Detailed Explanation of the New Cotton "Simple, Dwarf, Dense" Cultivation Technique

The main content of the cotton "simple, dwarf, dense" cultivation technique is based on transgenic insect-resistant cotton, adopting such techniques as chemical weeding to reduce intertillage, simplified pruning supplemented by chemical regulation, wide-row dense planting, regulating fertilizer with water, and integrated pest and disease control, to achieve the cultivation goals of dwarfed dense planting and increased yield and efficiency.

The yield target is 200-250 kg of seed cotton per mu, and the yield structure is: a density of 4000-6000 plants per mu, 55000-60000 bolls per mu, and a single boll weight of 4.0-4.5 grams. The growth process is: sowing and film mulching from April 15 to 20, the seedling emergence stage at the end of April, the squaring stage in early June, the flowering stage in early July, the boll-opening stage in late August, and finishing flower picking and pulling up the cotton stalks in early November.

Main cultivation techniques:

1. Pre-sowing preparation:

1. Select good varieties. The selected variety should have the following characteristics: good high yield, mainly strong boll-setting ability; resistance to fusarium wilt and tolerance to verticillium wilt; a medium-maturity or slightly early-medium-maturity growth period; strong growth vigor, good late development, and no premature senescence; good insect resistance, with high resistance to cotton bollworm.

2. Apply sufficient base fertilizer. In conjunction with land preparation, apply sufficient base fertilizer all at once. Apply 20 kg of urea, 20-25 kg of diammonium phosphate, and 10-15 kg of potassium chloride per mu. For irrigated cotton fields, adopt the method of applying fertilizer first and then watering, so that nutrients leach down with the water, requiring only harrowing rather than plowing; for dryland cotton fields, the method of applying fertilizer in plow furrows is better.

3. Build up and preserve soil moisture. In normal years, there is little rain or snow in winter and spring, and the soil has insufficient bottom moisture, so measures such as winter irrigation or early spring irrigation to build up soil moisture can be adopted.

2. Sowing and film mulching:

1. Chemical weeding. Before sowing, spray trifluralin or acetochlor and mix with soil, at 100-125 grams per mu.

2. Row spacing arrangement. Use a 50 cm and 90 cm wide-narrow row configuration or 80 cm equal row spacing planting.

3. Determine the sowing date. The suitable sowing date is before the last frost, that is, "the tail of the cold and the head of the warm." The suitable sowing date for film-mulched cotton in central and southern Hebei is mid-April, and in eastern Hebei it is from the end of April to early May.

4. Agricultural machinery operations. Cotton seeds are coated or dressed with chemicals, and sowing and film mulching are completed in one pass using a sowing and film-mulching machine.

3. Seedling stage management:

1. Replanting and thinning to a stand. In early May, transplant seedlings early to fill gaps in missing or broken rows, and thin to a stand when there are 2-3 true leaves, taking care to remove weak and diseased seedlings.

2. Control insect pests: if cutworms cause damage during the seedling emergence stage, use 50% phoxim emulsifiable concentrate at 1000 times dilution or 55% Chondile at 1500 times dilution for root drenching, or use a WS-16 sprayer with the nozzle plate removed for spray irrigation.

3. Remove the film early. When the cotton seedlings grow to 4-5 true leaves, remove the plastic film.

4. Bud and boll stage management:

1. Water to prevent premature senescence. Watering in mid-June is a key measure to prevent premature senescence of cotton. For cotton fields with insufficient nitrogen fertilizer in the base fertilizer, apply 10-15 kg of urea per mu as a topdressing in conjunction with watering.

2. Simplified pruning. Top the plants in mid-July, leaving 11-13 fruiting branches per plant. Fine pruning of cotton is cumbersome and labor-intensive, so under appropriate row spacing and density arrangements, chemical regulation can be used to minimize pruning operations.

3. Plant shape control. There are two ways to shape the cotton plant: first, removing the upper cluster tips; if continuous rainy weather occurs in July-August and the cotton plants grow excessively, the tips of the upper part and vegetative branches can be pinched off. Second, chemical regulation with mepiquat chloride; the amount of mepiquat chloride should be determined according to factors such as variety characteristics, amount of rainfall, cotton plant growth vigor, and soil fertility. For varieties sensitive to mepiquat chloride, the dosage must be controlled even more carefully. In drought, chemical regulation may not be needed, and in rainy years it should also be carried out on the principle of small amounts applied multiple times and light application. The general dosage is 1.0-1.5 grams per mu at the full squaring stage, 2-3 grams at the early flowering stage, and 3-4 grams at the full flowering stage, each diluted with 40-50 kg of water for spraying.

5. Insect pest control:

The 2nd generation cotton bollworm generally does not need control; the 3rd-4th generation cotton bollworm should be controlled flexibly according to the degree of occurrence. Pay attention to controlling cotton mirids, red spider mites, cotton thrips, cotton aphids, and other pests, with special attention to the control of cotton mirids. In mid-May, 20% imidacloprid soluble concentrate at 2500-3000 times dilution can be sprayed, using 25-30 grams per mu diluted with 60-75 kg of water, to control cotton aphids, thrips, mirids, and others. Using 1.8% abamectin at 3000 times dilution and 40% Leiman at 2000-3000 times dilution gives good results against red spider mites. When cotton bollworm infestation is severe, Bacillus thuringiensis or a mixed spray of 5% flufenoxuron plus beta-cypermethrin at 2000 times dilution can be used, and 40% profenofos can also be used for control:

6. Timely harvesting:

After September, pick fully opened cotton boll lint, picking once every 7-10 days. After picking in the morning, dry for 2 days; after picking in the afternoon, dry for 1 day. Remove stiff bolls and sell by grade or store in stacks.