Decision Resources for Fertilizer Use Optimization in Africa.

Decision Resources for Fertilizer Use Optimization in Africa The vast majority of farmers in sub-Saharan Africa have severe financial constraints to fertilizer use and need very high returns on their small investments with little risk. Well-determined crop-nutrient response functions for the major crops of a farmer and the means to consider these functions in the farmer’s context are essential for maximizing net returns to fertilizer use. Under the AGRA-supported project Optimizing Fertilizer Recommendations in Africa (OFRA), research teams of 13 countries participated in developing resources for optimization decisions. The OFRA response function database has >5800 geo-referenced response functions for food crops determined from past and OFRA-related research with 49% from the latter. The Arc-Python OFRA Inference Tool uses information from nine spatial layers to find research results from production areas homologous to the targeted recommendation domain. Excel-Solver optimization tools that employ linear optimization across up to seven crops and four nutrients were developed for 67 recommendation domains across the 13 countries. The optimization tools consider the farmer’s land allocation to different crops, fertilizer costs, commodity values, and money available for fertilizer use and recommends the various crop-nutrient-rate combinations expected, on average, to give the most profit. Paper versions of the optimization tools were developed for routine advising of farmers and these provide the 4Rs of fertilizer use for each crop at three financial levels and provide application guidance to achieve the correct rate of application. Extension training resources, the OFRA book Fertilizer Use Optimization in sub-Saharan Africa and the above mentioned resources can be downloaded from http://agronomy.unl.edu/OFRA.