Onion, a biennial herb of Allium in Liliaceae, is native to western China, Central Asia and West Asia.
Onions are cold and heat resistant and have strong adaptability. It is widely planted. It is rich in nutrition and has a spicy and aromatic smell. Can be used for raw food and cooked food, and has sterilization and medical value.
First, select improved varieties of green onions.
We should choose high quality, high yield, disease and insect resistance, strong stress resistance, wide adaptability and good commercialization. The main varieties are: Changbao, Yuancang and Jinchang No.3.
Second, the soil selection of green onions.
Choose a plot with Gao Shuang topography, deep soil layer, no onion and garlic, rich organic matter, loose sandy loam and pH value of 7-8.
Growth cycle of scallion
The whole growth period of Welsh onion can be divided into two stages: vegetative growth and reproductive growth.
1. Onion vegetative growth period
(1) During germination, it takes about 14d from sowing to the appearance of straight hook in cotyledons.
(2) At the seedling stage, from direct hooking of buds to colonization. The seedling stage of autumn sowing onion is about 250d, and it needs to go through the seedling stage before winter, the wintering stage and the turning green stage before it can enter the vigorous growth period. Spring-sown onions have a seedling stage of 80-90 days, and soon enter a vigorous growth period after being unearthed.
(3) The formation period of pseudostem (Welsh onion) can be divided into three periods from planting to harvesting according to its production characteristics:
① It takes about 10d after new roots are implanted in the slow seedling stage. After entering the hot summer season, the plant grows slowly and the leaf life is short. It takes about 60 days to slow down seedlings in summer.
(2) The more pseudostems (onions), the lower the temperature in Xia Hou, which is suitable for onion plant growth. At this time, the leaf life is longer, which makes the pseudostem elongate and thicken rapidly.
(3) After the pseudostem (Welsh onion) is filled with frost, its vigorous growth stops, and the nutrients in the leaf body and the outer leaf sheath are transferred to the inner leaf sheath, which enriches the pseudostem and improves the quality of the Welsh onion.
(4) During the winter dormancy period in northern China, Welsh onion was forced to hibernate at low temperature, and spent the vernalization period during this period.
2. Reproductive growth stage
(1) The bolting flowering period is from pulling out the leaf sheath to breaking the bud. Mainly used for the development of flower organs.
(2) The flowering time of flowers in the same inflorescence is different, and it takes 20 ~ 30 days from flowering to seed maturity.
Requirements of green onions on environmental conditions
1. temperature Welsh onion has strong cold resistance and poor heat resistance. Seeds can germinate at 2℃ ~ 5℃. In the range of 7℃ ~ 20℃, the time required for seeds to germinate and emerge is shortened with the increase of temperature, but it will not germinate when the temperature exceeds 20℃. The leaves grow vigorously at 13℃ ~ 25℃, while the green onions grow vigorously at 10℃ ~ 20℃, and grow slowly when it exceeds 25℃. Onion is a green vernalization plant, and plants with more than 3 leaves can survive vernalization at 2℃ ~ 5℃ for 60 ~ 70 days.
2. Onion is a mesophilic plant. As long as it is vernalized at low temperature, it can bolt and bloom normally under long or short sunshine. The light intensity of scallion is not high, the light saturation point is 25klx, and the light compensation point is 1200lx.
3. Water roots are drought-resistant and waterlogged-resistant, and leaf growth also requires low air humidity.
4. Soil nutrition Welsh onion has wide adaptability to soil, and loose loam with deep soil layer, good drainage and rich organic matter is convenient for the cultivation and softening of Welsh onion. The requirement of soil pH for green onions is pH 7.0~7.4. Every production of 1000kg fresh onion needs to absorb 2.7kg nitrogen, 0.5kg phosphorus and 3.3kg potassium from the soil.
Planting season and stubble arrangement
Welsh onion has wide adaptability to temperature, and can be planted in stages and supplied all year round. In southern China, seeds are usually sown in autumn or spring. After sowing in spring, green onions can be harvested in winter that year, but the yield is low. In northern China, winter storage of green onions mostly adopts the methods of sowing in the open field in autumn, planting in the following spring and harvesting green onions in late autumn and early winter. In order to prevent bolting in early spring, seedlings can be raised in facilities for production.
Cultivation techniques of scallion
(1) Cultivation techniques of spring onions sown in the open field in autumn
1. Seeding and seedling raising
(1) Although the sowing date varies from place to place, it is advisable that the seedlings have a growth period of 40-50 days before overwintering, and can grow into 2-3 true leaves, with a plant height of about 10cm and a stem diameter of less than 0.4cm.
(2) 5000 kilograms of decomposed farmyard manure and 25 kilograms of calcium superphosphate were evenly spread on every 667 square meters of seedbed. Make it 1.0m wide and 8 ~ 10m long. When sowing, water is poured into the soles of feet, and after sowing evenly, fine soil with a thickness of 1cm is covered. The seed dosage for planting 667 square meters of scallion is 3k ~ 4kg.
(3) Seedling management
① Management before winter: Generally, it is enough to water 1 ~ 2 times in the pre-winter growth period, and at the same time, intertillage weeding is required. Generally, topdressing is not needed before winter, but before the soil freezes, topdressing and freezing water should be combined. Suitable overwintering seedlings grow to 2 leaves 1 heart.
② Spring seedling management: When the average daily temperature reaches 13℃ in the following year, it is not advisable to water green water too early to avoid lowering the ground temperature. In case of drought, 1 times of small water can be poured at noon on sunny days, and topdressing can be used at the same time to promote seedling growth. You can also apply decomposed farmyard manure in the border to raise the ground temperature, water green water in a few days, then intertillage, interplant and weed, with the spacing between plants being 2-3 cm. When the seedling height is 20cm, replant 1 seedling with a spacing of 6 ~ 7 cm, and then squat 10 ~ 15d. After squatting, topdressing along the water, applying ammonium sulfate 10kg and manure every 667m2 to meet the needs of vigorous growth of seedlings. When the seedlings grow to 50 cm high and have 8 ~ 9 leaves, stop watering, exercise the seedlings and prepare for transplanting.
Soil preparation and fertilization
Avoid continuous cropping of green onions, and the previous crops should be non-onion and garlic crops. Apply 5,000 ~10,000 kg of decomposed farmyard manure every 667m2, turn the stubble shallowly, mix the soil and fertilizer, rake it flat and then furrow it for planting. The planting ditch should be north-south, so that the light can be received evenly, and it can also reduce the lodging of green onions caused by strong winds in the north in autumn and winter.
Field planting
(1) Planting time After planting, the growth period of green onions should be130 days, usually from early June to early July. When the plant grows to 30 ~ 40 cm in height and the transverse diameter is 1.0 ~ 1.5 cm, it is suitable for planting.
(2) Before seedling raising, seedling selection and grading, the seedbed should be watered for 1 ~ 2 days. Shake off the soil when raising seedlings, select seedlings for classification, remove diseased, weak, disabled and bolting seedlings, and divide onion seedlings into three grades, namely, large, medium and small, and plant them respectively. Those that can't be planted that day should be placed in the shade with their roots down to prevent the onion seedlings from getting hot, yellow or rotting.
(3) The row spacing of planting green onions varies with varieties and product standards. Short onion varieties should adopt narrow rows and shallow ditches with row spacing of 50 ~ 50~55cm, ditch depth of 8 ~ 10 cm and plant spacing of 5 ~ 6 cm, and 20,000 ~ 30,000 plants should be planted every 667m2. When the varieties with long green onions have high requirements on the quality of green onions, wide rows and deep ditches should be adopted, with the row spacing of 70-80 cm, the ditch depth of 40-50 cm and the plant spacing of 6-7 cm, and the plants should be planted every 667m2 12000- 15000 plants. The planting method of scallion can be adopted, that is, seedlings are put in the planting ditch according to the spacing between plants, and then covered with soil for irrigation. You can also irrigate along the ditch first, and then put onion seedlings to cover the soil after underwater infiltration. The advantages of this method are fast planting and less labor, but the scallion is easy to bend. When planting onions, the method of inserting onions is often used, that is, the onion seedlings are vertically inserted into the loose soil at the bottom of the ditch with a small stick, and the onion seedlings are inserted first and then watered, which is called dry insertion and water insertion.
Tiantuan management
(1) Generally, water and fertilizer are not applied after field planting to promote root system development, and drainage should be paid attention to after rain; In the first half of August, the weather turned cold, and it was watered 2-3 times, followed by 1 foliar fertilizer attack. Apply high-quality decomposed manure 1 0,000-10,500 kg, urea1500kg and calcium superphosphate 25kg on the furrow and ridge every 667m2, intertillage and mix evenly, hoe in the furrow, and then water. After the summer heat and before the first frost, the green onions enter the peak growth period. During this period, the water demand increased, and 1 time water was poured every 4 ~ 5 days, resulting in a large amount of water. Therefore, fertilizer should strike again. Once, at the end of August, 5000kg of decomposed farmyard manure was applied according to 667m2, and potassium sulfate 15kg was added, which could be applied to both sides of onion chops. After intertillage, the soil is ridged and watered. The second time, in mid-September, urea 15kg and potassium sulfate 25kg were sprinkled between rows, and watered after shallow tillage. After the first frost, the temperature dropped, and the onion basically grew up, and it entered the period of pseudo-stem (onion) enrichment. Plant growth is slow, water demand is reduced, soil is kept moist, and green onions are tender and plump. Water is stopped 5 ~ 7 days before harvesting, which is convenient for harvesting, storage and transportation.
(2) While strengthening the supply of fertilizer and water, the cultivated green onions can soften the false stems, increase the length of green onions and improve the quality of green onions. Welsh onion enters the vigorous growth period, and timely intertillage and cultivate the soil, so that the original ridge platform becomes a ridge ditch, and the ridge ditch becomes a ridge platform. Cultivate the soil to the junction of leaf sheath and leaf body, and don't bury the leaf body to avoid leaf rot. From beginning of autumn (early August) to harvest, it is generally cultivated for 3 ~ 4 times. See you during the cultivation of green onions.
Harvest storage
Onion can be harvested and marketed at any time according to market demand, and fresh onion can be marketed from September to 65438+ 10. However, the green onions on the market cannot be stored for a long time. Generally, in winter, scallions should be harvested after late frost. Dry properly after harvest. The principle of cooling rather than heating should be mastered when storing. Under natural conditions, it is best to store it in the open air at 1 ~ 3℃ and sell it at any time.
Key points of storage and cultivation techniques of germinated green onions in greenhouse
In recent years, it is a promising cultivation mode to store and plant the green onions with poor growth in autumn in the open field at the end of winter and supply the sprouted fresh onions to the Spring Festival market by using the inefficient greenhouse or the inefficient area with poor temperature and light conditions in the efficient greenhouse.
Before planting, dry onion with short and thin false stems and low commercial value is selected, and before the Spring Festival 1 month, it is made into high ridges and low ridges with a width of 1.5m in the greenhouse with poor temperature and light conditions or the low-efficiency areas under the gable and back wall of the high-efficiency energy-saving sunlight greenhouse for producing warm-loving vegetables, and the surface is leveled. Bundle the selected dried onions into small bundles, plant them one by one in the border, cover them with fine sand, fill the gaps, and spray a small amount of water to make the fine sand sink. After a few days, new roots appear at the base, and when new leaves begin to grow, water them 1 time. In the future, the amount and frequency of watering will be determined according to the weather and plant growth. On sunny days, when the temperature is high, the watering amount can be slightly larger; On cloudy and snowy days, the temperature is low and it is not suitable for watering. The growth of new leaves of germinated onion depends entirely on the nutrients stored in the false stems, so there is no need to apply fertilizer during hoarding and planting, and the increase of yield mainly comes from the water absorbed by the plants. Although the yield has not increased much, the price can be greatly increased because of the fresh quality, and the economic benefit is obvious, which fills the gap in the supply of fresh onions in the market during the Spring Festival.