Cotton harvest should be managed well in July and August

I. the importance of the decisive battle in July and August the cotton flower and boll period is the longest stage in the cotton growth period, and it is the period with the most abundant natural resources such as light, heat and water, which is very conducive to the growth and development of cotton. However, there was also a disadvantageous side in this period, not only frequent natural disasters such as wind, hail, drought and waterlogging, but also serious harm to diseases and insect pests. There is a saying in the agricultural proverb that "cotton is a volley grass, good can be bad, bad can be good." Therefore, this period is a critical period for winning a bumper cotton harvest, especially this year, when the cotton growth process is 7 to 10 days later than in previous years, and the seedling situation is generally not as good as in previous years, according to the growth characteristics of cotton, make full use of natural advantages, overcome unfavorable factors, strengthen cotton management, it is even more important to fight against disasters and win a bumper harvest in July and August.

II. Key points of management of cotton flowering and boll stage

1. Steady application of bud fertilizer, re-application, early application of flower and boll fertilizer, supplementary application of top fertilizer. According to the investigation of my association's service in the countryside, due to the influence of low temperature, overcast and rain, some cotton fields have not blossomed so far. bud fertilizer should be applied in time for this kind of cotton field, generally applying urea 5kg / mu, phosphate fertilizer 50kg or diammonium phosphate 15kg / mu, boron fertilizer and zinc fertilizer 0.51kg each, combined with ploughing and soil cultivation. In the cotton field entering the flowering stage, the flower and boll fertilizer should be applied early and re-fertilized. generally, the flower and boll fertilizer should be 20 kg urea per mu (30 kg in high-yield fields) and 15-20 kg potash fertilizer. when the amount of fertilizer is more, it can be used twice, once in the early flowering stage and once in full bloom. Capping fertilizer is generally applied in late July and early August. Capping fertilizer should not be too late to prevent greedy green late ripening. Before opening bolls and after topping, 2% urea solution or diammonium phosphate and compound fertilizer leachate were used for extra-root topdressing in cotton fields, once every 7 days, and sprayed 3 times in a row.

two。 Do a good job of chemical control in accordance with local conditions. Chemical control with Suojiaan can not only shape the ideal cotton plant shape and control plant height, but also adjust the nutrient distribution of cotton plant, prevent the growth of aboveground, promote the development of root system, and improve the ability of disease resistance and insect resistance. In order to prevent excess, the principle of a small number of times should be adopted according to local conditions. the general dosage per mu is 0.3 / 0.5g at bud stage, 1g / mu at early flowering stage, 3g / 4g at peak stage and 5g / 6g at 7 days after topping. Through chemical control, the plant height of cotton at full flowering stage is controlled at 80cm to 90cm in the south, about 130cm after topping, and about one meter in the north.

3. Fine pruning and topping in time. Fine pruning is a traditional technique for increasing and stabilizing cotton yield, which should be continued and improved. It is generally appropriate to hit the top time around July 15, so that time to unequal branches, branches to unequal time. For late transplanting cotton fields, early beating can be appropriate in order to prevent late ripening. In the cotton field with simplified pruning and no pruning, the top of the leaf branch should be removed when the leaf branch grows 3 secondary leaf branches. The topping time of the main stem can be appropriately earlier than that of fine pruning.

4. Do a good job in the prevention and control of major diseases and insect pests. Since July, cotton blind stink bugs have entered a period of overlapping and alternating generations, which is also the most difficult period to control. According to the habits of blind stink bugs, the control should be carried out in the early morning or evening in the nymph stage and early damage stage of blind stink bugs, and the policy of complete control should be adopted. In order to achieve this requirement, it is necessary to do a good job in forecasting and prevention and control when the rate of top newly damaged plants reaches 3% to 5%. Cotton fields with serious occurrence should be inspected in time after prevention and cure, if not thoroughly, continuous prevention and control should be carried out until thoroughly. The specific drugs for the control of Toona sinensis are golden bell bug, followed by flufenyanide, Lesbon, malathion and so on. The above pesticides also have high control effect on cotton bollworm, and can be used in many ways. Red spiders occur seriously after drought, which should be checked and controlled in time. The specific drug is avermectin, the peak period of aphid occurrence is in mid-July, and the specific control drugs are acetamiprid, imidacloprid, imidacloprid and so on.

5. Strictly guard against explosive pests. The main explosive pests are whitefly, beet armyworm, small bridge worm and so on. The main occurrence period of whitefly is in August and September, and unified control should be carried out at the initial stage of occurrence. The effective agents are acetamiprid wettable powder, bifenthrin, avermectin and so on. The outbreak period of beet armyworm and bridge worm is in the middle and late August, and the main specific control drugs are metamectin, abamectin, etc., which should be controlled in the critical period before the third instar.

6. Dry and waterlogged drainage. When managing cotton in July and August, it is necessary to cultivate the soil in conjunction with mid-tillage, so that waterlogging can drain and drought can irrigate, so as to ensure the normal growth of cotton.