Key Technical Points for Cultivation and Management of Cotton under Hose Drip Irrigation

As the crop area in Jimsar County has increased year by year, water resources have become scarce, and the cost of cotton has risen, the comparative benefit of cotton has declined year by year. For this reason, we introduced and promoted the technique of cotton drip irrigation under film at normal pressure (hose).

I. Main indicators

1. Yield

100-130 kg of lint cotton per 667 sq m. Yield composition: 13,000-15,000 harvested plants per 667 sq m, 5-6 bolls per plant, 5 g per boll, lint percentage 33%-35%.

2. Fertilizer and water

Apply 130-140 kg of standard fertilizer per 667 sq m, with a nitrogen, phosphorus and potassium ratio of 1:0.4-0.45:0.1. Drip water 5-6 times during the growth period, with a total water use of 320-360 cubic meters per 667 sq m.

3. Configuration

Use 145 cm wide film, 3 films with 12 rows, row spacing 27+50+27 cm, connecting row 60 cm, plant spacing 9.5 cm, theoretical plant number per 667 sq m 16,132 plants, one pipe laid per film, and one pipe drip-irrigating 4 rows of cotton. This configuration is suitable for clayey soil and medium loam plots.

II. Pre-sowing preparation

1. Land preparation

① For autumn and winter irrigation, carry out stubble irrigation in late September, applying 70-80 cubic meters of water per 667 sq m, irrigating evenly and thoroughly. For plots without stubble irrigation, carry out winter irrigation after autumn ploughing, applying 80-100 cubic meters of water per 667 sq m.

② Autumn ploughing: before mechanical stalk crushing and stubble removal, manually recover waste pipes and residual film from the cotton field, then carry out autumn ploughing, and in combination with autumn ploughing apply all phosphate fertilizer and 30%-50% of the nitrogen fertilizer and potassium fertilizer deeply over the full layer.

③ Land preparation and chemical weeding: before land preparation, apply 150 ml of pendimethalin or 120-150 ml of trifluralin per 667 sq m, mix with 50 kg of water and spray evenly on the soil surface, ensuring no misses and no overlaps, then prepare the land according to soil type and moisture conditions. The quality of land preparation must meet the six-character standard of "even, level, loose, fine, clean, moist".

2. Preparation of agricultural machinery and tools

Before sowing, inspect and adjust the seeding machinery, and install the hose-laying device. The horizontal shaft guide wheel is required to rotate flexibly, without edge wear, and the tape must be laid loosely.

3. Seed preparation

① Variety selection: select cotton varieties with a growth period of about 120 days, compact plant type, moderate to slightly small leaves, short petioles, strong and concentrated boll setting, suitable for close planting, single boll weight 5-6 g, and good fiber quality.

② Seed treatment: treat seeds with 3911 (60%) at 0.8%-1% of seed weight; the amount of seed coating agent is 2% of seed weight (agent-to-seed ratio 1:50), and the water amount is 1%-1.5% of seed weight. Uniform coating, consistent color, and good film formation are required. The seed coating agent should be selected according to local conditions; in areas with severe seed rot, use Weifu, while in areas with severe seedling death, use Duofujia.

III. Sowing technique

Carry out sowing when the 10 cm soil temperature in the open field stably passes 10°C for 3 consecutive days. In normal years, trial sowing is on April 15, sowing is completed by April 25, and no later than April 30. Use hole sowing on film, sowing 2-3 seeds per hole, with an empty-hole rate required to be less than 2%, sowing depth 2.5-3 cm, and uniform soil covering over the seed row with a thickness not exceeding 1 cm. The hose is laid under the film at the same time as sowing. The sowing quality must meet the goals of straight sowing rows, accurate connecting rows, appropriate hose tightness, flat film surface, and a light-receiving surface reaching four lines and five faces.

IV. Cultivation and seedling thinning

Carry out 1 mechanical intertillage before emergence to increase soil temperature and speed up the emergence of cotton seedlings in the border rows. For cotton fields sown in holes on film, break the surface crust promptly after rain to ensure a sufficient number of retained seedlings. After seedling thinning, carry out intertillage 1 more time, ensuring no large clods are raised, no furrows are pulled, and no seedlings are buried, meeting the requirements of "level, loose, fine". Begin seedling thinning when the row is visible, and finish seedling thinning at the 2 true-leaf stage, removing weak plants and keeping strong ones, with one seedling per hole.

V. Drip irrigation and fertilization

Lay the branch pipes and central main pipe 3-5 days before the first drip irrigation. The spacing between branch pipes is 50 m. The branch pipes and central main pipe should be laid on higher terrain. Drip water 5-6 times during the growth period. Drip the first water in early June, about 50 cubic meters per 667 sq m. After that, drip water once every 10-13 days. The 2nd, 3rd and 4th drip irrigations coincide with the peak water demand period of the cotton's whole life, with 60-70 cubic meters per 667 sq m. Stop watering on August 20 to ensure the soil remains moist in early September. During the whole growth period, drip 320-360 cubic meters per 667 sq m. In combination with drip irrigation, apply the remaining 50%-70% of potassium fertilizer and nitrogen fertilizer in 3 split applications with the water at the early flowering stage and the flowering and boll stage, with the amount of fertilizer applied each time depending on the seedling condition.

VI. Chemical regulation

Carry out chemical regulation 3-4 times during the whole growth period. Determine the timing of chemical regulation according to the leaf age index, and determine the dosage according to different varieties, seedling conditions, soil fertility status and climatic conditions. Generally, Xinluzao 7 and Xinluzao 8 may not need chemical regulation at the seedling stage, but for some vigorously growing strip fields, 0.5-0.7 g of mepiquat chloride per 667 sq m can be used for 1 light regulation. At the bud stage, use 1-2 g of mepiquat chloride per 667 sq m, plus 100 g each of potassium dihydrogen phosphate and urea, mixed with 30 kg of water for foliar spraying. Before the first drip irrigation, carry out the 2nd chemical regulation, using 3-4 g of mepiquat chloride per 667 sq m, plus 150 g each of potassium dihydrogen phosphate and urea, mixed with 30 kg of water for foliar spraying. At the early flowering stage, carry out the 3rd chemical regulation, using 5-6 g of mepiquat chloride per 667 sq m; after topping, carry out the 4th chemical regulation, using 6-10 g of mepiquat chloride per 667 sq m. At the same time, in combination with these two chemical regulations, add 200 g each of urea and potassium dihydrogen phosphate per 667 sq m, mixed with 30 kg of water for foliar spraying.

VII. Topping and pruning

Determine the topping time according to variety and planting density. Generally, topping begins at the end of June and ends before July 10. For cotton fields with fewer than 13,000 plants per 667 sq m, the plant height after topping is 65-70 cm, retaining 7-8 fruit branches; for strip fields with more than 13,000 plants per 667 sq m, the plant height after topping is 60-65 cm, retaining 6-7 fruit branches. For vigorously growing cotton fields, prune by removing vegetative branches to reduce nutrient consumption and achieve the goals of increasing boll weight and promoting early maturity.

VIII. Plant protection work

For the prevention and control of cotton field diseases and insect pests, adhere to the policy of prevention first and integrated control; take ecological plant protection as the foundation, protect and make good use of natural enemies, achieve controlling pests with beneficial organisms, and realize green plant protection.