Inter-Comparison of CERES-Rice and Apsim-Oryza for Climate Change Impact Assessment at Farmers Field.

Inter-comparisons of models is an important method to evaluate the models performances. Models differ with one another in their simulations procedure and making. CERES-Rice and ORYZA are two popular models that are widely used in several countries. To compare the performances of two crop models, two year field experiments were conducted with three sowing dates and four varieties during 2009-10 at Agronomic Research Farm, University of Agriculture, Faisalabad-Pakistan. For intercomparisons of crop models, two year field data were compared to models outputs. After comparison at experimental farms, models were used to simulate the 155 farmers’ field yield. The crop management and yield data were collected through the survey of rice growing districts of Punjab. For intercomparison and evaluation of models Root Mean Square Errors (RMSEs), R² and D-stat (index of agreement) were calculated. In simulations of Oryza, RMSEs were 202 kg ha⁻¹ and 770 kg ha⁻¹ of yield for 2009 and 2010, respectively. The value for d-stat (0.59) for 2010 was good as compared to d-stat (0.35) value of 2009. While in case of CERES-rice, RMSEs were 199 kg ha⁻¹ and 222 kg ha⁻¹ of yield for 2009 and 2010, respectively. At rice farms, CERES-rice simulated yield of 155 farms with an R² of 0.52, a RMSE of 425 kg ha⁻¹, and a d-stat of 0.78, while for Oryza-model the R² was 0.42, the RMSE was 440 kg ha⁻¹, and the d-stat was 0.78. Overall, results of study showed the good performance of both crop models.