Simulation of Soil Salinity and Maize Yield under Saline Water Application Using SWAP and SALTMED Models

Using simulation models is a strategy in agricultural water use management and in predicting effect of saline water on crop yield and soil salinity. In this study, soil salinity and forage maize yield were evaluated under alternating application of saline water with fresh water using SWAP and SALTMED models. For this purpose, field experiments were carried out under different treatments of fixed and cyclic use of saline (salinity levels of 3.5 and 5.7 dS.m-1) and non-saline water (non-saline water application in every one, three, and five saline water application) in Karaj region. Electrical conductivity of the non-saline water was 0.4 dS.m-1. Crop yield and soil salinity were simulated via both models and compared with their corresponding measured values. In SWAP model, coefficient of determination (R2) values were 0.754 and 0.587 for soil salinity and crop yield, respectively, while these values were 0.758 and 0.846, respectively, for SALTMED model. Absolute Relative error (|RE|) of SWAP model varied between 1.7% and 26.3% in crop yield estimation and varied between 2.5% and 32.4% in soil salinity estimation. Also, |RE| of SALTMED model ranged from 0.9% to 24.7% in estimation of crop yield, and ranged from 2.2% to 38.2% in case of soil salinity estimation.