Agricultural Intensification and the Threat to Soil Fertility in Africa: Evidence from the Jos Plateau, Nigeria

Abstract

This paper challenges the view that agricultural intensification is a threat to soil fertility in Africa. On theJos Plateau, intensification has continued since the 1970s despite low levels of soil fertility and crop production. This intensification has locally enhanced soil fertility despite shortages of inorganic fertilizer, cash and labour. At least, soil fertility has been sustained through indigenous knowledge of: mixing ash, organic and inorganic fertilizers; careful soil conditioning; substitution of ash and organic fertilizer; switching to less demanding crops and crop rotation; cultivation of legumes and careful spacing of crops; more effective use of inorganic fertilizers; and generating more cash to buy fertilizer. Use of this knowledge was apparently encouraged by economic and population pressures. A broader, relative concept of soil fertility is called for, as are recognition of the farmers' viewpoint and cultural variation in soil fertility management. Given appropriate incentives and marketing opportunities, it is hypothesized that resource-poor farmers elsewhwere in Africa will also apply their knowledge toward maximizing the fertility of their soils rather than mining them.