Analysis of drought conditions over major maize producing provincs of South Africa

In this study, two commonly used drought indices; the Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI), were analyzed in order to understand the impacts of drought on maize yield over four main maize production provinces of South Africa. The drought was characterized using three Drought Monitoring Indicators (DMI) i.e., the Drought Duration (DD), Drought Severity (DS), and Consecutive Drought Months (CDM). The results indicate that maize yield is significantly affected by drought across the entire study area, although the impacts are localized. A comparison between the SPI and SPEI with maize yield suggests that the SPEI is more correlated and sensitive to maize yield than the SPI. The maize yield is particularly most sensitive to the 3-month SPEI. The 3-month accumulation period coincides with maize growing season (r = 0.59; p < 0.05). The analyzed results illustrate that drought affects maize yield by up to 35% across the study area. Additionally, results depict inherent spatial patterns of DMIs demonstrating that there are differentiated drought impacts across the maize production areas. The results suggest that management strategies that allow for optimal water use within the first 1- and 3-month periods would be most effective for sustainable maize production within the study area. This research study contributes towards a deeper understanding of the characteristics of drought and their impacts on maize crop production. Such knowledge is important in e.g., the formulation of drought monitoring and prediction strategies including drought early warning systems.