Modeling rice development and field water balance using AquaCrop model under drying-wetting cycle condition in eastern China

Various crop growth models have been developed to simulate the crop development and were used to assess the effects of climate, cultivation and irrigation methods. To evaluate the feasibility of water driven model-AquaCrop in simulating crop development, production and field water balance in paddy soil under drying - wetting cycle condition, the model was calibrated and validated based on data during 2012-2013 rice season in Eastern China. Results showed that the accuracy of this model in simulating canopy cover (CC), evapotranspiration (ET), biomass, yield were generally acceptable, with the root mean square of error (RMSE) less than 10% for CC, 1.0 mm for ET, 0.61t ha(-1) for biomass and with relative deviation of 3.6% for yield. Meanwhile, AquaCrop tended to overestimate CC, biomass and yield slightly during the midseason. Yet, its performance in simulating soil moisture content was not as good as expected. It tended to underestimate soil moisture with a RMSE of 14.81%, but overestimated the water deficit coefficient (Ks). The method for Ks calculation incorporated in AquaCrop should be revised for rice under drying-wetting cycle condition.