Simulating maize yields when irrigating with saline water, using the AquaCrop, SALTMED, and SWAP models

• Field experiments were carried out for forage maize production under cyclic and constant use of saline and non-saline water.
• AquaCrop, SALTMED and SWAP models were calibrated and validated using the experimental data.
• The SALTMED and SWAP models performed better than AquaCrop model in estimating maize yield under salinity stress.

Using simulation models is a strategy in agricultural water use management and an effective way in predicting effect of irrigation management and water quality on crop yield provided that the accuracy of the models is proved. In this study, three different models, i.e. AquaCrop, SALTMED and SWAP, were evaluated under application of the frequency of saline water with non-saline water in order to estimate forage maize yield. For this purpose, field experiments carried out for nine treatments (under different condition of using non-saline and saline water) in Karaj region, Iran. All three models were calibrated and validated based on the experimental data. The coefficient of determination (R2) between observed and simulated data of maize yield were obtained 0.733, 0.846 and 0.594 for the AquaCrop, SALTMED and SWAP models, respectively. Absolute relative error values varied between 2.9 and 30.8% for AquaCrop, 0.9 and 24.7% for SALTMED, and 0.3 and 19.3% for SWAP model. The SALTMED and SWAP models had better performance than the AquaCrop model in estimating maize yield under salinity stress.