Impact of climate change on grain yield and its trend across Guanzhong region

Climate change dominated by warming has a significant impact on grain yield. From an examination of grain yield, climatic yield and climate potential productivity (CPP), this paper systematically analyzed the response of grain yield to climate change in Guanzhong, Shaanxi, one of China's main food-producing areas. Datasets were climate variables at 8 meteorological stations, grain yield statistics from Guanzhong region during 1983-2016, and the precipitation and temperature simulation results from 4 global climate models of the Intersectoral Impact Model Intercomparison Project for 2021-2050. Mutation analysis, trend analysis, and sensitivity analysis were all used in the study. The results showed that the annual average temperature of Guanzhong region was increasing significantly at the rate of 0.05 ℃·a^-1, and a significant increase in the maximum temperature was contributing most to this trend. Meanwhile, annual average precipitation showed a decreasing trend at the rate of -1 mm·a^-1 but was not significant. During 1983-2016, the average annual grain yield of Guanzhong region was 3 599 kg·hm^-2. Although showing fluctuations, it increased at the rate of 57.17 kg·hm^-2·a^-1 (P < 0.001). There was a positive correlation between the climatic yield and temperature in many parts of Guanzhong. The increase in temperature had promoted an increase in climatic yield in Guanzhong to a certain extent, but not significantly (the increase was 0.85 kg·hm^-2·a^-1 and P>0.05). The CPP of Guanzhong region ranged between 7 000-12 000 kg·hm^-2 over 34 years. Due to the fluctuations in temperature, the average CPP after 1995 was higher than that before 1995, which meant that the change in CPP after 1995 was the main driving source of the increasing trend of CPP during the whole study period. During 2021-2050, the average CPP of Guanzhong region under RCP 2.6 scenario will be higher than that of RCP 6.0. However, the CPP decreases under the RCP 2.6 scenario but increases under the RCP 6.0 scenario. There is a plenty room for promotion of climate resources used by crops in Guanzhong region, and climate change has had a positive effect on the grain yield in Guanzhong, but this effect will not persist.