Abstract: In this study,the relationship between the change trend of water demand of cotton plant and the meteorological factors was lucubrated so as to explore the change trend of water demand of cotton plant in different growing seasons in Tacheng Prefecture. The purpose of the study was to provide the theoretical and scientific bases for the irrigation and drainage of cotton field under climate change. The data of daily air temperature,precipitation,sunshine duration,wind speed,relative humidity,etc. during the period from 1961 to 2013 were used to calculate the water demand and irrigation water volume of cotton plant in the study area in recent 53 years,and to explore its response to climate change. The results showed that: ① In recent 53 years,the water demand of cotton plant in Tacheng was generally decreased,particularly at the flowering and boll setting stage. The climate tendency rate was -1.51 mm·(10a)^-1; the water demand of cotton plant was 103.96 mm at the flowering and boll setting stage and higher than that in other growing seasons: ② Irrigation water volume of cotton plant was generally in a decrease trend,in which it was the highest at the flowering and boll setting stage,its average volume was 77.79 mm,and its reduction at the flowering and boll setting stage was the most obvious (the climatic tendency rate was -2.90 mm·(10a)^-1,P<0.01); ③ There was a high correlation between meteorological factors and the crop water demand and irrigation water volume in all the cotton growing seasons. Among the meteorological factors,the effect of precipitation was the most significant.

Key words: crop water demand, irrigation water volume, climatic factor, cotton, Tacheng Prefecture