The Study Of Delayed Cool Injury Index In The Cotton Region Of Northern Xinjiang By Field Experiment

In mid-latitude region Xinjiang is a major high-quality cotton production bases in China. Heat is the most essential meteorological factor in affecting the Xinjiang cotton cultivation. Research in recent years realized that the biggest meteorological disaster affects the Xinjiang cotton production is the cold damage question, especially delayed cold damage. Heat not only affects the growth speed of cotton but also have close of relation with yield and quality.The Shihezi cotton region of northern Xinjiang studied in this paper is our country most boundary of cotton. The primary disadvantage factor in this region is shorter growth season,heat change greatly in annual,usually suffer from delay cool damage. These factors cause cotton slow-growing,quality descends,underproduction. Study agricultural meteorology index of Shihezi cotton region of northern Xinjiang has the vital economic significance and the high academic value.This article uses the geography to sow seeds by stages, carrying on the experiment in the Wulanwusu Agrometeorological Experimental Station and Mosuwan Agrometeorological Station. Through experimental material study the relationship between eight factors and output (accumulated temperature above 10℃,growth period,the sum of daily mean temperature,the sum of mean monthly temperature,the sum of daily minimun temperature,number of days of three stages in growing,total sun hours in growing season).Obtained delayed cool injury index different degrees in cotton region of northern Xinjiang.1. Accumulated temperature above 10℃index: In the Shihezi cotton region of northern Xinjiang, accumulated temperature≥10℃is less 135℃·d than average year, it will appear mild delayed cold damage; accumulated temperature≥10℃is less 203℃·d than average year, it will appear serious delayed cold damage. After examination 66.7% climate underproduction years match this index, so the Accumulated temperature above 10℃index is reliable.2. Accumulated temperature above 15℃index: In the Shihezi cotton region of northern Xinjiang, accumulated temperature≥15℃is less 111℃·d than average year, it will appear mild delayed cold damage; accumulated temperature≥15℃is less 167℃·d than average year, it will appear serious delayed cold damage. After examination 100% climate underproduction years match this index, so the Accumulated temperature above 15℃index is reliable.3. The sum of monthly mean temperature:In the Shihezi cotton region of northern Xinjiang, the sum of monthly mean temperature is less 6℃·d or 9℃·d than average year, it will appear serious delayed cool injury. After examination all of the 9 climate underproduction years match this index, so the sum of monthly mean temperature index is reliable.4. The sums of daily minimun temperature of growing season index: In the Shihezi cotton region of northern Xinjiang, the sums of daily minimun temperature of growing season is less 408℃·d and 611℃·d than average year, it will appear serious delayed cool injury.5.Growth period index: In the Shihezi cotton region of northern Xinjiang, the flowering time is 4 days later than avreage year,or split boll stage is 7 days later than avreage year, it will appear mild delayed cold damage; the flowering time is 6 days later than avreage year,or split boll stage is 11 days later than avreage year,it will appear serious delayed cool injury.