Improvement of the CERES-Rice model using controlled experiments and a Meta-analysis

Abstract

Extreme heat has occurred more frequently in recent years and will intensify in the future, and this change has serious impacts on rice (Oryza sativa L.) yields. Thus, it was crucial to evaluate its influence on rice yield reductions. Recent papers have shown that a lack of experimental data makes it difficult for most crop models to capture the impacts of heat stress. Therefore, this paper explored how to improve the performance of crop models under extreme heat stress based on the Decision Support System for Agrotechnology Transfer (DSSAT) CERES-Rice model. This study primarily focused on (i) quantifying spikelet fertility based on daily temperature and durations derived from controlled experiments, (ii) improving the performance of the CERES-Rice model under extreme heat stress, and (iii) simulating historical and future rice yields using the improved model. Specifically, a meta-analysis method was utilized to build a new heat stress function between spikelet fertility and temperature and heat day duration with high realization. Subsequently, independent artificial controlled experiments at two sites were proposed to calibrate and validate the CERES-Rice model. The results showed a higher R2 (> 0.739) and a lower RMSE that was reduced by 38~68% after incorporating the new heat stress function in the CERES-Rice model compared with that of the original model. Furthermore, a historical simulation (1980–2010) demonstrated that an improved CERES-Rice model could better capture rice yield in response to extreme heat. Using an ensemble of five climate model datasets and four Representative Concentration Pathways (RCPs), the analysis of the projected future (2020–2099) rice yield showed that the rice yield reduction caused by high temperature was considerable; however, the rice yields were overestimated by 34% and 18%, respectively, at the two sites. Some regions rarely affected by heat are likely to experience yield reductions in the future due to climate change.