Impact assessment of climate change on rice yields using the ORYZA model in the Sichuan Basin, China

Abstract

Understanding how different climate factors interact and impact rice yield is essential for effective agricultural management strategies and policies. However, the potential impacts are less clear at the regional scale. In this work, we used the latest version of the ORYZA crop model to evaluate the impacts of climate change and carbon dioxide (CO2) on rice yields in the Sichuan Basin of China based on high‐quality agricultural experimental, meteorological and soil data and the incorporation of future climate data generated by five general circulation models (GCMs) under three newly released representative concentration pathway (RCP) 2.6, 4.5 and 8.5 scenarios.Considering climate change alone, our modelling results indicated a continuing rice reduction for most stations by 2–17, 4–28 and 1–43% under the RCP2.6, 4.5 and 8.5 scenarios, respectively; when considering the CO2 fertilizer effect, rice yields increased by 3–10, 4–13 and 5–20% under the RCP2.6, 4.5 and 8.5 scenarios, respectively. However, for most stations, the CO2 fertilizer effect could not completely offset the negative impacts of climate change on rice yields. In addition, temperature and radiation were the main climate factors that cause yield variation by affecting the rice maturity periods (DAE), spikelet fertility factor (SPFERT) and spikelet number (NSP). The uncertainty arising from the climate models was less than 10% under the RCP2.6 scenario, 15% under the RCP4.5 scenario and 20% under the RCP8.5 scenario, indicating good consistency in rice yield simulations. These findings offer insight into the physiological mechanisms and the degree of climate change impacts on rice yields, thus informing appropriate adaptive strategies for rice planting in the Sichuan Basin, China.