Abstract:

The article was based on data about the mean daily and minimum temperatures of Xinjiang cotton-growing area of 22 stations from 1961 to 2009. The article analyzed not only the change characteristic of ≥10℃ terminal day and the first frost date, but also the effect of cotton growth. The results showed that the latest ≥10℃ terminal day and the first frost date were Turpan regions, followed by cotton-growing areas in southern Xinjiang, delayed from west to east in the Tarim Basin, and cotton-growing areas in northern Xinjiang and Hami was the first. During the 49 years, the change in trend of ≥10℃ terminal day was later in Yili and Shihezi cotton-growing areas, but there was not a clear trend in the rest of the cotton-growing areas in Xinjiang. The change in trend of first frost was later in northern Xinjiang, there was not a clear trend in the rest of the cotton-growing areas in Xinjiang. There was significant linear correlation between ≥10℃ terminal day and the first frost in the most of cotton-growing areas. The most stable ≥10℃ terminal day was Turpan regions, followed by cotton-growing areas in southern Xinjiang. Motion the range cotton-growing areas in northern Xinjiang were biggest. The change in trend of first frost period in Eastern regions was smaller than in Northern regions and southern Xinjiang cotton-growing areas. The change in trend of first frost period in Eastern regions, in Northern regions and southern Xinjiang cotton-growing areas were bigger than ≥10℃ terminal day. Particularly, Tarim Basin south-eastern cotton-growing regions were the most obvious. most of the cotton-growing areas in Xinjiang 90 years and from 2001 to 2009，the change in trend of ≥10℃ terminal day, only a small part of the site as early as year-round, the rest were later than the year-round. Especially the northern cotton region, Turpan cotton region and western Tarim Basin cotton region late more. Most of Xinjiang early frost delay trend was clearly cotton, and most of the cotton area from 2001 to 2009 the average first frost was last of the era. These were beneficial for the later growth of cotton, mainly as heat and more favorable conditions for cotton growth later reduced the risk of frost encountered before frost high yield, good quality. And ≥10℃ terminal day and the first frost date change to a large extent affected the cultivation of cotton boundaries extend north and west Xinjiang cotton area in recent years. Therefore, the production and the cotton could the local accumulated temperature ≥ 10℃ and select the appropriate state change first frost of cotton varieties, easy to achieve high yield and efficiency of cotton production.