1. Seeding

1 seed selection

Mainly choose high-quality and high-yield varieties, strong resistance, strong adaptability, good commerciality, insensitive to long-term sunshine response. Jiangsu area mainly uses Hongfei F1, Hongsheng F1, Ziyang and other fine varieties.

2 Sowing in time

The selection of onion sowing time should be based on the local temperature, light and ripeness of the selected varieties. The Jiangsu area is generally sown on September 10-20, with a seedling age of 50-60 days.

3 Seedbed preparation

Seedbeds should be selected for plots with high topography, easy irrigation and drainage, and no onion or garlic planted for 2 to 3 years. After the previous crops are harvested, shallow tillage and fine rakes are applied in time, and sufficient base fertilizer is applied to make flat borders. Generally, 3,000 to 3,500 kg of decomposed high-quality organic fertilizer is applied to each acre bed, mixed with 50% phoxim emulsifiable concentrate 400 ml and wheat bran 6.5 kg, mixed well and mixed with organic fertilizer to control underground pests. Then turn the ground to mix the soil and fertilizer, rake thin, level, and make the border. 40～50 kg of diamine phosphate and 25 kg of potassium sulfate are applied per mu in the border. The seedlings are raised with high borders, with a border width of 1.2 m and a border width of 0.3 m. Do a good job of bordering, pour enough water into the bottom, and sow after the water seeps down. Planting 1 mu of field onions requires seedlings of 60-75m2.

4 Sowing methods

Before sowing, soak the seeds in warm water at 50℃ for 10 minutes; or use 50% Fumeishuang and 35% Metalaxyl wettable powder, and mix the seeds according to the seed weight 0.3%. Seeds are mixed with 3 to 5 times of fine soil, evenly spread on the border, then covered with 0.8 to 1.5 cm thick fine dry soil, and covered with plastic film on the border. The seeding amount of 1 m2 seed bed is generally controlled at 2.5～3.0g.

5 Seedling management

Generally, seedlings start to emerge 7 days after sowing. After more than 60% of the seeds emerge, the plastic film is removed in the afternoon. Keep the seedbed moist after sowing. When “drawing the bow” (the young stem grows to a length of about 4 cm, the cotyledons of the plant are bow-shaped and tight) and “stretching the waist” (the upper half of the cotyledon pulls the lower half and the seed coat out of the ground), There must be no shortage of water. Properly control water about 15 days before planting to promote root growth. Seedlings generally do not need top dressing. If the seedlings grow weaker, apply 5 kg of diammonium phosphate per mu of seedbed in combination with watering.

6 Strong seedling standard

The standards for strong onion seedlings vary depending on the variety and the season of seedling growth. Generally, the plant height is 15-18 cm, the pseudo-stem thickness is 0.6-0.8 cm, it has 3 to 4 leaves, the seedling age is 50 to 60 days, the plant is strong, and there is no pest. 2. Reasonable colonization

1 Fertilize, prepare the land, do the furrow

For medium soil fertility, 3000-4000 kg of decomposed organic fertilizer per mu, 15-20 kg of diammonium phosphate, and 5-10 kg of urea are used as base fertilizers. After fertilization, flatten the rake and make it 1.5 to 1.8 m wide, flatten the flattened surface, pour enough water, use 72% metolachlor emulsifiable concentrate 50 ml or 33% pendimethalin emulsifiable concentrate 100ml per mu For 50 kg of water, spray the entire field to control weeds evenly, then cover with plastic film to compact it.

2 Colonization time

The Jiangsu area is generally planted in mid to late November.

3 Colonization density

The planting density of onions should be determined according to the variety, soil fertility and seedling size. Generally, the plant spacing is 15-16 cm, the row spacing is 15-18 cm, and 23 000-29 000 plants can be planted per mu.

4 graded seedling selection

When planting, choose seedlings with well-developed roots, strong growth, and uniform size. After the seedlings are planted, classify them according to the size of the seedlings. Remove seedlings with diseased, weak, injured, and false stem diameters greater than 0.9 cm or less than 0.4 cm. Colonize separately.

5 Colonization methods

Before planting, cut the roots of the seedlings to 2 cm, then dip the roots with 50% carbendazim 500-800 times solution. When planting, plant according to the size of seedlings. First plant holes according to plant and row spacing, and then plant seedlings into the planting holes. The planting depth should be such that the stem discs are buried and the leaf holes are not buried.

3. Field management

1 watering

After the onion is planted, the planting water is poured immediately, and the planting is overwintering. The temperature is low and the growth is slow. The irrigation should be properly controlled. The main cultivation is to protect the soil moisture. The frozen water is poured once before the soil is frozen. After returning to the green in the second year, pour water back in time to promote the growth of the seedlings. Watering in the leaf spring of the early spring should not be too diligent. Keep the soil dry and wet. Generally, water once every 7 to 10 days. When the bulb begins to swell, the water should be properly controlled to squat seedlings for about 10 days. After squatting the seedlings, the bulbs start to swell, which is the key period for top dressing and irrigation. Irrigation should be done frequently, preferably morning and evening irrigation. Stop watering 8 to 10 days before harvest.

2 Fertilization

According to soil fertility and growth conditions, top dressing in stages. When returning to green, apply 10 to 15 kg of ammonium sulfate and 20 to 30 kg of superphosphate per mu. After returning to green, the plant enters Ye Wangsheng growing season for the second top dressing, with 15-20 kg of ammonium sulfate applied per mu. 50 to 60 days after greening, 10 kg of nitrogen, phosphorus, and potassium compound fertilizers were applied topped with water at the stage of bulb enlargement, and applied again at intervals of 15 to 20 days. Bulbs are in full bloom and fertilize as needed. The last time of top dressing should be more than 30 days from the harvest period.

3 Picking buds and sprouting

Onion often appears in the early bolting process during the spring growth process, and bud picking and bolting methods are often used in production to promote lateral bud differentiation and obtain some yield. According to the experience of some vegetable farmers in Shandong and Tianjin, it is better to remove the buds at the top of the flower stems in the early stage to avoid nutrient waste. There is also the splitting method, which splits the flower sedge in half from top to bottom to promote the growth of lateral buds, squeeze the stalk stem aside, and finally form a fuller bulb. Jishan Huayao 4. Disease and Pest Control

In accordance with the plant protection policy of "prevention first, comprehensive prevention and control", priority is given to agricultural prevention, physical prevention and biological prevention methods, and scientific and rational use of chemical prevention and control techniques. Use 75% chlorothalonil wettable powder 500 times or 70% mancozeb 500 times solution or 58% metalaxyl manganese zinc 500 times solution to prevent purple spot disease during growth, and use 72% manganese zinc· cream urea wettable powder 600 times solution or 64% umin·manganese zinc wettable powder 600～800 times solution to prevent downy mildew, use 40% pyrimethanil emulsifiable concentrate 1000 times solution or 40% gray mold sclerotium net suspension agent 1 200 times solution to prevent ash mildew. In the early peak period of Liriomyza sativae adults and the peak period of larval leaf damage, it is controlled with 1.8% avermectin emulsifiable concentrate 2000-3000 times solution or 75% desfluramine wettable powder 3000 times solution.

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