Improve late-season cotton ripening to enhance cotton quality and profitability
The fundamental measure to prevent premature senescence in cotton is to start with strengthening the basic construction of the cotton field, that is, deep plowing and thorough harrowing of the cotton field, increasing the application of organic fertilizers, and maintaining the balance of various soil elements. Once cotton enters the late growth stage, only the following remedial measures can be taken: 1. Fertilizer and water management should be based on the condition of the cotton plants...
For late-developing cotton fields and high-yield cotton fields with late-maturing varieties, there are more autumn bolls. If early frost comes early and normal boll opening cannot occur before frost, ethephon should be sprayed at the right time and in the right amount to promote early boll opening and increase yield and quality. Generally around October 1, choose a sunny day with a temperature above 20°C to spray ethephon, using 150--200 mL of 40% ethephon per mu, mixed with 50 kg of water, and spray the entire cotton plant, focusing on the upper autumn bolls, which can promote early boll opening and increase yield. Precautions: 1. The spray solution should be prepared fresh each time; 2. It cannot be mixed with alkaline pesticides. In addition, a new type of cotton ripening agent, "Tuotulong," can also be used. In the late stage of cotton, people commonly use ethephon for ripening, but its disadvantages are that it has no defoliation function and ripens slowly. Boll opening only begins 15 days after use, and dead leaves remain, which can easily contaminate the lint with dead leaf fragments, resulting in poor cotton grade and a low proportion of pre-frost cotton. In recent years, test results have shown that using the new cotton ripening agent "Thidiazuron" (produced by Bayer, Germany) for ripening can avoid the above disadvantages. Its main advantages are: 1. Thidiazuron can rapidly desiccate cotton, with early and fast leaf drop, taking effect 10 days after use. It quickly promotes cotton maturity and boll cracking, inhibits excessive vegetative growth, and causes the late autumn bolls of cotton to mature evenly and earlier, with maturation time tending to be uniform, facilitating concentrated manual cotton picking. 2. After the cotton leaves drop early, it can improve ventilation and light penetration conditions in the cotton field, reduce boll rot, and also facilitate the sowing and transplanting of the next crop, as well as early and deep autumn plowing. 3. It can promote the early formation of an abscission layer at the base of the cotton petiole, causing the cotton leaves to fall off before withering, avoiding contamination of the lint by dead cotton leaves and fragments. Moreover, after leaf drop, the cotton plant does not die and continues to grow, which can significantly increase the proportion of pre-frost cotton, thereby improving cotton grade and yield.Suitable application time: When cotton leaves show signs of aging and the vegetative growth of old bolls enters a stagnant development period, at which point cotton leaves are prone to dropping, and there are still five unopened bolls above the opened bolls on the main stem, generally spray 15 days before Frost's Descent (late September to early October).
Method of use: Use 4 grams of "Thidiazuron" plus a specialized adjuvant per mu of cotton field, mixed with 30 kg of water, and spray the entire field.