Assessment of changing pattern of crop water stress in Bangladesh

The Palmers’ crop moisture index (CMI) was used to assess the changing pattern of crop water stress of Bangladesh. Daily rainfall and temperature data for the period 1961–2010 recorded at eleven meteorological stations distributed across the country were used to estimate the time series of CMI. The run theory was used to estimate a set of metrics from CMI to define different characteristics of annual and seasonal crop water stress. The Mann–Kendall trend test was used for the assessment of the significance of the changes in crop water stress indicators at 95% and 99% level of confidence. The results showed that crop water stress in Bangladesh has increased in recent years, particularly in the pre-monsoon season. The annual and pre-monsoon cumulative crop water stress index was found to increase significantly in 5 and 4 out of 11 stations, respectively. As the major portion of total crop in Bangladesh is grown during pre-monsoon season, increasing crop water stress can affect agriculture and food security of Bangladesh. The set of matrices developed in this study can be to understand the different characteristics of water stress and adopting necessary mitigation measures in the context of climate change.