How to grow onions
10 Before sowing, plough, apply fully decomposed, mashed and sieved farmyard manure, with the amount of fertilizer per mu not exceeding 2000kg, then plough twice, with a depth of about 20cm or more, so that the fertilizer and soil are fully mixed, and then level the border with a flat rake for sowing.
There are two kinds of border specifications: one is a small high border with a border width of 1.6m, a border width of 0.2m and a border depth of 0. 1m, and each border is transplanted with 8 lines. This boundary is suitable for cohesive soil or fields with small gaps. 2. Flat border: the border is 2m wide, the ridge is 0.27m wide and the height is 0.2m, and each border is planted 10 row. Flat border is suitable for sandy soil.
2. Transplanting and density
The transplanting period can be divided into:
1) The suitable transplanting period of plastic film mulching field is 1 1 month 15 to 20 days (around beginning of winter).
2) The suitable transplanting period of plastic film-free field is1October 20th (around the first frost). Conventional density should be increased or decreased according to soil fertility, fertilization level and management level. Generally, the planting row spacing is 20cm, the plant spacing is 16~ 17cm, and the density per mu is 20,000 plants.
In order to prevent bolting, seedlings with leaf sheath diameter of 6~7mm, fresh weight of 4~6 g per plant and suitable size are generally selected. Eliminate big seedlings, weak seedlings and poor seedlings. Before planting, large and small seedlings should be planted separately, managed at different levels, and increased production in a balanced way.
Extended data:
Growing environment:
1, temperature
Onions are very adaptable to temperature. Seeds and bulbs can germinate slowly at 3 ~ 5℃ and start to germinate at 65438 02℃. The suitable temperature for seedling raising is 12 ~ 20℃, the leaf is 18 ~ 20℃, and the bulb is 20 ~ 26℃. Strong seedlings can tolerate the low temperature of ~ 6 ~ 7℃. Bulbs need higher temperature to expand, and bulbs can't expand below 15℃. The optimum growth temperature is 2 1 ~ 27℃. If the temperature is too high, it will grow and decline and enter dormancy.
2. Lighting equipment
Onion is a long-day crop, which needs more than 14 hours of long-day sunshine during bulb expansion and bolting flowering. Under the condition of high temperature and short sunshine, only leaves grow and onions cannot form. The suitable light intensity of onion is 20000 ~ 40000 lux. ?
Step 3: Moisture
Onion should get sufficient water supply during germination, seedling growth and bulb expansion. However, water should be controlled at seedling stage and before overwintering to prevent seedlings from growing white and suffering from freezing injury. Irrigation should be controlled before harvest 12 weeks to enrich bulb tissue, accelerate maturity and prevent bulb cracking. Onion leaves are drought-tolerant, suitable for 60% ~ 70% humidity, and diseases are easy to occur if the air humidity is too high.
4. Soil and nutrition
Onion has strong adaptability to soil, so it is suitable to use fertile, loose and well-ventilated neutral loam. Sandy loam is easy to obtain high yield, while clayey loam has full bulbs, good color and storage resistance. The root system of onion has a weak ability to absorb fertilizer, so it needs sufficient nutritional conditions to achieve high yield.
Every1000kg onion needs to absorb 2kg nitrogen, 0.8kg phosphorus and 2.2kg potassium from the soil. The application of trace elements such as copper, boron and sulfur can significantly increase the yield.
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