Evaluation of SWAP Model in Simulating Yield of Wheat and Fodder Maize in Simultaneous Condition of Water and Salinity Limitations

In this study, evaluation of SWAP model in simulating crop yield, water and salt movement in soil were investigated in the wheat- fodder maize cultivated units. The research was conducted in the Voshmgir network, Golestan province. The crop yield, soil humidity and moisture data in different times of agriculture year of 2007-2008 were measured. The measured and simulated data were analyzed. The statistical comparison which was done base on the root mean square error (0.49 ton/ha), correlation coefficient (0.85) and modeling efficiency (0.84), for estimating the total crop dry matter of wheat and fodder maize showed that the estimated crop yield by SWAP agree well with observed values. Suitable values of statistical indexes obtained for estimating soil moisture and soil salinity by SWAP, indicated that considering suitable bottom boundary condition in SWAP which has important role on water and solute balance in soil, has affected on estimation of soil moisture and salinity considerably.