EVALUATING THE PERFORMANCE OF HYDRUS-1D BY CALIBRATING AND VALIDATING THE MODEL RESULTS FOR VERTICAL MOVEMENT OF WATER AND SALTS USING SALINE IRRIGATION WATER UNDER GREEN HOUSE CONDITIONS

Evaluation of the effects of irrigation water quality and quantity on soil salinity and drainage fluxes are necessary to plan and manage irrigation schemes under different soil and climatic conditions. Different analytical and numerical models have been developed to predict water flow and solute transport in the vadose zone. Model results can be very helpful in decision making to plan and manage different irrigation and fertilization schemes. HYDRUS-1D model simulates water flow and solute transport in vadose zone soil. In this study, HYDRUS-1D software package was used to evaluate the data obtained from the greenhouse pot experiment. The model was able to successfully simulate drainage flux, soil water storage, root zone salinity, as well as yield reductions due to salinity stress based on root water uptake. Observed and HYDRUS-1D predicted values were compared using different statistical parameters and our results showed a close agreement between the observed and model predicted values. This indicates the applicability of HYDRUS-1D to simulate water movement, and storage as well as salinity buildup in the soil profile.