Optimizing maize–bean cropping systems for sustainable intensification in southern Ethiopia

Abstract

Declining productivity and scarcity of cultivable land in smallholder systems call for exploring sustainable intensification options to increase productivity. Field experiments were conducted at five sites (Sites 1-5) of the Sidama region, southern Ethiopia, in 2018 and 2019 to determine the effects of cropping systems on maize (Zea mays L.) and common bean (Phaseolus vulgaris L.) productivity. The intercropping of common bean with maize at varying planting times (simultaneous, relay) and number (frequency) of legume intercropping (once or twice) per growing season were compared with monocultures of the components in randomized complete block design with four replications. Cropping system affected the agronomic parameters (pod number plant −1 and 100-seed weight) of common bean, more so than maize.Specifically, the results revealed that cropping systems affected both maize and bean yields, although the magnitude of the effect varied with sites. The highest maize yield was recorded in fertilized monoculture maize at Sites 1, 2, and 5, and in relay and sequential bean intercropping at Sites 3 and 4, respectively. Moreover, the highest bean yields were obtained in double common bean monoculture whereas, the lowest yields were recorded in relay intercropping. The total land equivalent ratio (LER) ranged from 1.2 to 1.8 and partial LER of maize was higher than that of the common bean. Sequential intercropping (Sites 1, 2, and 5) and relay intercropping (Sites 3 and 4) were economically more beneficial than the other cropping systems.Therefore, farmers could benefit more from maize-bean intercropping systems than monocultures in areas where maize is a staple crop.Abbreviations: 100-SW, hundred seed weight; ATER, area time equivalent ratio; Bn, common bean monoculture; Bn+Bn, double common bean monoculture; LER, land equivalent ratio; M+Bn, simultaneous common bean intercropping with maize; M+Bn+Bn, sequential common bean intercropping with maize; M+BnR, relay common bean intercropping with maize; M+F, maize monoculture with fertilizer; MAI, monetary advantage index; M-F, maize monoculture without fertilizer.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Evaluation of the Role of Legumes in Crop Rotation Schemes of Organic or Conventionally Cultivated Cabbage

“…Besides the increased yield in subsequent crops [30] and soil N enhancement that could lead to reduced dependency on N fertilizers, the incorporation of legumes into cropping systems can be beneficial to a wide range of ecological and human health perspectives. Indeed, the ecosystem services of legumes range from reductions in greenhouse gas emissions [31], plant-parasitic nematode and weed management [32,33], biodiversity conservation [34], sustainable intensification, which is of paramount importance for smallholder agriculture viability [35], and increased feed and forage self-sufficiency [36]. Moreover, the increased use of legume-derived products (e.g., protein) can lead to more healthy and sustainable diets [37,38].…”