The Role of Animal Manure in Sustainable Soil Fertility Management in Sub-Saharan Africa: A Review

ABSTRACT Sub-Saharan Africa contains soils that have been cropped for generations. Consequently, their inherent fertility has been severely depleted. In such soils, net negative balances of nutrients are a common problem. The current soil nutrient depletion rates are contributing towards decreasing crop yields. The search for sustainable soil fertility replenishment techniques is, therefore, an urgent need. A key resource in this respect is animal manure. Such manure can increase and maintain soil fertility by providing N, P, K, S, Ca, Mg, Na and other trace elements such as Fe, Mn, Cu, Zn. It also improves the pH of acid soils and calcareous soils, increases soil organic matter content and cation exchange capacity, improves soil aggregate stability, soil macro-structure, infiltration, water holding capacity and erosion resistance. However, animal manure cannot meet crop nutrient demand over large areas, because of the limited quantities available and the relatively low nutrient content of the materials. ...