Soil moisture simulation of cerealalfalfa rotation system in the aridland Loess Plateau based on EPIC model

Soil moisture is a key factor affecting the crop production in the Loess Plateau. Erosion Productivity Impact Calculator (EPIC) model has been widely applied to effectively simulate soil water throughout the world since it has been established. The longterm experimental data from foragecereal rotation land (alfalfaalfalfaalfalfaalfalfapotatowinter wheatwinter wheatwinter wheat) was used to evaluate the accuracy of simulated soil water by EPIC model. This study showed that mean correlation coefficients between simulated and observed soil moisture in alfalfa land, winter wheat field and potato field were 0.756, 0.973 and 0.790 respectively, and mean value of RMSE were 0.028, 0.011 and 0.023 m/m respectively, which indicated that the distribution of simulated soil water from top soil layer to the depth soil layer was generally consistent with distribution of observed soil water. This study suggested that EPIC model could be used to simulate the change and distribution of soil water of alfalfacereal rotation land in the Loess Plateau of china, and that the simulation precision of soil moisture could be improved by building reasonable soil database and proper equation of root distribution.