Effects of Preceding Cowpea on the Performance of Maize in Cowpea-Maize Sequential Cropping

Field experiment was conducted at the Federal University of Agriculture in 2004/2005, 2005/2006 and 2006/2007 cropping seasons to investigate the effects of cowpea varieties on succeeding of maize crop. The experiment was laid out in split-plot design and the treatment replicated three times. The main plot treatment was sprayed and unsprayed cowpea (Vigna unguculata L.) while variety constituted the subplot treatment (IT90K-76, IT90K-277-2, Drum, Olo, Oloyin, Mallam and Sokoto varieties). Maize variety cv TZESR-W was planted as the test crop in the early cropping season of 2005, 2006 and 2007 on each subplot of the preceding cowpea. The biomass of cowpea in the spray plots were higher than those of unsprayed at 8, 10 WAP in 2004. Olo variety had significantly lower biomass compared to others in 2004. The grain yield of cowpea from the sprayed plots was significantly higher than the unsprayed plots in all the years. IT90K-76 variety had the highest grain yield whereas Mallam and Drum had the lowest in all the years. Maize grain yields from the preceding cowpea plots were significantly higher than that of 0 N kg/ha. The fertilizer equivalent of the preceding varieties of cowpea ranges between 24 and 38 N kg/ha. Thus, preceding cowpea enhances the performance of succeeding maize.