Cassava-legume intercrop: II. Effects of relative planting dates of legumes on the productivity of legumes

ABSTRACT

The degree of complementarity vis-à-vis competition amongst the component crops, which is influenced by their relative planting dates, may affect the productivity of intercrop systems. This study assessed the effect of the relative planting dates of legumes on yield and yield components of three legume species. Field experiments were conducted in two consecutive years at two sites with contrasting soil types. Grain yield and yield components were determined at harvest maturity. A 4-weeks delay in incorporating legumes caused total yield loss of cowpea at both sites, decreased chickpea yield by 82% at the clay soil site, and led to negligible yield of Bambara groundnut in loamy sand soil. In contrast, sowing legumes 2 weeks after cassava decreased grain yield of cowpea (both sites), chickpea (clay soil) and Bambara groundnut (loamy sand soil). Intercropping decreased grain yield of chickpea (year 1) and Bambara (year 2) at the clay and loamy sand soil sites, respectively, but had no effect on cowpea yield. Although planting the legumes same time with cassava gave the highest grain yield, we suggest more studies, including sowing the legumes prior to planting cassava, before making categorical recommendations.