A Study on Northern Boundary of Winter Wheat during Climate Warming: A Case Study in Liaoning Province

In this paper, based on geographic planting data of winter wheat and present meteorological data, climatic northern boundary of winter wheat in Liaoning province was studied systematically. The grey correlation analysis revealed that the accumulated temperature and precipitation before overwintering, the negative temperature during the overwintering, and the precipitation of May and June were the four key affecting factors. By analyzing the factors of the accumulated temperature before overwintering and negative accumulate ground temperature of tillering node level and evaluating the real climatic productivity, the result indicates: the northern boundary of winter wheat would be Benxi-Fushun-Faku-Zhangwu-Fuxin-Beipiao-Chaoyang (about 42.5°N). It will move 1-2 latitudes to north comparing with past boundary (along the Great Wall line). The result not only has important guiding significance to the northern boundary of planting winter wheat, but also has reference effect to reconstruction of historical climate by using crop planting boundary in historical periods.