Plants in the spotlight
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CTA. 2006. Plants in the spotlight. Spore 121. CTA, Wageningen, The Netherlands.
Permanent link to this item: http://hdl.handle.net/10568/47997
Internet URL: http://spore.cta.int/images/stories/pdf/old/spore121.pdf
Series of articles published by Spore during the last 20 years on plants and their uses
Cattle just love calliandra Calliandra calothyrsus is an extraordinarily versatile species. In April 2002, Spore wrote about its useful ability to release allelopathic or growth inhibiting compounds into the environment, which can reduce infestations of striga weed. In Uganda where dairy farmers were supplied with imported cows, calliandra is helping to solve another problem how to satisfy the bovine newcomers appetite for greenery without causing deforestation and erosion. Farmers found that a winning combination is zero-grazing with calliandra as high-octane fodder. Dina Twesase is one small-scale farmer who relies on this formula. She feeds her single Friesian cow with calliandra, which she began growing with the help of the Africare 2000 and the World Agroforestry Centre (ICRAF). Farmers in the region have learned the benefits of planting C. calothyrsus in contour hedgerows to conserve soil and water, improve soil fertility, and obtain fencing materials, firewood, stakes and bee forage. But, as Dina has discovered, calliandra really scores as a source of protein for dairy cattle. A supplement of 3 kg of calliandra is equivalent to 1 kg of expensive commercial dairy meal. She grows the calliandra amongst her crops, avoiding the need to convert any of her small property to pasture. In return for the fancy diet, her cow produces 20 l of milk per day. Marvellous marula In parts of Africa, the marula tree is valued so highly that giving someone the seed kernel is considered a true sign of friendship. Its small golden fruit featured most memorably in Spore 90, which reported how elephants got tipsy when the berries fermented in their stomach. In its native southern Africa, the fruits of the marula tree (Schlerocarya birrea) are used to make a liqueur. More recently, producers have tuned into the potential of this valuable fruit which has four times more vitamin C than oranges as a basis for a whole range of other products. A community-based company in the Limpopo Province of South Africa makes fruit pulp, seed oil and skin conditioner from organic marula. Marula Natural Products Pty Ltd operates on fair trade principles and, as well as processing the fruit, acts as intermediary between African producers and export buyers. Cowpea Plants battle cowpea pests Cowpea, Vigna unguiculata (L.) Walp., needs no introduction. Spore has written about this useful grain legume on many occasions, and ACP farmers prize the crop for its high protein levels, resistance to drought and ability to fix atmospheric nitrogen. But while the cowpea s virtues are well known, the plant does have a major drawback it is highly susceptible to pests and diseases, with losses of up to 90%. Indeed, Spore has often examined this seemingly intractable problem. There are some encouraging signs, however. Scientists at the International Institute for Tropical Agriculture (IITA) have developed high-yielding varieties with resistance to major diseases, insect pests, nematodes and parasitic weeds. Varieties with resistance to parasitic weeds such as Striga are currently being tested in farmers' fields and early maturing varieties with increased drought and shade tolerance are also being developed. Meanwhile, cowpea producers in Benin, Burkina Faso, Ghana, Mali, Niger, Nigeria, and Senegal are learning how to make and use plant-based insecticides. Projet Niébé pour l Afrique (PRONAF) uses high-yielding varieties that are resistant to key pests, diseases and weeds including flower thrips (Megalurothrips sjostedti), pod borer (Maruca vitrata), storage weevils (Callosobruchus maculatus) and Striga combined with botanical insecticides, solar drying, and triple bagging storage techniques. Effective plant-based pesticides include pawpaw, neem and extracts from pepper and tobacco. The many uses of moringa Moringa oleifera, the oleaginous tree found in most tropical countries of Africa, Asia and America, is no stranger to the pages of Spore. It made its first appearance in Spore 19 when we wrote about its seeds, which offer an ecological solution to filtering and purifying water. Moringa is also a very generous tree of life . Its leaves, which are rich in vitamins, minerals and proteins, can be made into a sauce and eaten with cereals. Dried and powdered, they help combat malnutrition, especially in children. This tree may be used in many ways, whether traditional or innovative. In 2002, Spore 100 counted no fewer than 19 different applications. A number of other avenues of research are still being explored, including potential uses as animal fodder, as a vegetable growth hormone, as paper pulp, green fertiliser and as a phytopharmaceutical product. It seems as if moringa has yet to reveal the full range of its virtues. The magic grass vetiver For centuries, the oil extracted from the roots of vetiver grass (Vetiveria zizanioides) has been used in the perfume trade. In October 2004, Spore wrote about how rural dwellers in Mali and Nigeria were selling vetiver to the cosmetics industry. This remarkably useful plant is also used for soil and water conservation, and increasingly, as an environmental tool. When planted as a contour hedge, vetiver acts as a filtering system that slows down rainfall runoff, reduces rilling and collects soil sediments at the hedge face. In ACP regions, vetiver is used to halt erosion, for example, in the Caribbean, Madagascar, Nigeria, Senegal and parts of the Pacific. In Ethiopia and Malawi, the grass is planted on sloping ground to reduce run off and sediment flows in upper watersheds, thus improving water quality further downstream. Spore 80 reported that trials in Thailand had shown that planting rows of vetiver grass could help absorb agrochemicals, particularly pesticides. Similar trials have since been successfully carried out in China and there is now interest in spreading this technology further afield. In South Africa, vetiver has been used to reclaim toxic mine dumps.Vetiver has the advantage of thriving in both wet and dry conditions, and on both highly acidic and alkaline soils. It also has a high tolerance to pests and diseases. Perhaps its most remarkable feature is its extraordinarily long roots, which will grow to depths of 3 to 4 m. Many cultivars are non flowering, which means the plant cannot become a weed. Once established, vetiver needs little maintenance, and its leaves and roots can be used for thatching and weaving. No wonder the Americans call it magic grass! Grain amaranth makes a comeback Grain amaranth is one of the world's forgotten foods . Grown extensively by the Incas and Aztecs of Central and South America, this versatile, hardy grain is packed with vitamins and minerals and may hold out hope for improving food security in dryland ACP regions. Spore 119 wrote about Kenyan farmers who are planting Amaranthus hybridus one of several varieties suitable for grain production with the help of the local NGO Strategic Poverty Alleviation Systems (SPAS). In Nigeria, a USAID project is also helping farmers to discover the benefits of this long neglected crop. Grain amaranth is especially suitable for hot, dry conditions, and has good resistance to pests and diseases. It grows rapidly and with little water, and is exceptionally high in lysine, a critical amino acid often deficient in plant protein. SPAS has supplied certified seeds for planting, and the hope is to tap growing export markets, as well as domestic ones more than 40 products containing grain amaranth are currently on the health food market in the United States alone. Photos: © ICRAF, © Syfia International, © bio.uu.nl, R Myers © Institute Grain Amaranth, © Gully