Maize Yield in Tanzania-Mainland: Can Farms Exceed the 3.5 t/ha Potential? A Multivariate Empirical (MVE) Simulation Approach

Abstract

This study evaluates the probability that maize yields exceed a policy-relevant threshold of 3.5 t/ha across Tanzania Mainland’s agro-ecological zones using data from the 2019/20 National Sample Census of Agriculture. Six farming systems were analyzed, combining local and improved seed types with three fertilizer regimes (none, organic, and inorganic). A Monte Carlo Simulation approach was applied to estimate zone-specific yield distributions and associated production risks. The results show that farms using improved seeds with  inorganic fertilizers (Farming_5) consistently achieved the highest probabilities of exceeding 3.5 t/ha and the lowest risk of yields falling below 1.5 t/ha across all zones. Improved seeds combined with organic fertilizers (Farming_4) also generated moderate yield gains, particularly in livestock-dense zones such as the Northern Highlands and Lake Zone, although performance remained lower than inorganic fertilizer-based systems. Strong regional heterogeneity was observed, with the Southern Highlands exhibiting high responsiveness to improved input use, while the Eastern–Coastal Zone showed persistently low yield probabilities under all farming systems. Based on these findings, the study identifies three actionable policy priorities: (i) scale up access to improved seeds and inorganic fertilizers in high-potential zones; (ii) promote integrated nutrient management, including organic fertilizers, in livestock-rich areas with limited fertilizer access; and (iii) operationalize agroecology-specific input and extension strategies through local government and extension systems. The study provides evidence to support not only Tanzania’s Seed Sector Development Strategy 2030, but also contributes to SDG 2 (Zero Hunger) by informing targeted, risk-aware maize intensification policies.