Study on Characteristics of Winter Wheat Water Requirements in 45 years in Shanxi

[Objective] The purpose of this research was to study the response mechanism of ecological water requirements of winter wheat with climate change.[Method] Based on the meteorological data and the agrometeorological observation data in 1961-2005 at the meteorological and agrometeorological observation station of winter wheat producing counties in Shanxi,winter wheat water requirements in five winter wheat regions divided by phenology law in Shanxi were computed by using Penman-Monteith formula FAO recommended and Crop coefficient,and the changes of winter wheat water requirements and shortage in different growth period and interannual variability were analyzed.[Result]The results showed that winter wheat water requirements in Shanxi were between 436.1 mm and 446.0 mm,gradually increased by the light drought-drought-severe drought region.The winter wheat water requirements intensity from heading stage to grainfilling stage was the biggest,the most important period was tillering stage before winter and from the jointing stage to the grainfilling stage.Ecological water shortage was about 260 mm,the ratio was more than 60%,the water shortage ratio during green-turning stage and jointing stage was biggest.On the background of climate warming of global and China,the trend of regional winter wheat water requirements was descend and shortage was increase.Water requirements declined obviously in the last century 80′s,so the water shortage rate was small.Crop water shortage was serious in the last century 90′s when the climate became warming and drying obviously.[Conclusion] Paying more attention to water utilization in the key periods of wheat growing and optimizing the irrigation system is very improving for improving winter wheat yield.