Research On The Key Agronomic Technologies Of Machine-harvested Cotton In South Xinjiang

Accelerating the development of cotton produce entire mechanization is an effective measure to reduce cost and increasing the profit of cotton.In order to explore the key agronomic technologies of machine-harvested cotton in the south area of Xinjiang and provide extension theoretical bases for intensive production of machine-harvested cotton,field experiments were conducted to study the effect on the development,yield,cotton fiber quality and machine-harvested quality under the conditions of different varieties,cropping pattern and defoliants.The main results are as follows:1.The suitablity of cotton variety for machine-harvested were experimented.Two varieties,Zhongmian 57 and Xinluzhong 47 were suitable for machine-harvested in Alar area in our study,which not only could meet the requirements of cotton machine-harvested and fiber quality,the loss rate was less than 5.4%,the fiber length was more than 30.7 mm and the fiber strength was more than 30.1 cN/tex,but also the lint yield was higher than 3100 kg/ha.The former should increase the single boll weight and the latter increase the both total boll number per unit area and single boll weight when further tap the potential productivity.However,we also could should choose Lvyi10 that with high-quality fiber if the yield was not changed or reduction appropriately.2.Cotton cropping patterns of machine-harvested were defined.Increasing the bolls of per plant and populations were the guarantee,with 6.4 bolls/plant and 18.9×104 plants/ha,total bolls per hectare could up to 1.2 million,the lint yield of(66 cm+10 cm)×10.5 cm and(64 cm+12 cm)×10.5 cm planting patterns reached 3000 kg/ha,but the shedding rates of buds and bolls as high as 69.1%.Through increasing number of harvest to improve the total bolls within unit area probably was the main reason that made the cropping pattern of(64 cm+12 cm)×10.5 cm obtain high link yield(3041 kg/ha),which total bills was higher 65 thousand than that of(66 cm+10 cm)x 10.5 cm,and the ratio of middle bolls was up to 50.4%.3.Defoliant form and dosage were determined.Spraying time of defoliant has significantly effect on the defoliation rate and boll opening rate of cotton,delayed spraying could reduce the defoliation rate range from 18.6%to 58.1%,and the rate of defoliation was decreased by 1.7%per day in 5 days after spraying.Rate of open boll could reach more than 50%under early spraying within 5 days after spraying while delayed spraying decreased by over 16%.Among the different defoliating agents,the picking net rate both in Tuotulong and Ruitulong were more than 96%,the residual cotton rate was less than 2.1%,and the residual of cotton leaves content was the lowest.Considering the rate of defoliation and boll opening,the preferred defoliant agent should be Ruitulong and Tuotulong,and the dosage was 375g and 180ml,respectively,and 1050ml of ethephon was compounded.