What are the suitable sowing periods and precautions for cotton in Xinjiang?

It is expected that in 2017 the suitable sowing period for cotton in most cotton areas of southern Xinjiang and eastern Xinjiang will be slightly earlier, while in the western cotton area of southern Xinjiang it will be slightly later. South of the Flaming Mountains in Turpan from March 29 to April 5, in most cotton areas of western southern Xinjiang and Aksu from April 5 to 15, in most of Bayingolin and north of the Flaming Mountains in Turpan from April 8 to 17, and in most cotton areas of Hami from April 12 to 20 are relatively suitable for large-scale sowing. In all areas, when the “dry sowing and wet emergence” sowing technique is used, the cotton sowing period can be appropriately advanced.

Production Measures and Recommendations

1. All cotton areas in southern Xinjiang and eastern Xinjiang should complete cotton pre-planting preparation work early, adapt measures to local conditions, and in combination with local rolling weather forecasts, do a good job of revising and refining the suitable sowing periods for cotton in different climatic zones. Seize the “cold tail and warm head” to sow at the right time, and strive for a full stand from a single sowing.

2. During the cotton sowing and emergence period, there is a relatively high possibility of strong winds and dusty weather, so all cotton areas should pay close attention to weather forecasts from meteorological stations at all levels and prepare in advance for meteorological disasters.

The cotton sowing time is approaching. In order to ensure sowing quality and ensure a full stand from a single sowing, cotton farmers should pay attention to the following points:

1. Deep plowing of the field

First, remove residual cotton stalks, plastic film and other debris from the cotton field, so as to reduce cotton field pollution and disease and create a good environment for cotton growth.

Before sowing, the cotton field should be deeply plowed to break the plow pan, break up soil compaction, improve soil properties and promote cotton root growth. On the basis of building up sufficient bottom soil moisture, fine plowing and careful harrowing should be carried out. Generally, spring plowing should be 13-16 cm. Combine with fertilization to further prepare the land well. The quality requirement for land preparation is a loose top and firm bottom. When harrowing, the requirements are “neat, level, loose, fine, clean, moist”, meeting the standards of neat (planned neatly; during mechanical operations such as plowing and harrowing, no blank strips may be left at the field edges or in the middle), level (after plowing, harrowing, manual leveling and other operations, the ground surface is flat, with no ridges or obvious pits on the soil surface), loose, fine (the soil plow layer is loose, with a loose top and firm bottom, and the soil is finely broken, with no clods larger than 2 cm in diameter on the surface), moist (plow when soil moisture is suitable; at this time the soil is loose and land preparation is easy, and it can also keep appropriate water content in the soil at sowing, which is conducive to seed germination and drought prevention and moisture conservation), and clean (no crop stubble, weeds or waste plastic film in the field).

Two points should be noted in harrowing operations:

1. Nowadays, wheeled high-horsepower machines are used for harrowing. When harrowing, it is better if the soil is a bit dry, because when the soil is wet, the places pressed by the wheels during harrowing are prone to compaction, and compacted areas are not conducive to seed emergence.

2. When harrowed land is waiting for sowing, if it rains, unless the rain is especially heavy, it is best not to harrow again. Too many operations easily compact the soil, and mixing the dry surface soil with the wet soil below is also not conducive to seizing moisture for emergence. Repeated harrowing also easily makes the surface too loose, which is not conducive to emergence after sowing.

After plowing and turning the cotton field, harrow and level it promptly. Land preparation is best completed 3-5 days before sowing.

2. Prepare improved seed and treat the seed

1. Seed selection. When purchasing improved seed, do not blindly pursue novelty and high yield; choose according to each area's soil fertility, yield and management level. Excellent cotton varieties with good insect and disease resistance, strong growth vigor, concentrated boll setting, easy management, and early maturity without premature senescence should be selected, and attention should be paid to selecting excellent varieties suitable for local planting.

When selecting new cotton varieties, this should be done on the basis of trials and demonstrations. In the first year, plant only a small amount on trial. When disease resistance, growth vigor, boll-setting ability and yield-increasing performance all exceed those of the original variety, expand planting in the second year.

To buy high-quality cotton seed, go to legitimate seed departments and select high-quality seed with good purity, high germination rate and guaranteed quality.

For coating, please read the relevant content on plant protection of the Corps.

2. Sunning the seed. Sunning the seed can promote after-ripening of the seed, accelerate the absorption of water and oxygen, increase the seed germination rate, and also have a sterilizing effect and reduce disease. Sunning the seed can be done about 15 days before sowing, choosing sunny days for 4-5 consecutive days, until the seed rattles when shaken by hand. Be careful not to sun the seed on concrete or stone slabs, so as to avoid excessive water loss from the seed and the formation of hard seeds, which lowers the germination rate. While sunning the seed, remove broken seeds, insect-damaged seeds, shriveled seeds and abnormal seeds, and keep plump, sound seeds that conform to the characteristics of the variety for seed use, so as to improve seed purity, germination vigor and germination rate.

3. Determine the seed germination rate. The germination vigor and germination rate of cottonseed determine the number, quality and speed of emergence as well as the sowing rate. Therefore, before sowing, germination vigor and germination rate must be determined. In production, generally a germination rate above 85% is required for seed use. The method for determining germination rate generally uses the germination test method. Take 100-200 cottonseeds soaked until they have absorbed enough water, keep the temperature at 25-30°C, the percentage that germinate on the 3rd day is the germination vigor, and the percentage that germinate on the 9th day is the germination rate.

3. Prepare pesticides

At present, coated seed is generally used, so there is no need to prepare insecticides and fungicides; mainly prepare herbicides. For herbicide, prepare 160-180 ml of 33% pendimethalin emulsifiable concentrate per mu. Use it 2-5 days before sowing.

Requirements for herbicide spraying operations:

When spraying herbicide, make sure the sprayer nozzles are not blocked, the spray is uniform and consistent, with no overlapping or missed strips, so as to avoid herbicide damage and help ensure uniform emergence.

4. Prepare techniques

First, prepare the technique for a full stand from a single sowing and master sowing at the right time; second, prepare the technique for reasonable close planting, and determine the row and plant spacing according to the characteristics of the selected variety and soil fertility conditions; third, prepare the technique for pest and disease control at the seedling stage, and apply pest and disease control methods from the start of sowing.

Requirements for cotton sowing operations:

1. Sowing must achieve uniform seed drop and a low rate of empty holes.

2. Uniform soil covering and consistent depth; firm film pressing, which is conducive to seed emergence and wind resistance.

3. Straight sowing rows, which are conducive to field mechanical operations and mechanical harvesting cleanliness.

5. Trial-period sowing

1. Sowing time: when the 5 cm soil temperature under the film stably passes about 14°C and the relative soil humidity is 65%-80%, and cottonseed seedlings after emergence can avoid late frost, this is the suitable sowing period. In order to gain an effective growth period, “sow before frost, emerge after late frost” is mostly used.

2. Sowing density: generally determined according to the requirements of the selected variety.

3. Sowing depth: determine plant spacing according to the selected density and ridge spacing. Shallow sowing depth is about 1.5 cm, and soil covering should not exceed 2 cm.