When is cotton planted?

Cotton planted too early may suffer damage from late spring frost, which not only advances the growth and development of the cotton but also increases the risk of boll rot. In addition, if cotton switches from the vegetative growth stage to the reproductive growth stage too early, a large amount of nutrients will be consumed to support the opening of flowers and the formation of bolls, which will cause the vegetative growth of cotton to become weaker. In the middle and late stages of growth, the growth of cotton may be weakened, thereby increasing the occurrence of premature aging. So when is cotton planted?

When is cotton planted?

In northern cotton-growing areas, the appropriate sowing time depends on local climatic conditions. For areas where the temperature gradually and steadily rises in spring, sowing can be carried out when the ground temperature at a depth of 5 cm stably reaches 12-14 degrees Celsius. This is usually called the "cold tail and warm head" sowing time. Alternatively, sowing can be carried out according to the principle of "sowing after the last frost to ensure emergence after the last frost". Generally speaking, the last frost period is between April 10 and 20, so the suitable sowing period is usually in mid-April.

For areas where spring temperature fluctuates greatly, it is recommended to sow seeds after the last frost when the ground temperature at a depth of 5 cm is stable at above 14 degrees Celsius. Such sowing period is usually between April 15th and 25th.

In China's major cotton-growing areas, the sowing time and suitable temperature are as follows:

Northwest Inland Cotton Area: The spring temperature in Xinjiang is low and unstable. The spring temperature in southern Xinjiang rises quickly and stably, and the suitable sowing period is from April 5 to 15. The frost-free period in northern Xinjiang is relatively short, only about 150 days, and is easily affected by late frosts. Under the condition of mulch covering, the recommended sowing period is from April 15th to 20th, following the principle of "sowing before frost and seedlings emerging after frost". The temperature in Turpan area rises rapidly in spring, and the sowing period of plastic film cotton is usually in early April.

Precautions before sowing cotton

1. Land preparation

Whether land preparation is needed after tillage in the fall or winter depends on local climatic conditions and soil characteristics. In areas with heavy rain and snow in winter and spring or with irrigation conditions, harrowing can be omitted to allow the soil to remain moist in winter and absorb spring rainwater. In areas with less rain and snow, the land should be harrowed in time after plowing. In the northern cotton-growing areas, harrowing in spring is a key measure to maintain soil moisture, because the temperature rises quickly, the wind is strong, and the soil evaporation is large. Spring harrowing should be done as soon as the ground begins to thaw and completed promptly after thawing.

The quality of land preparation must be high. Whether it is rotation land or continuous cropping land, it should meet the six standards of "moist, flat, loose, broken, clean and even" to ensure the quality of sowing and achieve full seedlings. The six standards include: the soil has sufficient surface and bottom moisture; the ground is flat and without bumps; the upper layer of the soil is loose and the lower layer is compact, with no compaction in the middle; the surface layer is fine and there are no large lumps of soil; the soil is free of residual crop stubble, grass roots and residual film, and the entire field is clean; the land is trimmed to every corner, forming neat squares and straight lines. Among them, "moisture content" is the key to successful land preparation. In order to ensure sufficient bottom moisture, it is necessary to irrigate the bottom soil and do a good job of moisture conservation in spring. Knowing the right tillage period for the soil is crucial for "leveling, loosening and breaking up", especially for soils with heavy clay. To prevent weeds, the soil should be treated with dimethoate or other pesticides 1-3 days before sowing, ensuring that the spraying is even without duplication or omission.

2. Seed treatment

Seed treatment before sowing helps disinfect and sterilize and promote germination. Seed treatment methods include depilation with sulfuric acid, seed mixing with chemicals, and seed soaking. With the rapid development of China's cotton seed industrialization, cotton seed coating agents and their supporting technologies have been widely promoted throughout the country, and the production, processing and sales of seeds can be completed by specialized cotton seed companies.

Seed dressing with pesticides is essential to kill pathogens carried by seeds or in the soil after sowing. Usually, 0.5% of the active ingredient of carbendazim is used to mix seeds (that is, 1 kg of 25% carbendazim wettable powder is mixed with every 50 kg of cotton seeds) and stored in a sealed container for about half a month, which can effectively prevent and control damping-off disease and anthracnose.

Seed coating agent is a pesticide preparation made from pesticide raw materials, fertilizers , growth regulators, film-forming agents and supporting adjuvants through a specific process. It can be coated on the surface of seeds directly or after dilution to form a protective layer film with certain strength and air permeability. The seed coating agent can solidify into a film when it meets water in the soil and is almost insoluble, ensuring the normal germination of seeds. At the same time, substances such as pesticides and seed fertilizers are slowly released, extending the effective period of the pesticide, saving pesticides and fertilizers, reducing the number of applications, and improving seed quality.

3. Pick up the remaining poles

Picking up residual stems is a key step to ensure sowing quality. Surveys in recent years have shown that due to residual film, the seedling failure rate may be as high as 8%. Mechanical picking up of residual stalks should be carried out after the cotton field is prepared, and avoid being carried out after the herbicide is applied, so as not to damage the film layer and affect the effect of the herbicide.

4. Weeding before sowing

Weeding before sowing is a key link in cotton field management, and the weeding effect directly affects the harvest. Due to the heavy spring rainfall in recent years, weeds are prone to grow in the fields, especially malignant weeds such as Solanum nigrum. It is recommended to use 33% pendimethalin emulsifiable concentrate for pre-sowing weeding, preparing 160-180 ml per acre. Application should be done 2 to 5 days before sowing. When applying herbicides, ensure that the spray is uniform and consistent, avoid duplication or omission to avoid pesticide damage, and facilitate uniform emergence.

The above is an introduction to the cotton sowing time and key points before sowing. The specific cotton sowing time depends on the local climatic conditions. If you want to increase the yield, the preparation work before sowing is also very important.