Simulation of Wheat Cultivar Response to Irrigation Treatments using of CERES-Wheat Model

Problem statement: Crop models are used as tools for enhancing agricultural research through the identification of gaps in knowledge as well as by providing support for decision making in agricultural planning. Approach: In order to evaluation of CERES-Wheat model on five cultivars of winter wheat under Karaj weather condition in Full Irrigation (FI) and Terminal Irrigation at Flowering (TIF) an experiment conducted in form of split plot in based on randomize complete block design with four replicate in research field Islamic Azad university of Karaj branch in 2009. Results: Two irrigation levels located in main plot and cultivars as sub plot. In this study simulation of some traits such Grain Yield (GY), Leaf Dry Weight (LDW), Plant Height (PH), Biomass (B), Leaf Number per plant (LN) and Leaf Area Index (LAI) evaluated by use of CERES-Wheat model. According to simulation results, model was successful in simulation of traits whole under two irrigation treatments. Rate of R² was low in regression curve of measured versus simulated for traits of LAI and LDW. Model simulated GY with high vigor for both irrigation conditions. Conclusion/Recommendations: Variation dimension of R² in FI and SI obtained 80.89-80.91 and 80.88-81.01, respectively. The variation dimension of Wilmot coefficient (d) FI and TIF is 0.73-0.75 and 0.61-0.72, respectively. Simulation precise in TIF is lower than FI. We can after evaluation and calibration model by means of experimental replication and reduce of Root Mean Square Error (RMSE) as a result used for research objective management programming in Karaj zones. We proposed for increasing predicting precise by model must be determinate genetic coefficient correctly and soil data and weather data supplied in experimental filed.