不同类型脱叶剂对长绒棉脱叶效果、产量和品质的影响OA

Spraying defoliant is the key link of long-staple cotton machine picking to improve quality and efficiency.The experiment was carried out in Shaya County,Aksu Prefecture in 2023 and 2024 to study the effects of different defoliant types on defoliation rate,defoliation speed,wilt leaf rate,boll opening rate,yield and quality of long-staple cotton.With clear water as blank control(CK)and 50％thidiazuron as control drug(T1),5 types of defoliant were used for treatments including 54％thiobenzene-dioxalon(T2),81％thio-benzene-dioxalon(T3),65％diuron-thidiazuron-ethephon(T4),50％thidiazuron+2％pyraflufen-ethyl(T5),and 54％thiobenzene-dioxalon+2％pyraflufen-ethyl(T6).The results showed that spraying defoliant could significantly improve the defoliation and ripening effects in both years,among which,T5 and T6 had the best defoliation effect with the defoliation rate more than 99％,while T1 had a poorer defoliation effect with the defoliation rate ranging from 93.20％to 97.41％.In 2023,when cold weather was encountered during the pre-application period,the defoliation speed of T5 and T6 was significantly higher than that of the other treatments 5 to 10 days after application,which were 9.40％/d and 9.42％/d,respectively.In 2024,when the meteoro-logical temperature was favorable,the defoliation speed of T5 and T6 was not significantly different from the other defoliant treatments in the former period after application(at 5 to 15 days).After T5 and T6 treatments,the rate of wilt leaves was lower,averaging 3.94％and 4.40％over the two years,respectively,while that was higher after T1 and T3 treatments,averaging 7.15％and 9.63％over the two years.There was no significant difference in ripening effect of the defoliant treatments,and the boll opening rate was higher than 94％,which was significantly higher compared to CK.The defoliant treatments had no significant effects on the yield of seed cotton and lint cotton compared to CK,indicating they did not cause yield reduction in long-staple cotton yield.The defoliant treatments also had no significant effects on cotton fiber quality,and the quality was overall bet-ter than that of CK.In summary,in the experiment conditions,50％thidiazuron+2％pyraflufen-ethyl and 54％thiobenzene-dioxalon+2％pyraflufen-ethyl had better effects on defoliation and ripening of long-staple cotton,had no negative effect on yield,and improved fiber quality to a certain extent,so they were suitable for defoliation and ripening of long-staple cotton during pre-mechanical harvesting period.