Analysis of Drought Conditions and Their Impacts on Maize Yield

Understanding how climate extremes such as drought’s impact on crop yield are critical in ensuring future global food security. Two major drought indices; the Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI) for accumulation period of 1-, 3-, 6-, and 12-month were analyzed. Consequently, three Drought Monitoring Indicators (DMI) i.e., Drought Duration (DD), Drought Severity (DS), and Consecutive Drought Months (CDM) were computed from the drought indices. Spearman correlation between the individual climatic variables and maize yield indicated that potential evapotranspiration has the highest correlation and total precipitation for November explained about 61% of the variation in observed yield. The comparison between the 2 indices showed that the SPEI is more correlated and more sensitive to maize yield than SPI. Furthermore, the result indicates that maize yield is negatively affected by drought across the entire study area. The yield is most sensitive to 3-month accumulated drought coinciding with maize growing season (r = 0.59; p <0.05). The result further indicates that about 35% in maize yield variation can be accounted for by drought. This study, illustrate the spatial patterns of drought showing locations with drought severity, frequency, and intensity which has the potential to influence crop yield. The result suggests that management strategies that allow for optimal water use within the first 1-3-month will be most effective for sustainable maize production within the study area. This study provides bases for the implementation of an early warning system that focuses on drought impact on crop yield.