Water-saving cultivation of cotton in semi-arid saline-alkali soil

Cotton has always been an important economic crop, and the continuous improvement of cotton yield and quality is of great significance to increase agricultural efficiency and increase farmers' income. Over the years, through gradual exploration, a set of relatively complete cotton cultivation techniques in semi-arid saline-alkali land have been formed, and drought-resistant cotton planting has achieved the goal of early maturity, high yield and high quality. The problems of cotton seedling emergence, seedling protection, slow growth and late ripening in saline-alkali soil were solved due to the lack of water resources.

The yield-increasing technology of cotton in semi-arid saline-alkali land mainly includes seed preparation, fertilization, chemical control, pruning and so on.

Seed preparation:

Insect-resistant cotton resistant to cotton bollworm, drought, premature senility, waterlogging, barren and saline-alkali tolerance was selected, such as Ji 668, Ji 669, Guoxin Mian 3, Jifeng 197 and so on.

The determination of sowing amount: the sowing amount per mu is larger than that of the land with good water and fertilizer conditions, and the sowing amount of mechanically sown cotton fields should be controlled at two kilograms per mu, not less than 3 to 4 grains per hole, and 1.5 kilograms for artificial sowing cotton fields. With sufficient seeding rate, sufficient seedling density can be ensured. Attention should be paid to: 1. The germination test must be done before sowing, and the suitable sowing amount should be determined according to the germination rate. 2. When sowing coated seeds, do not soak the seeds, but should sow the dry seeds. 3. Drying seeds before sowing can not only promote seed ripening, increase germination rate, but also sterilize and reduce seedling disease.

Adopt plastic film mulching technology

Plastic film mulching can increase temperature, preserve soil moisture, increase soil moisture, promote early emergence of seedlings, control weeds and inhibit soil salinization. The return of saline-alkali land to saline-alkali land is not conducive to the emergence and early emergence of cotton, often due to late boll setting, less cotton flowers before frost, resulting in poor cotton quality, low yield and low efficiency. This problem can be solved by plastic film mulching. It is proved by production practice that the growth rate of plastic film cotton is obviously higher than that of open field cotton and has obvious drought resistance effect. Cotton has many flowers before frost and has good quality. Planting plastic film cotton should pay attention to: the sowing depth should be shallow, generally about 3 cm.

Suitable time for sowing

Sowing sooner or later has a great relationship with the early, complete, uniform, uniform and strong cotton seedlings. The sowing time of plastic film cotton in semi-arid land should be controlled from April 20 to April 25, and the sowing of open field cotton should begin after April 25 and end around May 1. Be careful not to plant too early, lest freezing injury, rotten seeds, rotten buds and seedling diseases occur at low temperatures.

Reasonable close planting

The soil fertility of semi-arid saline-alkali land is poor, cotton does not grow, and the plant is dwarfy. the growth period is short, high yield should be obtained by large population, and the seedlings should be properly dense. It can increase the number of bolls near the main stem, so as to improve the yield and quality. It generally reaches 3500 plants / mu to 4000 plants / mu. And different varieties because of the different degree of compactness of plant type, the density is also different, compact varieties can be slightly denser, loose varieties can be slightly thinner. It is better to adopt the planting form of large and small rows, with a wide row of 80 cm, a narrow row of 50 cm and an average row spacing of 65 cm.

Balanced fertilization

Balanced fertilization can not only improve fertilizer use efficiency, but also promote cotton root extension, absorb deep soil water, and play the role of water saving and drought resistance. In order to achieve high yield and high quality of cotton in semi-arid saline-alkali soil, it is necessary to continuously supply all kinds of nutrients needed for cotton plant growth through fertilization, and increasing base fertilizer and improving soil fertility are important measures. give priority to base fertilizer and topdressing as a supplement. The base fertilizer is mainly organic fertilizer, combined with the application of nitrogen, phosphorus and potassium, and the heavy application of flower and boll fertilizer can obviously increase the yield. In order to reach the level of 250 to 300 kg per mu of seed cotton, it is recommended to apply base fertilizer per mu: 10 to 15 kg of urea, 20 kg of diammonium and 10 to 15 kg of potassium sulfate. Another 15 kg of urea was applied to cotton at flowering and boll stage. In the middle and later stage, 0.5 to 1.0 kg of urea, 2 kg of potassium dihydrogen phosphate or 15 ml of rich potassium per mu, a small amount of boric acid and 50 kg of water were sprayed once every 7 to 10 days for a total of 2 to 3 times.

Pruning and branching

The key point of cultivating cotton in dry land is to prune and branch in time, and the key point is to hit the crazy branch, the top and the group tip. The crazy branch under the first fruit branch should be knocked off in time. The peak time is usually before July 15, with 10 to 13 fruit branches left on each cotton plant. To hit the top of the crowd is usually finished before August 10. There can be 2-3 fruit nodes on each fruit branch in the lower part of the cotton plant, 3-4 fruit nodes on each fruit branch in the middle, and 2-3 fruit nodes on each fruit branch in the upper part.

Chemical Control Technology of Cotton

It includes two aspects: Shengjiaan control and ethephon ripening. In the application of Suijiaan, the dosage should be strictly controlled and used flexibly according to variety, climate, soil quality and growth. In general, in the whole growth process of cotton, the number of chemical control is 3 to 4 times: the first chemical control time is in full bud or early flowering stage, the dosage is 0.5 to 1 gram per mu, the second chemical control is in full flowering stage, the dosage is 2 to 3 grams; the third chemical control is in flowering and boll stage, the dosage is 3 to 4 grams.

In the later stage of cotton growth, the temperature drop is relatively fast in autumn, and some late cotton bolls can not mature naturally, or even can not crack and open bolls. Ethephon can be used to accelerate the maturation of cotton bolls, increase the number of flowers before the box, and improve yield and quality.

Control of cotton diseases and insect pests

Diseases: mainly seedling disease, Fusarium wilt, Verticillium wilt and so on. Seed coating can effectively control seedling diseases. Verticillium wilt can be controlled by comprehensive measures such as crop rotation, selection of disease-resistant varieties, timely removal of diseased plants and so on.

Insect pests: mainly control aphids, red spiders, blind bugs, thrips and other pests. Attention should be paid to the prevention and control of blind bugs, and the time for prevention and control should be in the evening. In the year of heavy occurrence of cotton bollworm, the peak chemical control occurred once or twice in each generation, and the control index was 20 2nd instar larvae of 100 cotton bollworm plants.