Trends and determinants of fertilizer use by nutrient type in Tanzania: insights from trade, production, macroeconomic, and policy perspectives

Improving fertiliser use in Tanzania is critical for enhancing agricultural productivity and achieving food security. This study examines the determinants and trends of agricultural fertiliser use in Tanzania from 2000 to 2024, disaggregated by nutrient type: Nitrogen (N), Phosphate (P₂O₅), and Potash (K₂O). Utilised descriptive statistics and a fixed effects (FE) model with Driscoll–Kraay standard errors to evaluate how trade, production, and policy variables influence fertiliser consumption. Results indicate that total fertiliser use increased from 82,000 tons in 2000 to 431,000 tons in 2024, with nitrogen-based fertilisers constituting over 60% of total application. Although domestic production rose moderately from 15,000 to 65,000 tons, fertiliser imports dominated the supply structure, contributing over 85%, while exports remained below 10,000 tons, yielding an export–import ratio under 0.2. Econometric estimates revealed that fertiliser imports (p < 0.01), domestic production (p < 0.05), agricultural credit (p < 0.05), and subsidy interventions (p < 0.01) significantly promote fertiliser use. Conversely, fertiliser prices (p < 0.05) and exports (p < 0.10) exert negative effects, while GDP per capita (p < 0.10) exhibits a mild positive influence. Robustness and endogeneity tests confirm the reliability of these findings. Fertiliser use has increased in Tanzania but remains highly import-dependent. Strengthening domestic production, credit access, subsidies, and balanced nutrient use is vital for sustainable agricultural growth.