Optimizing Fertilizer Use for Tropical Food Legumes in Sole Crop and Intercrop.

Optimizing Fertilizer Use for Tropical Food Legumes in Sole Crop and Intercrop The project Optimization of Fertilizer Recommendations in Africa (OFRA) is a network of research teams in 13 sub-Saharan Africa nations addressing the economic efficiency of fertilizer use. OFRA outputs are especially important to poor farmers whose use of fertilizer is financially constrained and who need to maximize profit from the small amount that can be applied. This requires optimization of the crop-nutrient-rate choices. Food legumes are produced in sole crop and in intercrop. Response functions of food legumes have been integrated into decision tools specific for 67 recommendation domains (RD), and depending on local importance, including for bean, cowpea, faba bean, groundnut, and pigeonpea. Nutrient response information fully derived from field research is relatively abundant for major cereal crops but very scarce for intercrop. Therefore, procedures were developed to estimate intercrop response functions by adjusting the RD-specific cereal sole crop response functions. Such procedures have been developed using field research results for maize-bean, maize-pigeonpea, sorghum-groundnut, and pearl millet-cowpea intercropping. Productivity and profitability of fertilizer use, determined on a cereal grain value equivalent, is consistently greater for intercrops compared with cereal sole crops.