Integrating fish farming and agriculture
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CTA. 1992. Integrating fish farming and agriculture. Spore 38. CTA, Wageningen, The Netherlands.
Permanent link to this item: http://hdl.handle.net/10568/45711
Present systems of farming will not meet the projected food needs for most ACP countries in the twenty-first century. Where sufficient water is available and soils are suitably water retentive, the integration of aquaculture with agriculture could...
Present systems of farming will not meet the projected food needs for most ACP countries in the twenty-first century. Where sufficient water is available and soils are suitably water retentive, the integration of aquaculture with agriculture could make a significant contribution to food supplies. Many current farming methods degrade the environment and unrelieved poverty continually forces farmers to adopt non-sustainable systems of tillage and grazing. Slash-andburn farming, which was sustainable when populations were very much smaller, now contributes to widespread deforestation and erosion. One estimate is that 142 million hectares of rainfed crop land in Southern and Sudano-Sahelian Africa have become 'decertified' as a direct result of agriculture, while salinization of irrigated land has affected five million hectares in the same regions of Africa. Several states in the Caribbean and Pacific are also witnessing similar despoilation of once productive forest and farm land. Rural people recognize the consequence of their actions but their poverty generally precludes them from adopting alternative ways of deriving a living. They have to use land and water resources ever more intensively and, in the absence of sustainable systems, exploitative techniques prevail. The need for new sustainable farm systems has been recognized for decades but there has been a general lack of agreement as to how they might be developed. One major reason for this failure may be that research workers have been locked into specialist disciplines, whereas what is required is a multi-disciplinary systems approach. However, recent developments in Farming Systems Research and Extension (FSRE), particularly in agroecosystems analysis, offer guidelines for scientists to see how resource use may be intensified and diminished environments regenerated by integrating agriculture with fish-farming. Waste not want not Aquaculture provides a way of using agricultural waste to make marginal lands more productive, provided that soils are water retentive. This will vary with the local geology but experience has shown that suitable soils are to be found in many localities. However, test digging must precede any major commitment to pond construction. Fish convert plant and animal waste into high quality protein and simultaneously enrich pond mud for use as fertilizer on crop land. Such a cyclic, sustainable system where elements of crop, livestock and fish production reinforce each other is illustrated diagrammatically in Figure 1. The value of this kind of integrated system to intensify farming and also to regenerate the environment through diversification and recycling has been demonstrated through collaborative research by the Philippines based International Centre for Living Aquatic Resource Management (ICLARM) in Malawi. Farmers in Malawi's Zomba district recognize six land types, from mountain to river plain. The agroecosystem analyst arranges the land types in sequence to form a 'composite' transect listing all enterprises, soils and water characteristics (Fig 2). There are major differences between high water-table floodplain types; the sandier soil, low water-table flat types; and the sloping land types. Flood plain lands are further divided according to whether they are cultivated or not. Crop and livestock enterprises vary accordingly, as Fig. 2 shows. Fishponds are constructed in wet lands and homestead land when a nearby stream or spring permits. Zomba's agroecosystem transect suggests many points for joining together land and pond 'crops'. Pond mud would revitalize vegetable plots. Pond water could irrigate vegetables and water animals. Animal manure, together with crop residues, weeds, tree leaf litter and rotten fruit and vegetables could fertilize ponds as well as soil. Other crop by-products such as maize and rice brans could also be fed to fish. Already some farmers are exploring these connections to intensify use of their resources. Some have upgraded impoverished land into orchards, fishponds, fodder and vegetable plots. In essence they are intensifying the use of land and water resources in a sustainable manner through species diversification and nutrient recycling. In many cases resource productivity increases, farmers' incomes rise, soils are improved and the water kept clean. Water quality and production Integrated aquaculture systems involve many variables and are therefore highly site-specific. Most systems depend on simple ponds with limited, if any, water exchange. This allows a build up of the nutrients that support the growth of natural feeds, especially if fertilizers, manures or other waste products are added. In consequence, natural feed levels in such ponds may reach far higher levels than those found in most natural aquatic systems. However, it is essential that there is a balance between added organic matter and fish population in order that a healthy ecosystem is maintained. The density of fish that can be maintained in a pond is largely related to the availability of food. As a result, integrated agriculture aquaculture systems are very flexible and ideal for utilizing the range of raw materials available in rural areas. A comparison of different levels of pond management shows that whereas unfertilized, poorly-managed ponds yield 50-200kg/ha/year, ponds which benefit from agricultural waste feeding and stock management yield 500010,000kg/ha/year. Even 50kg of fish per year provides variety in the diet and additional animal protein. Yields of 200kg can meet a family's needs and leave surplus for occasional sale, whilst higher yields demand guaranteed regular market outlets. Actual yield depends also on the species of fish stocked, as different species feed on different organisms and plant matter. In all situations the aim of successful pond culture is to manage the different pond organisms in order to maximise the utilization of waste materials and their conversion into edible protein. An efficient waste-fed pond can support growth of 30kg/ha/day. If this were available year round, the potential production would be 1090kg/ha/year. In practice, because of availability of fry (young fish) or water, climate changes, and the need to drain and harvest ponds, there are usually 200-250 growing days per year. 6000kg/ha/year would be an excellent output for such ponds. Africa is a relative newcomer to aquaculture, compared with most Asian countries, and lack of experience and training has led to many disappointments. However, farmers in several African countries are developing their own expertise and several aquaculture specialists have commented favourably on their progress and potential. Fig. 2 - Agroecosystems transect, Zomba, Malawi Andre Coche, who spent 17 of his 26 years' service with FAO in Africa and is an eminent authority on aquaculture, believes that while the most widespread system is still one where fish growth depends on naturally available food, integrated systems are preferred by the farmers who are increasingly contributing to the development of aquaculture in Malawi, Zambia and Zimbabwe. Mr Coche points to the vast possibilities offered by culture-based fisheries for intensifying the use of local resources and regenerating the environment. It is his opinion that the general potential for development is high in Malawi, Tanzania, Zambia and Zimbabwe and it is relatively good in Lesotho and Swaziland. Angola and Mozambique present good opportunities for the future. African experience In Cote d'Ivoire freshwater aquaculture in rural areas is practiced mainly on a smallscale, for instance in the region of Bouake in the centre of the country. Fishponds have also been introduced in some schools to encourage pupils to participate in agriculture and aquaculture, as well as to contribute to feeding the school's pupils. The main species farmed is Tilapia nilotica, which yields on average three metric tonnes/ha/ year. In Nigeria, many fish-farms have incorporated agricultural activities to diversify and to increase revenue. Live stock, poultry and crop production have all been l integrated successfully, and the most popular combination is crops livestock-fish. Where poultry or pigs are part of the system the animal or bird houses can be built over the water or, in the case of pigs and cattle, the wastes can be allowed to drain into the pond. In rice-fish farming the rice provides a spawning ground for the fish, a very common and ancient system in Asia. Where rainfed agriculture is the norm, maize, groundnut and soya are being planted specifically to provide fish feeds. In Luapula Province of north-east Zambia the Zambian Department of Fisheries and the FAO supported programme, Aquaculture for Local Community Development (ALCOM) has encouraged small-scale pond fisheries. ALCOM is based in Zimbabwe and is a regional programme covering the SADCC countries. It aims, through extension methods, development and testing, to assist in the growth of small-scale aquaculture throughout the region. Research into practical techniques in Zambia is being assisted by the University of Sussex and the Institute of Aquaculture at the University of Stirling. In the past, agriculture in Luapula has been based around citemene, a form of slash-andburn cultivation. However, a combination of government pressure and increased population density has led to more settled agriculture. The rural dietary staple is cassava, supplemented with millet, maize, groundnuts, and a limited range of vegetables. In certain parts of the province protein malnutrition, particularly of young children, is among the highest in the country. The protein shortage, the fact that fish is a favourite food of Luapulans, and the abundance of surface water, all make for a promising potential for aquaculture development. Indeed, recent years have seen a rapid spread of aquaculture Fish-rearing provides work for the whole family among small-scale farmers and in some villages virtually every household has at least one pond. Most ponds in Luapula are less than 200m2 and at present two species are produced: Tilapia rendalli and, to a lesser extent, Oreocromis macrochir. Inputs to fish ponds are largely plant materials, both agricultural byproducts and natural vegetation. Animal manure is also used where available but is generally scarce. Climatic factors limit production to the rainy season (September/October to March) and current outputs are extremely variable. The best yields are estimated to be about 500kg/ha/ year, although most active farmers produce significantly less. Nevertheless, despite this seemingly low productivity, many farmers declare themselves to be happy with their ponds. Less encouraging are reports that although many ponds are being dug in Luapula, management practices are often very poor. Ponds are badly sited or incorrectly constructed, fish are fed only infrequently despite the availability of food, compost cribs are either not constructed or are poorly maintained, and ponds are left unstocked. Evidently much has to be learned about which farmers adopt integrated agriculture-aquaculture systems and what factors influence the success of some and the failure of others. Success or failure? Some farmers will recognise the benefits of integrating fish into their farming system, while others may not feel that they can cope with the added workload, investment or more complex management. Studies by ALCOM in Zambia show that farmers with the fewest options for employing their time, land and water are often early adopters and achieve the highest yields of fish. This is advantageous because the poorer the farmer's household, the more likely that the increased income from fish production will ensure a long-term increase in productivity in the farm as a whole. Conversely, if a farmer is fully occupied and already earning a good income from the land and water available to him or her, there is little justification for persuading him to take up fish farming. However, some successful farmers will have the imagination, financial resources and energy to develop their farming business even further by integrating aquaculture into their crop and/or livestock enterprise. Research workers from the Universities of Sussex and Stirling are undertaking work on why some farmers in Luapula Province, who have the potential to undertake fish farming, fail to do so. The indications are that those who adopt fish farming tend to be slightly better educated, slightly better off financially, and are more likely to be male, than non-fish farmers. Evidence shows that women have been slower to take up fish farming than men and, overall, relatively few Luapula women have ponds in their own right. There are signs that one major constraint for women is the difficulty they have in constructing their own ponds: there seems to be a general unwillingness by menfolk to assist with pond construction while the women already have other domestic and farming responsibilities and so have little time to spare. Women may also not have direct access to tools for digging. It is not yet clear what the role of emergent fish farmers in communities where aquaculture is a strategy for survival at subsistence level will be. There is the potential for some to specialize as suppliers of fingerlings to others to their mutual benefit, but there is a danger also that a few 'elite' farmers will take over the prime means of production and dominate fish production to the detriment of their neighbours. However, this is probably less of a risk where fish farming is a part of an integrated system because, once established, external inputs are minimal. The future The current ways in which farmers in many ACP countries use their land and water can neither meet the demands for food and income, nor for environmental conservation. Intensification of food production is required, but without the usual environmental degradation. And yet any system that fulfills these criteria must be within the management and financial capabilities of large numbers of resource-poor farmers. Integrating fish farming with agriculture appears to be such an option. Aquaculture can be integrated with agriculture to the benefit of farmers and the environment but it is a new production system with many aspects that are totally novel to the great majority of rural people in ACP countries. If such a new system is to be successful government assistance will be essential for training, initial supply of fingerlings, advice on management while farmers gain experience and encouragement of the less advantaged who could benefit most. There is a growing database of practical experience to draw on from ICLARM, ALCOM, FAO projects in francophone Africa and private enterprises in Nigeria. The efforts that governments should put into aquaculture will depend on several factors, including its expected contribution to economic growth, by raising consumption of fish. However, an additional economic factor that must be taken into account is the synergistic effect on food production that will result from integrating fish farming with agriculture, and its beneficial effects on the environment by reducing, and even reversing, degradation.