The Effects of Climate Change on Irrigation Requirements of Winter Wheat and Summer Maize in Henan Province

Based on the meteorological data of Henan province from 1961 to 2012,the effects of rainfall and potential evapotranspiration on crop irrigation requirement were analyzed.The results showed that the average irrigation requirement was 59.8~334.3mm for winter wheat,and 14.5~131.2 mm for summer maize in Henan province,both increasing form south to north.The irrigation requirements of winter wheat and summer maize in most stations had a downside,because of the increasing rainfall and decreasing potential evapotranspiration.Rainfall was the primary factor which influenced the irrigation requirement,and the amount and distribution in time of rainfall had a notable impact.However,the impact could not be ignored in spite of its weaker influence for potential evapotranspiration than rainfall.Irrigation requirement showed a larger fluctuation under the mutual effects of rainfall and potential evapotranspiration.