Onions are not called scallions, onions, jade, etc. They are biennial herbaceous plants of the genus Liliaceae. Different spheres are related to early and late maturity. Generally, the flatter the more mature the spheroids, the different yields of the cultivars are different, and the early maturity is flat. The variety is generally 4,500 to 5,500 kilograms per mu, and the mid-late and late-maturing varieties are generally 5,000 to 5,500 kilograms per mu.
Onion cultivar
1. Red onion: The onion is purple-red, the scales are slightly reddish, flat or spherical, with a diameter of 8 to 10 cm. Resistant to storage, transportation, short dormancy, early germination, from early maturity to mid-maturing, harvest from late May to early June. It is widely cultivated throughout East China. Representative varieties are Shanghai Red Leather and so on.
2, yellow onion: onion head brass to pale yellow, scales fleshy, yellowish and soft, spicy and strong. It is oblate and has a diameter of 6 to 8 cm. More resistant to storage, transportation, early maturing to medium maturity. The yield is lower than that of the red skin, but the quality is good and can be used for dehydration processing. Representative varieties are Lianyungang 84-1, DK Huang, OP Huang, Dabao, Lai Xuan 13 and so on.
3, white onion: white onion, scales fleshy, white, oblate spherical, and some are high round and spindle shape, diameter 5 ~ 6 cm. High quality, suitable for raw materials for dehydration processing or ingredients for canned food. However, the yield is low and the disease resistance is weak. It is premature in the autumn of the Yangtze River, and it is easy to convulse in advance. Representative varieties include Hami white skin and so on.
Onion growing conditions
1. Temperature: The adaptability of onion to temperature is strong. Seeds and bulbs can be slowly germinated at 3～5°C. The suitable temperature for seedling growth is 12～20°C. The robust seedlings can withstand the low temperature of ～6～7°C, and the bulbs are swollen. A higher temperature is required, but if the temperature is too high, the growth will decline and go to sleep.
2, light: Onion is a long-day crop, in the bulb expansion period and twitching flowering period requires more than 14 hours of long-day conditions to grow normally, under high temperature and short-day conditions, only long leaves can not form onion, suitable light The strength is 20,000 to 4,000 lux.
3. Moisture: Onions should be supplied with sufficient water during the germination period, the seedling growth period and the bulb expansion period. However, it is necessary to control the water during the seedling period and before the winter, to prevent the seedlings from growing and suffering from freezing damage. Drought-tolerant, suitable for 60 to 70% humidity, high humidity is prone to disease.
4. Soil: Onion has strong adaptability to soil. It is suitable for fertile and loose aerated neutral loam. Sandy loam is easy to obtain high yield, but clay loam is full of bulbs, good color and storage resistance. Onion roots have a weaker ability to absorb fertilizer, and high yields require adequate nutrient conditions.
Onion seedling technology
1. Sowing time: The selection of onion is the key to cultivating strong seedlings. Seeding is too early, the seedlings are easy to be bolted after winter, the seedlings are weak, the cold resistance is poor, and the phosphorus stems are small and the yield is low. Taking the Huanghuai River Basin as an example, the best sowing date is mid-September.
2. Seeding quantity: Under normal conditions, the seeding rate per acre of seedling bed is 4-5 kg. Considering the need to eliminate and weak 20% of weak and inferior seedlings, the cultivation area should be 15 times that of the sowing seedbed. If the rate is below 70%, the amount of seeding should be increased as appropriate.
3, for 畦 fertilization: 畦 height 1.4 ~ 1.5 meters, 畦 width 27 cm, after the surface is leveled, 15 kg per phosphate per mu of superphosphate, fermented organic soil mixed fertilizer 4 acres per mu as base fertilizer, combined with watering after emergence Spraying quick-acting nitrogen fertilizer, applying 10 kg of urea per mu.
4, sowing method: After the surface is leveled, water first, then spread evenly. After covering 0.8 cm of nutrient soil, ensure that the seedlings are seeded. After the broadcast, if the sensation can not meet the requirements of emergence, water can be sprayed with watering can be used to promote emergence, and it can also be germinated after sowing.
5, emergence management: onions should pay attention to the prevention and treatment of mildew and blight after emergence. The method is to use 50% carbendazim or 40% chlorothalonil 150 g per acre, and spray evenly on water 30-40 kg.
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