Climate Change and Impact Analysis of Winter Wheat Overwintering Period in Changji City in Recent 30 Years

Changji City is located in the main producing area of winter wheat in Xinjiang. It is of great significance to study and analyze the regional climate change and its impact on the overwintering period of winter wheat for making full use of the ratio of light, heat and water resources and developing grain production according to local conditions. The data of national meteorological station and the observation data of winter wheat development period in Changji City from 1995 to 2024 were selected. The linear regression equation, climate tendency rate, Mann-Kendall and Pearson correlation coefficient method were used to analyze the variation characteristics of average temperature, maximum temperature, minimum temperature, precipitation, sunshine hours, ≥0°C accumulated temperature and other climatic factors during the overwintering period of winter wheat in Changji City, and to judge the key climatic factors affecting the overwintering period of winter wheat. The results showed that: (1) During the overwintering period of winter wheat in Changji City, the daily average temperature, daily maximum temperature and daily minimum temperature all showed a significant downward trend, and the downward rates were 1.3, 0.5 and 2.2°C/10a, respectively. The downward trend of precipitation was not significant, and the changes of sunshine hours and ≥0°C accumulated temperature were not obvious; (2) There was a strong negative correlation between the number of winter wheat overwintering days and the daily average temperature, daily maximum temperature, daily minimum temperature and ≥0°C accumulated temperature. (3) In recent 30 years, the number of winter wheat overwintering days in Changji City showed an increasing trend, which was related to the significant decrease of daily average temperature, daily maximum temperature and daily minimum temperature.