Study on the Response of Rice Yield and Water Consumption to Climate Change in the South China—A case study of the Nanliujiang Catchment

Abstract

Rice growth is very sensitive to climate factors such as precipitation, air temperature and carbon dioxide concentration. The change in the global climate has potential risks to rice production and agricultural irrigation in the South China. In this study, the SWAT model is used to analyse the changes of rice yield and water consumption in the Nanliujiang Catchment in Guangxi Province. A method of subbasin delineation is used for the model setup to reflect the differences between irrigation areas in yield and water use of rice, and the simulation values of rice yield, evapotranspiration and runoff are validated. Finally, the outputs of HadGEM2-ES under three RCPs (RCP2.6, RCP 4.5, RCP 8.5) are fed to the SWAT model to study the effects of future climate change on rice yield and water consumption in the Nanliujiang Catchment. The results showed that the SWAT model is an ideal tool to simulate rice growth and water consumption; the yield of irrigated rice under three RCPs decreased by 2.3%, 0.67% and 3.4%, respectively, and the yield of rain-fed rice decreased by 2.7%, 1.0% and 3.7%, respectively. Under the three RCPs, the production water consumption of irrigated rice is reduced by 4.5%, 4.6% and 6.9%, respectively, and that of rain-fed rice is reduced by 3.6%, 2.5% and 5.1%, respectively. This study can provide a scientific basis for the formulation of relevant policies to cope with future climate change in the study area.