Technical guidance on Management in the later stage of Cotton production in 2016

In order to ensure the stable increase of cotton production and income in China this year, according to the production situation and climate characteristics of different cotton areas, the cotton expert guidance group of the Ministry of Agriculture put forward technical guidance for the late management of the three major cotton areas.

Northwest inland cotton area

The key period of cotton boll formation and growth is from late August to October. In view of the late development of cotton in northern Xinjiang, serious boll disease in southern Xinjiang, premature senescence and greed for green and late maturity, the following guiding suggestions are put forward.

The management of cotton field should strengthen the management of fertilizer and water in the middle and later stage, ensure 2 to 3 times of drip irrigation, the amount of drip irrigation is 2030 cubic meters per mu, and topdressing urea 3 kg / mu during drip irrigation. according to the condition of leaves, urea or clear water can be applied properly in the last watering. For premature senile cotton fields, irrigation should be ensured and water suspension should be postponed to the end of August or early September. Urea or potassium dihydrogen phosphate foliar fertilizer solution should be sprayed once every 7-10 days, continuously for 1-2 times. In greedy green late-maturing cotton field, artificial pruning, pushing plants and ridges and other methods can be adopted, and ethephon can be applied timely to accelerate ripening.

Cotton bollworms, aphids and red spiders occurred frequently in the middle and later stages of cotton fields. Cotton fields with serious damage should be treated with pesticides in time and unified spray control. Helicoverpa armigera should choose pesticides with little killing effect on natural enemies (such as Saidan, etc.), red spiders can choose special acaricides and so on. Spraying carbendazim, chlorothalonil and methyl thiophanate should be used to control boll disease in cotton field.

Scientific harvester cotton field according to cotton field growth, cotton variety, population density and other scientific selection dosage form appropriate spraying defoliant, spraying should be carried out when the cotton boll at the top of the cotton is basically mature, more than 80% of the cotton boll reaches more than 45 days, and the air temperature is stable at 18: 20 ℃, and the defoliation ripening agent must be sprayed 18 and 25 days before harvest. Mechanical harvesting can be carried out when the defoliation rate of the cotton field is more than 90% and the boll opening rate is more than 95%. Hand-picked cotton should be harvested according to the standard, and the mixing of "three filaments" into seed cotton should be strictly controlled.

Cotton area of the Yellow River Basin

Since late July, the cotton area of the Yellow River Basin has suffered heavy precipitation and extreme high temperature for many times, and some cotton fields have signs of overgrowth of cotton plants, shedding of buds and bolls, premature senescence and so on. In view of the current cotton growth trend, we should focus on increasing early autumn peaches and preventing premature senescence, and do a good job in cotton field management in the later stage.

Scientific management of topdressing. For cotton fields with premature senility due to de-fertilization, 3% urea and 0.5% potassium dihydrogen phosphate solution should be foliar sprayed 2 times 4 times, each time at an interval of about 7 days. Water control. The cotton fields with drought should be irrigated in time, and the farmland ditches should be further cleaned and dredged in case of autumn rain and waterlogging to ensure smooth drainage. Prune. Beat the heart early in the morning, promote the knot of early autumn peaches, flourish cotton fields, late stubble cotton fields, and cotton fields that suffer from overcast and rainy weather in autumn, remove the old leaves in time and cut off the empty branches.

The control of Cordyceps sinensis should strengthen the control of cotton field planthopper, cotton bug bug, Spodoptera litura, beet armyworm and other pests, and reduce the probability of large-scale diseases and insect pests in cotton field caused by excessive growth of cotton plants or greedy green late maturity and other factors. Malignant weeds such as tall weeds and dodder should be cleared in time, plants should be pushed into ridges, and the field should be ventilated and transparent.

Chemical control, harvest, chemical control. Late maturing cotton fields and early rotation cotton fields should be accelerated by spraying ethephon according to the weather and growth trend. The spraying period is more than 45 days, the temperature is more than 20 ℃, and the spraying time is 20 days before the first frost period. The demonstration fields of mechanical cotton picking should focus on chemical regulation according to the weather and growth situation, and should be regulated by meth in time so as to do a good job of defoliation and ripening. Harvest. Normal cotton bolls should be harvested after 5-7 days, and can be harvested for 2-4 times according to the situation of boll opening. Seed cotton color should be paid attention to in harvesting, drying, packaging and storage, and the mixing of "three filaments" should be strictly controlled to ensure the quality of raw cotton.

Cotton area of the Yangtze River Basin

In the middle period of cotton growth in the Yangtze River basin, the cotton area suffered heavy rain, high temperature and other bad weather, and some cotton fields showed a trend of premature senescence. All localities should make full use of the favorable climatic conditions of sufficient light and suitable temperature in the later stage of production, strengthen production guidance and bear more autumn peaches, so as to reduce the impact of bad weather on cotton yield and quality.

Topdressing, pruning, topdressing. From late August to late September, 0.3% potassium dihydrogen phosphate was used for foliar topdressing and sprayed every other week. For potassium-deficient and boron-deficient cotton fields, potassium and boron fertilizers were applied in time to supplement nutrients in the later stage to prevent cotton buds from shedding and premature senescence. Prune. Remove ineffective fruit branches in time, old leaves and buds in the middle and lower parts, enhance ventilation and light transmittance, increase boll formation rate and boll weight in the upper part of cotton plant, and prevent boll rot.

Disaster prevention and disaster reduction in various localities to make disaster relief plans, dredge the three ditches inside and outside the cotton field in advance, and rush to drain the stagnant water in the cotton field in time in case of waterlogging. If the typhoon causes lodging, it is necessary to help the cotton plant in time, loosen and cultivate the soil at the right time, and improve the air permeability of the cotton field. Pay close attention to the occurrence of the fourth generation of cotton bollworm, red spider, cotton bug, Bemisia Tabaci and other pests.

Ripening harvest from the end of September to the middle of October, when more than 80% of the cotton bolls reached 45 days, choose a sunny day with a temperature above 20 ℃, and spray ethephon to accelerate ripening. It is suggested that it should be carried out in two stages, the first spraying the middle and lower part of the plant, and the second spraying the upper part of the plant a week later. Ethephon can be sprayed on cotton fields with late sowing and late sowing, more autumn peaches, greedy green and late ripening, or cotton fields with low temperature and little rain in the later stage, which can not crack and puff normally, to promote the cotton boll to mature faster. In the links of seed cotton harvest, drying, packaging, etc., we should adhere to separate collection, drying, storage and sale, so as to put an end to the mixing of "three filaments" and other foreign fibers.

Cotton expert guidance Group of the Ministry of Agriculture (August 2016)