Synergistic effects of maize defoliation and common bean relay cropping in Western Ethiopia

Abstract Background Maize defoliation is practiced to enhance crop management by improving light penetration, nutrient allocation, controlling weeds, and providing supplementary feeds for livestock. A rapid decline in soil fertility and low crop yields associated with maize‐based monocropping has prompted the recent introduction of maize common bean relay‐cropping, though information on its productivity remains limited. Thus, a field experiment was conducted to evaluate suitable common bean varieties for maize‐based relay cropping systems, evaluate the effect of leaf defoliation at dough stages on the yield of common bean and maize components, and compare the yield performances of maize and common bean in relay cropping versus sole cropping systems. Factorial combinations of two maize varieties (BH546 and Gibe‐3), two common bean varieties (Nasir and Anger), and five different leaf defoliation intensities of maize were laid out in a randomized complete block design (RCBD) with three replications, and one sole maize and common bean variety was used as a control. Results Maize grain yield was increased with decreasing leaf defoliation intensity and vice versa. The highest maize grain yield (10,000 kg ha −1 ) was recorded from relayed maize with the Anger bean variety defoliated below ear placement at Bako. In contrast, the highest maize grain yield (1010 kg ha −1 ) was obtained from all maize parts, which were not removed until harvest maturity at Uke. The highest net benefit (2650.6 and 2916.9 USD ) was recorded from all maize removal as green cobs and stover at the time of the dough stage, respectively, at the Bako and Uke sites. Considering maize defoliation, all leaf removal below ear placement resulted in higher net benefits of 2294.8 USD . Conclusion These findings concluded that the removal of all maize parts as green cobs and maize defoliation below ear placement is more profitable and recommended for the farmers in the study areas.