When to Top Cotton? A Detailed Guide to Timing and Methods
If you want to increase cotton yields, topping is the core of cotton pruning work. Topping eliminates the cotton plant's apical growth advantage and adjusts the transport direction of water and nutrients within the plant, which helps improve both yield and quality. So when is the best time to top cotton? How should you do it? 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 both give poor yield increases. There are three standards for the scientific timing of cotton topping. First, when the growing tip of the cotton plant is level with the top two leaves; second, when plant height reaches 60 cm; third, when 8-12 fruit buds have formed. Around mid-July. The sign of topping too early is that the plant's growing tip is lower than the top 1-2 unfolded leaves; the sign of topping too late is when the plant's growing tip rises above the top two leaves. Topping time should also be flexibly adjusted according to the actual conditions of the cotton field and the weather, topping appropriately based on real conditions.
2. Topping Methods
When topping cotton, remove the top one leaf and one bud. For topping different plots, top the weak-growing cotton fields first, then the strong-growing ones; within the same cotton field, top each plant individually regardless of size, do not top in batches, and do not miss any plants. After topping, growth control should be carried out; generally 1-2 rounds of growth control are needed after topping. For cotton that is weak-growing, densely planted, has poor fertilizer and water conditions, or has flowers reaching the top, growth control can generally be done 5-7 days after topping; the second round of growth control is generally carried out moderately after the first application, and if the cotton is growing excessively vigorously, the dosage can be appropriately increased for the second round of growth control.
3. Topdressing After Topping
After topping, cotton should be topdressed appropriately according to its growth condition. Generally speaking, ordinary cotton fields can be topdressed with 5-8 kg of NPK compound fertilizer per mu. Saline-alkali plots can be topdressed with 3-5 kg of NPK compound fertilizer per mu. In addition, boron fertilizer should be appropriately supplemented during topdressing; 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, and achieve a yield increase.
4. Watering After Topping
Generally speaking, after topping, cotton quickly enters the peak growth period of flowers, buds, and bolls. This is the peak water demand period of the entire cotton growth cycle, so after topping, watering must be sufficient. When watering, use small amounts but water thoroughly, avoiding a single excessive watering. Later watering should be stopped at the right time according to the cotton's growth, so as to prevent the cotton from staying green too long and maturing late.
The above is an introduction to cotton topping time and methods. We hope it helps you. For more related knowledge, please stay tuned to us.