Solar irrigation has emerged as a critical solution for enhancing agricultural productivity in arid and semi-arid regions of Ethiopia's highlands, where water scarcity is prevalent. The methodology involves a comparative analysis of data from 50 randomly selected farms equipped with solar irrigation systems versus those using conventional water pumps over two growing seasons. Data on yield, input costs, and profitability were collected and analysed using a mixed-effects model. Solar irrigation systems demonstrated an average increase in crop yields by 20% compared to traditional methods, primarily in crops like maize and beans. The findings suggest that solar irrigation significantly reduces operational costs for farmers while increasing their profitability. The mixed-effects regression model estimated a mean effect size of the solar system on yield improvement at 19% with robust standard errors around ±2%. Given these results, policymakers should prioritise the deployment of solar irrigation systems to smallholder farmers in Ethiopia's highlands, considering both financial and environmental benefits. The empirical specification follows $Y=\beta_0+\beta^\top X+\varepsilon$, and inference is reported with uncertainty-aware statistical criteria.