Experimental Investigation of Soil Evaporation and Evapotranspiration of Winter Wheat Under Sprinkle

Sprinkler irrigation is one of the typical irrigation technologies used for the winter wheat-summer maize double cropping system in the North China Plain.To evaluate the evapotranspiration(ET) of winter wheat under sprinkler irrigation in Beijing area,field experiments were conducted in growing seasons through 2005-2008,in the experimental station located in Tongzhou County,Beijing,China,with different irrigation depths.Results indicated that a relatively large variation of soil water content occurred within 0-40 cm soil layer.The seasonal ET of winter wheat generally increased with increasing irrigation amount,while the seasonal usage of soil water had a negative relationship with irrigation amount.Soil evaporation(Es) was about 25% of winter wheat ET during the period from reviving to maturity.Es increased while Es/ET decreased with increasing irrigation amount.Sprinkler irrigation scheduling with relatively large irrigation quota and low irrigation frequency can reduce Es and promote the irrigation water use efficiency.