How accurate is the SALTMED model in simulating rapeseed yield and growth under different irrigation and salinity levels?

Crop modeling is a valuable tool in agricultural research for studying the response of plants to environmental parameters. The purpose of this study was to assess the precision of the SALTMED model in simulating the growth and yield of rapeseed under different levels of irrigation water and soil salinity in a semi-arid region. The normalized root mean square error (NRMSE), Nash–Sutcliffe efficiency coefficient (EF), and index of agreement (d) for grain yield simulation were 0.052, 0.917, and 0.96, respectively, at the calibration stage of the model, and 0.054, 0.881, and 0.96, respectively, at the validation stage. The results showed that the accuracy of the model was satisfactory and acceptable in simulating the grain yield and dry matter of rapeseed, as well as the soil water content and soil salinity. Therefore, the results of this study can be used for modeling the effect of climate change and abiotic environmental parameter variations such as terrain, climate, and soil and water properties on agricultural production systems. However, there were some discrepancies observed between the measured and estimated data for soil water content simulation. Some possible defects in the model theory that may contribute to its inaccuracy were discussed.