Key technical points for mid-season management of cotton during the Major Heat solar term

Focus on promoting growth, combining promotion with control, achieve control of large seedlings, promotion of small seedlings, and supplementation of weak seedlings, promote the transformation of weak seedlings, achieve balanced growth of strong seedlings, and build a high-yield framework early.

Scientific fertilizer and water management: First, apply bud fertilizer early and steadily. For weak seedlings, apply bud fertilizer early and steadily, generally applying 5-7 kg of urea per mu, and 25-50 kg each of cake fertilizer and phosphate fertilizer. Second, apply flower and boll fertilizer early and heavily. Generally in late early July, when 1~2 large bolls appear on the lower part of the cotton plant, carry out topdressing, applying 15~20 kg of urea per mu. Third, supplement with topping fertilizer. Generally in late July to early August, for cotton fields with medium to high fertility, apply 2.5~3 kg of urea per mu to strive for more bolls and larger bolls.

Reasonably manage pruning: First, remove leaf branches. Remove leaf branches with no useful value early to reduce nutrient consumption. Second, top the plants. After entering the mid-growth stage of cotton, top and prune promptly according to the seedlings and the field. The general topping time is around July 20 for medium-fertility fields, and can be postponed to the end of July for high-fertility fields. Third, remove side shoots. Around the Major Heat solar term, for shaded cotton fields, also remove side shoots to control horizontal growth of the cotton plant, generally keeping 3-4 fruiting nodes per fruiting branch. In addition, promptly remove the redundant buds and rampant branches growing from the leaf axils of the main stem and fruiting branches.

Timely chemical regulation: For vigorously growing cotton fields, following the principle of small amounts applied multiple times, use 0.5~1 g of mepiquat chloride per mu, diluted with 15~20 kg of water, and spray on the surface of the cotton plants to control the growth vigor of the cotton plants. 7~8 days after cotton topping, generally use 3~5 g of mepiquat chloride per mu, diluted with about 15~25 kg of water, and spray on the top and side shoots of the cotton plants. This can simplify later pruning, increase the setting of early autumn bolls, increase boll weight, and prevent excessive vegetative growth and late maturity.

Clear irrigation and drainage ditches: This year, rainfall in the Yellow River basin may be 20 to 50 percent more than last year. On the basis of intertillage and hilling during the bud stage, dredge ditches early to ensure smooth drainage and prevent waterlogging disasters.

Comprehensive prevention and control of pests and diseases: For the control of cotton bollworm, the focus should be on protecting buds, tops, and bolls, achieving the "four combinations," namely: combining chemical dripping on the heart with trapping and killing adults, combining control in cotton fields with control in other crop fields, combining chemical control with biological control, and combining field management with manual egg removal, to achieve the purpose of improving control effectiveness and saving costs. At the same time, strengthen the control of pests such as aphids, red spiders, mirids, and tobacco whiteflies. For Fusarium wilt and Verticillium wilt, there are currently no effective pesticides. Measures such as spraying multi-element micro-fertilizers to enhance nutritional resistance, strengthening pruning management in cotton fields to improve field ventilation and light conditions, and pulling out diseased plants can be taken to prevent large-scale spread.

Yangtze River basin cotton region

In view of the severe imbalance in seedling conditions this year, especially the "plum rain" weather, "based on disaster resistance, improving the living environment of cotton plants, and quickly building a high-yield cotton framework" is the central task of cotton field management in the next stage.

Destroy stubble and weed to promote rapid growth: At present, the harvest of the previous crop in cotton fields @#@245@#@ has ended, and the rush transplanting of middle-season rice has entered its final stage. Farmers should be mobilized to speed up intertillage and stubble destruction in cotton fields, loosen the soil and remove weeds, so as to improve the living environment of cotton seedlings and promote their rapid growth.

Apply flower fertilizer early to promote framework building: Combined with intertillage, soil loosening, and stubble destruction, apply flower and boll fertilizer early from late June to early July. The amount is generally 4~6.25 kg of pure nitrogen and 10~12.5 kg of potassium oxide per mu. In view of the reality of high chemical fertilizer prices this year, encourage and guide farmers to accumulate and apply farmyard manure, solidly promote soil testing and formulated fertilization, and especially apply "relay fertilizer" well when removing film for transplanted film-mulched cotton and direct-seeded film-mulched cotton, to ensure the nutrient needs for normal cotton growth and development.

Chemical regulation to ensure stable growth: For first- and second-class cotton fields with good growth (8 leaves or more), seize sunny days or breaks in the rain to spray plant growth regulators such as mepiquat chloride, so as to coordinate vegetative growth and reproductive growth of cotton. Especially for transplanted film-mulched cotton and direct-seeded film-mulched cotton that already show a tendency toward vigorous growth, appropriately increase the amount of mepiquat chloride to control vigor and promote sturdiness, and promptly remove vegetative branches. For overly sparse cotton fields, 1~2 vegetative branches can be retained for transformation, and the tips of the vegetative branches should be removed.

Clear the four ditches to prevent waterlogging: When the rainy and concentrated "plum rain" period arrives, in plain and lakeside cotton regions along rivers and lakes with high groundwater levels, while strengthening the renovation of flood control facilities and making preparations for flood control and disaster resistance, strengthen the clearing of the "four ditches" in cotton fields, so that surface water can be drained and subsurface water can be filtered, effectively lowering the groundwater level in cotton fields and reducing losses caused by waterlogging disasters.

Strengthen pest and disease control: Agricultural departments at all levels should closely monitor the occurrence and development trends of cotton "two wilts" disease, red spiders, aphids, and other pests and diseases, do a good job in forecasting, and guide farmers to select appropriate pesticides for timely control.

Northwest inland cotton region

With the main goal of achieving coordinated progress of reproductive growth and vegetative growth, more budding, rapid budding, and early flowering, and in view of the growth and development characteristics of cotton, strengthen classified guidance and management.