Abstract: Based on the daily meteorological data of Zhengzhou in 2003-2004 when the precipitation in winter wheat growth season was of somewhat shortage, the water deficit at different growth stages of winter wheat was analyzed, and the effects of limited irrigation on the water use efficiency (WUE) of winter wheat were studied with the DSSAT-CERES Wheat model after parameter calibration. Four treatments were designed, i.e., no irrigation, irrigation once, twice, and three times with limited (100 mm) water, and water management response indicators (WMRIs) were introduced as an integrative evaluation reference for the design of optimal irrigation schemes. Limited irrigation alleviated water stress to some extent, and promoted the grain yield and WUE. Comparing with no irrigation, limited irrigation increased the grain yield by 13.1%-73.3%. Irrigation twice showed the best effect in promoting the water absorption and utilization by winter wheat, followed by irrigation three times, and irrigation once. The WUE was the highest when watering at wintering and grainfilling stages, while the utilization efficiency of irrigation water reached the highest when watering at elongation stage. Therefore, elongation stage was the best phase to actualize limited irrigation.

Key words: Trichogramma confusum, T.pretiosum, Corcyra cephaloica, Interspecific competition