Bundling solar-based irrigation and vermicompost using a living lab approach in Ethiopia: impacts on crop yield, soil moisture and rural livelihoods

This study in Ethiopia's Rift Valley tested two hypotheses: integrating solar-based irrigation with vermicompost would considerably increase crop yields and soil moisture retention; and smallholder farmers would perceive solar irrigation as contributing positively to livelihood diversification, household income, food security, livestock feed availability and environmental co-benefits. Participatory on-farm trials and key informant interviews were conducted to address these research questions. The trial used cabbage and pepper as test crops and employed a randomized complete block design with three treatments: Treatment 1/Control (solar-based irrigation with farmers' current practices); Treatment 2 (Treatment 1plus 4 t ha−1 of vermicompost); and Treatment 3 (Treatment 1 plus 8 t ha−1 of vermicompost). The first hypothesis was confirmed: bundling vermicompost with solar-based irrigation increased yields (pepper +78.6%, cabbage +14.3%) and improved soil moisture retention. These yield gains were economically viable, with benefit–cost ratios ranging from 0.38 to 2.46 across sites. The second hypothesis was supported: 88% of farmers adopted 2–5 new crops (75% citing improved water access), shifting toward vegetables, fruits and fodder, with reported gains in income, food security, nutrition, dry-season fodder and environmental co-benefits. Solar irrigation therefore delivers greater agronomic and livelihood benefits when integrated with vermicompost, supporting the scaling of bundled interventions.