Simulation of Rice Yield under Different Cultivation Methods and Irrigation Regimes Using DSSAT Model

Water shortages driven by climatic and anthropogenic factors demand efficient planting and irrigation practices for sustainable agriculture. Water-saving methods such as Direct Seeded Rice (DSR) and System of Rice Intensification (SRI) can enhance water productivity in rice significantly. Crop models can be used to simulate the performance of these methods under different irrigation regimes, aiding in the identification of the best management practices to enhance water productivity in rice. In this study, the grain yield under DSR, SRI and Conventional Puddled Rice (CPR) cultivated in Trans-Gangetic plains of India was simulated using the Decision Support System for Agrotechnology Transfer (DSSAT) model. Two-year field study was conducted at the research farm of ICAR-Indian Agricultural Research Institute, New Delhi, with first year data used for model calibration and second year data for model validation. The prediction error for grain yield during validation was observed to be 28%, 10% and 11% for DSR, SRI and CPR, respectively. Model validation for DSR, SRI and CPR showed nRMSE and R² values of 21% and 0.79, 6% and 0.88, 8% and 0.72, respectively. Additionally, Nash-Sutcliffe efficiency >0.93 and d>0.98 across all the methods indicate model’s reliability under diverse cultivation methods. The validated DSSAT model can be effectively used to support the selection of appropriate rice planting methods to enhance the water productivity of rice in the Trans-Gangetic Plains of India.