Parameterization and Evaluation of the SSM-iCrop2 Model for predict the cotton growth and yield in Iran

Cotton is the most important fiber crop in Iran and as well as the world. The acreage of cotton is about 80,000 ha in Iran. The present study aims to determine the parameters of the SSM-iCrop2 model and evaluate the ability of the model to simulate cotton growth and yield in different regions and environmental conditions of Iran. Different aspects of crop growth are organized as sub-programs including phenological development, leaf area changes and dry matter production and distribution. Soil water balance sub-program is entered in the model to simulate changes in soil water and determination of stress severity. Simulation by the model is done on a daily basis and requires data related to atmosphere, soil and crop management. The model was tested for Iran conditions. To estimate the coefficients and evaluation of the model, data obtained from experiments conducted in various areas of the country were used. The model was evaluated using independent data following estimation of genetic parameters. The results indicated acceptable efficiency of the model in prediction of daily simulation including days to maturity (RMSE=8.4 day, CV=6.5 %) and seed cotton yield (RMSE=56.6 g/m2 and CV=13.9 %) for parameterization and seed cotton yield (RMSE=50.4 g/m2, CV=12.8 %) for evaluation. Also, the results showed that RMSE and CV values for simulation of yield, Evapotranspiration, and used water were respectively (77.6, 12.9%), (150.3 and 16%) and (178.5 and 19.6%) in major cotton production areas of Iran. These results indicate that estimates for variables are acceptable.