Responses of wheat yields and water use efficiency to climate change and nitrogen fertilization in the North China plain

Ensuring food security for the 1.4 billion people of China is a critical challenge, and therefore the accurate assessment of crop yield responses to climate change is a key scientific issue. However, the extent to which the variation in crop growth can be accounted for by the variability in climate variables or by management adaptations remains unclear. Based on daily weather data and management information at six stations, we constructed three sets of simulation experiments using the Crop Environment Resource Synthesis (CERES)-Wheat model. This allowed quantifying the responses of wheat yield and water use efficiency (yield/evapotranspiration, WUE) to climate change and nitrogen (N) fertilization for the period 1981 to 2008 in the North China Plain. Our results indicated that the simulated median values of the wheat yield/WUE decreased (2.62% to 14.26%)/(1.58% to 9.33%) with increasing temperature (T), increased (0.17% to 6.81%)/(0.70% to 4.55%) with elevated CO2 concentration, and changed little with decreasing precipitation in 15 simulation experiments of individual climate variables. Under the combined changes in temperature, N fertilization (T/N), and CO2 concentration, the effects of changes in T/N fertilization on wheat yields and WUE were stronger than the effects of change in CO2 concentration. Interactions between T and CO2 concentration, N fertilization and CO2 concentration appear to play very significant roles in wheat yield. Our study suggests that proper N fertilizer application, changing crop establishment dates, and cultivating new cultivars could be efficient measures for food production prediction and climate change adaptation in the North China Plain. A main result of this work is therefore that proper N application, shifts in crop establishment dates, and the cultivation of new high-temperature tolerant wheat cultivars could contribute safeguarding food security in China, and globally.