A Monte Carlo simulation to investigate fertilizer use and productivity of maize production in Tanzania

Maize is Tanzania’s principal staple crop, yet yields remain well below the agronomic potential of 3.5 t/ha due to limited and inefficient fertilizer use. This study assesses the effects of three fertilizer strategies (no fertilizer, organic fertilizer, and inorganic fertilizer) on maize productivity across Tanzania’s agroecological zones (AEZs). Using nationally representative data from the 2019/2020 National Sample Census of Agriculture, a non-parametric stochastic simulation model was applied to estimate yield distributions under two scenarios: probabilities of yields below 1.0 t/ha, above 2.0 t/ha, and between 2.0 and 3.5 t/ha. Farms without fertilizer face the highest risk of yield failure, while inorganic fertilizer substantially reduces low-yield probabilities and modestly increases the likelihood of high yields across most AEZs. Organic fertilizers provide moderate gains but rarely enable high-end productivity. Fertilizer impacts vary spatially, underscoring the need for region-specific strategies. The findings support Tanzania’s ASDP II and SDG 2 objectives by informing targeted productivity-enhancing interventions.