In this study, the growth periods of summer maize was divided into seedling, booting and flowering-grain stage. Based on the simulation results of AquaCrop model, the drought loss sensitivity of summer maize in different growth periods was analyzed. The sensitivity curves fitting using the soil moisture content of the effective root zone and the fixed soil layer both indicated that the booting stage was the most sensitive to water stress, which was the critical period for irrigation, followed by the seedling stage. Compared with the curve parameters fitted by the soil water content of the effective root zone, the maximum Biomass Loss Rate fitted by the fixed soil layer water content was higher and the Drought Hazard Index corresponding to the disaster-causing point and the turning point in the seedling stage moved backward. Accordingly, the best irrigation opportunity may be missed and resulting in a large reduction in production if an irrigation scheme is formulated at the seedling stage based on the sensitivity curve of summer maize fitted by the water content of a fixed soil layer. This study also adapted the Jensen model to calculate the normalized moisture sensitivity coefficient and studied the response of final crop yield to water deficit in different growth periods. The results showed that the normalized moisture sensitivity coefficients at the seedling stage, booting stage, and floweringgrain stage were 0.251, 0.524, 0.224 respectively, which verified the rationality and feasibility of using the cumulative loss of biomass to measure the final yield loss.

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