Simulated impact of elevated CO2, temperature, and precipitation on the winter wheat yield in the North China Plain

We studied the separate and interacting effects of changes on CO2, temperature, and precipitation on the growth and yield of winter wheat in five representative sites on the North China Plain using a crop yield simulation model, known as the Environmental Policy Integrated Climate (EPIC) model. The daily-maximum/minimum temperature and precipitation data obtained using a comprehensive climate model, that is, the Model for Interdisciplinary Research On Climate (MIROC), based on the scenario A1B for 2085-2100 were calibrated using a novel statistical algorithm and used as the climate change scenario in the EPIC model. The results indicated that an increase in the CO2 concentration of up to 680 ppm would increase the winter wheat yield by 24.8 and 43.1 % in irrigated and rainfed fields, respectively. Increases in the average maximum temperature of up to 4.9 degrees C and the average minimum temperature of up to 4.8 degrees C would increase the crop yield by 5.2 % in irrigated condition, but decrease it by 7.2 % in rainfed condition. By contrast, the yield of irrigated field decreased by 5.5 % when the annual precipitation increased by 317 mm, whereas that of rainfed field increased by 30.1 %. The interacting effects of simultaneous increases in the parameters were also simulated. With a constant CO2 level (370 ppm), the EPIC model predicted that the effects of temperature and precipitation on yield would be -0.9 and -1.9 % for irrigated and rainfed fields, respectively. When the CO2 level increased to 680 ppm, the interacting effect of elevated CO2, temperature, and precipitation increased the average yield by ca 23.1 % with the irrigated treatment and by ca 27.7 % with the rainfed treatment. The results also indicated that with a climate change scenario, the temperature-stress days decreased during the period of winter wheat growth whereas the nitrogen-stress days increased significantly in the North China Plain. These simulated separate and interaction simulations may be useful for identifying appropriate management or genotype adaptations of winter wheat to cope with a climate change scenario in the North China Plain.