield 180 kg carcasses of good quality”. The rearing of Materials and Methods MBCs could augment meat exports and provide raw material for the domestic leather industry, thereby The study consisted of 2 experiments: developing a new avenue for rural employment.  Experiment 1: 1 December 2015‒27 February 2016 Leucaena leucocephala is high quality forage, which is (2 MBCs) highly regarded in seasonally dry environments in eastern  Experiment 2: 5 January 2017‒1 August 2018 (4 Indonesia, due to its excellent ability to produce year-round MBCs) fodder if properly managed and regularly pruned (Panjaitan A pasture of L. leucocephala cv. Wondergraze + et al. 2014; Nulik and Kana Hau 2015). In previous research Cenchrus ciliaris cv. Laredo (buffel grass) was in India, no ill-effects on the general health of MBCs fed established on a 4,000 m2 area at ‘Tambmal’ farm of the 70% of their dry matter requirements as L. leucocephala Nimbkar Agricultural Research Institute (NARI) by were observed, although daily bodyweight gains were less sowing 1 kg leucaena seed on 13 July 2015. Twin rows of than 50% of those of the control group given 3.5 kg leucaena were planted with inter-row spacing of 4.5 m. concentrates and 3.5 kg wheat straw daily (Gupta et al. This was followed by sowing of 1 kg buffel grass seed on 1986). This may have been due to reduced dry matter intake, 13 August 2015 in the inter-row space (between the lower levels of serum triiodothyronine (T3) and thyroxin leucaena twin rows). Another pasture was established on 8,000 m2 (T4) and increased aspartate transaminase (AST) and at alanine transaminase (ALT) activities in plasma as reported ‘Madhura’ farm at Jadhavwadi village near Phaltan, ___________ Correspondence: Nandini Nimbkar, Nimbkar Agricultural Research *Poster paper presented at the International Leucaena Conference, Institute (NARI), Tambmal, Phaltan-Lonand Road, P.O. Box 44, 1‒3 November 2018, Brisbane, Queensland, Australia. Phaltan – 415523, Maharashtra, India. Email: nnimbkar@gmail.com Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 446 N. Nimbkar, S. Choudhari and B. Nimbkar where buffel grass cv. Laredo was planted with slips in acquired on 5 January 2017 for Experiment 2. No 2013. About 1,300 seedlings of leucaena cv. Tarramba measures were undertaken for internal or external parasite were planted in this pasture at a spacing of 4 × 1 m in control in these 4 MBCs. They were shifted between the October 2016. Both pastures were located near Phaltan 2 farms (buffel or leucaena + buffel pastures at Madhura town (17.98° N, 74.43° E; 568 masl) on medium black and Tambmal farms, respectively), depending on the basaltic soils. Growth of the leucaena seedlings was slow, availability of fodder, and were housed at night. It was presumably due to the competition from the buffel grass. decided to feed fresh leucaena fodder to them as much as Gliricidia sepium trees (gliricidia) were planted around possible, but sometimes due to its shortage, other fodders the boundary of the experiment, and we planned to feed such as chopped sweet sorghum stalks (dried or fresh) or their foliage to the MBCs. However, even after repeated stripped sweet sorghum leaves were fed. For about half of attempts, the calves refused to consume fresh, wilted or this experiment the MBCs grazed buffel grass pasture and dried foliage of gliricidia. the other half leucaena-buffel grass pasture. The different In the first experiment, the 2 MBCs (about 7‒8 months feeds and the periods during which they were supplied to old and weighing 79 and 89 kg) were allowed to graze in the the MBCs are presented in Table 1. leucaena-buffel grass pasture for 3 months. The MBCs were The animals were difficult to handle despite being removed from the pasture every Saturday evening and castrated (13 December 2017), making it difficult to returned to it on Monday morning. This was a precaution weigh or measure them once they exceeded about 100 kg against them being stolen over the weekend. During these 40 live weight, and there was no facility for weighing at hours away from the pasture they were fed with sweet Madhura farm. sorghum leaves and fresh leucaena forage from 3‒5 trees The feed supplied was measured where possible (Table (not weighed). The sorghum leaves were fully consumed, 1). Fresh leucaena forage (300 kg per week) was sent to but some leucaena leaves were always left over. Madhura farm for about 15 weeks during the second period The 2 MBCs were weighed weekly. After they showed of grazing. This was fed to the MBCs throughout the week satisfactory growth, they were sold and 4 additional either during the morning before they were taken to the MBCs (about 3‒4 months old and 37‒51 kg) were buffel grass pasture or after bringing them back in the Table 1. Feed offered to the 4 male buffalo calves (Experiment 2). Dates No. days Grazing Fresh leucaena leaves Sorghum leaves Other 5.1.17 to 32 - Weight not recorded 5.2.17 6.2.17 to 54 Buffel grass pasture - - - 31.3.17 1.4.17 to 10 Leucaena-buffel Buffel grass + leucaena leaves + sorghum leaves (all fresh) + fresh or dry chopped 10.4.17 grass pasture (day) sorghum (total 100 kg) 11.4.17 to 12 Leucaena-buffel - - - 22.4.17 grass pasture 23.4.17 1 Leucaena-buffel - 4 kg (at night) - grass pasture 24.4.17 to 15 Leucaena-buffel - - - 8.5.17 grass pasture 9.5.17 to 10 Leucaena-buffel 12‒15 trees per day (at - - 18.5.17 grass pasture night) 19.5.17 to 124 Leucaena-buffel - - - 19.9.17 grass pasture 20.9.17 to 218 Buffel grass pasture 300 kg once a week - Solution of 200 g urea sprinkled 25.4.18 from 2.12.17 to 20.3.18 on 5‒10 kg buffel grass and fed 5 (15 weeks) times from 29.12.17 to 27.1.18 26.4.18 to 43 Leucaena-buffel 3,098 kg - - 7.6.18 grass pasture 8.6.18 to 55 Leucaena-buffel 733 kg from 30.6.18 to 100 kg from - 1.8.18 grass pasture 31.7.18 (4.5 weeks) 2.7.18 to 30.7.18 Total 574 Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena for rearing male buffalo calves 447 evening. Rainfall was measured at the Tambmal farm over Table 2. Average daily gain (kg/hd/d) as affected by pasture the course of the experiments. Both farms have irrigation type (February 2017‒August 2018). facilities and flood irrigation was provided on a weekly basis to the buffel grass pasture, while leucaena-buffel grass Sr. Pasture No. Calf Calf Calf Calf Mean pasture received 3 flood irrigations in total during February No. type days 1 2 3 4 1 Buffel grass 54 0.14 0.10 0.0 0.0 0.06 and May 2017 and February 2018. 2 Leucaena- 161 0.43 0.33 0.36 0.35 0.37 buffel grass 3 Buffel grass 229 0.36 0.30 0.26 0.44 0.34 4 Leucaena- 98 0.97 0.76 0.58 0.75 0.76 buffel grass Total Buffel grass 283 0.25 0.20 0.13 0.22 0.20 Leucaena- 259 0.70 0.54 0.47 0.55 0.57 buffel grass The cost of establishing the buffel grass-leucaena pasture on the 4,000 m2 area was about INR 25,000 with 50% being spent on manual weed control. The cost of putting up a barbed wire fence around this pasture was INR 40,000. The 3‒4 month old MBCs cost about INR 5,000 each. This makes the total cost of the operation INR 85,000. The price realized for 250‒300 kg MBCs is INR 25,000‒40,000 each. Even with the lower figure of INR Figure 1. Four MBCs grazing in buffel grass-leucaena pasture. 100,000 for 4 MBCs, about INR 15,000 net income can be expected from them in 1.5‒2 years. This is expected to Results and Discussion increase to about INR 75,000 from the next 4 MBCs kept on this pasture. Rainfall was variable over the 2 growing seasons. In 2017, 733 mm was received, which is about 200 mm above average, with 70% falling in September‒October, while Conclusions no rain fell in January, February, April, November and December. In 2018, 145 mm rainfall was received from The study has demonstrated that the use of leucaena as a January 1 to July 31, which is below average with no rain source of high quality protein feed can result in high in January‒March. levels of liveweight gain in MBCs compared with being In Experiment 1, weights of the 2 MBCs increased to fed grass alone and this can be highly profitable. Local 125 and 137 kg, respectively, after 88 days in the farmers should be encouraged to take up the planting of leucaena-buffel grass pasture, giving growth rates of 466 leucaena to feed their buffalo male calves and possibly and 716 g/d, respectively. other ruminants as well. For Experiment 2, average daily gains for different pasture types are given in Table 2 with final weights of Acknowledgments the 4 MBCs after 574 days ranging from 218 to 305 kg. Average daily gains ranged from 304 to 452 g/d, with the We thank Mr Somnath Jadhav, the owner of Maharashtra highest daily gains (582‒970 g/d) during the trial Foods Processing and Cold Storage, Phaltan, who gave us occurring in the last 98 days when leucaena was fed. the 4 calves for the second experiment of the study free of Overall, growth rates were much higher when animals cost. We are grateful to Mr Harishankar for taking the grazed leucaena-buffel grass pasture than on buffel grass photograph. alone (Table 2). Feeding leucaena forage on the buffel pasture increased weight gains but daily weight gains on References leucaena-buffel grass pasture were 2.8 times greater than (Note of the editors: All hyperlinks were verified 21 August 2019.) on buffel grass pasture. No overt signs of mimosine toxicity were observed but Gupta HK. 1995. Mimosine degradation, its residual effect on hair was lost from the bodies of the MBCs by the end of milk and meat in animals on Leucaena leucocephala diet. the first year and there was no need to shave them as is Ph.D. Thesis. National Dairy Research Institute, Karnal, the normal practice. India. krishikosh.egranth.ac.in/handle/1/68927 Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 448 N. Nimbkar, S. Choudhari and B. Nimbkar Gupta PC; Virk AS; Khatta VK; Kumar N. 1986. Effect of Panjaitan T; Fauzan M; Dahlanuddin; Halliday MJ; Shelton feeding Leucaena leucocephala hay on the nutrients HM. 2014. Growth of Bali bulls fattened with Leucaena utilization and growth performance in buffalo calves. Indian leucocephala in Sumbawa, Eastern Indonesia. Tropical Journal of Animal Sciences 56:147‒148. Grasslands-Forrajes Tropicales 2:116‒118. doi: 10.17138/ Nulik J; Kana Hau D. 2015. Daily body weight gain of Bali TGFT(2)116-118 cattle fed with Leucaena leucocephala as the main ration in Sharma DD; Sehgal JP; Singhal KK; Ghosh MK. 1995. West Timor, East Nusa Tenggara, Indonesia. Proceedings of Fattening of growing male buffalo calves for quality meat the 6th International Seminar on Tropical Animal production. NDRI-Al-Kabeer Consultancy Project Report. Production, Yogyakarta, Indonesia, 20‒22 October 2015. p. National Dairy Research Institute (ICAR), Karnal, Haryana, 147‒150. bit.ly/2NmpY0Y India. (Accepted 9 January 2019 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):449–454 449 DOI: 10.17138/TGFT(7)449-454 ILC2018 Keynote Paper* Potential of Leucaena spp. as a feed resource for ruminant animals in Thailand Potencial de especies de Leucaena como recurso forrajero para rumiantes in Tailandia G. NAKAMANEE1, S. HARRISON2, K. JANTHIBORDEE3, W. SRISOMPORN4 AND C. PHAIKAEW3 1Nakhonratchasima Animal Nutrition Research and Development Center, Pakchong, Nakhonratchasima, Thailand 2Srakaew Animal Nutrition Research and Development Center, Klonghad, Srakaew, Thailand 3Bureau of Animal Nutrition Development, Department of Livestock Development, Bangkok, Thailand. en.dld.go.th 4Roied Animal Nutrition Research and Development Center, Suwannaphumi, Roied, Thailand Abstract While Leucaena leucocephala grows wild in Thailand, some Leucaena spp. have been introduced and evaluated for their edible forage yield and quality. Experiments on appropriate management were performed in different environments and productivity was found to be affected by species or cultivar. Environmental conditions, plant spacing, age of plant and cutting height significantly affected growth and performance. Edible forage yield was in the range of 5‒6 t DM/ha/yr. Most species and cultivars contain high protein concentrations and are suitable for use as feed supplements as well as total ration for livestock. The effects of leucaena feeding on livestock are shown in lower mortality and increased productivity. While the leaf meal processing of leucaena for livestock feeding is increasingly recognized and practiced, cultivation of this crop is still minimal and insignificant. The role and importance of leucaena for livestock production, as well as its nutritional quality and factors which limit its use, are reviewed. The need for increased cultivation and integration of leucaena into local farming systems is emphasized. There is an urgent need to increase research support for the efficient cultivation of leucaena and an education campaign to dispel concerns about toxicity aspects. Keywords: Livestock feeding, management, shrub legumes, utilization. Resumen A pesar de que Leucaena leucocephala crece en forma silvestre en Tailandia, se han introducido algunas otras especies de Leucaena para evaluar su rendimiento y calidad forrajera. Se realizaron experimentos sobre manejo apropiado en diferentes sitios y se encontró que la productividad es afectada por especie o cultivar. Las condiciones ambientales, la distancia entre plantas, la edad de la planta y la altura de corte afectaron significativamente su crecimiento y desempeño. La producción de forraje comestible estuvo en el rango de 5‒6 t materia seca/ha/año. La mayoría de especies y cultivares registraron altas concentraciones de proteína cruda y se consideraron aptas para uso en alimentación de rumiantes tanto como suplemento como ración total. La alimentación de ganado bovino con leucaena se manifiesta en una menor mortalidad y mayor productividad animal. Si bien el potencial de leucaena para uso como harina de hoja en vez de forraje fresco es cada vez más reconocido y practicado, la adopción como cultivo es aún mínima. El rol y la importancia de la leucaena para la producción animal, así como su calidad nutricional y los factores que limitan su uso, son revisados. Se enfatiza la necesidad de incrementar el cultivo y su integración en los sistemas de producción agropecuarios locales. Además debe incrementarse la investigación para mejorar la eficiencia del cultivo de leucaena y apoyar campañas de educación para disipar las preocupaciones de los productores sobre posibles efectos tóxicos de la leucaena. Palabras clave: Alimentación animal, leguminosas arbustivas, manejo, utilización. ___________ Correspondence: G. Nakamanee, Nakhonratchasima Animal *Keynote paper presented at the International Leucaena Conference, Nutrition Research and Development Center, Pakchong, 1‒3 November 2018, Brisbane, Queensland, Australia. Nakhonratchasima 30130, Thailand. Email: ganda.nak@gmail.com Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 450 G. Nakamanee, S. Harrison, K. Janthibordee, W. Srisomporn and C. Phaikaew Introduction In an attempt to counter the psyllid, resistant species and varieties of leucaena have been selected or bred. In Thailand is located at the center of peninsular Southeast 1996 Leucaena spp. from Oxford Forestry Institute (OFI) Asia occupying 513,120 km2; development has been and from Australia were introduced to Thailand by generally based on agricultural production, which Department of Livestock Development (Bureau of employs 49% of the labor force. Forty-six percent of the Animal Nutrition 2018). Eight accessions of Leucaena total land mass is engaged in the agricultural sector, of spp. were evaluated for psyllid resistance and edible which 47% is incorporated in paddy fields, as rice is the forage yield during April 1996–March 1999, when most important crop grown in the country (Office of planted in rows with spacing of 1 × 0.5 m (Figures 1 and Agricultural Economics 2018). However, livestock 2). Three accessions, L. pallida OFI 137/94 (CQ 3439), production is very important to the Thai economy; beef L. diversifolia CPI 46568 [in Hughes (1998) listed as cattle, dairy cattle, goats and buffalo are the most L. trichandra] and L. leucocephala K376, exhibited important ruminant livestock. In 2017 there were high psyllid resistance, but edible forage yield of 4,876,228 beef cattle, 584,357 dairy cattle, 1,029,924 L. leucocephala K376 (12.2 t DM/ha/yr) was higher than buffalo, 652,964 goats and 45,628 sheep (Department of those of L pallida OFI 137/94 (9.2 t DM/ha/yr) and Livestock Development 2018). Most ruminant livestock L. diversifolia CPI 46568 (4.2 t DM/ha/yr) with 17.7% farmers in Thailand are small-holders; beef cattle farmers crude protein (CP) (Thinnakorn et al. 2003). own approximately 6 cattle/farm and dairy farmers keep Additional experiments on psyllid resistance and approximately 33 dairy cattle, while goat farmers have edible forage yields of leucaena were conducted in the approximately 12 goats. Beef cattle are fed primarily central part of Thailand in Petchaburi Province (20 grass plus agricultural and agro-industrial by-products, varieties), and in the northeastern part of Thailand in while dairy cattle are fed grass, rice straw and concentrates. Although many species of herbaceous Nakhonratchasima Province during 1997–2001 (17 legumes have been introduced and evaluated for use as a varieties). Both sites used cv. Cunningham as control. The protein source in animal production systems, only 2‒3 best cultivar in Petchaburi was L. leucocephala hybrid species are used commercially. The leguminous tree K584 × K636, while good yields were obtained with Leucaena leucocephala, native to Guatemala and Mexico, L. leucocephala cv. Cunningham, L. leucocephala OFI was introduced to the Philippines and Southeast Asia, 34/92 and L. leucocephala K636 (now = cv. Tarramba) including Thailand, during the period 1565–1825. It was (Polbumrung et al. 2003). In Nakhonratchasima previously used in Thailand for reforestation but was performance of L. leucocephala OFI 34/92 was better introduced to Thailand as an animal feed in 1962. than that of the other 16 accessions in terms of edible forage yield (8.3 t DM/ha/yr) and quality (22.5% CP). Agronomic evaluation under cutting Leucaena was destroyed by psyllid infestation in a short period during the dry season (December‒February) and Manidool et al. (1976) compared 10 varieties of Leucaena L. leucocephala OFI 34/92 recovered better than the other leucocephala introduced from Australia, Hawaii, Ivory accessions (Phaikaew et al. 2005). These results have Coast, Taiwan, El Salvador and New Guinea in Pakchong, been confirmed by Rengsirikul et al. (2011). Northeast Thailand, where mean annual rainfall is 1,145 mm. With cutting 3 times per annum cv. Ivory Coast Crop management produced the highest leaf yield (9,500 kg DM/ha). These initial evaluations failed to lead to recommendations for use Leucaena leucocephala OFI 34/92 produced annual by farmers. Cultivar Cunningham was also introduced from yields of edible forage of 6 t DM/ha from 1.5 × 0.25 m Australia in 1972 and is the most widely used cultivar in spacing (Srisomporn et al. 2015). Research on different Thailand. The leucaena psyllid, Heteropsylla cubana cutting intervals and cutting heights in Petchaburi (Homoptera: Psyllidae), infests both the ‘common’ and Province in central Thailand indicated that leucaena can ‘giant’ types of leucaena (L. leucocephala ssp. leucocephala achieve annual yields of 24 t DM/ha at 100 cm cutting and ssp. glabrata, respectively) resulting in leaf loss, which height and 25.7 t DM/ha with 10-week cutting interval depresses yields. While all types of leucaena in Thailand are (Ratchadapornvanitch et al. 2015). Chotchutima et al. susceptible to the psyllid attack, the degree of damage ranges (2016) reported that sulphur application (187.5 kg from moderate to severe throughout the country. Infestation gypsum/ha) led to an overall higher total edible biomass is seasonal, occurring from October–November to April– yield (4.5 t/ha/yr) than without sulphur (2.3 t/ha/yr). The May (Napompeth 1990). maximum rate of P fertilization (750 kg triple super- Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena species and cultivars in Thailand 451 phosphate/ha) produced the highest leaf, branch, woody Animal production stem and total biomass yields. Leucaena leucocephala is a valued fodder for ruminants, e.g. cattle, buffalo and goats. It can be grazed, fed fresh as cut-and-carry forage or conserved as hay or silage for feeding later. A number of studies have been conducted to evaluate the potential of leucaena to improve animal performance. A long-term study over 4 years in Srakaew Province in the eastern part of Thailand assessed the effects on reproductive performance of breeding does of feeding fresh L. leucocephala as the sole diet. Five crossbred Anglo-Nubian yearling does (20‒25 kg body weight) and a 30 kg yearling buck were housed in a 10 × 10 m pen and fed only fresh leucaena leaf. Over the 4 years there were 54 kiddings resulting in 92 kids (38.9% single births, 51.8% twinning and 9.3% triplets). Figure 1. Evaluation of Leucaena spp. at Pakchong. Mortality of kids at parturition was 3%. Average birth weight was 2.01 kg and weaning weight at 3 months was 9.43 kg. These data indicate that feeding fresh L. leucocephala for 4 years to breeding does should not affect their reproductive performance. They showed no symptoms of mimosine toxicity. The feeding regime was continued with some of the male goats to assess growth performance. Initial weight was 16.43 kg and final weight after 176 days of feeding was 26 kg, giving a growth rate of 54.6 g/d and a feed conversion rate of 13.3 g DM/g gain (Janthibordee and Kodepat 2009). In a second study crossbred Anglo-Nubian goats rotationally grazing Paspalum plicatulum were supplemented with leucaena silage ad libitum or 14% CP commercial concentrate at 1% body weight. Conception rates, percentage of births and number of twins were higher on the leucaena treatment than on the concentrate treatment (Ted–arsen et al. 2017). In an experiment in Prachuapkhirikhan Province, 20 crossbred goats were used to compare the responses from feeding supplements of leucaena silage and commercial concentrate at 0.5, 1.0 Figure 2. Experiment on the effect of row spacing on forage and 1.5% body weight. Intakes of organic matter and CP yield and quality of leucaena at Pakchong. and daily growth rates were greater for the leucaena treatment than for the concentrate groups, but the lowest Chemical composition feed cost was for the 0.5% concentrate supplement (Sengsai et al. 2015). Beef cattle receiving rice straw plus Crude protein concentration in Leucaena spp. is high, 4 kg of fresh leucaena leaves had significantly higher ranging between 18.0 and 27.9% in different species and daily growth rates and total DM intakes than animals fed cultivars (Phaikaew et al. 2005; Table 1). Dry matter rice straw treated with urea-molasses (3% urea and 10% digestibility (nylon bag technique) at 48 h was in the range molasses). No symptoms of toxicity were observed during 43–80%. Ratchadapornvanitch et al. (2015) reported that, as the feeding period of 364 days (Sanitwong et al. 1983). in most plant species, CP concentration of leucaena Buffalo fed dehydrated sugarcane tops supplemented with decreases with increase in the cutting interval, declining fresh leucaena leaves (12 kg/hd/d) gained 0.7 kg/hd/d from 21% for 6-week cutting interval to 16% for 12-week more than buffalo fed dehydrated sugarcane tops alone cutting interval. Ca concentration was 1.4% and P was 0.2%. (Sanitwong et al. 1986). Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 452 G. Nakamanee, S. Harrison, K. Janthibordee, W. Srisomporn and C. Phaikaew Table 1. Nutrient composition and dry matter digestibility (DMD) of edible material of different Leucaena species (Phaikaew et al. 2005). Species % (DM basis) % DMD CP ADF NDF Lignin Hemicellulose Mimosine Tannin (48 h) L. leucocephala ssp. glabrata cv. 23.1 23.7 34.7 8.2 11.1 3.2 0.9 75 Cunningham L. collinsii ssp. zacapana OFI 56/88 24.6 23.2 35.0 6.4 11.9 2.4 0.5 75 L. collinsii OFI 52/88 25.0 25.5 36.2 8.5 10.7 3.2 1.8 73 L. diversifolia OFI 83/92 21.8 23.0 34.1 10.3 11.1 2.9 2.1 72 L. diversifolia ssp. stenocarpa1 20.2 27.0 38.0 11.4 11.0 2.1 2.3 52 OFI 53/88 L. esculenta ssp. esculenta OFI 47/87 18.4 23.3 34.7 8.6 11.4 1.1 3.2 65 L. esculenta ssp. paniculata2 OFI 52/87 22.3 24.9 38.0 10.0 13.1 1.6 0.9 67 L. lanceolata OFI 43/85 23.2 25.0 37.9 7.7 12.9 3.1 1.0 74 L. lempirana OFI 6/91 22.5 25.9 38.9 10.5 12.0 2.3 0.4 71 L. leucocephala ssp. glabrata OFI 34/92 22.2 23.9 35.9 8.6 12.1 3.3 1.1 80 L. macrophylla ssp. nelsonii3 OFI 47/85 23.9 31.0 43.3 11.8 12.3 2.9 0.9 53 L. multicapitula OFI 81/87 23.6 35.4 44.0 3.5 3.6 2.4 0.5 58 L. pulverulenta OFI 83/87 20.0 25.4 35.9 12.0 10.4 2.2 3.4 44 L. salvadorensis OFI 17/86 19.8 29.3 42.2 10.0 12.8 2.0 0.3 69 L. shannonii ssp. magnifica4 OFI 19/84 19.9 29.8 41.5 11.0 11.7 1.9 0.3 68 L. trichodes OFI 61/88 27.9 25.7 39.3 9.5 13.7 3.3 0.3 65 L. pallida OFI 137/94 (CQ 3439) 21.4 26.0 36.4 10.4 10.4 1.6 2.7 59 1In Hughes (1998) listed as L. trichandra. 2In Hughes (1998) listed as “Leucaena? hybrid”. 3In Hughes (1998) listed as L. macrophylla ssp. istmensis. 4In Hughes (1998) listed as L. magnifica. Use of leucaena in farming systems company has their own leucaena field of cv. Tarramba, established with seed bought from Australia, they Leucaena is fed to animals in many forms in farming encourage farmers to plant Tarramba for sale to the systems. Where it grows naturally, farmers have evolved company. The company sells leucaena leaf meal as well feeding systems utilizing freshly harvested leucaena for as concentrate feed containing leucaena, and produces feeding goats and cattle ad libitum, while in some areas 50‒80 t/d of leucaena leaf meal. wild leucaena is collected, chopped and ensiled (Phaikaew et al. 2012). Leucaena leaf meal is also fed as Constraints to leucaena production and adoption a supplement for dairy cows consuming grass. A number of farmers actually produce dried leucaena leaf for sale While wild leucaena is used by livestock farmers in many in different areas. One farmer in Nakhonratchasima places, its cultivation by farmers is limited. Establishment Province produces dried leucaena leaf and sells it to dairy of leucaena is limited by the ready availability of wild farmers in his area as well as to the commercial feed leucaena and the fact that most farmers own less than 8 ha industry, which uses it for poultry feed. The amount of of land, which they use for diverse purposes. Another leaf meal produced is 80‒90 t/month. Initially he alone factor limiting cultivation of leucaena is the possibility of harvested wild leucaena but the increasing demand for low germination in the field and slow seedling growth. To dried leucaena leaf for animals led to an increase in the stimulate planting of leucaena the Department of number of leucaena producers and a decrease in the Livestock Development commenced a project called availability of wild leucaena. He planted about 2 ha of ‘Planted leucaena as edible fence’. Since people consume leucaena on his own land which he harvested every 2‒3 young leaves and seed pods of leucaena as a vegetable, if months. This reduced his cost of production by reducing farmers plant leucaena they can harvest these components the cost of fuel to find and harvest wild leucaena. He also for food for the family, while the remainder will be left as buys from other farmers who collect wild leucaena, while feed for their animals. As part of the project leucaena seed he does the processing, i.e. chopping and drying, before can be obtained via livestock officers located in every selling it to the feed industry (Chantarasiri et al. 2018). In province. Lopburi Province, farmers collect wild leucaena and Unfortunately there is no satisfactory project sell it to a company, which then processes it. While the implementation plan. While many farmers throughout the Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena species and cultivars in Thailand 453 country feed their animals with leucaena, some are Animal Production Science 52:283–286. doi: 10.1071/ reluctant to do so because of the risk of mimosine toxicity, AN11239 which might result in deaths of animals or decreased Polbumrung T; Phaikaew C; Booncharatcha J; Paothong S. 2003. Study on Leucaena spp. for psyllid resistance (b) in reproductive performance. While the purpose of pointing Petchaburi Province. Annual Research Report 2003. Animal out possible toxic effects of mimosine is to make farmers Nutrition Division, Department of Livestock Development, aware of potential risks, it is important not to discourage Ministry of Agriculture and Cooperatives, Bangkok, the use of leucaena to feed ruminant animals. An Thailand. p. 215‒227. (in Thai) goo.gl/Wn8oZp education plan is needed to stimulate its use. 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Number of Agriculture and Cooperatives, Bangkok, Thailand. p. 1–8. livestock in Thailand year 2017. (in Thai) goo.gl/ShXeUE Sanitwong C; Manmeechai S; Klingason K. 1986. Performance Hughes CE 1998. Leucaena: A genetic resources handbook. of buffaloes fed on dehydrated sugarcane tops with and Tropical Forestry Papers No. 37. Oxford Forestry Institute, without leuceana leaf as a protein supplement. Annual Oxford, UK. goo.gl/2sryXE Research Report 1986. Animal Nutrition Division, Janthibordee K; Kodepat W. 2009. Feeding goats with Department of Livestock Development, Ministry of Leucaena leucocephala. Forages Crop News 14:19–23. (in Agriculture and Cooperatives, Bangkok. p. 17–34. Thai) goo.gl/fD5fVC goo.gl/MmvKeA Manidool C; Torsakul P; Sirikiratayanond N. 1976. Yield and Sengsai A; Paothong S; Soonthornwat S; Pojun S. 2015. The nutritive value of ten Leucaena cultivars in Thailand. use of leucaena silage as roughage source combined with Department of Livestock Development, Bangkok, Thailand. different levels of concentrate meal in Anglo-Nubian goat. Napompeth B. 1990. Leucaena psyllid in Thailand – A country Annual Research Report 2015. Animal Nutrition Division, report. In: Napompeth B; MacDicken KG, eds. Leucaena Department of Livestock Development, Ministry of Agri- psyllid: Problem and management. Proceedings of an culture and Cooperatives, Bangkok, Thailand. p. 22–31. International Workshop, 16–21 January 1989, Bogor, Srisomporn W; Jantipbadee K; Nakamanee G; Kampayae S. Indonesia. p. 45–53. 2015. Effect of plant spacing on yield and quality of Office of Agricultural Economics. 2018. Agricultural statistics Leucaena leucocephala subsp. glabrata. Proceedings of the of Thailand 2017. Center of Agricultural Information, XXIII International Grassland Congress, New Delhi, India, Office of Agricultural Economics, Ministry of Agriculture 20–24 November 2015. and Cooperatives, Bangkok, Thailand. goo.gl/n2CJA4 Ted-arsen C; Silapacharoen S; Prajakboonjessada S; Phaikaew C; Thinnakorn S; Nakamanee G; Worajirawanit S. Donsawai S; Kacharat S. 2016. Research and 2005. Species evaluation of Leucaena as animal feed. Annual development on feeding of goat for meat production. 2.6 Research Report 2005. Animal Nutrition Division, Department Study on productivity of Anglo-Nubian crossbred goats of Livestock Development, Ministry of Agriculture and grazing on Paspalum plicatulum pasture with Leucaena Cooperatives, Bangkok, Thailand. p. 28–47. (in Thai) leucocephala and concentrate feed supplementation. Phaikaew C; Suksaran W; Ted-arsen J; Nakamanee G; Annual Research Report 2016. Animal Nutrition Saichue A; Srijundee S; Kotprom N; Shelton HM. 2012. Division, Department of Livestock Development, Incidence of subclinical toxicity in goats and dairy cows Ministry of Agriculture and Cooperatives, Bangkok, consuming leucaena (Leucaena leucocephala) in Thailand. Thailand. p. 29–41. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 454 G. Nakamanee, S. Harrison, K. Janthibordee, W. Srisomporn and C. Phaikaew Thinnakorn S; Nakamanee G; Phaikaew C. 2003. Study on Animal Nutrition Division, Department of Livestock Leucaena spp. for psyllid resistance (a) in Nakhon Development, Ministry of Agriculture and Cooperatives, Ratchasima province. Annual Research Report 2003. Bangkok. p. 1–16. (in Thai) goo.gl/83uq2s (Accepted 16 January 2019 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):455–458 455 DOI: 10.17138/TGFT(7)455-458 ILC2018 Poster and Producer Paper* Production of Leucaena leucocephala ‘silage’ for sale as animal feed: A case study from Sikiew District, Northeast Thailand Producción de ‘ensilaje’ comercial de Leucaena leucocephala: Un estudio de caso en el distrito de Sikiew, Noreste de Tailandia S. HARRISON1, W. SRISOMPORN2 AND G. NAKAMANEE3 1Srakaew Animal Nutrition Research and Development Center, Klonghad, Srakaew, Thailand 2Roied Animal Nutrition Research and Development Center, Suwannaphumi, Roied, Thailand 3Nakhonratchasima Animal Nutrition Research and Development Center, Pakchong, Nakhonratchasima, Thailand Keywords: Forage conservation, forage utilization, shrub legumes. Introduction Producing Leucaena leucocephala ‘silage’ in Sikiew District Worldwide, leucaena (Leucaena leucocephala) is used not only for fodder for livestock but also for fuelwood and In 2008, a group of 5 farmers was established to make human consumption. It was first introduced to Thailand a ‘partial’ leucaena silage for sale. ‘Partial silage’ is the term long time ago and has been used for reforestation for long used to describe fresh forage which is sealed in plastic bags periods. Leucaena has now become naturalized in many but is often consumed before the full fermentation process regions of Thailand. Farmers harvest this naturally associated with conventional silage making has been occurring leucaena and use it to feed their animals in a completed. Farmers collect wild leucaena, chop and pack it number of ways. In Sikiew District, Nakhonratchasima in bags and sell it in the form of fresh bagged leucaena. Province, in Northeast Thailand, a group of farmers have Currently 3 of these farmers continue to produce this adopted a novel approach and make ‘partial’ leucaena feedstuff for sale. Mr Charoon is 1 of the 3 who continue to silage for sale. do so. Each day from 07:00 h to 11:00 h he, his wife and 2 workers collect wild leucaena in the village area (Figures 1 Site characteristics and 2), travelling up to 65 km in the dry season to obtain enough material. They transport the leucaena home in a Nakhonratchasima Province, located in the lower part utility at about 11:00 h, before chopping it with a small of Northeast Thailand (15º N, 102° E), consists of 32 machine (Figures 3 and 4) and packing it into plastic bags districts with a total area of 20,494 km2. For Sikiew (30 kg), which are tied tightly at the top (Figures 5‒7). No District, annual average daily temperature is 27.4 ºC, special attempt is made to extract air before tying. The real average humidity is 71% and average annual rainfall is cost of production is US$ 0.052/kg. 970 mm, which is received in April–October (LNRHIC Livestock farmers buy this material once or twice a 2018). Sikiew District is in the upland area at 200‒250 month for feeding to their stock (Figure 8) rather than masl. Cassava, maize, sugar cane and livestock are the having to obtain fresh forage daily. They immediately main agricultural products from the district (DOPA start feeding the material in a fresh state and continue to 2018). feed it out until the supply is consumed, which might take ___________ Correspondence: W. Srisomporn, Roied Animal Nutrition Research *Poster paper presented at the International Leucaena Conference, and Development Center, Suwannaphoom, Roied 45130, Thailand. 1‒3 November 2018, Brisbane, Queensland, Australia. Email: watanawans@gmail.com Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 456 S. Harrison, W. Srisomporn and G. Nakamanee up to 30 days. No obvious spoilage occurs despite the exposure to air. The price charged is dependent on the distance between the village, where the ‘silage’ is made, and the livestock farm. While most customers are in the same district, some farmers are in another district, which is about 89 km away. The ‘farm gate’ price is US$ 0.049/kg, and the delivered price increases in proportion to the distance to the livestock farm, e.g. US$ 0.062/kg for nearby areas and US$ 0.072/kg for farms in other districts. Although cost of production is higher than the selling price, silage producers accept this arrangement Figure 1. Harvesting wild leucaena. because they deduct only costs of hired labor plus fuel from the amount they receive at sale to determine their net returns. Six dairy cattle farmers and 3 dairy goat farmers have contracted to purchase 3 t silage/month/farm. A second leucaena producer conducts a similar business with only family labor. Each day he and his wife collect leucaena for 5 hours and spend 2 hours chopping it up and filling bags. He has 10 contracted farmers who purchase 3 t silage/month/farm. Approximate chemical composition of ‘silage’ that they produce is as follows: CP 21.9%, crude fat 1.46%, crude fiber 16.4%, ash 7.7%, NFE 52.5%, ADF 37.8%, NDF 56.0%, ADL 9.6%, cellulose 28.2% and hemi- celluloses 18.0%. Figure 2. Loading green leucaena onto truck. Figure 3. Feeding leucaena through small chopper. Figure 4. Chopped leucaena. Figure 5. Filling plastic bags with chopped leucaena. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Leucaena ‘silage’ for sale in NE Thailand 457 Figure 8. Dairy cows eating leucaena silage. One of Mr Charoon’s customers, Mr Wiwat Figure 6. Weighing filled bag. established a dairy farm more than 10 years ago and feeds his cows (75% Holstein Friesian crossbreds) with Napier grass silage (4 kg/hd/d), leucaena (4 kg/hd/d), cassava peel (16 kg/hd/d) and 18% CP concentrate pellets (9‒10 kg/hd/d). Average milk yield is 22‒24 kg/hd/d, cost of feed for 1 kg milk is US$ 0.20 and price of milk is US$ 0.56/kg. While all cows conceive, the calving interval is 14‒15 months. He has not observed symptoms of mimosine toxicity in his cows despite feeding leucaena for more than 10 years. Another customer is a dairy goat farmer who feeds his goats with leucaena silage (2.4 kg/hd/d) plus 12% CP concentrate pellets (500 g/hd/d). Average milk yield is 9 kg/hd/d. The price of goat milk is US$ 1.38/kg. Acknowledgments The authors thank all farmers for their time and co- operation in providing valuable information. References (Note of the editors: All hyperlinks were verified 21 August 2019.) DOPA (Department of Provincial Administration). 2018. Sikiew District development plan. DOPA, Phra Nakhon, Figure 7. Tying top of bag. Bangkok, Thailand. goo.gl/5sQjGN Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 458 S. Harrison, W. Srisomporn and G. Nakamanee LNRHIC (Lower Northeastern Region Hydrological Irrigation region. LNRHIC, Nakhon Ratchasima, Thailand. goo.gl/ Center). 2018. Hydrology irrigation for lower north-eastern s16dEp (Accepted 25 October 2018 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):459–464 459 DOI: 10.17138/TGFT(7)459-464 ILC2018 Poster and Producer Paper* Leucaena in West Timor, Indonesia: A case study of successful adoption of cv. Tarramba Leucaena en Timor Occidental, Indonesia: Un estudio de caso de adopción exitosa del cv. Tarramba DEBORA KANA HAU AND JACOB NULIK The East Nusa Tenggara Assessment Institute for Agricultural Technology, Kupang, Indonesia. ntt.litbang.pertanian.go.id Keywords: Extension methodology, smallholder farmers, tree legumes. Introduction History of leucaena in the region Between 2013 and 2016 the sub-districts Fatuleu and Central Fatuleu and Central Fatuleu sub-districts were new to Fatuleu in Kupang District of West Timor, Indonesia growing and using leucaena as fodder for cattle feeding. were selected to study the opportunities for and barriers Prior to the introduction of Tarramba leucaena in 2001‒ to adoption of leucaena (Leucaena leucocephala cv. 2003, the communities free-grazed their cattle on communal Tarramba) for growing and fattening cattle. These were sub- lands, mainly for breeding, and sold bulls only when they districts where the cultivation and use of leucaena was not needed cash. normal practice such as has been reported for the sub-district At that time, only farmers in the sub-district of Amarasi, of Amarasi (Nulik 1998; Piggin and Nulik 2005). also in Kupang District, were known to feed up to 100% In collaboration with Dinas Peternakan (District and leucaena after the Indonesian Government’s Livestock Provincial Livestock Service) and BPTP (National Services introduced a cattle-fattening program in the 1970s Assessment Institute for Agricultural Technology) in West (Nulik 1998). However, there had been very little adoption Timor and with the support of ACIAR (Australian Centre of the concept in other areas. This approach has now for International Agricultural Research), a project was changed following the introduction of Tarramba leucaena. initiated to encourage farmers to adopt the growing of the The Bersaudara, Setetes Madu and Amtoas Farmer groups psyllid-tolerant leucaena cv. Tarramba for feeding and now concentrate mainly on fattening of Bali bulls, although fattening cattle. The selection of farmer groups to participate some farmers still retain some cows for breeding on the free- in the program was the result of collaboration between these grazing communal lands. agencies. As grazing lands had been heavily grazed, they were invaded by Chromolaena odorata with the result that very Description of villages little palatable forage was available for grazing. Animals would reach market live weight of 250‒300 kg at 4–5 years The study was conducted in 3 villages in Kupang District of age or older and sometimes even failed to reach the target (sub-districts Fatuleu and Central Fatuleu), West Timor, weight before sale. With the introduction of Tarramba Indonesia (Figure 1). Some details are presented in Table 1. leucaena forage, farmers now fatten bulls to reach market Oebola Dalam village was selected in the initial phase of the weight in 2‒3 years. Some of our collaborating farmers were adoption study, while the remaining 2 (Camplong II and awarded championship medals during the 2017 yearly beef Nunsaen) were selected in the second phase (Kana Hau and cattle competition in Kupang District (Annex 1a). Nulik 2017). All 3 villages, comprising 7 farmer groups, In terms of toxicity management, many farmers now have their own adoption stories, which have enriched our understand that, when naïve cattle are first fed leucaena, understanding of the opportunities for and barriers to they initially show symptoms of salivation plus loss of successful adoption of leucaena in the District of Kupang. hair and appetite but adapt and recover in 1‒2 months. As ___________ Correspondence: Debora Kana Hau, The East Nusa Tenggara Assessment *Poster paper presented at the International Leucaena Conference, Institute for Agricultural Technology, JL. Raya Timor, Km 32 Naibonat- 1‒3 November 2018, Brisbane, Queensland, Australia. Kupang, Indonesia. Email: debora_nulik@yahoo.com Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 460 D. Kana Hau and J. Nulik Figure 1. Map of eastern Indonesia, showing the three study villages ( Oebola Dalam, Camplong ll and Nunsaen) in the west of Timor Island, East Nusa Tenggara Province. Source: Wikipedia/ Ewesewes. a result, farmers now gradually increase the amount of Oebola Dalam village leucaena fed to animals initially until their health has recovered. The Bersaudara Farmer Group in Oebola Dalam consisted of individually-owned and clan-owned lands. The group Table 1. Description of villages in adoption study. started with no leucaena, relying on free-grazing, and at times during the dry season, the stealing of forages from Village Participating Tarramba Cattle the protected forestry area near the village. With our farmer group area operation support, they planted 6 ha of Tarramba leucaena in the planted first year (2013) and approximately 25 ha in 2014. Oebola Dalam Bersaudara 125 ha Fattening Initially, the research team worked with just 5‒6 (Fatuleu) and innovators from the group of 20 farmers who were willing breeding to participate in planting pre-grown poly-bag seedlings. Camplong II Setetes Madu 250 ha Fattening At the beginning, some participating farmers doubted the (Fatuleu) Talekomonit and Tunas Muda breeding wisdom of growing leucaena; wives protested that the Sabu Bani family does not have cattle, and “we don’t eat leucaena Sanam Tuan but corn”. However, the participating members agreed to Nunsaen Amtoas 150 ha Fattening continue planting leucaena. As plants became established, (Central and farmers found that there was demand for fresh leucaena Fatuleu) breeding forage from the nearby weekly cattle market at Lili. This provided an opportunity for farmers to earn some cash for their daily needs and for cultural ceremony purposes. Progress of adoption, early challenges and successes Farmers increased the area planted to Tarramba leucaena, selling fresh leucaena even during the dry season, when The program began in the rainy season of 2012/13, there was no other production from their dry land. following commencement of the ACIAR project in 2011. Free-ranging animals belonging to non-participating Progress with the farmer groups is described below and farmers were initially a serious concern for participating illustrated in Annexes 1a‒1h. farmers at Oebola Dalam, and this discouraged some Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tarramba in West Timor 461 farmers from growing leucaena. Some participating technology, have established ~250 ha of Tarramba farmers even abandoned their plots of leucaena when leucaena. The area is increasing annually. they were prematurely grazed by the free-ranging Setetes Madu farmers initially planted their 20 ha animals. However, during the next wet season, when with the intention of producing and selling Tarramba they fenced their plots for planting corn, the grazed seed and resisted harvesting their mature leucaena leucaena plants recovered and became well established. trees to concentrate on harvesting seed. The research Farmers found they could integrate corn cultivation team encouraged some participating farmers to with the establishment of Tarramba leucaena, thus establish a feeding demonstration using available affording protection to establishing leucaena seedlings. weaned calves (5 calves) obtained from their free- No fertilizer was applied to the leucaena other than that grazing herd. This demonstration was successful and applied to the corn plants. This encouraged farmers to convinced them to expand cattle feeding with leucaena plant more leucaena. as they noticed the improved weight gain of their Plant height was kept to about 1.5‒2 m by regular calves. Outside investors were attracted to establish a pruning for cattle feeding. Pruning frequency was share-fattening cattle business with the group. The every 2‒3 months during the rainy season and every 3‒ investor has contributed to the installation of a deep 4 months during the dry season. Number of trees cut bore well to supply watering facilities (water tower per day would depend on the number and weight of tank, some on-ground tanks and solar panel pumping animals to feed and the production of forage per tree. system) costing 1 billion IDR. These investments now Farmers used cut-and-carry feeding methods, as it gave support up to 60‒70 bulls being fattened in each better cattle daily liveweight gains. fattening period. Most farmers in the village now have established their own leucaena. They have continued to increase Nunsaen village their area planted even after project activities terminated and currently the village has ~125 ha The Amtoas farmer group in Nunsaen village initially established. The head of the farmer group informed us planted about 75 ha of Sesbania grandiflora. Their first that another 5 ha was being prepared for the 2018/19 plantings of Tarramba leucaena seedlings (pre-grown planting season. The technology of planting and in a nursery) occurred under the existing Sesbania feeding Tarramba leucaena was spreading to the grandiflora plants with some direct seeding on newly bordering villages and farmers. cleared land. This created a problem with plant competition for leucaena at the outset. The farmer Camplong II village group of Nunsaen (Amtoas) has now established ~150 ha of Tarramba for cattle fattening, and for providing a The Setetes Madu Farmer Group in Camplong II high quality supplementary forage for their free- consisted of only clan-owned land (more than 100 ha) grazing animals. managed by the clan elders. The land was sparsely planted with cashew nut trees on the more fertile soils, Limitations/challenges and benefits to leucaena while the majority of the land consisted of less fertile production coral soils (Black Mollisols) invaded by Chromolaena odorata due to over-grazing by community cattle. Biophysical – climate, soils Planting of leucaena began in Camplong II in 2014/15. In general, adoption was faster in Camplong On sites with marginal soils such as on Sumba Island, II, where 4 farmer groups were involved. Initially, the Tarramba leucaena has not performed well. However in group planted 20,000 seedlings of Tarramba leucaena Timor, Tarramba leucaena is well adapted to the highly on 20 ha and found that leucaena grew well on the alkaline coralline soils (Mollisols and Alfisols) coralline soils. encountered in many areas, such as in Camplong II and The Setetes Madu group increased the area planted Oebola Dalam villages. With the long dry seasons to leucaena each year to a current total of >50 ha. experienced, farmers have difficulty finding water for Currently all farmer groups (Setetes Madu, Tunas watering seedlings in nurseries; thus seedling Muda, Talekomonit, Sabu Bani and Sanam Tuan) in the preparation is often conducted in the early wet season village of Camplong II, who have adopted the (November-December-January) with transplanting of Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 462 D. Kana Hau and J. Nulik seedlings occurring in February-March-April, before practice to improve food crop productivity and soil the beginning of the dry season in May. quality in the region should be investigated. Economic benefits Conclusions and implications The economic conditions of participating farmers and The success of the farmer groups in Fatuleu and Central villages have improved significantly as a result of Fatuleu sub-districts in Kupang District of West Timor, leucaena-based cattle fattening. When the project Indonesia has changed agricultural practices and has commenced at Oebola Dalam village, most farmers had improved economic conditions and livelihoods, land houses with dirt floors and a palm-leafed roof; quality and thus farming conditions generally. currently most farmers have constructed brick-walled The success of adoption of Tarramba leucaena has houses with corrugated iron rooves. Using earnings encouraged and inspired many individual farmers, from sale of seed and fattened cattle, some individual farmer groups, non-government organizations, farmers were able to buy a motor cycle, or a pick-up Government staff and Bupatis (Mayors), including the utility (previously rented in the village) for cattle Governor of the Province, to support and introduce the transportation to the market and for selling leucaena use of Tarramba leucaena for cattle feeding into their forage at the nearby cattle market. Farmers continue to development programs and livestock development look for economic opportunities. plans and practices. The new economic opportunities being generated The new Governor of NTT (2018‒2023), after from leucaena plantings in the village include: (i) sale visiting the sites of Setetes Madu, Talekomonit and of fattened cattle; (ii) sale of Tarramba forage and seed; Sabu Bani farms, said that: (iii) sale of bare-stem cuttings to neighboring farmers; Last night when we discussed cattle farming in NTT, I (iv) plans to develop tall trees to harvest wooden poles had no courage to develop plans for a livestock for supporting cement floor construction for multi- development program; but today, you have showed me storey buildings [5,000 Rupiah (AU$ 0.5) for each the improvement that is possible with lamtoro pole], or for housing construction (roofing, door and (leucaena), even on this marginal land. Now I have window frames etc.); and (v) other business confidence that NTT can be significantly improved in opportunities such as car and motor cycle rentals. cattle production if we can adopt these practices. At Setetes Madu site, when the project commenced, He immediately asked to purchase 1,000 kg of the meeting place was under the shade of a Kesambi Tarramba leucaena seed from the farmer groups tree (Schleichera oleosa). The co-operating farmers (Setetes Madu, Sabu Bani and Talekomonit) as a start have now established an iron-roofed meeting house and to his beef cattle development program. some farmers own hand-tractors, while some have In conclusion, it is especially pleasing that, purchased motor cycles. Successful farms have become following the many benefits from the introduction of demonstration sites for many visitors, including Tarramba leucaena, planting of this valuable forage Bupatis (Mayors), Provincial Governor and farmer source is being promoted by Indonesian Government groups who wish to learn about the successful agencies at National, Provincial and District levels conversion from free-grazing practices to intensive after the ACIAR project ended in 2016. fattening with leucaena. References (Note of the editors: All hyperlinks were verified 21 August 2019.) Future of leucaena development options Kana Hau D; Nulik J. 2017. Kajian Pengembangan dan More research is needed on using leucaena leaf for Pemanfaatan Tanaman Pakan Leguminosa Mendukung supplementary feeding of calves during the dry season Peningkatan Produksi Ternak Sapi di Nusa Tenggara to reduce calf mortality, and on a comparison of the Timur. Prosiding Seminar Nasional Teknologi different techniques for plant establishment (poly-bag Peternakan dan Veteriner 2017:585‒594. doi: 10.14334/ seedlings vs. 2‒3 year plantlets from under or between Pros.Semnas.TPV-2017-p.587-596 mother trees). Combination plantings of leucaena with Nulik J. 1998. The use of Leucaena leucocephala in farming grass and herbaceous legumes as a conservation systems in Nusa Tenggara, eastern Indonesia. In: Stür Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tarramba in West Timor 463 WW, ed. Proceedings of the Third Regional Meeting of Piggin C; Nulik J. 2005. Leucaena: Sustainable crop and the Forages for Smallholders Project, Samarinda, livestock production systems in Nusa Tenggara, Timur Indonesia, 23‒26 March 1998. CIAT Working Document Province, Indonesia. Tropical Grasslands 39:218. No. 188. p. 178‒182. hdl.handle.net/10568/56538 goo.gl/BgDmbh (Accepted 2 April 2019 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Annex 1 a. Bali bull fed leucaena wins bull-fattening prize. b. Oebola Dalam village in wet season. c. Oebola Dalam village in dry season. d. Farmers seeding poly-bags with Tarramba leucaena. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 464 D. Kana Hau and J. Nulik e. Tarramba leucaena being cut-and-carried for feeding. f. Bali bulls being fattened on Tarramba leucaena in Oebola village. g. Newly elected Governor to Province of Nusa Tenggara h. Camplong II village in front of 9-month-old Tarramba Timor (white shirt) visiting Camplong II village. leucaena. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):465–468 465 DOI: 10.17138/TGFT(7)465-468 ILC2018 Poster and Producer Paper* Seasonal growth of Leucaena leucocephala cv. Tarramba in dry land of west Sumbawa, Indonesia Crecimiento de Leucaena leucocephala cv. Tarramba en la región de sequía estacional del oeste de Sumbawa, Indonesia YUSUF AKHYAR SUTARYONO, DEDI SUPRIADI, IMRAN AND RYAN ARYADIN PUTRA Faculty of Animal Science, University of Mataram, Mataram, Lombok, Indonesia. unram.ac.id Keywords: Forage acceptability, forage production, seasonality of production, tree legumes. Introduction Materials and Methods Sumbawa Island in Nusa Tenggara Province is one of the The study was conducted in Seteluk village, Sumbawa main cattle-producing areas in eastern Indonesia. In 2017 the District. To obtain seedlings for planting a raised cattle population in Sumbawa was around 350,000 head seedbed was prepared and seeds of cv. Tarramba were (Dinas Peternakan Report 2017). Most cattle are raised in a spread at high density on the surface in mid-May 2015, traditional free-grazing system, where they are released to covered with soil and watered daily. Four months after roam at will and find their own feed, which is obtained sowing, at the start of the rainy season in September mainly from communal grassland and fallow land. Owing to 2015, plants, which had established from germinated the strongly seasonal rainfall in Sumbawa the production seeds, were manually pulled from the ground, foliage and availability of forage for cattle fluctuate during the year. was trimmed to about 40‒50 cm and roots were While the annual rainfall is 1,400 mm, 88% falls in the severely trimmed (Figure 1) and plants transplanted months of November–April. Both availability and quality of into alluvial soil as bare stumps (Setiawan 2010). feed in the dry season are poor. Availability of fallow land There were 5 blocks consisting of 25 plants/block at for grazing has been reduced as a result of the construction spacings of 2 × 1 m. No fertilizer was applied. Plants of a water reservoir, which is used to irrigate rice fields, were allowed to grow for 12 months and plant height resulting in more intensive use of land for rice and maize and main-stem diameter were measured at monthly cultivation. In addition, communal grazing lands are intervals. At 12 months after transplanting all plants being progressively invaded by weedy plants, such as were cut at 1.5 m above ground level. During the Chromolaena odorata, Lantana camara and Ziziphus subsequent year, forage above 1.5 m was harvested mauritiana, resulting in reduced grass production, forcing every 2 months. Biomass was weighed fresh and farmers to find alternative feed sources for their cattle. subsamples dried in an oven at 70 °C until constant Improved forage species are needed to improve the weight to determine dry matter percentage. For this, nutritional regime for grazing livestock. 10 plants were randomly sampled at each harvest in Wild leucaena (Leucaena leucocephala) has been used each block. At each harvest main-stem diameter was by farmers as a source of high protein feed for their cattle determined at 1.5 m above ground level and number of and recently the improved cultivar Tarramba was introduced all new regrowth primary branches was measured. to Sumbawa. Acceptance of cv. Tarramba by farmers should Following sampling the remaining plants in each block not pose a problem, as it is merely a change from a wild plant were cut to 1.5 m as well. All harvested material was to a cultivated plant (Dahlanuddin et al. 2017). We weighed, fed to cattle and the consumed portion conducted basic observations on the growth and biomass calculated, based on the unconsumed amount which production of cv. Tarramba in a rain-fed grazing area of was weighed. Data were then analyzed for average Sumbawa throughout the year and results are reported here. values and standard deviations. ___________ Correspondence: Yusuf A. Sutaryono, Faculty of Animal Science, *Poster paper presented at the International Leucaena Conference, University of Mataram, Jln. Majapahit no. 62, Mataram, Lombok, 1‒3 November 2018, Brisbane, Queensland, Australia. Indonesia. Email: ysf_25@yahoo.com Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 466 Y.A. Sutaryono, D. Supriadi, Imran and R.A. Putra Figure 1. Leucaena seedling nursery and bare-stump seedlings ready for transplanting. Rainfall received during the study (Figure 2) started in into the field (Figure 3). This result confirms the November 2015 about one month after transplanting the previous work on the growth of Tarramba reported by leucaena, and heavy rain continued until April 2016, with Panjaitan et al. (2015). The highest growth rate (42±0.3 the heaviest falls during February. Some rain was cm/month) was achieved during the peak of the rainy received in September 2016, when the initial cut was season (February‒April) and the lowest (9±2.5 applied to the plants. Relatively high rainfall continued cm/month) during the driest months of September‒ from October 2016 to April 2017 with heaviest falls in October. The differences in growth rate in the different December‒February. For the 2016/17 rainy season, when seasons reflected the different levels of plant-available biomass production was measured, the rainy season was water in the soil. wetter and longer than in previous years, e.g. when Although there were big differences in height increase compared with rainfall registered 2013–2015 (essentially between the wettest and driest months, cv. Tarramba no rain during June–November). continued to grow and produce biomass during the dry season. This was most likely a function of the Tarramba Results and Discussion root system, which is sufficiently deep to allow access to water deeper in the soil profile. Pachas et al. (2018) Height showed that leucaena roots could reach as deep as 400 cm. Furthermore, a previous study by Nulik et al. (2013) Tarramba grew very well in this study, achieving a showed that cv. Tarramba grows very well in vertisols and height of 3.7±0.1 m at 12 months after transplanting alluvial soils. 500 464 435 450 400 333 350 313 302 300 255 237 250 215 216 224 215 199 200 168 174 158 162152 139 135 150 99 109 109 89 97 107 100 66 69 71 54 51 59 40 44 43 50 50 3 0 0 5 13 19 1 0 0 0 0 2 0 0 0 4 6 0 0 0 Figure 2. Rainfall during the study period in Sumbawa (BPS 2018). Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) May-13 Jun-13 Jul-13 Aug-13 Sep-13 Oct-13 Nov-13 Dec-13 Jan-14 Feb-14 Mar-14 Apr-14 May-14 Jun-14 Jul-14 Aug-14 Sep-14 Oct-14 Nov-14 Dec-14 Jan-15 Feb-15 Mar-15 Apr-15 May-15 Jun-15 Jul-15 Aug-15 Sep-15 Oct-15 Nov-15 Dec-15 Jan-16 Feb-16 Mar-16 Apr-16 May-16 Jun-16 Jul-16 Aug-16 Sep-16 Oct-16 Nov-16 Dec-16 Jan-17 Feb-17 Mar-17 Apr-17 May-17 Jun-17 Jul-17 Aug-17 Sep-17 Oct-17 Seasonal growth of cv. Tarramba in Sumbawa 467 Biomass production and forage consumption 0 363 374 40 349 331 350 305 274 Biomass production at the initial harvest 12 months after 300 232 transplanting was 1.1+0.04 kg DM/tree, while subsequent 250 189 regrowth (every 2 months) yields varied between 0.77 and 200 147 0.91 kg DM/tree (Figure 5). There was minimal variation 150 114 in production between November and July but growth 87 100 61 69 rates declined slightly in the July‒September period to 0.77 kg DM/tree. Thus cv. Tarramba was able to produce 50 significant amounts of biomass for cattle during both wet 0 and dry seasons in this environment, suggesting it could be a useful feed source for cattle in rain-fed areas of Sumbawa. Figure 3. Progressive height of cv. Tarramba during the establishment year (2015-2016) under rain-fed conditions in Initial cut Regrowth Sumbawa. 1.2 1.1 1.0 0.9 0.9 0.9 0.9 Stem diameter 0.9 0.8 0.8 0.8 0.8 0.8 0.7 0.7 0.6 Main-stem diameter increased to 30 mm during the 12 0.6 0.5 months following transplanting but only a further 2.4 mm 0.4 during the subsequent 12 months, when being harvested 0.2 regularly (Figure 4). A longer study would be needed to 0.0 determine what changes would occur as the plants matured. Sep-16 Nov-16 Jan-17 Mar-17 May-17 Jul-17 Sep-17 Since plants were cut regularly, the nutrients produced from photosynthesis during the harvesting period must have been Biomass production Biomass consumed used more for the formation of new branches and leaves than Figure 5. Biomass production and biomass consumed of cv. for growth of the main stem. The number of new primary Tarramba at 12 months after transplanting (initial cut) and at regrowth branches produced between harvests remained subsequent 2-monthly regrowth cuts under rain-fed conditions relatively constant, varying between 13 and 15. This in Sumbawa (2016-2017). relatively constant number of primary regrowth branches enabled plants to produce a relatively constant amount of When the harvested forage was fed to cattle, the biomass (Figure 4) throughout the year, provided soil animals consumed an average of 76±11% of total moisture levels were adequate. harvested biomass (86±1% in the rainy season vs. 64±1% in the dry season) (Figure 5). The higher percentage of 35 8 32.9 33.0 biomass consumed in the rainy season was due to a higher 30.6 31.4 31.9 32.4 32. percentage leaf, softer branches and lower percentage of 30 woody branches, making it more palatable for cattle. 25 Although there were large differences in height increase 20 in trees between wet and dry seasons (by a factor of 3‒4), 13.5 14.5 14.6 14.3 15 13 13.2 DM production varied by only 15.4% and consumed 10 biomass by 37.2%, indicating that plants devoted more nutrients to woody growth in the dry season than in the 5 wet. As these plants were in the development stage, 0 results might have been different once trees matured. Sep-16 Nov-16 Jan-17 Mar-17 May-17 Jul-17 Sep-17 Thus longer-term studies are needed. Number of branches Main-stem diameter (mm) Conclusions Figure 4. Main-stem diameter and number of primary branches of new regrowth produced by cv. Tarramba at 12 months after This study has shown that leucaena cv. Tarramba transplanting (September 2016) and at subsequent 2-monthly established well in the rain-fed areas of Sumbawa when regrowth cuts under rain-fed conditions in Sumbawa. planted by the bare-stump technique early in the rainy Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Height (cm) Kg DM/tree 468 Y.A. Sutaryono, D. Supriadi, Imran and R.A. Putra season and plants were allowed to grow until the late dry productivity and farm profitability. Tropical Grasslands- season before initial harvesting. Our findings suggest that Forrajes Tropicales 7:428–436. doi: 10.17138/TGFT(7)428- Tarramba would provide a valuable feed source for cattle 436 in Sumbawa in both rainy and dry seasons and support the Dinas Peternakan Report. 2017. Livestock and Animal Health Office of Sumbawa District Sumbawa, West Nusa Tenggara, findings of Dahlanuddin et al. (2019). Further studies are Indonesia. needed to determine the production of cv. Tarramba as Nulik J; Dahlanuddin; Kana Hau D; Pakereng C; Edison RG; plants mature as well as optimal harvesting regimes Liubana D; Ara SP; Giles HE. 2013. Establishment of throughout the different seasons. Leucaena leucocephala cv. Tarramba in eastern Indonesia. Tropical Grasslands-Forrajes Tropicales 1:111–113. doi: References 10.17138/TGFT(1)111-113 (Note of the editors: All hyperlinks were verified 21 August 2019.) Pachas ANA; Shelton HM; Lambrides CJ; Dalzell SA; Murtagh GJ; Hardner CM. 2018. Effect of tree density on competition BPS (Badan Pusat Statistik). 2018. Sumbawa Regency in Figures. between Leucaena leucocephala and Chloris gayana using a Central Agency on Statistics, Sumbawa, West Nusa Tenggara, Nelder Wheel trial. II. Belowground interactions. Crop and Indonesia. Pasture Science 69:733–744. doi: 10.1071/CP18040 Dahlanuddin; Panjaitan TS; Halliday M; Ash A; Shelton HM. Panjaitan T; Fauzan M; Dahlanuddin; Halliday M; Shelton HM. 2017. Scaling out cattle fattening based on Leucaena 2015. Agronomic performance of Leucaena leucocephala cv. leucocephala cv. Tarramba in Sumbawa, Indonesia. Tarramba in tropical environment of Sumbawa. Proceedings of Proceedings of the 5th International Seminar of Animal the 6th International Seminar on Tropical Animal Production, Nutrition and Feed Sciences, Senggigi Lombok , Indonesia, Faculty of Animal Science, UGM, Yogyakarta, Indonesia, 10– 7–9 November 2017. 14 November 2014. p. 1365–1368. bit.ly/2ZbVQwz Dahlanuddin; Panjaitan T; Waldron S; Halliday M; Ash A; Morris Setiawan I. 2010. Developing agricultural sector in Sumbawa ST; Shelton HM. 2019. Adoption of leucaena-based feeding Regency based on local primary commodities. M.Sc. Thesis. systems in Sumbawa, eastern Indonesia and its impact on cattle Institute Pertanian, Bogor, Indonesia. (Accepted 9 August 2019 by the ILC2018 Editorial Panel and the Journal editors; published 3 September 2019) © 2019 Tropical Grasslands-Forrajes Tropicales is an open-access journal published by International Center for Tropical Agriculture (CIAT), in association with Chinese Academy of Tropical Agricultural Sciences (CATAS). This work is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) Tropical Grasslands-Forrajes Tropicales (2019) Vol. 7(4):469–478 469 DOI: 10.17138/TGFT(7)469-478 ILC2018 Summary* International Leucaena Conference 2018: Highlights and priorities Conferencia Internacional sobre Leucaena 2018: Aspectos destacados y prioridades H. MAX SHELTON School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD, Australia. agriculture.uq.edu.au Preamble interactions and thoughtful discussions/comments by participants from many parts of the world, each with A very successful International Leucaena Conference his/her own point of view” - Daniel Real, Department of (ILC2018) and field tour, organized by The University of Primary Industries and Regional Development, Western Queensland, was staged from 29 October to 3 November Australia. 2018. Approximately 120 conference delegates from 12 “A highlight was the high level of landholder input in a countries, comprising researchers, consultants, producers comprehensive program that included presentations and and students, shared their research knowledge and discussion of both benefits and negatives associated with practical experiences regarding leucaena. Many excellent leucaena” - Shane Campbell, University of Queensland, speakers exchanged information, and challenged the ideas Australia. and conceptions of those attending regarding how we “Great to hear about the extensive leucaena R&D plant, manage and use leucaena around the world. occurring across the tropical world, and interestingly, Engagement and networking ensured there was there were similarities in the animal productivity benefits enthusiastic and fruitful discussion on future priorities in a range of situations. It was very interesting to hear and collaborative opportunities. how cattle in some countries were fed 100% leucaena without toxicity issues and achieved high liveweight General comments about conference from delegates gains”- Stuart Buck, Queensland Department of Agriculture and Fisheries, Australia. “Thanks for a very productive and encouraging conference. This was the most networking I have done at any conference in my career” - Travis Idol, University of Hawaii, USA. “The papers and discussions were of a high standard and the meeting had a great feeling of cooperation and collaboration” - Bev Henry, Agri Escondo Pty Ltd, Australia. “There was a great amount of information on leucaena experiences from around the world. The Conference was an excellent opportunity to share information with peers and to meet researchers and practitioners from different regions and to hear their perspectives” - Julián Chará, CIPAV, Colombia. “The pre-conference tour of several leucaena producers with different production systems was enriched by the Conference delegates. Photo: Mic Halliday. ___________ Correspondence: H.M. Shelton, School of Agriculture and Food *Summary and conclusions of the International Leucaena Sciences, The University of Queensland, Brisbane, QLD 4072, Conference, 1‒3 November 2018, Brisbane, Queensland, Australia. Australia. Email: m.shelton@uq.edu.au Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 470 H.M. Shelton Conference in session. Photo: Mic Halliday. Cunningham in Australia in 1976. These cultivars of ‘giant’ leucaena displayed broad environmental adaptation, but lacked tolerance of cold temperatures (and frost) and adaptation to acid soils. The spread of the psyllid insect pest (Heteropsylla cubana) from the Caribbean in the early 1980s devastated both ‘common’ and ‘giant’ leucaena all around the world. However, some giant leucaenas exhibited a degree of tolerance to the psyllid pest and were released in Australia as cultivars Tarramba and Wondergraze and in Hawaii as cv. LxL. Cvv. Wondergraze and Cunningham were the most productive in northern New South Wales (Harris et al. 2019), while cv. Tarramba has been successful in eastern Indonesia (Nulik et al. 2019). Since the 1990s, plant breeding programs to develop cultivars with greater psyllid Field tour participants. Photo: Nahuel Pachas. tolerance, derived from the interspecific hybridization between L. pallida and L. leucocephala ssp. glabrata, Highlights and priorities resulted in the release of cv. KX2-Hawaii in Hawaii for timber and forage production, and cv. Redlands in Australia The principal topics and issues discussed during the as a forage cultivar. Conference are now summarized. Leucaena genetic resources. The paper by Abair et al. (2019) provided both new insights into phylogenetic relationships in Germplasm resources of leucaena leucaena, resolving some outstanding uncertainties, and guidance on where future breeding of leucaena for forage Existing varieties. In his plenary presentation, Dalzell might focus. They concluded that the Leucaena genus (2019) noted early use of leucaena by humans was based comprises 24 species, belonging to the mimosoid clade of the entirely upon the very narrow germplasm of a single legume subfamily Caesalpinioideae. Of these, they defined genotype of Leucaena leucocephala ssp. leucocephala (‘common’ leucaena), that had spread pantropically from 19 self-sterile diploid species in 3 clades, which occupy its center of origin in Mexico. Genetic improvement largely allopatric (separate locational) distributions. began in the 1950s when vigorous ‘giant’ leucaena They further confirmed 5 tetraploid species of Leucaena genotypes (L. leucocephala ssp. glabrata) were of hybrid origin, i.e. allopolyploids, implying sympatry of identified. Cultivars such as Hawaiian Giant K8, Peru and their diploid parental species, which is rare among wild El Salvador were selected and promoted in silvopastoral diploid populations, but consistent with the anthropogenic systems in Australia and in multipurpose agroforestry backyard allopolyploid-formation hypothesis, i.e. parental systems throughout the tropics. Plant breeding for species were brought together by humans for purposes of improved forage production resulted in the release of cv. cultivation. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) ILC2018: Conference summary 471 Their molecular analysis has led to some important etc. However, this catalogue is dated and needs review conclusions, namely: and updating to improve formatting of germplasm  L. trichandra has contributed to the origins of 4 information to account for new taxonomic classifications of the 5 tetraploids (L. confertiflora, L. diversifolia, and new material in new collections. L. involucrata and L. pallida), which have low nutritive quality, probably reflecting the poor Establishment and management of leucaena nutritive value of L. trichandra. The fifth tetra- ploid species, the pantropically naturalized Establishment. Buck et al. (2019a) outlined what is L. leucocephala, is derived maternally and paternally widely regarded in central and southern Queensland as from L. pulverulenta and L. cruziana, respectively. best practice to achieve successful establishment of  There are unlimited genetic markers available for leucaena. In these grazing situations, best outcomes with genetic improvement of leucaena and to be exploited existing commercial varieties occur on deep, fertile, well- in breeding programs designed to identify and breed drained neutral-alkaline soils in the 600‒800 mm rainfall for sterility, decreased mimosine content and zone, while psyllid-tolerant cv. Redlands is better adapted adaptation to salinity, cold, drought, etc. in higher rainfall environments. Recommendations are to plant into fully prepared seedbeds with ample stored Priorities for new varieties. In his plenary paper Dalzell moisture and corrected for nutrient deficiencies, in twin (2019) identified ‘development of sterile leucaena’ as a high rows approximately 6 m apart. Seed should be scarified, priority. It was argued that a sterile leucaena would lead to inoculated with rhizobium and treated for insect control increased adoption in regions, e.g. Western Australia, where prior to planting with beetle bait applied after planting. sowing of leucaena is not permitted currently owing to The significance of good early weed control, especially concerns over potential weediness (Revell et al. 2019). Early regarding companion grasses, was emphasized (Buck et al. research to achieve this goal was reported by McMillan et al. 2019a). An adapted inter-row grass can be introduced when (2019) and Real et al. (2019). leucaena is >1 m tall, permitting a first light grazing when Other priorities included: plants are ~1.5‒2 m tall, followed by full grazing when  Generation of artificial tetraploids from diploid plants are 3‒4 m tall. species to increase cross-compatibility, and triploids Differences in the levels of mechanization and the costs from the cross of tetraploid L. leucocephala with of establishment and maintenance between regions were diploid L. collinsii ssp. collinsii. This latter species highlighted by Zapata Cadavid et al. (2019). has high digestibility and high psyllid resistance (Dalzell et al. 1998; Mullen et al. 1998). Planting configuration. Differences in production systems  Development of a cold-tolerant leucaena, which is and therefore recommendations on planting configuration needed for high-altitude tropical locations, e.g. in were highlighted in presentations from different regions of Latin America, Hawaii and East Africa. Cold the world (Pachas et al. 2019). tolerance, which exists within L. diversifolia, would In Australia and some countries in Latin America also expand adaptation of leucaena to fill winter feed (Paraguay and Argentina), leucaena is planted in single or deficits and to sites experiencing light frosts. twin hedgerows with inter-row alleys between 6 and 10 m wide (1,000‒5,000 trees/ha), the focus being on beef Germplasm collections and evaluation. The conference production, with grass a major and sometimes the principal endorsed the need to coordinate international G × E component of the diet (Pachas et al. 2019). evaluations of existing and new leucaena cultivars and As a contrast, in Colombia, Mexico, Cuba, Venezuela selection of elite germplasm due to limited R&D and Northeast Brazil, intensive silvopastoral systems (ISPS) resources. There are numerous opportunities to share data are promoted. Leucaena is planted at high density (>10,000 and effective methodologies for hybridization and trees/ha) in combination with improved tropical grass and vegetative/micro-propagation of elite leucaena germ- high-value timber species (200‒400 trees/ha) and plasm, e.g. sterile hybrids. intensively managed with rotational grazing (Chará et al. It is essential that all R&D personnel involved in 2019; Pachas et al. 2019). leucaena plant evaluation are aware of the origins of the In some Latin American countries (e.g. Cuba; Ruiz et al. genetic material they are using and the location of 2019) and countries of Southeast Asia (Indonesia and international collections of leucaena. The Leucaena Thailand), leucaena is established as a protein bank using Catalogue, first published in 1997, provides detailed single/multiple rows often for cut-and-carry feeding to beef passport information, including origins, collector, local and dairy cattle, goats and dual-purpose animals. In these ID identifiers for cross-referencing with other collections systems, leucaena is often the major component of the diet, Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 472 H.M. Shelton sometimes constituting 100% of the ration, especially during vegetative propagation methods for leucaena. Delegates the dry season (Dahlanuddin et al. 2019). The arboreal reported that vegetative propagation would be variety cv. Tarramba is especially suited to the cut-and-carry advantageous for: expediting breeding programs; systems in Indonesia (Sutaryono et al. 2019). distribution of sterile materials; planting in non-arable R&D priorities. Inter-row spacing and grass:legume balance locations; small-scale hand-plantings in Asia; and even were contentious issues at the conference. Foreign delegates for planting on smaller holdings in coastal Queensland, questioned why Australian graziers were extending the where commercial seedling planters might be effective. width of inter-rows to 10 m, while also insisting that “more Provided soil moisture is adequate, advantages are leucaena = more beef”. New research (Pachas et al. 2017) quicker establishment plus better resistance to challenge showed that wide inter-rows (~10 m), exacerbated by grass from weeds, domestic animals and wildlife. competition, reduced the production of leucaena in the Idol et al. (2019) compared methods for vegetative pasture to <20% of total feed on offer. Thus questions arise propagation of several sterile hybrids of leucaena with concerning width of the inter-rows, namely: propagation via seeds. Rooted cuttings proved the best  What is the effect on animal productivity of closer option for operational-scale propagation, but a misting row spacing and a higher % of leucaena in the diet? system or carefully controlled non-misting environment Does more leucaena mean increased liveweight is required for their production. gain/ha/year? The JK Paper Ltd company in Gujarat, India, in their program to produce higher-yielding clones for paper pulp,  What is the role of the grass component? uses misting chambers to produce rooted cuttings of their  Can system productivity be increased by cultivating best clonal selections of L. leucocephala and of a triploid the inter-row areas with forage oats, forage sorghum hybrid of L. leucocephala × L. collinsii (Khanna et al. or other legumes? What is the feasibility and effect on 2019). Nulik and Kana Hau (2019) reported success with overall productivity and profitability of inter-row bare-stem seedlings generated in purpose-sown high- cropping of old sugarcane lands in Hawaii, or density nurseries or by retrieval of volunteer seedlings intensive leucaena systems in Southeast Asia with under established tree rows. corn or horticultural crops, or the incorporation of high-value timber in Latin American systems? Feeding and management for animal production  What is the influence of soils and climate, especially rainfall, on planting configuration? Animal productivity. Conference delegates confirmed that Conference delegates highlighted the need for flexibility leucaena is a highly palatable, productive and profitable in planting guidelines for different environments within forage option used by beef producers in northern countries. For instance, notwithstanding decades of leucaena Australia (Buck et al 2019a; 2019b) and by beef, dairy establishment experience in central Queensland, Australia, and goat producers in Colombia (Pachas et al. 2019; where best results are obtained from full cultivation and Rivera et al. 2019; Zapata Cadavid et al. 2019;), Mexico preparation of a fine tilth seedbed as used for planting of (Ramírez-Avilés et al. 2019), Paraguay (Glatzle et al. field crops, there are environments in Western Australia 2019), Argentina (Radrizzani et al. 2019a; 2019b), (Revell et al. 2019) and north Queensland with existing tree Indonesia (Dahlanuddin et al. 2019; Waldron et al. 2019), cover or non-arable landscapes due to rocks, where Myanmar (Aung 2019), India (Nimbkar 2019), Thailand specialized approaches need to be developed. (Nakamanee et al. 2019a; 2019b), Venezuela (Escalante While usage of fertilizers with leucaena plantings 2019) and Cuba (Ruiz et al. 2019). around the world is minimal, the benefits of fertilizer were All of the above results were with L. leucocephala so highlighted on poorer soils in Thailand (Tudsri et al. the positive economic response to incorporation of 2019) and Australia (Buck et al. 2019a). Radrizzani et al. L. diversifolia in a Colombian cattle system experiment (2010) demonstrated that maintenance fertilizer was especially interesting (Enciso et al. 2019). application is necessary in older leucaena plantations. In Australia, when sown with either native or exotic While we now have good understanding of critical leaf companion grasses, leucaena provides significant tissue values for a range of nutrients (Radrizzani et al. productivity, economic (Bowen et al. 2016), environ- 2011), there is limited understanding of the rates, mental and social benefits (Buck et al. 2019b). Cattle on placement and frequency of fertilizer applications to leucaena-grass pastures will gain 250–300 kg/year, and at achieve best results (Buck et al. 2019a). a higher stocking rate than on straight grass pastures, Vegetative propagation. There are many reasons to while production per hectare can be 2‒4 times that from develop efficient cost-effective micro- and macro- run-down buffel grass pasture. Leucaena-fed steers can Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) ILC2018: Conference summary 473 reach 600 kg live weight at 24–30 months of age, 6–12 cereal grains, cassava, molasses, rice bran and crop months earlier than those on grass-only pasture. residues. While substitution of the basal leucaena in the A significant benefit of the rapid liveweight gains of diet by the energy sources might occur, this allowed more cattle is increased flexibility in targeting domestic and animals to be supported, especially if there was limited export markets to achieve the best prices. If the area of leucaena available. Some Australian graziers supplement leucaena is limited, it is often reserved for the most their cattle on high leucaena diets with low quality valuable stock, to fill autumn-winter protein gaps and to roughage and molasses (Heatley 2019). produce animals to target specific premium markets. Grazing management. Appropriate grazing management Leucaena-grass pasture makes it possible to reach high is necessary to maximize production from leucaena-grass meat quality standards, such as Meat Standards Australia pastures; however, many graziers do not manage this (MSA) and Pasture-fed Cattle Assurance System (PCAS), aspect well and it can be costly to correct. In Colombia, without grain feeding. Zapata Cadavid et al. (2019) reported that overgrazing In Indonesia, Dahlanuddin et al. (2019) reported that leading to reduced productivity was common. In farmers with an average of 2.8 ha of land and 0.8 ha of Australia, the reverse often occurs with undergrazing of planted leucaena fattened Bali bulls in a cut-and-carry leucaena paddocks, especially on large areas, leading to system which Waldron et al. (2019) reported to be highly excessive growth of the trees, requiring expensive profitable. Mean liveweight gains ranged from 0.4 to 0.6 machine cutting (Harris and Harris 2019). These authors kg/d and were at least double those achieved in the stated: “When cattle eat the leucaena we make money, but traditional rearing system. Average daily gains peaked when we have to mulch it, it costs us money”. A range of (0.56–0.61 kg/d) in the months of May, June and January, commercial and home-made slashing devices are used to when feed supply and percentage leucaena in diets were mechanically cut tall leucaena to bring it into the reach of highest (close to 100%). The most efficient individual grazing animals (Harris and Harris 2019; Heatley 2019). farmers achieved monthly maximum weight gains ≥0.8 While delegates noted the need for more bushy kg/d, close to the genetic potential of Bali bulls. varieties to reduce excessive height of leucaena, improved In Colombia, Zapata Cadavid et al. (2019) reported the animal management using high-density short-duration work of the CIPAV Foundation (Centro para la rotational grazing was recommended to control excessive Investigación en Sistemas Sostenibles de Producción height. Zapata Cadavid et al. (2019) recommended a Agropecuaria) on the establishment, management and rotational grazing system of 1–5 days grazing followed by promotion of intensive silvopastoral systems (ISPS). 45–50 days for recovery. Australian graziers reported Leucaena is planted at high densities (>10,000 plants per using rotational grazing systems, moving cattle every 14 ha) in rows 1–1.5 m apart, with 0.3–0.6 m between days (Heatley 2019) and using high stocking rates of at leucaena trees within rows, and inter-planted with a range least 5–10 head/ha (Craig Antonio pers. comm.). Large of tropical grasses. ISPS are grazed rotationally by beef cattle, especially lactating cows, achieved best height and dual-purpose dairy cattle. At stocking rates of 2.5–4.5 control (Peter Larsen pers. comm.). Rotational grazing head/ha, beef cattle gained 0.65–0.8 kg/hd/d, while dairy also achieves rapid nutrient cycling and permits rationing cows yielded 5–14 kg milk/cow/d, depending on animal of leucaena, although it is costlier to set up and manage. genetics, season and supplementation, with up to 17,000 R&D priorities. Delegates identified that information is kg milk/ha/year. needed on the best dietary combination of leucaena and Goat production systems in the tropics and subtropics grass, or leucaena and crop residues to maximize were reviewed by Cowley and Roschinsky (2019) and productivity. Dietary intake information of this nature would described in case studies from Thailand (Harrison et al. allow optimum planting strategies, including row spacing, 2019; Nakamanee et al. 2019a, 2019b). They concluded configuration and alignment, companion grass species that goats are well adapted to leucaena, and are productive selection and fertilizer needs, as well as optimum stocking in terms of liveweight gains, milk production and rates and spelling periods, to be determined. Hopkins et al. reproduction on diets containing up to 100% leucaena. (2019) found that measurement of leucaena content of the Successful feeding systems included both grazed and cut- diet of cattle grazing leucaena-grass pastures, using current and-carry intensive strategies. broad calibration NIRS equations, was associated with Energy supplementation of leucaena-fed animals was substantial errors and needs further refinement. reviewed by Harper et al. (2019). They reported that Southeast Asian delegates expressed interest in production (liveweight gain or milk production) from conservation technologies (hay and silage) as a leucaena was increased by the addition of supplements management strategy for smallholders employing cut- containing fermentable metabolizable energy, such as and-carry systems to provide a store of fodder for dry Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 474 H.M. Shelton season feeding. The strategic use of conserved leucaena S. jonesii as reported by Aung (2019). An audit of or as a forage bank to supplement dairy cattle and total mimosine ingested versus total DHP voided breeding cows to increase pre-weaning calf growth was a in urine and faeces might indicate the priority (Dahlanuddin et al. 2019). contribution of other micro-organisms in the Leucaena toxicity. It is well known that leucaena contains detoxification of DHP. the non-protein amino acid mimosine (Honda and Borthakur 2019), and that cattle, naïve to leucaena, can be affected Alternative uses of leucaena initially by mimosine toxicity, showing symptoms of hair loss, salivation and loss of appetite. It is also known that There is increasing interest in leucaena as a dual-purpose mimosine is rapidly converted to DHP, which is reported to plant suitable for producing both biofuel and feed for be chronically toxic (Shelton et al. 2019). However, most livestock. Tudsri et al. (2019) reported that the chemical livestock raisers in Australia and internationally observe that composition of leucaena was excellent for heat generation symptoms are short-lived, with animals quickly recovering on combustion. They reported that the arboreal character to show excellent production (Shelton et al. 2019). The and wood yield of cv. Tarramba, as well as many hybrid current understanding in Australia is that graziers with cattle lines, showed excellent potential as biofuel and on leucaena are wise to inoculate cattle with Synergistes recommended planting configurations that provided triple jonesii as protection against toxicity. However, new bottom-line benefits. evidence from Bali cattle being fed diets up to 100% Khanna et al. (2019) reported that India was a major leucaena in Indonesia showed that conjugation of DHP by producer and consumer of paper and pulp products and the liver, and not S. jonesii, though ubiquitously present at has developed leucaena plantations to provide raw low populations (McSweeney et al. 2019), was the major materials for industry. One of the largest Indian paper detoxification pathway, and inoculation was not necessary companies (JK Paper Ltd) has promoted establishment of (Shelton et al. 2019). Since no other country has access to leucaena plantations in Gujarat, Maharashtra and Madhya the laboratory-fermented source of S. jonesii, this finding, if Pradesh States with >7,800 farmers planting areas widely applicable, has the potential to remove a major totalling >18,400 ha for producing paper pulp. The world-wide barrier to adoption of leucaena for feeding company’s R&D network, using genetic improvement ruminants. through mutation techniques and hybridization programs R&D priorities for preventing leucaena toxicity. The for wood quality improvement, has developed high following issues are deserving of priority: production clones, and established clonal seed orchards.  While there is evidence of similar hepatic conjugation of DHP in ruminants consuming leucaena in Australia Leucaena and the environment and other countries where leucaena is being fed, this new hypothesis needs to be confirmed by additional There are multiple environmental benefits from planting studies in those countries. and managing leucaena for livestock production based on  Further study is also needed to clarify the effects of its system sustainability that provides triple bottom-line feeding high leucaena diets on the reproductive benefits (environmental, social, economic) including performance of ruminants as there are published carbon storage, animal welfare and reduced enteric (Holmes 1980; Holmes et al. 1981) and anecdotal methane emissions. reports (O’Neill and O’Neill 2019) that pregnant In addition to the animal welfare benefits from more females, naïve to leucaena, can suffer reduced calving high-quality feed during the dry season and during percentages if grazing leucaena prior to and during droughts, livestock raisers interviewed in Thailand, joining. It may be possible to avoid negative effects on Vietnam, the Philippines and Indonesia claim that herd reproduction by appropriate herd management consuming leucaena delivers control of many internal (Shelton et al. 2019). parasites. Organic beef production in Australia is possible  A number of other specific issues regarding leucaena from leucaena pastures on fertile soils. toxicity need further clarification, namely: Leucaena and greenhouse gas implications. A subject a. Understanding the relative significance of metal area which provoked extensive discussion was the ion chelation versus negative effects on thyroid positive impact of leucaena plantings on reducing GHG hormones as the principal mode of toxicity of emissions with papers by Tomkins et al. (2019) from DHP (Shelton et al. 2019); and Australia, Chará et al. (2019) from Colombia, Banegas et b. Additional investigation of alternative rumen al. (2019) from Argentina and Ramírez-Avilés et al. organisms for degradation of DHP other than (2019) from Mexico. Tomkins et al. (2019) reported data Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) ILC2018: Conference summary 475 that showed soil C in rangelands after 40 years was 17–  Acknowledge the potential detrimental environmental 30% higher under leucaena-grass pastures than under issues, while highlighting the positive environmental grass-only pastures. Other Australian work showed that benefits; enteric methane emissions were reduced (~20%) in cattle  Work collaboratively with weed scientists and attend grazing leucaena-grass pastures compared with cattle weed control conferences convened by Local grazing grass only. Chará et al. (2019) reported results on Government and environment groups; and GHG emissions from soil and pastures in an intensive  Consider developing a self-auditing process for leucaena silvopastoral system (ISPS) with leucaena in Colombia growers to demonstrate that they are being proactive in that generated 30% less CO2, 98% less CH4 and 89% less preventing leucaena from escaping their properties. N2O soil emissions per ha per month, when compared Biodiversity. Dr Julián Chará, while in Australia, with an adjacent conventional farm with irrigation and commented on the low diversity of the Australian high fertilizer inputs. Ramírez-Avilés et al. (2019) leucaena-cattle systems and specifically the low density reported experiments in which methane emissions were of trees. He said that Colombian experience indicated the reduced by >50% as leucaena in diet was increased from importance of planting other multipurpose trees to 0 to 80%, and carbon storage was increased by 38% in provide additional sources of income (diversification) and leucaena-grass systems compared with pure grass pasture. to obtain the advantages of trees, e.g. reduction in the King and Burgess (2019) reported that Emissions impact of frost events, improvement in biodiversity, Reduction Fund (ERF) payments might be possible in enhancement of nutrient cycling and promotion of carbon Australia based on reduced CH4 and N2O emissions (N2 storage. fixation, dung and urine) and soil C storage. However, Delegates from CIPAV proposed intensive silvopastoral since the current price of carbon or an Australian Carbon systems (ISPS) with an upper tree layer to provide Credit Unit (ACCU) is $13.52/t, Tomkins et al. (2019) environmental services and economic returns (wood). Chará observed that animal production benefits from leucaena et al. (2019) reported that ISPS “increased complexity of the plantings on-farm would outweigh income potential production system with measurable positive effects on generated from carbon credits. biodiversity supporting more species of birds, ants, dung Weediness. Despite the many positive attributes, beetles and woody plants than conventional pasture environmental concerns about the weed potential of monoculture. ISPS contributed to landscape-scale leucaena remain a major issue in Australia and worldwide connectivity and environmental services”. (Campbell et al. 2019; Idol 2019). Conference delegates agreed that the potential of It is generally accepted that leucaena does not invade leucaena internationally should not be limited to livestock undisturbed ecosystems (Idol 2019; Zapata Cadavid et al. production. Livestock raisers would have a stronger 2019). Nevertheless, if not properly managed, current argument against the negative environmental views held by commercial varieties of leucaena produce long-lived seed some sectors of society regarding farmers and graziers, if that can spread initially between rows and eventually leucaena was integrated into diverse agricultural landscapes outside of planted paddocks onto roadsides and along and delivered a variety of environmental services. riparian zones. Several control options are available, namely: development of a sterile variety of leucaena Adoption of leucaena technology (McMillan et al. 2019); promotion of The Leucaena Network’s Code of Practice that provides guidelines to There was general agreement at the conference that, reduce and control unwanted plants (Christensen 2019); despite overwhelming evidence for the high productivity, and collaboration with government and chemical profitability and sustainability of leucaena feeding to companies to formally register a broader range of ruminants around the world, adoption of the innovation herbicides for control of leucaena (Campbell et al. 2019). was universally well below expectations. Presentations It was concluded that the benefits of leucaena need to from Australia (Buck et al. 2019b; Kenny and Drysdale be promoted as they will become increasingly important 2019), Colombia (Zapata Cadavid et al. 2019), Argentina with time due to global and community pressures for (Radrizzani et al. 2019a; 2019b), Mexico (Ramírez- attention to GHG reduction strategies, animal welfare, Avilés et al. 2019), Indonesia (Dahlanuddin et al. 2019), product quality, soil improvement and production system Thailand (Nakamanee et al. 2019a), Myanmar (Aung sustainability. 2019) and India (Nimbkar 2019) all reported that more Nevertheless, it was recommended by Campbell et al. needs to be done to increase adoption of this highly (2019) that leucaena growers should: successful innovation. Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775) 476 H.M. Shelton Mr Bruce Mayne, a grazier delegate from central Concluding reflections Queensland, said that, given the many ‘good news’ stories on leucaena feeding from around the world, “it was There is huge potential to expand the area of leucaena puzzling therefore to see that the uptake of leucaena into pastures in northern Australia and around the world. Much pastures across the world has been moderate at best. What is now known about its establishment and plant and animal is the stumbling block? Is it difficulty in establishment, management requirements. Delegates were unanimous in high cost of establishment, lack of variety suitability or agreeing that the momentum for collaboration and other limitations that constrain it from the expansion information exchange established during the conference worthy of the gains that farmers are able to achieve”? should be continued. It was suggested that a research agenda, This problem of low adoption is not unique to encompassing the priorities identified, should be created and leucaena. Shelton et al. (2005) acknowledged the low studies mounted at several locations internationally. levels of adoption of tropical pasture legume technology The Indonesian team suggested planning for the next around the world despite decades of R&D. They advanced leucaena conference and offered to host a conference in an analysis of the reasons for successes and failures of Indonesia. Latin American delegates proposed visits to efforts to achieve adoption. Colombia and Mexico to better appreciate the ISPS used in Strategies to increase adoption levels were reported these countries. The participation of researchers and farmers from Indonesia (Dahlanuddin et al. 2019) for leucaena in the next International Silvopastoral Congress to be held in feeding in cut-and-carry feeding systems. Kenny and Paraguay in September 2019 was encouraged. Drysdale (2019) suggested that the adoption analysis tool The Leucaena Network representative highlighted the (ADOPT) would be useful in assisting with design of new value of peer networking, information sharing and communication and extension messages. The program mentoring to facilitate greater connectivity internationally to highlights some of the issues that could limit adoption. capitalize on the different experiences in different locations. Establishment of on-farm demonstration areas that can be used as authentic examples of how leucaena can be Acknowledgments used to increase ruminant production, and subsequently promoted in field days and farmer visits, has been used The work of the Organizing Committee is deeply successfully in Australia (Rolfe et al. 2019a; 2019b) and acknowledged, especially the contributions of Dr Nahuel in Indonesia (Dahlanuddin et al. 2019). Pachas (UQ), Dr Scott Dalzell, Dr Nigel Tomkins (MLA) Nevertheless, there are many successful examples of and Mr Joe Rolfe (QDAF). Other contributors included adoption of leucaena for ruminant feeding around the world. Assoc. Prof. Chris Lambrides (UQ), Dr Michael Halliday Australian and international producers presented their (UNE), Dr Hayley Giles (UQ), Dr Dahlanuddin experiences at the conference (Antonio 2019; Heatley 2019; (UNRAM), Dr Tanda Panjaitan (BPTP), Dr Jacob Nulik Kana Hau and Nulik 2019; Ogg and Ogg 2019; O’Neill and (BPTP) and Ms Debora Kana Hau (BPTP). O’Neill 2019; Rea et al. 2019). One of the starkest contrasts The contributions of members of the Steering in terms of scale was between cattle fattening enterprises of Committee are also acknowledged, namely: Dr Julián successful Australian graziers (often with >500 ha leucaena) Chará (Fundación CIPAV, Colombia); Dr Enrique (Harris and Harris 2019) and smallholder cattle fatteners Murgueitio (Fundación CIPAV, Colombia); Dr Rogerio from eastern Indonesia (with 1‒2 ha leucaena per farmer) Martins Mauricio (Universidade Federal de São João del- (Kana Hau and Nulik 2019). Rei, Minas Gerais, Brazil); Dr Pablo L. Peri (Conicet- INTA, Argentina); Dr Alejandro Radrizzani (INTA, R&D priorities. In Australia, only a small percentage of Argentina); Dr Carlos Sánchez-Brito (Fundación Produce potential land area has been planted to leucaena. Michoacán, Mexico); Dr Michael Peters (CIAT, Delegates suggested that adoption could be increased if Colombia); Dr Daniel Real (DPIR WA, Australia); and greater effort was made to engage with environmentalists, Mr Stuart Buck (QDAF, Australia). catchment management groups, green-leaning city folk and all sectors of government ‒ federal, state, local etc. It References was argued that a public relations exercise was needed to (Note of the editors: All hyperlinks were verified 22 August 2019.) tell the great story of profit and sustainability in an environmentally friendly way emphasizing the many Abair A; Hughes CE; Bailey CD. 2019. The evolutionary environmental benefits and the strategies employed to history of Leucaena: Recent research, new genomic minimize undesirable spread, especially the program to resources and future directions. Tropical Grasslands- breed a sterile leucaena variety. 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