根据棉花各生育期的需水量及降水情况,适时适量排水、灌水,是保证棉花稳产高产的一项关键措施。 (一)降水量和棉花产量的关系在大面积生产中,皮棉亩产和棉花生长季节的降水量关系密切。从1964年以来的17年资料分析,皮棉亩产和棉花生长期5～9月份的降水量是负相关,相关系数r=-0.5068(N=15 t=2.277 P0.05=2.131)即产量随降水量的增加而下降。 5～9月降水量小于700mm的年份,皮棉亩产均在100斤以上,其中400～500mm的1965、1968、1979年,雨量分布均匀、产量最高。降水量小于400mm的年份,在灌水条件较好的市郊能获得高产。如1978年全市平 According to the demand of cotton in each growth period and precipitation, timely drainage and irrigation are the key measures to ensure stable and high-yield cotton. (A) the relationship between precipitation and cotton production In large-scale production, the lint mu yield and cotton growing season is closely related to the precipitation. From 17 years of data analysis since 1964, the yield of lint per mu was negatively correlated with the precipitation in May-September during the cotton growing season. The correlation coefficient r = -0.5068 (N = 15 t = 2.277 P <0.05 = 2.131) Precipitation increases and decreases. From May to September, the precipitation of less than 700 mm was more than 100 kg per mu, among which, the rainfall was evenly distributed and the yield was highest in 400-500 mm in 1965, 1968 and 1979. Precipitation is less than 400mm of the year, in the suburbs with better irrigation conditions to obtain high yield. Such as the 1978 citywide