1 Soil preparation and fertilization Planting shallots shall be selected as flat lands, and neutral soils with loose soil, strong water retention and fertility, and convenient drainage and irrigation. Soil preparation requires that the soil should be loosened by about 30cm, and the soil leveled and finely grounded. A high-quality, decomposed farmyard fertilizer of 45 tons, and a nitrogen-phosphorus-potassium compound fertilizer of 450-750 kg as the base fertilizer should be applied per hectare, and the fertilizer should be applied to a 15 cm layer. 2 sowing on April 5 to 10 sowing, the use of alfalfa as a method, the width of 12Ocm, including the surface of 90cm, both sides of each 15cm, plant spacing of 8cm15cm or 10cm15cm; using ridge, ridge distance 65cm, spacing of 8cm15cm, There are 63.0 to 675,000 strains of seedlings per hectare. 3 Field Management a. Fertilizer Water Management Onion roots are distributed in the soil surface and have a weak ability to absorb fertilizer and water. During the growing period, the green onions should be top-dressed in appropriate amounts to allow the plants to thrive and provide sufficient nutrients for the formation of masts. In the early stage of growth, hairy onion seedlings are applied with 150kg of ammonium sulfate and 75kg of potassium sulfate per hectare. When entering the peak period of the hairy leaves, 225kg of ammonium sulfate is applied per hectare, and applied continuously for 2 times. When the onion bulb starts to expand, 300kg of ammonium sulfate is applied per hectare. Potassium sulfate 75 ~ 150kg, continuous application 1 ~ 2 times. After the onion sowing, if the soil moisture before emergence is good, you do not need to water, in order to raise the temperature and promote rooting; if the drought is severe, should be timely irrigation according to flood conditions, but the amount of irrigation should not be too large. After emergence, it will increase the number of irrigation times, and it will be sprayed once every 7-8 days. After the seedling grows to a certain height, the bulb portion begins to expand. At this time, the amount of irrigation water should be controlled for seedlings and seedlings for 7-10 days. After seedling emergence, the green onion enters into the expansion period of the bulb. At this time, the number of irrigation should be increased. Generally, irrigation is performed once every 5 to 6 days, and the irrigation time is appropriate in the morning. When the bulb is mature, the number of irrigation should be reduced, 7-8 days before harvest, when the field plants began to appear natural lodging should stop irrigation, in order to reduce the water content of the bulb, improve the storage of the bulb. In a certain period of time, successive operations of top dressing and irrigation are sequentially performed. b. Diseases and Insect Pest Control The main diseases of onion include downy mildew, gray mold, purple spot, and pests such as onion thrips. Prevention and control of pests and diseases should be based on prevention, spraying once every 7 to 10 days after emergence, and selecting clear and windless days. Downy mildew and gray mold can be sprayed with 75% chlorothalonil wettable powder 1500 times spray; purple spot can be controlled with 72% agricultural streptomycin 2000 times foliar spray, even against 2 or 3 times; onion can be used 30% speed grams of EC 800 to 1000 times spray control. 4 Harvesting When two-thirds of the plants in the field turn yellow and begin to fall flat, the outer scales of the bulbs dry out and they are harvested. Harvesting is usually conducted before the arrival of the rainy season in early July to avoid drizzle and rain, which is convenient for storage.
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