Abstract: This study selected Wudaogou hydrological and water resources experimental station in Huaibei plain as a study area. The applicability of Hydrus-1D model in simulating the phreatic evaporation process of Winter Wheat in Huaibei plain was studied, and the law of phreatic evaporation during the growth period of winter wheat under different precipitation conditions was also discussed. The results suggested that the phreatic evaporation process simulated based on Hydrus-1D model was in high consistent with the phreatic evaporation process based on water balance and Bouchet complementary relationship theory. The correlation coefficient was 0.82, the absolute error was 0.04 mm/d, and the relative error was 12.4%. The total amount of phreatic evaporation during the growth period of winter wheat was affected by the precipitation amount, while higher phreatic evaporation was observed when the precipitation amount was higher. According to the phreatic evaporation of winter wheat at each growth stage, filling stage-maturity stage > heading stage-filling stage > jointing stage-heading stage > returning to green stage-jointing stage. The results could provide a theoretical basis for formulatina reasonable irrigation schedule in Huaibei plain.

Key words: Hydrus-1D model, winter wheat, soil moisture, phreatic evaporation, Huaibei Plain