Technical Guidance Opinions on Field Management in the Late Growth Stage of Cotton

Editor's note: To ensure stable yield and increased income of cotton this year, the Cotton Expert Guidance Group of the Ministry of Agriculture, based on the production conditions and climate characteristics of different cotton regions, has put forward technical guidance opinions on late-stage management. The technical opinions for the Yellow River Basin cotton region, where Hebei Province is located, are excerpted below for our readers.

Since late July, the Yellow River Basin cotton region has repeatedly suffered from heavy rainfall and extreme high temperatures, and some cotton fields have shown signs of excessive vegetative growth, bud and boll shedding, and premature senescence. In view of the current cotton growth, the focus should be on increasing the setting of early autumn bolls and preventing premature senescence, and late-stage cotton field management should be carried out effectively.

Scientific management of topdressing. For cotton fields showing premature senescence due to fertilizer deficiency, foliar spraying with 3% urea plus 0.5% potassium dihydrogen phosphate solution should be applied 2 to 4 times, with an interval of about 7 days each time. Water control. For drought-affected cotton fields, timely irrigation should be carried out; in case of autumn waterlogging, field ditches should be further cleared and dredged to ensure smooth drainage. Pruning. Tip the side branches early to promote the setting of early autumn bolls; for vigorously growing cotton fields, late-cropped cotton fields, and cotton fields affected by cloudy and rainy weather in autumn, old leaves should be removed in time and empty branches cut off.

Pest and weed control. Intensity efforts to control pests in cotton fields such as planthoppers, cotton mirids, tobacco cutworms, and beet armyworms, carry out unified prevention and control, and reduce the probability of large-scale pest and disease outbreaks in cotton fields caused by factors such as excessive vegetative growth or delayed maturity with excessive greenness. Tall weeds and malignant weeds such as dodder should be removed in time, and plants should be pushed together into ridges to increase field ventilation and light penetration.

Chemical regulation and harvesting. Chemical regulation. For late-maturing cotton fields and cotton fields that need earlier crop rotation, ethephon should be sprayed for ripening according to the weather and growth conditions. The spraying requirements are a boll stage of more than 45 days and a temperature above 20°C, and the spraying time should be 20 days before the first frost. For machine-picked cotton demonstration fields, chemical regulation should be the focus according to the weather and growth conditions, and mepiquat chloride should be used in time for regulation, with defoliation and ripening done well. Harvesting. Normal cotton bolls are best harvested 5 to 7 days after boll opening; centralized harvesting can be carried out 2 to 4 times according to the boll-opening situation. During harvesting, drying, packaging, and storage, attention should be paid to the color of seed cotton, and the mixing in of "three hairs" should be strictly controlled to ensure the quality of raw cotton.

Cotton Expert Guidance Group of the Ministry of Agriculture