Since late July, the cotton areas of the Yangtze River Basin have experienced high temperatures, low precipitation, and long duration, and drought has occurred in some areas. Currently, cotton is in its budding stage. Drought can easily cause a large number of budding bolls to fall off, affecting the development of cotton root systems and causing premature senescence of cotton plants in the later stages. At the same time, according to weather forecasts and the climate characteristics of “two droughts in three years”, autumn drought is prone to occur from September to October, which affects the development of cotton bolls, resulting in reduced boll weight and reduced quality. In view of the current weather characteristics and cotton growth conditions in the cotton areas of the Yangtze River Basin, the Planting Industry Management Department of the Ministry of Agriculture and Rural Affairs, together with relevant experts from the National Agricultural Technology Extension Service Center and the Cotton Expert Steering Group of the Ministry of Agriculture and Rural Affairs, have studied and formulated the following technical guidance for cotton drought resistance and production promotion in the Yangtze River Basin. .
1. Timely irrigation
You must look at the sky, the ground, and the seedlings to flexibly control the irrigation time. If it does not rain for 7 consecutive days, the top 3-4 leaves of the cotton plant will wilt at noon. The leaves become thicker, dark green, dull, and fail to return to normal by 3-4 pm, which indicates that the cotton plant is short of water and needs to be irrigated in time. Irrigation methods such as furrow irrigation, sprinkler irrigation, and drip irrigation should be adopted according to the actual situation and conditions to increase the relative humidity of the canopy air, reduce the soil and canopy temperatures, and improve the field microclimate. Generally, the amount of irrigation for land plots is 50-60 cubic meters per acre. Sandy soil has poor water retention, so irrigation can be divided into 2-3 times, preferably in the morning and evening.
2. Intertillage and soil cultivation
Shallow intercultivation and soil cultivation can be carried out on cotton fields that have not been closed after irrigation. Shallow cultivating can cut off soil capillaries, increase water penetration, reduce soil evaporation and water loss, improve soil permeability and fertilizer and water supply, and promote cotton plant root development. Cultivating the soil can also remove weeds, promote the formation of aerial roots, and enhance the lodging resistance of cotton. If there are still many weeds in the cotton field after cultivating, herbicides can be sprayed to completely eliminate the weeds in the field.
3. Scientific fertilization
It can be combined with pest control by spraying foliar fertilizers such as urea solution, potassium sulfate, and potassium dihydrogen phosphate solution 2-3 times. Sustained drought can easily cause boron deficiency in cotton. When the petiole banding rate of cotton in the field is high, the fruit branches are not strong enough, and the bud shedding rate is more than 10 percentage points higher than normal, it indicates a serious boron deficiency. Solubor, etc. should be sprayed in time. High boron content fertilizer.
4. Pest control
High temperature and drought will accelerate the spread of pests, especially aphids, spider mites, whitefly, Spodoptera litura, lygus weevils, cotton thrips, etc. Pests are prone to serious outbreaks under high temperature and drought conditions. Timely prevention and control of pests is an important part of field management in hot and dry seasons. Lygus bugs mainly damage the top buds, young leaves, flower buds and young bolls of cotton plants. They are generally active in the morning and evening and are easy to migrate. The suitable control time is before 8 a.m. and after 6 p.m. You can choose methylaminoavermectin, horsetail bugs, etc. Spray chemicals such as lathion. To control cotton bollworm, phoxim, profenofos, methomyl and other chemicals can be used, and the chemicals can be used in rotation. Use flufenuron and other methods to control Spodoptera litura, and apply after 4 p.m. Bemisia tabaci is prone to occur in places with densely packed vegetables, so bifenthrin can be used for drone control. To control cotton aphids, nitenpyram, chlorothiazide, carbofuran, etc. can be used in turn. Use abamectin to control red spider mites. Use acetamiprid, carbofuran, imidacloprid, etc. to control cotton thrips.
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