Validation of the EPIC model using a long-term experimental data on the semi-arid Loess Plateau of China

The EPIC model has been widely used in the world as an effective decision support tool in irrigation allocation and scheduling. However, there are still some uncertainties surrounding the soil water estimation of the EPIC model. In this paper the EPIC model was validated for soil water estimation in a semi-arid region, based on a set of long term experimental data on the Loess Plateau. Validation results showed that: (1) The EPIC model can be used as an effective tool in the semi-arid area, to research the dynamic change of soil water in different rainfall years and in different soil layers for different cropping systems, with reasonable validation for its input database. (2) Calculating equations for potential evapo-transpiration and soil moisture, the amount and variance of seasonal rainfall as well as the soil parameters such as sand content, silt content, loam content and bulk density affected the precision of simulated soil water by the EPIC model. A decision of these factors should be made wisely when its database is going to built up for the EPIC model in a special environment.