ABSTRACT

Alley cropping was a traditional practice of the Ibu tribe of eastern Nigeria (Kang 1997), who developed the concept in response to accelerating pressures on traditional shifting agriculture (Kang et al. 1990). It was described as a stable alternative to shifting cultivation in the sense that farmers no longer needed to shift from one cultivated field to another. Alley cropping combined both the fallow and cultivation phases. The key was the planting of N-fixing woody perennials in rows that followed the contours of the land (see color plate 48). Nutrient recycling was improved, greater quantities of nitrogen were biologically fixed, and nutrients that were once unavailable in deeper soil layers were brought to the surface by a nutrient pumping effect. Nutrient losses were reduced by recapture of leached nutrients or through reduced soil erosion (Kang and Wilson 1987; Raintree and Warner 1986).