What are the remedial measures after cotton suffers from waterlogging?

For waterlogged cotton that has been completely submerged for more than 3 days or soaked for more than 7 days, the root system rots and turns yellow, and the terminal leaves wither and die; such cotton seedlings have very little chance of survival and need to be replanted. Within 2 to 3 days after draining the water, if more than 500 surviving cotton plants per mu remain, they should be retained and given intensive management, with intercropping or relay intercropping of soybeans, corn, sesame and other crops; if fewer than 500 surviving cotton plants per mu remain, early replanting with a different crop should be carried out. After cotton is damaged by flooding, the root system is harmed, the taproot and lateral roots turn yellow, and the root tips become water-soaked; the stress-resistance contingency measures of "drain water quickly, loosen the soil early, apply heavy fertilizer, prevent diseases and pests, delay topping, and prune frequently" should be adopted.

Clear the field ditch system. Immediately after waterlogging occurs, clear the field ditch system, race against time to drain the water, deepen the furrow ditches and corresponding drainage ditches, lower the groundwater level as soon as possible, reduce waterlogging, and ensure normal cotton growth. At the same time, promptly wash the seedlings and rinse the mud off the leaves and stems to restore normal photosynthesis in the leaves.

Make an urgent effort to straighten and support the cotton plants. After the disaster, the cotton root system is damaged and the plants are prone to lodging, so they should be straightened and supported in time to improve the field environment and reduce the shedding of squares and bolls.

Loosen the soil and bank the roots in time. Within one week after the standing water in the field is drained, the soil should be loosened and the roots banked in time to break up the hardened layer on the soil surface, increase soil permeability, improve the root environment, and promote root recovery; at the same time, small raised ridges should be built to improve the cotton plants' lodging resistance. Afterward, cultivate and loosen the soil in time to promote root growth.

Apply recovery fertilizer scientifically. For cotton plants with relatively light damage, apply heavy flowering and boll fertilizer early; for those with relatively severe damage, first apply recovery fertilizer according to the seedling condition, generally 10 kg of urea per mu, then appropriately delay the application of flowering and boll fertilizer, skillfully apply topping fertilizer, and combine it with potassium fertilizer. The use of special compound fertilizer for cotton and organic-inorganic fertilizer is advocated, applied deeply in holes, to promote rapid and vigorous growth and bring the cotton into the peak period of increasing nodes, increasing squares, flowering and setting bolls as soon as possible.

Adjust chemical regulation reasonably. After cotton is waterlogged, its growth and development are hindered, so the amount of chemical regulation should be appropriately reduced or the timing of chemical regulation delayed, depending on the seedling condition.

Appropriately delay topping. For most waterlogged cotton, square and boll shedding is severe and the growth peak is relatively delayed. In order to increase boll setting at the top of the cotton plant and set more autumn bolls, topping should be delayed by about 5 days compared with normal.

Strengthen disease and pest control. After cotton is damaged by flooding, its growth and development are hindered and square and boll shedding worsens; if it is then harmed by diseases and pests, the yield loss will be even greater. After rain and waterlogging, cotton Fusarium wilt, Verticillium wilt, mirids and other diseases and pests occur more severely, and measures should be taken in time to prevent them. At present, the overall battle against cotton diseases and pests, mainly the third generation of mirids, should be given prominence, and monitoring of the third generation of cotton bollworm should be done well.

Pay attention to later-stage management. After cotton suffers from waterlogging damage, its growth and development are delayed, so later-stage management should be strengthened even more in order to make full use of cotton's self-regulation ability and reduce yield loss. During the recovery growth period, pruning must be strengthened to reduce new vegetative branches and superfluous buds, reduce ineffective nutrient consumption, and ensure a sufficient nutritional foundation for boll setting in the later stage.