The CERES-Rice model has been used to simulate rice plant responses to CO2 enrichment and climate change and to explore adaptation options. However, it was developed decades ago, contains many empirical equations, and the model parameters have little plant physiological meaning and have to be determined under specific conditions. Further, it does not incorporate recent knowledge about how crops respond to changing climates and management practices. For example, it uses an empirical Radiation Use Efficiency approach to calculate plant growth. There are evidences that these empirical equations could result in a wrong direction of interactions among involved factors. This study improved on the original model by using biochemical photosynthetic equations to develop a new approach. The revised model had better agreement than the original version between simulations and observations of rice growth and yield of three cultivars collected from four experiments with treatments of N applications combined with irrigations conducted in Thailand and the Philippines. The simulated rice yield showed increases or decreases in 2020, 2050, and 2090 depending on the climate scenarios and treatments. This study illustrated the potential for the revised model to improve rice yield gap analyses to find a solution that improves farmers’ yields, such as changing transplanting dates under different environmental conditions. However, further evaluation of the revised model is needed under changing climate conditions, such as with data from FACE experiments. The revised CERES-Rice model performs better than the original and can be used for forecasting rice yield and determining optimal management practices.

1. INTRODUCTION

2. THE CERES-RICE MODEL REVISIONS

2.1 Fraction of sunlit and shaded leaves

2.2 Radiation absorption

2.3 Calculation of day-length and hourly weather data

2.4 Leaf photosynthesis

2.5 Respiration

2.6 Spatial integration and temporal integration

3. COMPILING THE PROGRAM

4. TEST OF THE REVISED MODEL

4.1 Experimental data 4.2 Future climate data

5. RESEARCH RESULTS

5.1 Rice yield and growth under current environmental conditions

5.2 Rice yield and growth under future climate and CO2 conditions

5.3 Application of the CERES-Rice model

6. CONCLUDING REMARKS