Field Management of Cotton at Bud stage and Flower and Boll stage

The management of cotton bud stage and flower and boll stage is centered on the regulation of water and fertilizer, with the measures of ploughing, chemical adjustment and pruning, rational use of promotion and control techniques, promotion and control combination, strong and stable growth, high yield shelves, increasing bud bolls, reducing shedding, and realizing the full hanging of three peaches.

First, fertilizer and water management

The bud stage requires the cotton plant to grow steadily, so the fertilizer should be applied steadily and skillfully, and the use of nitrogen fertilizer should be controlled. Cotton fields with medium and high fertility are no longer fertilized. If the soil fertility is poor or the amount of base fertilizer is insufficient, urea is generally applied 5-7 kg per 667 square meters. When cotton enters the flowering and boll stage, the growth of stems, branches and leaves reaches the maximum, at the same time, a large number of buds, blossoms and bolls, and the absorption of nutrients reaches the peak, which is the key period of fertilization. During this period, the amount of nitrogen, phosphorus and potassium absorbed by cotton plants accounted for more than 60% of the whole growth period. On the basis of applying sufficient nitrogen and potassium fertilizer in the early stage, nitrogen fertilizer was applied again, generally 667 square meters topdressing 15-20 kg urea. The time of topdressing should be before the early flowering stage, the soil fertility is poor, the growth of cotton plant is weak and the early-maturing cotton can be in advance, about 15 days before flowering. Fertile soil, cotton plant growth can be in the cotton plant before the peach fertilizer again.

Capping fertilizer is the key to prevent the premature senescence of cotton in the later stage and realize the capping of autumn peach. In the cotton fields with signs of premature senescence, the cotton fields with signs of premature senescence should be applied early and heavy, and those with strong growth should be applied lightly or late. In the later stage of insect-resistant cotton, due to the strong boll setting per plant and the decrease of root function, foliar topdressing can be strengthened. The premature type should be sprayed with 0.2% urea aqueous solution, and the greedy type should be sprayed with 0.4% potassium dihydrogen phosphate or 3% calcium superphosphate leaching solution; spray once every 10 days for 3 times.

The cotton bud stage coincides with less precipitation in the cotton area of northern Xinjiang, while the field water consumption is increasing. In order to build a high yield shelf, it should be watered in case of drought. The flowering and boll stage is the period when the cotton plant needs the most water. If the water supply is not available, the cotton plant growth will be seriously affected and the bud and boll shedding will be increased. At the same time, the fertilizer in the water-deficient soil is also difficult to exert its effect. Therefore, it is necessary to water in time and adjust fertilizer with water to promote the decomposition of fertilizer and the absorption of nutrients by roots. Such as excessive rainfall, timely drainage, prevent waterlogging, reduce bud and boll shedding, reduce the probability of Fusarium wilt and Verticillium wilt.

II. Chemical control dosage

During chemical control, we should grasp the principles of "early, light, diligent" and "light in front and heavy after". Use 0.5g / 667 square meters / 667 square meters and 1.5 grams / 667 square meters in full bud stage. Chemical control should also be flexible according to growth, soil quality and weather. The dosage of thalidomide is 1.5 grams per 667 square meters in early flowering, 3.0 grams in full bloom, and 4 grams in 7 days after topping.

Third, pruning and topping

The bud stage is generally not pruning, mainly to control the vigorous growth, to achieve the stable growth. If there is a flourishing growth in the spot film, it is necessary to "take off the trousers and legs" as soon as possible and remove all the leaf branches. The florescence and boll period should be topped at the right time, and the cotton area in northern Xinjiang should top from June 25 to July 5, and finish playing bystander on July 10. Vegetative branches can beat off the sharp heart when they grow 2 or 3 fruit branches before July 10. Topping too early, resulting in a cluster of buds, fruit branches are too long, affecting ventilation and light, but also limit the number of fruit branches and fruit branches, reduce the effective bud boll, can not make full use of the effective growing season, but also prone to premature senility; topping too late, can not play the role of regulating nutrition distribution. The correct topping time should be determined according to cotton growth and frost period.

IV. Prevention and control of diseases and insect pests

The bud stage is the period when Fusarium wilt begins to occur and gradually aggravates, so it is necessary to do a good job in prevention and treatment. Fusarium wilt has five different symptom types: yellow reticulation type, yellowing type, bacterial wilt type, purplish red type and atrophic type. Mild diseased cotton plants were treated with 500 times of carbendazim and 800 times of thiophanate methyl, and seriously diseased cotton plants were treated with cotton disease nemesis and potassium permanganate as root irrigation treatment.

To control aphids, imidacloprid and aphids; avermectin and Avermectin to control cotton leaf mites; Tianhui and monocrotophos to control cotton thrips; and BT and NPV biological pesticides to control cotton bollworm. The main disease in flower and boll stage is Verticillium wilt, and the pests are the second and third generation cotton bollworm, aphid, cotton leaf mite and so on. The main control methods refer to the prevention and control of diseases and insect pests at bud stage.