The decline in soil fertility in smallholder is a major factor inhibiting equitable development in much of sub-saharan africa. Smaling et al. (1997) estimates that soils in sub-saharan Africa are being depleted at annual rates of 22kg/ha for nitrogen, 2.5 kg/ha for Phosphorus, and 15kg/ha for potassium. In many areas, farmers periodically fallow their land, that is, allow it to lie idle for one or more seasons primarily to restore its fertility. As population increases, fallowing and fallow periods are reduced, continous cropping becomes more frequent, and crop yields often decline. Cultivation is extended to marginal areas, causing soil degradation. The recent removal os subsidies on fertilizers in many countries has exacerbated these problems by causing fertlizer use to decline and consequently leading to reduced farm incomes.
Publication year
2003
Authors
Kwesiga, F.R.; Franzel, S.; Mafongoya P L; Ajayi, O.C.; Phiri D M; Katanga, R.; Kuntashula, E.; Place F; Chirwa T S
Language
English
Keywords
fallow, farming systems, organic matter, research, soil fertility, technology transfer
Geographic
Zambia
