EiA2030-ex-ante/ssa-yield-uncertainty

Site-specific maize yield response and risk-adjusted fertilizer profitability across Sub-Saharan Africa under joint climate and price uncertainty # SSA Yield Uncertainty — Risk-Adjusted Returns to Fertilizer Across Sub-Saharan Africa **A spatially explicit modeling framework that estimates site-specific maize yield response to fertilizer and the risk-adjusted profitability of fertilizer investment across Sub-Saharan Africa, under joint climate and price uncertainty.** > **🚧 Code release pending.** The analysis behind this repository is still being finalised. This repository currently documents *what* we model and *how* the pipeline is structured. The full R/Python pipeline, configuration, and final result maps will be published here once the working paper is complete. Watch/star the repo to be notified. --- ## 1. What is this project, in one paragraph? Fertilizer recommendations in Sub-Saharan Africa are usually built on *expected* yield response at *average* prices. But smallholders farm rainfed land with erratic rainfall and sell into volatile markets — what matters to them is not the average return but the **distribution** of returns, including the chance of losing money. This project builds, for every maize-growing pixel in Sub-Saharan Africa, that full distribution: it combines agronomic trial data, soil and climate layers, and predicted local input and output prices, then jointly simulates rainfall and maize-price realisations with a spatial copula Monte Carlo engine to map **where, and at what application rate, fertilizer is a good bet — not just a good average**. By separating climate risk from price risk and mapping high- and low-response zones, the framework supports precision targeting of subsidies, extension, insurance, and complementary interventions. ## 2. Why this matters - **Fertilizer use in SSA is strikingly low** — around **17 kg of nutrients per hectare** against a global average of ~135 kg/ha, and well short of the 2006 Abuja Declaration target of 50 kg/ha. - **Profitability, not awareness, is the binding constraint in much of the region.** Fertilizer is expensive at the farm gate …