Simulating the rice yield change in the middle and lower reaches of the Yangtze River under SRES B2 scenario

Abstract

As one of the most important crops in China, rice accounts for 18% of the country’s total cultivated area. Increasing atmospheric CO 2 concentration and associated climate change may greatly affect the rice productivity. Therefore, understanding the impacts of climate change on rice production is of great significance. This paper aims to examine the potential impacts of future climate change on the rice yield in the middle and lower reaches of the Yangtze River, which is one of the most important food production regions in China. Climate data generated by the regional climate Model PRECIS for the baseline (1961–1990) and future (2021–2050) period under IPCC SRES B2 scenario were employed as the input of the rice crop model ORYZA2000. Four experimental schemes were carried out to evaluate the effects of future climate warming, CO 2 fertilization and water managements (i.e., irrigation and rain-fed) on rice production. The results indicated that the average rice growth duration would be shortened by 4 days and the average rice yield would be declined by more than 14% as mean temperature raised by 1.5 °C during the rice growing season in 2021–2050 period under B2 scenario. This negative effect of climate warming was more obvious on the middle and late rice than early rice, since both of them experience higher mean temperature and more extreme high temperature events in the growth period from July to September. The significance effect of the enhanced CO 2 fertilization to rice yield was found under elevated CO 2 concentrations in 2021–2050 period under B2 scenario, which would increase rice yield by more than 10%, but it was still not enough to offset the negative effect of increasing temperature. As an important limiting factor to rice yield, precipitation contributed less to the variation of rice yield than either increased temperature or CO 2 fertilization, while the spatial distribution of rice yield depended on the temporal and spatial patterns of precipitation and temperature. Compared to the rain-fed rice, the irrigated rice generally had higher rice yield over the study area, since the irrigated rice was less affected by climate change. Irrigation could increase the rice yield by more than 50% over the region north of the Yangtze River, with less contribution to the south, since irrigation can relieve the water stress for rice growing in the north region of the study area. The results above indicated that future climate change would significantly affect the rice production in the middle and lower reaches of the Yangtze River. Therefore, the adverse effect of future climate change on rice production will be reduced by taking adaptation measures to avoid disadvantages. However, there is uncertainty in the rice production response prediction due to the rice acclimation to climate change and bias in the simulation of rice yield with uncertainty of parameters accompanied with the uncertainty of future climate change scenario.