Vulnerability of crop water footprint in rain-fed and irrigation agricultural production system under future climate scenarios

Agriculture is the sector most sensitive to climate change. It is of great significance to explore the response characteristics of crop water footprint (WF) in rain-fed and irrigation agriculture to climate change for guiding agricultural production. This study coupled and downscaled the meteorological data from 31 global climate models (GCMs) under two Representative Concentration Pathways (RCPs) in China, and used crop growth model AquaCrop in large scale to quantify the changes in yield and WF of maize in China from the 2030s to the 2090s. The Monte Carlo Method was used to calibrate the crop parameters in AquaCrop model, which improved the accuracy and spatiotemporal resolution of the crop model. Results showed that precipitation and temperature would increase in most regions in China, which was more obvious in the RCP8.5 scenario. Meanwhile, climate change resulted in larger crop evapotranspiration (ETc) for maize in the north than south. In the future, the increase of ETc in Southwest China would be relatively larger, while that in Northwest China would decrease. Maize yield would generally increase in most regions except for central China, where illustrated that increases in the north was greater than in the south. In terms of irrigation strategies, full irrigation could mitigate the reduction in maize yield caused by climate change. However, increasing irrigation would have fewer benefits to maize yield in humid regions compared with arid and semiarid regions in China. In addition, increasing irri-gation could not greatly reduce the WF of maize in humid regions. Due to different climatic and hydraulic soil characteristics in each region, the effects of climate change and irrigation strategies on WF of maize would vary in different regions. This study provided irrigation strategies guidance to mitigate the adverse effects of climate change on agricultural production and its water use.