Fertilizer subsidies, rainfall variability, and maize productivity among smallholder farmers in East Africa

Drawing on multi-wave panel data from over 5,000 households in the World Bank’s Living Standards Measurement Study–Integrated Surveys on Agriculture microdata across Ethiopia, Tanzania, Uganda, and Malawi, this study investigates how fertilizer subsidies interact with rainfall variability to influence maize productivity among East African smallholders. Using a difference-in-differences framework applied to household-level panel data combined with FAOSTAT indicators, the analysis compares yield responses of subsidy beneficiaries and non-beneficiaries under contrasting rainfall conditions. Results show that fertilizer subsidies significantly raise maize yields in normal rainfall years but provide limited benefits during drought or excessive precipitation, highlighting the conditional effectiveness of input support. Cross-country differences reveal that program design, especially targeting efficiency and the timing of subsidy delivery, strongly shapes yield outcomes. The findings emphasize the importance of integrating fertilizer support with climate information services, soil health interventions, and adaptive policy mechanisms. This study contributes empirical evidence for designing climate-smart and context-sensitive subsidy systems aimed at enhancing resilience and food security in East Africa.