Calibration and Evaluation of the IXIM Model for Simulation of Growth and Yield of Maize (SC 704) in Gorgan Climatical Conditions

The use of modeling in research and farm management is developing every day. IXIM is a new model and its evaluation has begun by researchers around the world. For calibration and validation of the IXIM model, two experiments (each in two years) were carried out at Agricultural Research Station of Gorgan, Golestan province . The model was calibrated using optimum irrigation treatments along with no stress of drought condition in 2012 and two treatments of the second experiment in 2007. The Evaluation of the model was done using planting date treatments of spring experiment (2008), planting date and deficit irrigation of experiments in 2012 and 2013. The evaluation results of the model indicated that the model simulated phenological stages (anthesis and maturity occurrence) with high accuracy at different sowing dates and different irrigation regimes. The highest root mean square error for anthesis belonged to 6 July with 2.24 days, therefore, this model could be used in the field programing management. Evaluation results in spring sowing (2008) and summer sowing dates (2012 and 2013) revealed that the model simulated dry matter and yield of maize with a high accuracy. Also, the model simulated reduction of dry matter and seed yield in different levels of irrigation (except for full stress) and had enough accuracy base on model’s statistical indices. The model had not enough accuracy in simulation of leaf area index (LAI) and evapotransopiration in irrigation treatments. Referring to results of this experiment, this model could be used in Gorgan climatic conditions to simulate growing stages, dry matter and grain yield of maize (SC704) in different sowing dates and different irrigation regimes.