Abstract: The paper calculated the water surplus and deficiency of the whole growth period,also the water surplus and deficiency of the early and middle and late growth stages,analyzed the spatial distribution and timing change trend of the water surplus and deficiency,explained the reasons of the water surplus and deficiency change,based on yearly data of precipitation,temperature,relative humidity,sunlight hours,wind speed during winter wheat growth period,from 48 weather stations in winter wheat areas of Hebei Province from 1965 to 2007.Three results have been gotten.First,in the whole growth period,the largest areas of water surplus and deficiency were the southeastern region of Hebei Province,and the change rate of water surplus and deficiency was less.In the middle stage,the water surplus and deficiency was most serious and the change rate was less.In the early and late stages,the water surplus and deficiency was less than in the middle and the change rate was more.Second,the water surplus and deficiency had decreasing trend in all growth periods which were caused by the change of water requirement.The third,main reasons of water requirement decreased were due to reduced sunshine duration and wind speed decreases in the whole and early growth periods,and the reasons of water requirement decreased were due to wind speed decreases and increased relative humidity in the late growth periods.

Key words: Winter wheat, Water surplus and deficiency, Change trend, Correlation

CLC Number: 

• S152.7