The latest timing and methods for cotton topping
To increase cotton yield, topping is the core of cotton pruning work. Topping can eliminate the apical growth advantage of cotton, regulate the transport direction of water and nutrients within the plant, and help promote higher yield and quality. So when is the best time to top cotton? How should it be done? Let's find out together.
1. Topping time
Generally speaking, the normal topping time for cotton is about 90 days before frost. Topping too early or too late will not give good yield-increasing results. There are three standards for the scientific period of cotton topping. First, when the growing tip of the cotton plant is level with the top two leaves; second, when the plant height reaches 60 cm; third, when 8-12 fruit-bearing branches have formed. Around mid-July. The sign of topping too early is that the growing tip of the cotton plant is lower than the top 1-2 expanded leaves; the sign of topping too late is when the growing tip of the cotton plant is higher than the top two leaves. The topping time should also be flexibly controlled according to the actual conditions of the cotton field and the weather, and topping should be done appropriately according to the actual situation.
2. Topping method
When topping cotton, remove the top one leaf and one bud. When topping different plots, first top the cotton fields with weak growth, then top the cotton fields with strong growth; in the same cotton field, top each plant one by one regardless of size, do not top in batches, and do not miss any. After topping, growth control should be carried out. Generally, 1-2 growth control applications are needed after topping. For cotton with weak growth, high planting density, poor fertilizer and water conditions, and flowering reaching the top, growth control can generally be carried out 5-7 days after topping; the second growth control is generally carried out moderately after the first application, and if the cotton growth is excessive, the dosage can be appropriately increased during the second growth control.
3. Topdressing after topping
After cotton topping, topdressing should be carried out appropriately according to the growth condition. Generally speaking, ordinary cotton fields can be topdressed with 5-8 kg of ternary compound fertilizer per mu. Saline-alkali plots can be topdressed with 3-5 kg of ternary compound fertilizer per mu. In addition, when topdressing, boron fertilizer should be appropriately supplemented. 50 g of borax can be dissolved in warm water, then diluted with 50 kg of water and sprayed on one mu of cotton field to supplement boron for the plants, increase the number of bolls set by the plants, and achieve a yield-increasing effect.
4. Watering after topping
Generally speaking, after cotton topping, it will soon enter the peak growth period of flowers, buds, and bolls. This is the peak period of water demand throughout the cotton growth period, so after topping there should be sufficient watering. When watering, use a small amount of water but water enough, avoid excessive watering at one time, and later watering should be stopped in good time according to the cotton growth condition, so as to avoid excessive vegetative growth and late maturity in the later stage of cotton.
The above is an introduction to the timing and methods of cotton topping. We hope it can help you. To learn more related knowledge, please stay tuned to us.