Evaluation of Daisy model for simulating the two-dimensional water movement in the soil and the sunflower yield

Using the simulated models can help the users to approach the attitude of applying different managements. Therefore, identifying and evaluating the models in this case is non-negligible. The Daisy model is one of the most comprehensive models for simulating of the water-soil-plant-atmosphere system whose performance was evaluated in this study. Based on the data of three irrigation treatments: Full irrigation (FI) and deficit irrigation (DI) at 75% and 55% level during two years, the conditions were defined in the model and the crop submodel was made for the sunflower. The yield parameters were measured and compared with simulated values based on R2, NRMSE and efficiency coefficients (EF). The model was validated based on the results of full irrigation treatments and the model performance was also evaluated based on irrigation treatments. The results showed that Daisy has a very acceptable performance by the mean of NRMSE for the leaf area index(LAI), height(H) and dry matter(DM) and water content estimated 0.059, 0.036, 0.031 and 0.064 and the mean EF were equal to 85.67, 33.82, 91.5 and 67 percent. the rang of R2 was 0.799-0.999. The significance of the difference between simulated and observed values was compared by T-test for the paired samples in SPSS. The total results showed that the model could simulate the full irrigation better than the deficit irrigation. In general, Daisy could be used as an applied model to simulate the conditions of irrigation projects under different management.