Assessment of maize-legume intercropping as a way for sustainable intensification in mixed farming systems for smallholder farmers in Jimma, Ethiopia

Ethiopia is one of the targeted countries in the SI-MFS project to represent highland MFS in East and Southern Africa. The agriculture sector is a source of livelihood for more than 80% of the population and contributes 45% to the GDP in Ethiopia, showing the importance of agriculture in the country (Dendir & Simane, 2019). Similar to other developing countries, MFS, especially animal production, plays an important role in supporting the livelihood of the population as Ethiopia has the largest livestock population (Worqlul et al., 2022). Crop production in Ethiopia is cereal-dominated (Belachew et al., 2022). Most crops are cultivated in the rainy season, from mid-June to mid-September, as almost all grain production by smallholders is rainfed (Belachew et al., 2022; World Bank Climate Change Knowledge Portal, 2021). The main calorie requirements are provided by maize (Zea Mays), teff (Eragrostis tef), sorghum (Sorghum bicolor L. Moench), wheat (Triticumaestivum L.), and barley (Hordeum vulgare) among cereals, and enset (Ensete ventricosum) provides the most among roots and tubers in the Ethiopian diet (Abate et al., 2015). Legume integration, specifically intercropping of legumes with maize was proposed as a potential technical innovation of the SI-MFS project in Ethiopia. Integration of legumes into the farming systems brings multiple benefits with different system levels, i.e., food system level, production system level, and cropping system level (Stagnari et al., 2017). Firstly, at the food system level, legumes are rich in protein and slow-release carbohydrates as well as minerals and vitamins. This makes them especially important in the diet of people with low income in developing countries (Tharanathan & Mahadevamma, 2003). Secondly, at the production-system level, legumes increase soil fertility by fixing atmospheric nitrogen. They also release high-quality organic matter in the soil and facilitate the circulation of soil nutrients. These features make legumes especially useful in low-input farming systems. Additionally, legumes also help reduce greenhouse gas emissions by replacing synthetic fertilizers and contributing to carbon sequestration. Thirdly, at the cropping-system level, the integration of legume species diversifies farming systems which are based on a few major species. This gives benefits such as breaking the cycle of pests and diseases (Stagnari et al., 2017). Besides, early ground cover by legumes reduces raindrop impact and soil water evaporation, therefore contributing to soil moisture conservation (Namatsheve et al., 2020). However, intercropping also has some potential challenges. Firstly, the design of an appropriate intercropping system, which is a prerequisite of successful intercropping, is quite complex. This is because the optimal intercropping design depends on the context such as the interactions between the component species, the available management practices, and the environmental conditions (Gaudio et al., 2021; Mahmoud et al., 2022; Qiao et al., 2022). Secondly, intercropping is generally more labour intensive as it requires extra work or more time-taking practices such as preparing and planting the seed mixture, weeding, and harvesting (Lithourgidis et al., 2011). For example, in the case of weeding, more careful operation was needed in the mixture of crops and with typically smaller companion crops (Rusinamhodzi et al., 2012). Therefore, careful assessment is needed to know the feasibility of intercropping in the targeted area as the viability of intercropping highly depends on each context. Whereas intercropping can increase the productivity per unit of land, it is necessary to well understand the context, namely farming systems, to assess if the practice fits the local area due to the context dependency of the feasibility of intercropping. And this assessment was not yet done thoroughly with the perspective of legume integration in Jimma, where trials of SI-MFS project in Ethiopia locate. Therefore, the overall research objective of this study is: describing the mixed farming systems in Jimma, Ethiopia, and assessing the feasibility of integration of legumes in the area by intercropping with maize for sustainable intensification. This is specified by five research questions (RQ) as follows. 1. RQ1. How are the current farming systems in Jimma characterized and how do they vary among farmers? What does it imply for the legume promotion? 2. RQ2. What is the trend of crop production in terms of area and the history of legume cultivation over the last 10 years? 3. RQ3. What are the opportunities and constraints that the farmers see in cultivation of legumes on their farms? 4. RQ4. What are possible advantages and disadvantages of intercropping legumes with maize for farmers in Jimma? 5. RQ5. What are the potential socio-technical innovation bundles to stimulate adoption of legume innovation?