Cowpea in evolving livestock systems

Demand for livestock products has been increasing through much of the semi-arid tropics and will likely continue to increase along with the use of purchased feedstuffs. As smallholder livestock systems evolve and become more market oriented, the type of diets fed to livestock may change and the importance of feed marketing may increase. Mixed crop–livestock systems are key to meeting this increasing livestock product demand and cowpea (Vigna unguiculata [L.] Walp.) fodder (haulms) is an important component of these systems in semi-arid regions of the tropics where its high nutritional quality allows it to be used as a supplement to livestock diets based on cereal stovers and other low-quality forages. Improving the nutritional quality of cowpea fodder for use by livestock is important to improving the productivity and profitability of these mixed farming systems. Legume fodders will remain an important part of changing livestock diets and the development of cowpea varieties that better feed both people and their farm animals will give farmers new and better choices for improving levels and efficiency of livestock production. Cowpea breeding programs have worked toward producing dual-purpose varieties that emphasize the production of grain and fodder since the late 1980s and have produced several that have become well accepted when tested on-farm. Systematic screening of cowpea genetic resources is important for advancing development of dual-purpose varieties. Involvement of cultivar release agencies and seed production programs are also important to advance the use of improved dual-purpose crop varieties

DRY MATTER YIELDS AND BOTANICAL COMPOSITION OF THREE GRASSES AND TWO LEGUME MIXTURES GRAZED BY CATTLE IN A DERIVED SAVANNA AREA OF NIGERIA

A field experiment was conducted at the International Livestock Research Institute Ibadan, Nigeria between July 1998 and August 2000 to evaluate the dry matter yields and botanical composition of Panicum maximum (local), Panicum maximum (Ntchisi) and Brachiaria ruziziensis planted in mixtures with Centrosema pubescens ILRI 152 and Stylosanthes guianensis ILRI 164 (CIAT 184 cv. Pucallpa) and these species in sole stands. The grass/legume and sole pasture species were mob-grazed by White Fulani and N’Dama cattle one year after planting beginning from March 1999. Thirty-two mature animals (average of 3 years old) of mixed sex, amounting to a stocking density of 250 head ha-1 grazed the plots at each grazing period. The pastures were evaluated for dry matter yield, botanical composition, and response of the species components to grazing effects. The dry matter yields of the pastures were lower at the year of planting than the subsequent years and the mean dry matter values averaged over the three years indicated that P. maximum (Ntchisi)/S. guianensis (9.7 t/ha), Sole P. maximum Ntchisi (10.2 t/ha) and sole S. guianensis (9.9 t/ha) produced significantly more than the other pastures. The yields by pastures that had B. ruziziensis (6.4 - 7.1 kg/ha) as sole crop or as grass/legume mixtures were among the lowest. During grazing, dry matter yields declined from March to December, apparently in response to effects of the intensive grazing. The mean values for dry matter yield indicated that P. maximum Ntchisi/S. guianensis mixture was more persistent under the heavy grazing effects with the value of 16.9 t/ha compared to 10.6 t/ha for sole B. ruziziensis. S. guianensis and C. pubescens constituted 18-21% and 24-25% respectively of the biomass of the grass/legume pastures one year after mob-grazing indicating that C. pubescens could be more resilient under intensive grazing in the derived savanna area of southwest Nigeria. &nbsp

Legume-Legume Complementary for Sustainable Pasture Development in the Tropics

The use of legume-legume mixtures to alleviate limitations of individual species in legume based technologies was investigated in subhumid Nigeria. The results indicate the potential of legume mixtures, through processes of complementation and compensation, to reduce the risk of legume establishment and survival and thus ensure sustainable legume yields and percentages. The implications for on-farm adoption of forage legumes are discussed

Multiple Uses of Tropical Forage Legumes for Sustainable Farming in the Moist Savannas of Africa

Ensuring that farming in the moist savannas of Africa is maintained, despite increasing population pressure and agricultural demands, necessitates the sustainable integration of crop and livestock enterprises; a role that forage legumes can fulfill. The potential of eleven herbaceous and two shrubby species of forage legumes in an improved fallow or ley-farming system to provide dry season fodder and beneficial effects to a subsequent cereal crop were investigated. Fodder dry matter yields were highest for Stylosanthes guianensis (9.9 t/ha), Centrosema pubescens, and Aeschynomene histrix. Maize yield following S. guianensis was 138% higher than after natural fallow. Similar increases were obtained after Calopogonium caeruleum, Arachis pintoi and Aeschynomene histrix. Sixty accessions of A. histrix were tested for their ability to stimulate suicidal germination of Striga hermonthica and thirteen accessions were found to significantly increase germination of striga seeds; this could further enhance farmersí acceptability of this species in areas where this parasitic weed is a devastating problem

Integrated Crop Livestock Systems--A Key to Sustainable Intensification in Africa

Mixed crop-livestock systems provide livelihoods for a billion people and produce half the world’s cereal and around a third of its beef and milk. Market orientation and strong and growing demand for food provide powerful incentives for sustainable intensification of both crop and livestock enterprises in smallholders’ mixed systems in Africa. Better exploitation of the mutually reinforcing nature of crop and livestock systems can contribute to a positive, inclusive growth trajectory that is both ecologically and economically sustainable. In mixed systems, livestock intensification is often neglected relative to crops, yet livestock can make a positive contribution to raising productivity of the entire farming system. Similarly, intensification of crop production can pay dividends for livestock and enhance natural resources management, especially through increased biomass availability. Intensification and improved efficiency of livestock production means less greenhouse gases per unit of milk and more milk per unit of water. This paper argues that the opportunities and challenges justify greater investment in research for development to identify exactly where and how win-win outcomes can be achieved and what incentives, policies, technologies and other features of the enabling environment are needed to enable sustainable, integrated and productive mixed crop livstock systems

Optimizing the Contribution of Cowpea to Food and Fodder Production in Crop-Livestock Systems in West Africa

Cowpea is important for the provision of both grain for food and fodder for livestock but there is often a trade-off between production of the two. To better understand influences on grain and fodder production, and how these may be utilized, research was conducted at 5 locations in west Africa using 12 cowpea varieties, with and without insecticide spray. Spraying had a dramatic effect on grain production, but less so for fodder, however there was an effect of spraying on fodder quality in terms of in sacco digestibility at Niamey. Accessions with the potential to produce grain and fodder with good quality were identified (IT89KD-391 and TVU 12349) and studies are continuing to optimise the contribution of such material to local production systems

High-throughput phenotyping and improvements in breeding cassava for increased carotenoids in the roots

Past research developed reliable equations to base selections for high β-carotene on near-infrared spectroscopy (NIR) predictions (100 genotypes d−1) rather than with high-performance liquid chromatography (HPLC) (<10 samples d−1). During recent harvest, CIAT made selections based on NIR predictions for the first time. This innovation produced valuable information that will help other cassava (Manihot esculenta Crantz) breeding programs. A total of 284 samples were analyzed with NIR and HPLC for total β-carotene (TBC) and by the oven method for dry matter content (DMC). Results indicated that NIR reliably predicted TBC and DMC. In addition, 232 genotypes grown in preliminary yield trials (PYTs) were harvested at 8.5 and 10.5 mo after planting (one plant per genotype and age) and root quality traits analyzed (by NIR only). Repeatability of results at the two ages was excellent, suggesting reliable results from NIR. In contrast to previous reports, age of the plant did not influence carotenoids content in the roots. The availability of a high-throughput NIR protocol allowed comparing results (for the first time) from seedling and cloned plants from the same genotype. Results showed very little relationship for DMC between seedling and cloned plants (R2 = 0.09). There was a much better association for TBC (R2 = 0.48) between seedling and cloned plants. It is postulated that variation in the environmental conditions when seedling and cloned plants (from the same genotype) may be responsible for these weak associations. Important changes in selection strategies have been implemented to overcome problems related to a lengthy harvesting season. (Résumé d'auteur

Soil fertility management and cowpea production in the semiarid tropics

Cowpea (Vigna unguiculata [L.] Walp.) is an important grain legume in the semiarid zone of West Africa as it is a major source of dietary protein for the people. It is usually grown as an intercrop with the major cereals, namely millet and sorghum. Despite its importance, its yields are very low due to several constraints including poor soil, insect pests, and drought. The soils in semiarid West Africa are inherently low in nitrogen and phosphorus. Soil, water, and nutrient management practices are inadequate to sustain food production and to meet the food requirements of the fast growing population. Research results show that proper management of organic amendments such as crop residues and manure, which are essential complements to mineral phosphorus fertilizers, can increase yields of cowpea and associated cereals more than three fold. Direct application of indigenous phosphate rocks can be an economical alternative to the use of imported, more expensive soluble phosphorus fertilizers for cowpea production in the region. The agronomic effectiveness of indigenous phosphate rock is about 50% compared to the imported single superphosphate. Furthermore, when the unreactive phosphate rocks are partially acidulated at 50%, their agronomic effectiveness can increase to more than 70%. Studies on cereal–cowpea rotation revealed that yields of cereals succeeding cowpea could, in some cases, double compared to continuous cereal cultivation. With effi cient soil fertility management, cowpea can fi x up to 88 kg N/ha and this results in an increase of nitrogen use effi ciency on the succeeding cereal crop from 20% in the continuous cereal monoculture to 28% when cereals are in rotation with cowpea. Furthermore, the use of soil nitrogen increased from 39 kg N/ha in the continuous cereal monoculture to 62 kg N/ha in the rotation systems. Future research needs to focus on understanding the factors affecting phosphorus uptake from different sources of natural rock phosphate. There is also a need to quantify the below-ground nitrogen fi xed by different cowpea cultivars. The increase of cowpea productivity in the cropping systems in this region will improve the nutrition of people, increase the feed quantity and quality for livestock, and contribute to soil fertility maintenance. This should contribute to reduction in poverty and environmental degradation

Integrated crop-livestock systems - A key to sustainable intensification in Africa

Mixed crop-livestock systems provide livelihoods for a billion people and produce half the world’s cereal and around a third of its beef and milk. Market orientation and strong and growing demand for food provide powerful incentives for sustainable intensification of both crop and livestock enterprises in smallholders’ mixed systems in Africa. Better exploitation of the mutually reinforcing nature of crop and livestock systems can contribute to a positive, inclusive growth trajectory that is both ecologically and economically sustainable. In mixed systems, livestock intensification is often neglected relative to crops, yet livestock can make a positive contribution to raising productivity of the entire farming system. Similarly, intensification of crop production can pay dividends for livestock and enhance natural resource management, especially through increased biomass availability. Intensification and improved efficiency of livestock production mean less greenhouse gases per unit of milk and more milk per unit of water. This paper argues that the opportunities and challenges justify greater investment in research for development to identify exactly where and how ‘win-win’ outcomes can be achieved and what incentives, policies, technologies and other features of the enabling environment are needed to enable sustainable, integrated and productive mixed crop-livestock system