Four key techniques to grasp in the management of cotton during the boll-opening stage

Grasp the “four key techniques” in cotton management during the boll-opening stage (skillfully manage fertilizer and water, skillfully prune, skillfully pick rotten bolls, skillfully promote ripening).

1. Skillfully manage fertilizer and water to promote nutrient transport. First, foliar topdressing. For cotton fields where leaves lose green too early and show premature aging due to nutrient deficiency, spray 50-60 kg per mu of 1%-2% urea solution onto the leaves to extend the functional period of the leaves. For cotton fields that grow too vigorously and show late maturity with excessive vegetative growth, foliar spray 0.2% potassium dihydrogen phosphate solution or 0.3% superphosphate soaking liquid to promote nutrient transport and help improve boll opening. Second, prevent autumn drought.

2. Skillfully prune and push plants to promote maturity. Limited by temperature, generally buds that appear after "Beginning of Autumn" and flowers after "White Dew" are all ineffective. The newly grown tender parts of the cotton plant should be removed in time, which not only saves nutrients but also reduces damage from the fourth generation of cotton bollworm. In cotton fields with severe canopy closure, due to poor ventilation, some excess old leaves can be removed on the premise of keeping one cotton boll for every 3-5 cotton leaves. Plants can also be pushed together across rows, that is, bringing two adjacent rows of cotton plants together in a V shape, and after 5-7 days, pushing them back to both sides.

3. Skillfully pick rotten bolls to improve quality. Dip the picked cotton bolls in 1% ethephon solution and then dry them in the sun to obtain cotton with better boll opening.

4. Skillfully time ripening promotion to advance boll opening. Spraying ethephon at the appropriate time can make cotton open bolls about 10 days earlier and increase the pre-frost cotton rate by 20%-30%. During spraying, it should be controlled when the bolls on the upper part of the cotton plant have grown for more than 40 days and about 20 days before the killing frost; the spraying amount is generally 150 grams of 40% ethephon per mu, mixed with 50-100 times clean water, and sprayed evenly. If spraying is early, the temperature is high, and the cotton plants are weak, about 100 grams per mu can be sprayed. If rain occurs 6 hours after spraying, it needs to be sprayed again (note that seed fields are not suitable for spraying).