This study investigates the impact of package adoption of inorganic fertilizers and improved maize seed varieties on yield among smallholder households in Kenya. We used a quasi-experimental difference-in-differences approach combined with propensity score matching to control for both time-invariant and unobservable household heterogeneity.
Our findings show that inorganic fertilizers and improved maize varieties significantly increase maize yields when adopted as a package, rather than as individual elements. The impact is greater at the lower end of the yield distribution than at the upper end. A positive effect of partial adoption is experienced only in the lower quartile of yield distribution. The policy implication is that complementary agricultural technologies should be promoted as a package, and should target households and areas experiencing low yields.