Management techniques of spring onions

First, watering: onions are generally not watered during the overwintering period, and there are no diseases and insect pests. From March to April, we should lightly irrigate the green water once; when we enter the vigorous growth period of leaves, we should strengthen irrigation properly; squatting seedlings should be carried out about 10 days before bulb expansion to inhibit leaf growth; when there are 6 functional leaves, water should be irrigated once, and then squatting seedlings for 10 days, in order to prevent the crazy growth of the plant from affecting bulb expansion. After squatting seedlings, the bulb begins to expand, which is the key period of topdressing and watering. However, due to the increase in temperature, evaporation and plant growth, it is the period that needs the most water, watering should be diligent, always keep the field moist, irrigation should be sooner or later. When it is found that early bolting should immediately remove the whole flower moss and form a bulb. Reduce watering times before ripening and stop watering one week before harvest.

Second, topdressing: onions enter the peak period of leaf growth, before turning green to expand the stem, the amount of fertilizer is the most, applying fertilizer twice, urea 15 kg per mu and potassium sulfate 5 kg per mu; proper application of phosphorus and potassium fertilizer is beneficial to the development of bulbs. When the small bulb grows to 2 cm, the amount of compound fertilizer is about 15 kg per mu, and the appropriate amount of fertilizer is added at the peak stage of bulb expansion, 15 kg urea per mu, and the interval between the two fertilizers is 10-15 days.

Third, timely prevention and control of diseases and insect pests: in order to harm onion diseases and insect pests are mainly Botrytis cinerea and Liriomyza huidobrensis, pay attention to the right medicine.

4. Harvest: the bulb of onion is hypertrophic, most of the plants are lodging, the lower part of 1 leaf is yellow, and the tip of the third to fourth leaf turns yellow. The harvest should be carried out on a sunny day, drying on the spot for 3 to 5 days after harvest, and drying only the leaves but not the head when drying (the back row of leaves can cover the front row of bulbs); after drying, it can promote the ripening of the bulb and dry the epidermis, which is beneficial to storage.