At present, due to the influence of continuous high temperature weather, cotton gradually enters the boll period, how to diagnose the seedling situation, promote the expansion of cotton peach, increase bell weight, prevent premature aging, prevent greed and late maturation, prevent shedding, prevent diseases and insects, promote the development of middle and upper cotton bolls, and further establish a reasonable cotton group structure.
First, the diagnosis of seedling conditions during the bolling period of cotton
(1) Normal cotton fields
Normal cotton field "Bayi flower upper tip". That is, at the beginning of August, white and red flowers can be seen at the top of the cotton field group, the leaf color turns darker, and the plant is old and healthy.
(2) Greedy green late-ripening cotton fields
At the beginning of August, there are no flowers at the top, the leaves are thick green, the group is tightly sealed and covered, the stems are green, and some of them are overgrown with extra buds.
(3) Premature aging cotton fields
In late July, the safflower covers the top, the plant is small, and the large row is not sealed. In August, the red stem ratio is greater than 95%, the leaf color is light green, the upper bud is small, and the top peach is less. Leaf spot disease or red leaf disease is more severe.
Second, cotton control measures
(1) Premature aging cotton fields
Apply foliar fertilizer, 200 g of urea plus 150 g of potassium dihydrogen phosphate 1-2 times per acre. In late July, the top fertilizer was supplemented, more nitrogen fertilizer was applied, and phosphorus and potassium fertilizer were stabilized. About 0.5 kg of urea and about 0.3 kg of potassium dihydrogen phosphate (or monoammonium phosphate and potassium sulfate) are applied per mu per day.
The interval between drip irrigation should be extended as much as possible, and small water and small fertilizer should be used. Rectify the branches in time, remove the invalid plants, erase the old leaves, extra buds, and fritters, open the field passage, and increase the ventilation and light transmittance between the rows. Continue to spray 6-10 g of accrylamine per acre to control cotton side branches and shoots. Urea was reduced on fertilization, and phosphorus and potassium fertilizer were applied steadily. It is recommended that urea per mu be 0.3 kg per day and potassium dihydrogen phosphate be about 0.3 kg.
(3) Normal cotton fields
At the end of July, cotton enters the bouquet period, during which the leaf area reaches the maximum value of its lifetime. This period is easy to cause secondary growth or rotten bells, according to the climate and group structure, growth appearance, control the humidity in the field, increase the field light, rather dry than wet, to prevent cotton bud bells from falling off. Do a good job in chemical control and pest control.
1. Control the long and anti-shedding
Cotton growth will cause nutrient waste, it is recommended to spray acetylamine in a timely manner during the growth period of cotton to inhibit side branches and shoots, and promote the transformation of excess nutrients of cotton plants into reproductive growth. The amount of amine per mu is generally 5 to 10 grams, but it should be flexibly grasped according to the growth of cotton, high temperature weather, fertility of cotton fields, the size of rainfall, etc., and the concentration of use should be "low rather than high". Focus on increasing the amount of phosphorus and potassium fertilizer for Wangchang cotton, and the rational use of potassium fertilizer can play a role in controlling the prosperity and improving the resistance of cotton plants, achieving the role of bud preservation, bell preservation, peach preservation and improving fiber quality.
2. Prevent premature aging
Although the amount of water fertilizer is not as large as the peak flowering period of cotton, the amount of water fertilizer should be reduced as appropriate, especially the amount of nitrogen fertilizer, which has a great effect on cotton boll expansion and dry matter accumulation. Nitrogen fertilizer is sufficient, there is a foot on phosphorus fertilizer, cotton will not be prosperous. In addition to drip fertilizer, foliar sprays of urea and potassium dihydrogen phosphate are applied.
3. Pest control
The main diseases and insect pests during the bolling period of cotton are cotton leaf mites, cotton bollworms, cotton aphids, cotton blind bugs and verticillium wilt, if not prevented in time, the yield of cotton will be greatly reduced.
The cotton aphid in northern Xinjiang began to fade in the normal year, and the investigation should be strengthened, and the control of the standard should be adhered to strictly prevent the fall of curly leaves and flowers.
For cotton leaf mites, avermectin plus spironyl ester or acetazole should be sprayed early according to the investigation.
For cotton bollworms, one is to adhere to the lure moth, and the other is to adhere to the standard control, and use chlorantranoid benzamide to control.
For verticillium wilt, a certain amount of fungicides, phosphorus and potassium, co-brassica or amino acid fertilizers can be applied dropwise for prevention and control.
Motorcycle spray is recommended to use a fan-shaped sprinkler, the nozzle from the rake standard cotton leaf or cotton top distance is greater than 20 cm.
Drone spray is recommended to use more than 1.2 liters of water per acre, and add fly prevention additives as well. It is not recommended to prevent insects or fertilize the high-pressure spray gun, which is very easy to hurt flowers and break leaves, fall buds and bells, and affect the normal growth of cotton plants.
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