Evaluation of CERES-Wheat model for wastewater irrigation and fertilizer interactions in wheat cultivation

Abstract. Irrigation with wastewater may alter the fertilizer requirements of crop cultivation. Crop simulation models can provide inexpensive and less time-consuming means of evaluating the optimum crop production under varying management conditions. In this study, Crop Environment Resource Synthesis (CERES)-Wheat model was used to simulate agricultural management practices wastewater irrigation and fertilizer applications, and their interactions were studied. Experimental data under irrigation with different blends of wastewater and freshwater and with and without fertilizer application were used. Crop management, weather, and soil data of a wheat cultivar (Triticum aestivum L. cv. Shatabdi) for three growing seasons were also collected. To assess the model performance, two deviations statistics- root means square error (RMSE) and forecasting efficiency (EF) and one test statistics such as coefficient of determination (R2) were calculated for observed and simulated growth and yield parameters. Results revealed that the simulated growth and yield parameters corresponded well with the observed values for the treatment– irrigation with raw wastewater and fertilized condition compared with irrigation with freshwater and unfertilized condition. Better model performance for the grain yield simulation was observed during the validation than the calibration period having RMSE, EF and R2 indicators within the permissible limits. The calibrated model could be used for operational purposes for predicting yield, optimizing resource use, and taking various management decisions.