ABSTRACT

Three field experiments were conducted in Michael Okpara University of Agriculture Umudike Research farm between 2006 and 2007. Experiment one evaluated the effect of component density on growth and yield of vegetable cowpea (1T92KD-.3- 4-1) and maize (Oba 98) under sole and intercrop, at four densities (0,10,000, 20,000 and 30,000), plants per hectare. Experiment two measured the effect of relative sowing time on the growth and yield of vegetable cowpea and maize under sole and the intercrop systems. Both component crops were either sown same day, 2, 3, or 4 weeks before and after. Experiment three assessed the effect of each component varietal differences on growth and yield of vegetable cowpea (1T92KD-263-4-1 and 1T99K — 1122) and maize (Oba 98 and Oba Super 2) in the system. The experiments were laid out in randomized complete block design (RCBD). Soil and climatic data of the experimental sites were obtained for the study. Results of the experiments showed that in experiment one, inter cropping significantly (P<0.05) differed from sole cropping system. The crop yields decreased as density increased. Optimum yields were obtained at 10,000 vegetable cowpea + 30,000 maize plants per hectare. In experiment 2, yield and yield components of component crops decreased with delayed sowing time. The component crop yield was highest with introduction of cowpea 4 weeks before maize. The experiments component varietal influence of the intercrop was significant (P<0.05) over the sole system in experiments. Optimum economic yields were obtained when Oba 98 maize was combined with 1T92 KD-263-4-1 vegetable cowpea cultivar. In all cases land equivalent ratio (LER) was > 1.0 indicating yield advantage of the intercropping system and that vegetable cowpea could be successfully intercropped with maize for optimum economic yields.