Abstract: Based on the measured soil moisture data of the top 20cm soil layer of eleven agro-meteorological stations in the North of the Yangtze River in Anhui Province from 1980 to 2000,the simulation models on the soil moisture for different seasons under different precipitation conditions were established.The critical precipitation(P0) in the time-interval for forecasting was defined,and four independent variables were cited such as initial soil relative moisture(θ′0),total precipitation(P),accumulated temperature(∑T>0) and hours of sunshine(∑R) in the time-interval for forecasting.As P>P0,P was modified to Ln(P).The simulated values of the relative soil moisture were validated by comparing with the observed values for both 2005 and 2006.It showed a highly coherence.Models could be used to forecast soil moisture in the field in North of the Yangtze River in Anhui Province.

Key words: Relative soil moisture, Relative soil moisture, Statistic, Simulation