1. Selection of preferences. The selection of fast-growing, invertable, coarse, short-lived, non-divisive, good-commodity varieties such as croaky, chinese and hebei onions。
Selective fertilization. Onion breeding fields should choose the land that is deep in the soil, fertile in soil, easy to drain and soothing in soil, and which is unplanted in the field, such as onions, garlic and herbs. The whole acre is combined with 5,000 kg of high-quality farmers, 20 kg of compound fattening, ploughing, full-mixed soil fattening, and is made to be 1 to 1. 5 metres wide and 10 metres long for field management。
3. Sowing in due time. Since onion spring seedlings take place at a relatively short time between seeding and planting, early planting is essential, and the south-central region is generally seeding in late march. The average acre is 2. 5-3 kg, and an acre is capable of planting 6-8 acres. The seed is soaked, pre-sowned, and, when the water is seep, the seed is evenly mixed with the appropriate amount of grasswood ash or dry soil, distributed several times, so that the seed is evenly distributed and then covered with 0. 5 centimetres of fine soil; it is also possible to sow the seed several times with a dredge and water with its feet. Both methods end up with plastic sheeting, which increases the temperature and humidity and results in early seeding, generally six to seven days after seeding and one to two days early in the field。
4. Field management. And when the onions come forth in half, the membrane shall be removed, lest it burn. Following the discovery of seymour, a relatively dense spot of onion seedlings was found at an early stage to ensure the same nutritional area for each seedling. During growth, the management approach is “promoting” with small water supplies, less fertilization, soil moisture and nutrients. As the temperature rises, onion seedlings grow, the demand for fat water increases, and the amount of water and fertilization increases accordingly, usually from 30 to 40 cubic metres per acre and 5 kilograms of urea. It is also a period during which weeds are grown, which can be uprooted artificially and can be removed with herbicides, while at the same time taking care to combat maggots and ensure that onion seedling groups grow in a consistent manner and are self-sufficient. A week before the planting, water was stopped and onion seedlings were practiced so that they could slow down as soon as possible。
