THE IMPACT OF CLIMATE CHANGE ON WATER DEFICIT AND PRODUCTION OF WINTER WHEAT IN NORTH CHINA

The water deficits in different development stages and the whole growing season of winter wheat in North China under climate change scenarios are analyzed based on the meteorological data,crop phenomenon and soil hydrological data of 30 weather stations.The results show that if the temperature rises,the potential evapotranspiration and crop maximum transpiration will in-crease 8%-10%;the actual evapotranspiration in whole growing season will increase about 1%-2%;and it seems to decrease in spring.The refore the water deficit status would deteriorate.Theamount of water deficit in whole growing season would increase 14%-30%,and the water deficit isolines might shift southward with maximum shift distance being 190 km.As a result the climatic suitability of winter wheat would change,and the variation rate of yield reduction will be 8%-20% of the present value which results in the declining output values.The irrigation amount would increase 25%-33%,and the agriculture cost might increase owing to additional irrigation.