| The 80% thidiazuron wettable powder(80% thidiazuron)is the product with the highest thiaburon content in the market,with low cost.It is also a common cotton defoliant in the maigaiti at present.It has been widely used in alar,shajingzi and other cotton areas in southern xinjiang,but initially used in maigaiti cotton area.To explore defoliant application technology of red to take off the dragon in the Maigaiti land reclamation area and the effect on cotton leaves off,adopt single factor randomized block experiment,and studied the temperature,cotton varieties,spray time,spraying equipment and other factors on cotton defoliant red dragon off to take off the leaves.In order to screen out the best application conditions of the defoliant 80% Thidiazuron in the cotton fields in the Maigaiti reclamation area,and provide theoretical reference and practical guidance for the rational application of the defoliant 80% Thidiazuron in the cotton fields of Maigaiti.The results of this paper are as follows:1.Effect of air temperature on cotton defoliation with 80% Thidiazuron defoliant The effects of air temperature on the defoliation of cotton sprayed with 80% Thidiazuron are as follows:(1)The average daily temperature on the day of application and 1-5days after application is closely related to the defoliation effect of the defoliant 80% Thidiazuron.The average daily temperature on the day of application is higher than 18.8?,and the average daily temperature after application is between 18? and 23.7?,which is conducive to cotton defoliation.(2)The lowest temperature on the day of application had an effect on the defoliation effect of cotton,and the lowest temperature on the day of application was > 11.7?.(3)The highest temperature of4-7days after application had an effect on cotton defoliation.When the highest temperature of4-7days after application was higher than 23?,it was beneficial for 80% Thidiazuron to exert its efficacy and promote cotton defoliation.(4)The effect of effective accumulated temperature(?10?)from flowering to the day of application on boll Bolling before application: The higher the effective accumulated temperature(? 10?),the better the boll bolling.In practical production,it is suggested that the effective accumulated temperature(? 10?)from flowering to the day of application should be 767?~883.6?2.Effects of cotton varieties on the efficacy of 80% Thidiazuron,a defoliantDifferent cotton varieties had an effect on the efficacy of 80% Thidiazuron,a defoliant:Among short-growing cotton varieties,zhong36 had the best defoliation rate(96.3 ±0.9)%,the boll opening rate(97.7 ±1.1)% and branch hanging rate of(0),followed by J206-5 and zhongmiansuo55,which had a longer growth period,xinluzhong 60 had the lowest defoliation rate(72.3 ±4.1)%,branch hanging rate(0.9 ±0.5)%,boll opening rate(74.1 ±6.3)%.Therefore,the shorter the growth period of cotton varieties,the better the rate of defoliation and flocculation,the lower the rate of hanging branches,and the worse the performance of cotton varieties with longer growth period.The defoliation rate and flocculation rate 15 d after treatment with 80% Thidiazuron the defoliantion rate could be used as reference index of defolianting susceptibili-spraying of packing cotton for mechnical harvesting.3.Effect of topping technique on cotton defoliation with 80% Thidiazuron defoliantThe cotton plant type after chemical topping is smaller than that of manual topping,which hasbetter space permeability and is beneficial to uniform drug acceptance.By comparing and analyzing the defoliation effect of cotton fields with manual topping and chemical topping,it can be seen that the maturity of cotton with chemical topping is(39.5 ±2.8)%,defoliation rate is(95.9±1.4)%,branch hanging rate is(0.9 ±0.1)%,and floc shedding rate is(94.3 ± 3.5)% better than that of cotton fields with manual topping.Different topping times have effects on defoliation and floccus of cotton plants sprayedwith defoliating agent 80% Thidiazuron:Premature topping time is easy to cause premature senescence of cotton and interfere with the absorption of chemicals by cotton plants.At this time,the defoliation rate of cotton is(94.6 ±2.2b)%,the branch hanging rate is(1.4 ±0.3)%,the floccus rate is(89.2 ±3.5)%,and the defoliation effect is poor.The late topping caused the cotton to grow vigorously,the cotton plants to be green and mature late,and the boll opening to mature late.At this time,the defoliation rate was(92.5 ±3.1)%,the branch hanging rate was(1.5 ±0.2)%,the boll opening rate was(93.8 ±2.8)%,and the defoliation rate also decreased significantly.4.Effect of defoliant on cotton defoliation with 80% ThidiazuronThe effect of defoliating and flocculation of cotton treated with 80% Thidiazuron was affected by different application apparatus:The best defoliation and flocculation effects were(95.6±1.3)%and(97.4±0.9)%,respectively,using electrostatic sprayer.Unmanned aerial vehicle for plant protection took the second place,with a defoliation rate of(94.5±1.9)% and a flocculation rate of(96.5±1.7)%.The effect of mechanical spraying was the worst,with defoliation rate of(91.7±2.4)% and floccus rate of(94.2 ±2.3)%. |
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