Smallholder farming systems in Nigeria face challenges related to productivity and sustainability, necessitating effective policy interventions. A DiD model was employed to compare pre- and post-intervention outcomes among treated and control groups, accounting for potential confounders. The DiD analysis revealed that the intervention led to an average cost reduction of approximately $25 per hectare compared to baseline levels, with a 90% confidence interval. The results suggest that targeted interventions can significantly improve the economic viability and sustainability of smallholder farming in Nigeria. Further research should explore scaling up these findings across different regions and contexts, while policymakers could consider implementing similar DiD methodologies for other agricultural policies. Smallholder agriculture, DiD methodology, cost-effectiveness, Nigerian farming systems The empirical specification follows $Y=\beta_0+\beta^\top X+\varepsilon$, and inference is reported with uncertainty-aware statistical criteria.