Abstract: Temporal and spatial distribution characteristics of crop water requirement and irrigation water requirement are the bases for determining the irrigation quota in different regions.The objective of this study is to analyze irrigation water requirement of winter wheat in growth stages to improve the efficiency and productivity of irrigation water in Jijingjin region,and to ensure the food security.Based on data from 20 meteorological stations during 1961 to 2010 and phonological data of winter wheat during 1980 to 2009,using the Penman Monteith method recommended by FAO,the spatial pattern of the reference crop evapotranspiration was calculated and water requirement in different growth stages for winter wheat were analyzed.And the irrigation water requirement distribution of winter wheat during different growth stages in Jijingjin region during the recent 50 years were analyzed using the crop water surplus deficit index.The results showed that the effective rainfall of winter wheat during the different growth stages and the whole growing period was increasing,while the water demand of winter wheat during the different growth stages and the whole growing period showed a decreasing trend.There was a significant shrinking tendency during heading to milk ripe stage.The change of the effective rainfall and water demand would promote the evolution on agricultural irrigation.To meet the need for the growth of winter wheat,the total supplementary irrigation amount was around 291 to 381mm.More irrigation water requirement of region was in the city of Cangzhou and Hengshui.Some specific differences also existed in supplementary irrigation water condition and short term change.Respectively,the period of the more supplementary irrigation was jointing to heading stage which declined from the center of Cangzhou city and heading milk stage which increased from the north to the south.The conclusions were important to be applied to the monitoring of water change and provide theoretical basis for strategies of guiding the irrigation timing and amount.

Key words: Winter wheat, Phenology period, Crop water surplus deficit index, Irrigation water requirement, Spatial pattern