SSA displays a combination of high soil nutrient deficits and very low fertilizer use. The region accounts for only 3% of global fertilizer consumption, a figure which has stagnated over the past two decades.
Zoé Druilhe and Jesús Barreiro-Hurlé, "Fertilizer subsidies in sub-Saharan Africa," ESA Working paper No. 12-04 July 2012 Agricultural Development Economics Division Food and Agriculture Organization of the United Nations. http://www.fao.org/docrep/016/ap077e/ap077e.pdf