Can farmers in sub-Saharan Africa (SSA) increase agricultural yields and improve food availability without using more mineral fertilizers? This question has been at the center of lively debates within civil society, policy makers and researchers. The “yes” supporters put forward the principle of “reduction of inputs” of agroecology, that is to say that by relying on agrobiodiversity, recycling and better efficiency, agroecological practices such as the use of legumes and manure can increase crop productivity without requiring more minerals fertilizer. The basis for this publication was extensive research that examined decades of scientific literature on nutrient balances in SSA, biological nitrogen fixation of tropical legumes, production and utilization of manure in smallholder agricultural systems, and the environmental impact of mineral fertilizers. Analyzes show that more mineral fertilizers are needed in sub-Saharan Africa for a range of reasons outlined in this publication.
