Growing-Season Drought and Gross Revenue Losses in Maize Production in the Colombian Caribbean

Drought limits maize production in regions exposed to climate variability; however, estimates of agricultural and economic impacts depend on the precipitation data used to characterize drought. This study evaluates the relationship between growing-season drought and historical maize yields and estimates corresponding losses in production and gross income in the Colombian Caribbean. Municipal-level data from 191 municipalities across different agricultural cycles were analyzed using the Standardized Precipitation Evapotranspiration Index (SPEI) at 3- and 6-month accumulation scales, derived from the CHIRPS v3.0, GPCC v2025, and MSWEP v2.8 precipitation products. Fixed-effects panel models estimated yield responses, accounting for municipality, cycle, year, and department-specific temporal trends. Drought severity, derived from SPEI03 during the growing season, was negatively associated with maize yield in the CHIRPS and GPCC models (estimated coefficients of −0.042 and −0.039, respectively), while the MSWEP estimate was close to zero. The corresponding cumulative production losses, calculated using the models, were 76.2 thousand metric tons for CHIRPS and 71.6 thousand metric tons for GPCC, equating to estimated gross revenue losses of 115,550 million COP and 106,500 million COP, respectively, at constant 2024 prices. In contrast, the MSWEP model yielded much lower estimates: 2400 metric tons and 3.76 billion COP, with confidence intervals that included zero for both results. The negative associations between yield and precipitation under the CHIRPS and GPCC frameworks generally persisted across several alternative drought definitions, although they weakened when the growing season was shifted one month later. These results show how sensitive estimated drought-related agricultural losses are to crop choice and precipitation data, and support presenting crop-specific estimates and uncertainty when assessing climate-related risks to traditional maize production.