Spatiotemporal Risk Assessment of Agricultural Drought Disasters in Aman Rice Growing Season in Western Bangladesh

Agricultural drought (AGD) is among the most well-known and devastating natural disasters on the globe, wreaking havoc on rain-fed agricultural countries, including Bangladesh. The Penman-Monteith (P-M) equation and a crop coefficient model were used to assess the spatial and temporal variability of the rainfed Aman rice season in western Bangladesh between 1980 and 2017. To reveal the spatiotemporal changes in drought during the Aman rice growing phases in western Bangladesh, the crop water deficit index (CWDI) was developed for AGD evaluation. In addition, based on risk formation theory, this study intends to construct a drought disaster risk index (DDRI) for rain-fed Aman rice for various growth phases. The results revealed that the crop water deficit was found to be the lowest in the vegetative phase and the highest in the ripening phase. Among all the areas, the CWDI was highest in the Rangpur and Rajshahi regions. Drought risk was relatively higher in the late phase of the crop growing period due to high temperatures, inadequate rainfall, climatic characteristics, and geographical setting. Precipitation, evapotranspiration, and a rapidly changing climate all contributed to variations in crop water deficits in the study region. Crop yields were reduced in all sub-areas. Spatially, higher values of DDRI were observed in the northern areas of western Bangladesh. New adaptive measures and policies are essential to improve the adaptability and mitigation capacity of AGD risk. Finally, this study suggests that farm-level adaptation, cropping patterns, and drought-resistant crops should be introduced in the study region.