The Monitoring Forecasting Assessing Decision-Making Service System of Soil Moisture Stress of Winter Wheat and Its Application in North China Region

During the growing season of winter wheat, the precipitation amount in the North China Region, where the water resource is seriously insufficient, amounts to only 100-250mm and can not meet the demand of winter wheat.This paper demonstrated the geographic distribution of the difference between the water demand and supply of winter wheat in different climatic years (guaranteed probability of precipitation during growth period of winter wheat at 75%, 50% and 25% respectively). The water differences were calculated with a field water balance equation.To determine proper irrigation time and amount, and to ensure stable and high production of winter wheat with limited water resource, Monitoring Forecasting Assessing Decision-Making Service System (MFADSS) of soil moisture stress of winter wheat was constructed on the basis of experimental research on the relationship between soil moisture and winter wheat. The techniques and functions of each subsystem are also demonstrated.The system was applied to more than 3 million ha. of winter wheat in 90 counties of the North China Region. Accuracy of the decision of the irrigation reached about 95 per cent. The water-saving and high yield function of the system was shown clearly. Obvious social, economical and ecological benefits were obtained during 1990-1995 under the support of the government.