Drought damage sensitivity assessment under continuous drought using a crop transpiration drought index and a three-phase disaster loss curve

Continuous droughts occur frequently worldwide, and drought damage sensitivity assessment is a core link in drought risk management. This study uses crop experiments in the Huaibei Plain to simulate maize growth processes under various continuous drought by a localized AquaCrop model. Then, a crop transpiration drought index (CTDI) is proposed, and three-phase drought damage sensitivity curves between the drought intensity (DHI) and yield loss rate are established. Thereupon, the drought damage sensitivity of maize yield formation is assessed. The results show that the CTDI considers the actual crop water supply‒demand balance and growth response under continuous drought, thereby it can accurately identify the real agricultural drought status. Furthermore, slight deficit irrigation can be carried out at the seedling stage, and moderate deficit irrigation can be implemented at the milking stage for maize. Nevertheless, severe drought during the seedling stage should be avoided to ensure the survival of plants. Moreover, when plants have suffered from drought during the seedling stage, an adequate water supply should be guaranteed at the jointing stage. Therefore, drought damage sensitivity curves have practical implications for rapid drought loss estimation and decision-making for drought reduction strategies in the Huaibei Plain.