Growing Season Characteristics under Varying Rainfall Probabilities in the Blue Nile Region, Sudan

Abstract

Rainfed agriculture is central to food security and livelihoods in Sudan, particularly in the semi-humid zones such as the Blue Nile Region where rainfall patterns dictate crop success. This study analyzes growing season characteristics under five rainfall probability levels (20%, 40%, 50%, 60%, and 80%) using 51 years (1971–2021) of rainfall and evapotranspiration data. Monthly rainy days were categorized by intensity, and seasonal rainfall amounts were analyzed across probabilistic classifications. Results indicate that the wet season (20% probability) experiences the highest rainfall and the longest growing season (154 days), while the dry season (80%) is limited to 111 days. Rainfall distributions follow a bimodal pattern with predominance of low-intensity events and limited moderate rainfall. Pre-season and post-season rainfall have significant implications for field accessibility, crop quality, and harvest efficiency. The study highlights the need for early field preparation, improved crop varieties, and conservation agriculture practices to mitigate climate risks and optimize productivity in the face of increasing variability.