Onion is a tillering onion, and each tiller has 1 or more than ten bulbs (preferably 4-6 bulbs) with irregular size, which is copper yellow and durable for storage. Plants are very cold-tolerant, rarely blossom and bear fruit, and reproduce in tillering bulbs. We should choose local varieties with strong cold resistance suitable for the climatic conditions in our province, such as Acheng Mao Cong, Tieli Mao Cong, Fujin Mao Cong and Yi 'an Mao Cong. The bulbs of seed plants are medium-sized, full and full, with high maturity, which does not hurt heat or freeze.

Second, soil preparation and fertilization

Fertilization in autumn, ploughing in autumn, ridging in autumn, and timely sowing in spring to conserve moisture. 5000kg of diammonium phosphate (65,438+00 ~ 65,438+05 kg) was applied to the base of 667 square meters until the soil and fertilizer were fully mixed and arranged at 70cm row spacing.

Third, timely sowing and reasonable close planting.

Sow in time in early April. Before sowing, hug the ridge surface into a platform and sow 3 ~ 4 rows per ridge. Plant spacing 15cm, "flower arrangement" sowing to form "outreach seedlings", and 667 square meters of seedlings are protected by 19057 ~ 254 10 plants. Seed consumption is 225 ~ 300 kg /667 m2. The appropriate sowing depth is about 3cm. If it is too deep, the overground part will grow too vigorously, and the bulb will not expand easily and be deformed easily. Too shallow, poor root growth, plants prone to lodging, bulbs exposed, easy to crack or turn green in the sun. In the early stage of bulb expansion, it is best to remove some plants with too many tillers and keep 4 ~ 6 tillers per plant.

Fourth, on-site management

1. Water should be ridged in autumn and sown in early spring. Generally, the soil moisture is very good, and no water is needed from sowing to emergence. Water the seedlings once they are fully grown. When the ground is slightly dry, shovel and loosen the soil in time, carry out intertillage and moisture preservation, raise the ground temperature and weed. The principle of keeping the soil dry and wet at seedling stage. In the Ye Sheng stage, water management should be strengthened, and the seedlings should be squatted 7 ~ 10 days before the bulb begins to expand, so as to promote the formation and expansion of the bulb; After the bulb begins to swell, it is the key period of fertilizer and water management, so it is necessary to water it frequently to keep the soil moist; When approaching maturity, watering should be gradually reduced and stopped 5 ~ 7 days before harvest.

2. Topdressing should be applied once at the peak of growth (combined with watering); Top dressing (combined with watering) again at the beginning of bulb expansion.

3. Chemical Weeding Because of the high planting density in Mao Cong, it is not easy to shovel weeds. Chemical herbicides have a good effect. You can use "Tian Bu" 200g/667 square meters to apply fields before or after sowing.

4, pest control

(1) The main pests are liriomyza sativae and ground maggots. The method of controlling leaf miner is to remove weeds and residual leaves in the field and on the edge of the ground in time to eliminate the source of the insect; Once the larvae are found lurking, a mixture of 800 times dimethoate and 2000 times enemy liquid should be sprayed in time. The method of preventing and controlling ground maggots is that the manure applied to the field must be fully decomposed, or a certain amount of pesticides should be mixed into the manure first. When there are a lot of onion flies (their adults), it is necessary to spray 2000 times of liquid enemy to kill them in time, once every 7 days and continuously for 2 ~ 3 times.