What are the main management techniques for cotton in July?
What is the main management for cotton in July? Please explain. The main management for cotton in July includes the following points: (1) Ditching and earthing up. This helps with watering and drainage, prevents both drought and waterlogging, and also helps with ventilation in the lower part of the cotton field, reduces humidity, increases the temperature difference between day and night, and helps improve the microclimate of the cotton field, which is useful for preventing boll rot...
What is the main management for cotton in July? Please explain.
The main management for cotton in July includes the following points:
(1) Ditching and earthing up. This helps with watering and drainage, prevents both drought and waterlogging, and also helps with ventilation in the lower part of the cotton field, reduces humidity, increases the temperature difference between day and night, and helps improve the microclimate of the cotton field. It also helps prevent boll rot and lodging, and promotes and protects roots. After the plastic film is removed from the cotton field, in combination with intertillage and loosening the soil, ditching and earthing up should be carried out wherever conditions allow, mainly by machine and animal power, with manual assistance. Where there is already a basis for intertillage, it can be completed in one pass or in two passes. Low-lying plots should have their drainage ditch systems cleared.
(2) Pruning and topping. The purpose of cotton pruning is, first, to regulate nutrient distribution, and second, to improve the population structure, ultimately making full use of resources such as water, fertilizer, light, air and heat to achieve high cotton yields. Do not go to extremes in using vegetative branches (referred to as leaf branches), either leaving none at all or removing none at all. In cotton fields with relatively high density and no missing plants, basically no leaf branches should be left, but in sparse areas, areas with missing plants, and at the ends and edges of fields, keep 1-2 strong leaf branches per plant, which can increase the number of bolls per plant; keeping all leaf branches is not advisable. Leaf branches that have not yet produced fruit branches and have very small flower buds must be removed in early July; for relatively strong leaf branches that have already grown fruit branches, the growing tip of the leaf branch can be pinched off immediately, and they must no longer be allowed to grow freely. If there are too many pre-dog-days bolls, this will bring many disadvantages to the cotton plant, such as premature senescence, hard locks and rotten bolls, so in early July all flowers that have already opened should be picked off, so that the cotton plant saves nutrients and sets more bolls when conditions are suitable. In the central-southern Hebei and northwestern Shandong regions, for cotton fields with 2500-3000 plants per mu, according to soil fertility and density, keep 13-14 fruit branches per plant and top in time, and be sure to achieve autumn bolls covering the top. Do not repeatedly delay topping and blindly leave too many fruit branches for fear of shedding and out of greed for more. When planting varieties with relatively high boll weight, seek both a relatively high number of bolls per mu and a relatively high single boll weight. Wanting few or no early bolls and late bolls will greatly improve the uniformity of cotton bolls.
(3) Seize chemical regulation. Generally, chemical regulation should be done 2-3 times in July. The first time is at the early flowering stage, using 1-1.5 grams of mepiquat chloride per mu; the second time is at the full flowering stage, using 1-2 grams per mu; the third time is after topping, using 3-5 grams per mu. Because the cotton plants are now relatively large, during chemical regulation use 20-25 kg of water per mu to spray the whole plant, making sure to spray the growing tip and the tips of the middle and upper fruit branches.
(4) Timely fertilizer supply. On the basis of applying sufficient base fertilizer, cotton generally does not need topdressing with quick-acting nitrogen fertilizer before flowering and boll setting, so as to avoid excessive vegetative mass or excessive vegetative growth; topdressing should be applied at the full flowering stage (when the 4th fruit branch flowers), applying 10-15 kg of urea per mu depending on soil fertility and cotton plant growth. If no potassium fertilizer was applied as base fertilizer, or the amount of potassium fertilizer was too small, it should be topdressed as early as possible. For topdressing cotton fields in July, apply it in the middle of the wide rows so that the cotton plants on both sides can absorb and use it. Never drill-apply it in the narrow rows, so as to avoid injuring the already weakened root system again. Every year there are cases of wilting caused by applying fertilizer too close to the cotton plants. For small seedlings that are delayed in development due to herbicide or disease damage, use 1% urea water to punch holes and irrigate the plants; if they still do not grow, spray gibberellin. For cotton fields with excessively weak vegetative growth due to drought or excessive phosphorus application, spray urea solution so that the growing tip and fruit branch tips extend as soon as possible. After cotton topping, nutrients are preferentially supplied to young bolls, so foliar spraying should be used to ensure the nutrients needed by the cotton plants, and foliar spraying should mainly be nitrogen and potassium. Urea and potassium sulfate are the best choices, with a spraying concentration of 2%, using more than 1 jin of fertilizer per mu each time, avoiding spraying at noon, and be sure to wet the underside of the cotton leaves. Spray immediately after topping, once every 8-10 days, nitrogen first and then potassium, and spraying can continue until August 10-15. The principle of cotton topdressing is not to apply excessive amounts before flowering and not to run short of fertilizer after flowering. Once fertilizer shortage occurs, it is very difficult to achieve autumn bolls covering the top. Applying sufficient quick-acting potassium fertilizer twice in the later stage is very important for setting more bolls and larger bolls in the upper part and for producing good lint. Potassium is indispensable for cotton fiber development, so applying potassium can increase lint percentage. In years with heavy rainfall during the dog days, especially in cotton fields that have once accumulated water, spraying potassium is even more necessary.
(5) Control diseases. Fish protein and Kehuangku are relatively good agents for preventing cotton Verticillium wilt and Fusarium wilt in the middle and late stages. Fish protein should be used once in early July, once every 10 days for 3 consecutive times, using 50-75 ml per mu each time. In disease-prone fields, spray Kehuangku twice between applications of fish protein, and in this way the goal of disease control can be achieved. Cotton fields sprayed with fish protein do not need to be sprayed with urea. Fish protein should not be used again in August to prevent late-maturing greenness, but the two potassium sprays in August still cannot be omitted.
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