Evaluation of AquaCrop vs SALTMED Models to Estimate Crop Yield and Soil Salinity

Application of simulation models is a strategy in agricultural water usage management and in predicting the effect of saline water on crop yield and as well on soil salinity. Recently, FAO has introduced a new version of AquaCrop model through which one can calculate the effect of irrigation water salinity on crop yield and on soil salinity. In the present study, AquaCrop and SALTMED models were evaluated under alternate application of saline vs fresh water for maize as a forage crop. The required field experiments were carried out in nine treatments (under different conditions of using non-saline vssaline water) in Karaj region. In SALTMED model, R2 values were obtained 0.843 and 0.733 for soil salinity and crop yield, respectively, while these values amounted to 0.758 and 0.846 respectively, for AquaCrop model. Relative error in AquaCrop model varied between 2.9 and 30.8% in crop yield estimation and between 5.9 and 45.8% in soil salinity estimation. The relative error in SALTMED model ranged from 0.9 to 24.7% to estimate crop yield while ranging from -2.2 to 38.2% in estimation of soil salinity.