Spatiotemporal Analysis of Drought and Impact on Millet Production across North Darfur State Using Standardized Precipitation Index (SPI) and Reconnaissance Drought Index (RDI)

Abstract

Drought severely affects the agricultural sector, and it has been made worse by the global warming climate scenario. Drought has been chiefly studied globally and often overlooked at the local or regional scale. Therefore, accurate and timely characterization of agricultural drought at a local or regional scale is essential for developing adaptation and mitigation strategies. This study analyzed the spatiotemporal trend of drought events and their impact on millet production in North Darfur State, Sudan, from 1981 to 2020. The Standardized Precipitation Index (SPI) and the Reconnaissance Drought Index (RDI) for the 3-month (June-August), 6-month (June-November), and 9-month (June-February) timescales were used to assess the drought events. The drought-yield relationships were assessed using the Pearson correlation coefficients (r). Results indicate that the RDI index is more sensitive to variabilities than the SPI index for detecting drought trends. Drought events affected North Darfur over broad spatial extents, particularly in 1989, 1990, 1992, 1999, and 2001; an extreme drought event was in 2003. The correlation coefficient analysis (r) between the SPI and RDI, and the standardized variable of crop yield (SVCY) for millet grain yield showed a strong agreement between them. Moderate to extreme reductions in millet crop yield occurred in 1992, 1999, 2001, and 2003, corresponding to the moderate to extreme drought indicated by the RDI. Severe crop losses were in Kabkabiya and Umm Kadadda. This study contributes to understanding future drought trends and formulating more effective policies and management of resources.

Keywords: North Darfur State, drought trends, millet yield, RDI, SPI, standardized variable of crop yield.