Review on Impact of Small-Scale Irrigation on Smallholder Farmers’ Income in Ethiopia: A Systematic Review and Meta-Analysis

Abstract Agriculture is the engine of the Ethiopian economy. It is the largest employer, accounting for 65% to 70% of the total labor force engaged in agriculture. Over the last three decades, the Ethiopian government has formulated and implemented agricultural development- led industrialization and small- scale irrigation expansion as strategies to improve rural households’ income. Several studies on the impact of small- scale irrigation on smallholder farmers' income have been conducted over the last decade and a half in the country. However, they have focused on location- specific contexts and have methodological differences that limit the generalization of the overall effect of small- scale irrigation interventions on smallholder farmers' income in Ethiopia. Therefore, this review aimed to generalize the findings nationwide using a rigorous methodology by combining several primary studies from all parts of the country. The review adopted a systematic review and meta- analysis approach. Based on the inclusion and exclusion criteria, 26 primary studies were included. However, two primary studies were excluded due to higher outliers in effect size. The majority of the studies were conducted in the Oromia regional state (50%), and the Amhara regional state was the second most common (16. 16.67%). The remaining 33. 33.33% were conducted in five regional states. Most of the primary studies employed the propensity score matching model for impact estimation (79. 79.17%), and only two (8. 33%) primary studies employed the endogenous switching regression model. The rest of the primary studies (12. 12.51%) used double hurdle, Heckman, and logit models. The meta- analysis result showed an overall effect size of 74%, with a standard deviation of 0. 42, a minimum of 0. 0.17, and a maximum of 1. 56. The meta- analysis output revealed that smallholder farmers who participated in small- scale irrigation earned about 74% more income on average than users of rainfed agriculture. Generally, small- scale irrigation improved farmers’ income, labor productivity, land intensity, and the welfare of rural households. This review suggested expanding small- scale irrigation in all parts of the country, based on available technologies and water potentials, to improve rural households’ welfare.