Projection of the irrigation requirement of potatoes under climate change in Northwest Bangladesh

Abstract

Abstract Climate change not only affect water resources but also water requirement and it is important to quantify the changes in irrigation requirements to ensure water and food security. In this study, CropWat model was used to estimate the crop water and irrigation requirement of potato in Northwest Bangladesh for two future time periods. Climate scenarios were prepared from five global circulation model outputs for moderate (RCP 4.5) and rapid (RCP 8.5) change following downscaling and bias correction techniques. An increase in reference crop evapotranspiration (ETO) during the potato growing months, especially during the mid-season and late-season stages of potato was observed. The increase in ETO was higher under rapid climate change. A future possible increase in potential crop water and irrigation requirement of potato under climate change was detected for fixed growth duration of potato. There was much variation among the different model estimates. However, the potential crop water requirement during 2080s was higher than that during the 2050s. Results indicate that rapid climate change in the short-run may cause a relatively smaller increase in the irrigation requirement compared to moderate climate change, but rapid climate change in the long-run would definitely cause a very high increase in irrigation requirement.