Excessive rainfall anomalies during the dry season (harvest period) and their impact on rainfed crop yields in Ethiopia

Rainfall variability contributes to crop failures and an increase in food insecurity in regions vulnerable to climate change, such as East Africa. Although the impact of growing period rainfall variability on crop yields has been well studied in East Africa, characterizing rainfall anomalies during the crop harvesting season and their effect on crop yields remains unexplored. Here, we evaluated the phenomenon of unexpected excessive rainfall anomalies during the dry season (RAD) and its impact on cereal crop yields in Ethiopia from 1996 to 2022. For the evaluation, we used the Climate Hazards group InfraRed Precipitation with Stations (CHIRPS), in situ meteorological stations, and crop yield data. Our results showed that the frequency and severity of RAD events vary across Ethiopia. On average, RAD events occurred 14 times during 1992-2022. Among regions in Ethiopia, Gambela, Southern Nations, Nationalities, and Peoples', and Oromiya experienced the highest frequency and severity of RAD events. During RAD events, most cereal crops showed an average reduction in yields compared to yields during normal rainfall events in the dry season. However, significant (P < 0.05) reductions in crop yields occurred mainly in the Oromiya and Southern Nations, Nationalities, and Peoples' regions. Maize showed the highest yield reduction compared to other cereal crops. Our findings underscore the need for regularly monitoring RAD events to mitigate their impacts on food security in the region.