Fertilizers to support agricultural development in sub-Saharan Africa: what is needed and why

Substantial growth in inorganic fertilizer use is a prerequisite for sustained agricultural growth in sub-Saharan Africa. Increased fertilizer use can lead to modest but immediate and important increases in yields, while the profitability of other technologies will be stifled without adequate plant nutrients. Average fertilizer application rates in sub-Saharan Africa need to increase from 10 kg/ha to 50 kg/ha within 10 years to prevent mining of soil nutrients. That implies an 18% annual growth rate. This is substantially higher than trends in the region, but within a reasonable range of historically observed levels from other parts of the world. While over-use of fertilizers can create environmental problems, this is not a widespread problem in sub-Saharan Africa, and should not become one as a result of applying 50 kg/ha of inorganic fertilizers. Rather, near-term environmental concerns in agriculture in sub-Saharan Africa will stem from the lack of intensification. Farmer demand for fertilizers and the physical capacity to make fertilizers available are the two key issues that determine whether a 50-kg/ha goal will be attained. However, demand-side incentives cannot be separated from fertilizer supply possibilities. Several studies document that the simple physical availability of fertilizers to farmers, in the appropriate quantity, packages and at the appropriate time of year, remains a main constraint on increased fertilizer use in sub-Saharan Africa.