Grain and forage yield responses of maize genotypes intercropped with lablab purpureus under Bako condition, western Ethiopia

The trials were laid out in a split plot design with four replications where cropping systems (with or without Lablab purpureus) was assigned to the main plots and maize varieties to the subplots during 1995-1998 cropping seasons at Bako Agricultural Research Center. During the 1995 and 1997 Lablab was grown with maize until 10% flowering stage was reached and the biomass was the chopped and incorporated into the soil to evaluate the residual effect during the subsequent years. Thus the 1996 and 1998 seasons were the years during which the residual effect of the incorporated Lablab biomass was assessed. For maize grain yield and other yield components, the effect of cropping system was not significant (p0.05). Grain yield was higher (86.0 q ha sup(-1) for the intercropping system as compared to the sole cropping. Significantly (p0.01) higher mean grain yield and total forage were recorded for the hybrid variety, BH-660. Highest percentage values for harvest index (87.34%) was recorded for BH-140. During the 1996, except for the leaf component, no significant difference (p0.05) between the two systems was observed for all traits. The effect of cropping system was not significant for all parameters during the 1997. Varietal differences were not significant (p0.05) for all traits except for total forage (p0.01). When averaged over the two cropping systems, higher grain yield and other plant fractions were recorded for BH-660. During the 1998, the effect of system, variety and their interaction was not significant (p0.05). Comparatively higher (59.48 q ha sup(-1) grain yield was obtained from the plots to which chopped biomass of Lablab was incorporated in 1997. The same was also true for leaf and total forage yields. The amount of forage biomass harvested from the legume component and incorporated into the soil varied from 1.7 - 1.8 ha sup(-1) in 1995 and 1- 1.25 t ha sup(-1) in 1998. Generally no appreciable yield reduction was observed during the years when Lablab was concurrently grown with maize and the yield variation observed between those plots which received the recommended land of fertilizer and those to which chopped biomass of Lablab was incorporated was not wide indicating the possibility of using this strategy to ensure stability of both grain and forage production for maize based system of Bako area and other areas having similar environments.