Assessment of indigenous soil and water conservation technology for smallholder farms in semi-arid areas in Africa and close spaced trash lines effect on erosion and crop yield

Runoff and soil erosion are responsible for about 83% of the land degradation worldwide. Many smallholder farmers in arid and semi-arid areas of Africa often use inexpensive indigenous soil and water conservation (ISWC) techniques to control runoff and erosion. This paper is a review of the ISWC methods and categorizes them into three: those suitable for semi-arid areas, those suitable for wet areas and those suitable for both semi-arid and wet areas. The usefulness of ISWC is generally appreciated but literature on the subject is scarce. A case study that investigated effects of 2-m spaced trash lines on runoff, erosion and crop yield in a cowpea – maize rotation is presented. Trash lines reduced runoff and soil loss and increased crop biomass yield three-fold. We conclude that ISWC like close-spaced trash lines are beneficial soil and water conservation methods and should be incorporated in future land resource conservation programmes