ABSTRACT

Low crop productivity due to soil fertility decline is a major challenge constraining maizebased smallholder farming systems in sub-Saharan Africa. The decline in soil fertility is largely due to continuous cropping without soil replenishment and reduced N2 fixation (Dakora and Keya, 1997). Most of the soils in this region contain low nutrient levels, for instance P levels range between 5 and 15 mg kg−1 and total N ranges between 0.02% and 0.07% (Sanchez, 2002). The situation is exacerbated by the presence of dysfunctional institutions, climate change and exorbitant costs of inorganic fertilisers following the removal of subsidies. Although most of the smallholder farmers are in need of mineral fertilisers to boost cereal crop productivity, over 60% are unable to afford the high prices (Morris et al., 2007). This has increased food, income and nutrition insecurity among smallholder farmers.