Key Technical Points for Film-Mulched Transplanting of Cotton after Wheat and Rapeseed

@#@245@#@ For transplanted cotton following rapeseed, the transplanting period is late and the growth period is somewhat delayed. Adopting film-mulched transplanting can raise temperature and conserve moisture, prevent waterlogging and drain excess water, and is an effective measure for achieving early vigorous growth, preventing stunted seedlings, and obtaining high yields.

Land preparation and film mulching: After harvesting wheat and rapeseed, promptly plow and prepare the land, open furrows and form ridges, spray a soil-closing treatment agent on the ridge surface, and then apply film mulch. Combined with land preparation, apply 2000-4000 kg of decomposed organic fertilizer, 40-50 kg of compound fertilizer, and 1-2 kg of Chilibor (boron fertilizer) per mu.

Transplant without delay: the transplanting period for rapeseed stubble must not be later than May 25, and for wheat stubble not later than May 30. Seedling age should not be too old; transplant when seedlings have 2-3 true leaves. For seedbeds sown early with older seedlings, timely chemical regulation and pot-moving seedling hardening should be carried out, and large and small seedlings should be planted separately. At transplanting, the pot surface should be 2 cm from the ground; after placing the pot, cover with half a hole of soil and water thoroughly; after the water seeps down, bury the pot body level with the ground. Transplanting density depends on soil fertility, with 1400-1800 plants per mu. After transplanting, strengthen field management such as intertillage and weed control.

Fertilizer and water management: promptly clear the "three ditches" so that all ditches are connected and drainage and irrigation are unimpeded. After seedling recovery, promptly apply a seedling-promoting fertilizer, using 3-5 kg of urea per mu. After budding in mid-to-late June, when there are 4 fruiting branches, apply a bud fertilizer, using 10 kg of urea and 10 kg of potassium chloride per mu. Entering the flowering and boll-setting stage, when 1-2 large bolls have set on the lower part, heavily apply a flowering and boll fertilizer, using 15 kg of urea and 15 kg of potassium chloride per mu. One week after topping (August 10-15), apply a top-covering fertilizer, using 5-10 kg of urea per mu. Apply fertilizer by opening furrows and placing it deep. After late August, spray foliar fertilizer according to plant growth; for weak growth, mainly spray nitrogen and potassium fertilizers, and for vigorous growth, mainly spray phosphorus and potassium fertilizers.

Pruning and chemical regulation: The first pruning should not be done too early, so as to promote vegetative growth and root system development; generally it is done when there are 2-3 fruiting branches, removing all leafy branches below the fruiting branches, but not removing large leaves. Subsequent pruning follows that for conventional cotton. Begin chemical regulation from the full budding stage; when the cotton plant has 4 fruiting branches, spray the top of the plant with 0.5 g of pure mepiquat chloride mixed with 25-30 kg of water per mu. The second chemical regulation is at the initial flowering stage; according to plant growth, use 1-2 g of pure mepiquat chloride per mu. Entering the peak flowering and boll-setting stage, that is, when bolls appear on the fourth fruiting branch, use 3-4 g of pure mepiquat chloride per mu. After topping, use 5-6 g of pure mepiquat chloride per mu. The amount of mepiquat chloride should be adjusted according to weather, seedling condition, and soil fertility.