Green onions can be sown in autumn or spring. The export of green onions, usually sown in spring, will be harvested at the end of that year 10, and then packaged and exported. The roots of Welsh onion are string-shaped fibrous roots, which are mainly distributed in the soil layer 30 cm underground and15-30 cm horizontally.
environmental requirement
1, temperature. Like cool climate conditions, the optimum temperature for germination is13-20℃, and the optimum temperature for plant growth is 20-25℃. When it is lower than 10℃, it grows slowly, and when it is higher than 25℃, its leaves are yellow and prone to diseases. At 35-40℃, it is in a semi-dormant state, and some outer leaves wither.
2. Moisture. Drought tolerance is very strong, but due to weak roots, it needs to reach 70-80% soil humidity, and it is beneficial to grow when air humidity is 60-70%.
3. Lighting. The demand for light is low, so it is suitable for close planting.
4. Soil nutrition. It grows well in loam with good drainage and deep and fertile soil layer. The whole growth process is dominated by nitrogen fertilizer, but more phosphorus and potassium fertilizer are needed in the later growth stage.
Cultivate strong seedlings
1, Miao Di choice. Onion is a vegetable that should not be continuously cropped, nor should it be continuously cropped in the nursery. Miao Di should choose high pits for non-onion and garlic crops in the previous crop. Don't choose grassland, or Miao Di will be overgrown with weeds. Someone should be responsible for raising seedlings.
2. After the previous crop is harvested, it is deeply turned over and bleached twice, and it is laid for 20 days. The seedling period of Chinese onion is as long as 50 days, so Miao Di needs to apply 1000 kg of fertilizer per mu for decomposition. The furrow width is 1.5 m, and a small flat furrow width of 1. 1 m is made. Fine soil preparation. Open a ditch system around.
3. The export varieties of green onions are generally designated by foreign businessmen, mainly including: Changbao, Changyue, Mingyan, Jinchang No.3 and so on. Every 1 00g of seeds requires 35-40 square meters of seedbed, so the seedlings can be transplanted to1mu of field. Generally, sowing is adopted, and the sowing should be very uniform. The regular sowing date is early April.
4. Water the seeds after sowing (add pesticides to the water) to reach 60% soil moisture, and do not water them before emergence. After watering, fine dry soil is 0.5 cm thick. After watering, it is not allowed to water to prevent soil hardening. Plastic film can be covered after sowing and before emergence, which is beneficial to warming, moisturizing and preventing soil hardening caused by rain. But to prevent the harm of high temperature.
5. The germination temperature of Welsh onion seeds is about 18℃, which is the fastest. Seedling can emerge 5-6 days after sowing. 60% of the seedlings were uncovered in time after emergence, which was too late and the seedlings were thin and weak. After the plastic film is removed, in order to prevent the heavy rain from washing away, a small ring shed should be set up, and the film should be covered on the small ring shed before the rain, and the film should be removed after the rain, especially within half a month after the seedlings are fully planted and before the seedlings are set up, otherwise a large number of seedlings will fall down after heavy rain.
6. When the seedlings stretch out, water can be poured once to straighten the cotyledons and take root and stabilize the seedlings. In the future, according to the soil moisture in the base area, water1-2 times. Water should not be too much, lest the seedlings grow in vain.
7. Top dressing for 3-4 times during the whole seedling stage, using quick-acting organic fertilizer and chemical fertilizer alternately, and the concentration of chemical fertilizer should be low, no more than 0.5%, which will promote the growth of seedlings and lay a good foundation for cultivating strong seedlings.
8. During seedling raising, if seedlings are exposed, dry fine soil should be covered in time, especially after heavy rain. Weeding and pest control should be done in the seedbed in time.
9. Standard for strong seedlings: the height of seedlings is 30 cm, the false stems are thick 1 cm, the leaves are dark green, there are no pests and diseases, and there are many nutrients accumulated. The seedling age is about 50 days.
Datian preparation
1, Welsh onion is suitable for growing in loam with good drainage and deep and fertile soil layer. Sandy loam is easy to insert onions, loosen soil and cultivate soil, with good aeration and easy to obtain high yield.
2. Because the green onions should be softened, the land must be deeply ploughed and carefully cultivated. Immediately after the previous crops are harvested, the soil is deeply ploughed by 25-30 cm, and the ploughing is sun-dried twice. In the last ploughing, 2,000 kg of high-quality decomposed organic fertilizer is applied per mu, and the amount of organic fertilizer should be increased correspondingly in the paddy field with low soil fertility. Rotary tillage and mixing. After ditching, the ditch is 30cm deep and 20cm wide, and the distance between two ditches is 1 m..
3, ploughing in the ditch, the depth of 20 cm. Base fertilizer should be applied at the bottom of the ditch, mainly decomposed fertilizer, with high quality fertilizer of 2000 kg per mu, so that the soil and fertilizer can be mixed, and the soil in the ditch should be loose and fine. At this time, the back of the ditch should be more than 30 cm above the bottom of the ditch, so as to soften it later.
4. The ditches around the field are matched, and a waist ditch is opened at an interval of 20 meters, which is beneficial to drainage.
Fine colonization
1, and the planting time is generally from late May to early June.
2. Before planting, separate the big and small seedlings, and eliminate the diseased seedlings, weak seedlings, excessively small seedlings and obviously bent seedlings. The plant spacing is 35-40 plants per meter, the row spacing is 1 meter, and about 23,000 plants are planted per mu. When planting, the onion seedlings should be avoided from breaking, and the depth of planting should not be buried. Too deep is not suitable for seedlings, and too shallow will affect the length of onion. When planting, the leaves should be arranged vertically with the planting ditch, which is beneficial to close planting and management.
3. The planting tool can be a garden iron skewer or a garden wooden pole with a diameter of about 1.5 cm. When planting, first make a shallow hole, perpendicular to the ground, then insert the seedlings, and then lift them up slightly to make the roots spread down and keep the onion seedlings straight. If it is bent, the stem will be bent until it is harvested later, which is a defective product.
4, planting should be planted on the same side of the onion ditch, which is conducive to drainage after the rain.
5. After planting, compact the loose soil on both sides of the onion plant, and then water it.
Field management
1, intertillage and watering
After planting, if the weather is not very dry, it is generally not suitable to water again. We should strengthen intertillage weeding, loosen topsoil and store water to conserve moisture to promote root growth. Pay attention to drainage in case of heavy rain to prevent water accumulation in onion ditch, resulting in high temperature and humidity and poor soil ventilation, leading to rotten roots, yellow leaves and dead seedlings. Therefore, preparations should be made for flood prevention and drainage before rain.
After beginning of autumn, as the temperature drops, you can start watering, watering lightly, early and late. In the future, with the vigorous growth of plants, the watering frequency will be gradually increased, and the ground must be kept moist frequently, generally 70-80% soil moisture should be maintained.
/kloc-in October/October, there is generally little rain, and water shortage in the field is easy to occur. The method of shallow water irrigation at night can be used to alleviate the drought, but the accumulated water in the field must be removed in time. This work should be carried out seriously. Watering must be stopped one week before harvest, otherwise the water content is too high and the export quality will be affected.
2, ridging and topdressing
At the same time, with sufficient fertilizer and water supply, raising soil is an important measure to soften and increase the length of scallion. Generally, after living the tree, a small amount of soil should be re-applied in combination with intertillage weeding. The re-applied soil can not bury the onion heart and cause the onion seedlings to bend. By the beginning of August, the planting ditch will be filled up. After the autumn is cool, cultivate the soil, and then cultivate the soil every half month. From mid-August to1early October, the soil was cultivated four times. It is an important measure to ensure the quality of exported white onions to keep the fake stems of onions straight every time the soil is cultivated. Soil-raising can be done by using a soil-raising machine or by hand. Soil-raising by using a machine saves labor and costs. Tillage shall be carried out in the morning when the dew is dry and the soil is cool. If the soil temperature is too high and the humidity is too high, it is easy to cause rotten stems. During the first and second ridging, the plants grow slowly and the ridging should be shallow. During the third and fourth times of soil cultivation, plants grow rapidly, and the soil cultivation should be thicker. Every time you cultivate the soil, you can't bury the onion heart. When you cultivate the soil, you can combine with supplementary fertilizer. To make the length of scallion more than 30 cm, it is necessary to bury the scallion stems more than 35 cm in the soil. Although some fields have been cultivated for four times, they must be continued before the length of scallion is reached. In typhoon season, it is necessary to strengthen soil cultivation to prevent the onion stems from bending due to lodging. The growth of Welsh onion requires more nitrogen fertilizer, but it needs more phosphorus and potassium fertilizer in the later stage of growth. Topdressing usually begins after cool autumn, combined with watering and soil cultivation. Topdressing is mainly based on nitrogen fertilizer, and phosphorus and potassium fertilizer are appropriately increased. Twice in August, each time urea is 8-10 kg per mu. After the first ten days of September, the climate is cool, the plants begin to grow vigorously, and the scallion grows rapidly. Pay attention to topdressing twice from September to the first ten days of 10-12 kg of urea per mu and 40 kg of imported compound fertilizer each time. After each topdressing, water should be poured in time to promote the growth of green onions without stopping.
Total fertilizer consumption per mu of field: fields with moderate fertility, 4000 kg of decomposed organic fertilizer, 80 kg of imported compound fertilizer and 40 kg of urea.
Pest control
The main diseases of onion are purple spot, onion rust and soft rot. The main pests are onion thrips, liriomyza sativae, Noctuidae and so on.
1, purple spot mainly damages leaves and pedicels. At first, it is white spots like water stains, and then it becomes light brown round or spindle-shaped slightly concave spots, and it continues to expand into brown or dark purple. The optimum temperature of the disease is 25-27℃, and the disease is serious in warm and humid summer, and the disease is serious in old seedlings and fertilizer-deficient fields. Control: crop rotation; At the beginning of the disease, spray with chlorothalonil 500 times or antivirus alum 500 times or chlorphenamine 1500 times. 7-1 0 day1time, 3-4 times in a row.
2. Onion rust mainly damages leaves, stems and pedicels. Orange or dark brown sores appear at first, and then orange or dark brown powder is scattered. The optimum temperature for germination of diseased spores is 9-18℃, and when it is higher than 24℃, the germination rate decreases obviously. In the years with low temperature, insufficient fertilizer and poor growth are more serious. Prevention and control: apply sufficient organic fertilizer and increase phosphorus and potassium fertilizer; At the beginning of the disease, 3000 times of Dipyridamole, 0/000 times of Mancozeb/KLOC-or 500 times of chlorothalonil were sprayed. 10 day 1 time, 2-3 times in a row.
3. Soft rot of scallion is caused by bacteria, and high temperature and humidity, mechanical injury and insect mouth injury are easy to cause epidemic diseases. The symptoms of the disease are that the aboveground part of the scallion falls, which is easy to pull up, the lower part of the stem rots and has a foul smell. Prevention and control: keep the field drainage unblocked, and do not accumulate water after rain; Prevent pests from spreading diseases in time, and avoid damaging green onions when cultivating soil. 500-fold solution of 77% Fenghuan (or 77% kocide) and 4000-fold solution of 72% agricultural streptomycin sulfate can be used for control.
4. Onion thrips. The adult is1.2-1.4 mm long, which is harmful to the heart leaves and buds of onion. When the temperature is below 25℃ and the relative humidity is below 60%, it is beneficial to the occurrence of onion thrips ...
5. Leaflet. Larvae eat in mesophyll tissue, eating mesophyll, resulting in yield reduction and quality decline, and at the same time spreading diseases. This area is harmful from mid-May to the end of 10. Prevention and control: 2500 times of Qianke or 0/500 times of Sukai/Kloc-0, 3000 times of Insecticides or 2000 times of pyrethrins. It is advisable to take medicine in the morning.
6. Noctuidae. Spodoptera litura and Spodoptera exigua also harm green onions, eating leaves and boring them. Generally, it is more harmful in the second half of the year. Spraying with 0/500 times of Kardiek/Kloc-or 0/500 times of Miman/Kloc-and 3500 times of Amphetamine. The spraying time of controlling Noctuidae is good in the evening or dusk. There is wax powder on the leaves of Chinese onion. In order to improve the adhesive force of the medicine, neutral soap should be added to the liquid medicine. Stop using the medicine 10 day before harvesting. Pest control must be organized by professionals to improve the quality and safe use of drugs.
Product harvest
/kloc-can be harvested from the end of 0/0, and harvested after dew is dried. Under good cultivation conditions, the total yield per mu is 3000-4000 kg. First, split one side of the ridge platform to expose the scallion, and then gently pull it out, so that the product will not be damaged and shake off the soil. Export products should be properly aired, and obviously bent plants and plants with scallion less than 30 cm long should be removed and bundled into small bundles. Transport to that processing plant without damage.
1, temperature. The initial germination temperature of Welsh onion seeds is 2 ~ 5℃, and the optimum germination temperature is15 ~ 25℃, which can germinate in 2 ~ 3 days. The optimum temperature for the growth of Chinese onion leaves is15 ~ 25℃. At10 ~ 20℃, the scallion grows vigorously, which is beneficial to the accumulation of nutrients in leaf sheaths. If it exceeds 25℃, the growth will be slow, and the quality of leaves and pseudostems will be poor. Onion can endure the low temperature of-20℃. Scallion and chive are cool-loving, grow at a suitable temperature13 ~ 20℃, and can withstand low temperature of about 0℃. When the temperature is above 25℃ and under strong light, their quality declines, and they only grow and tiller vigorously in spring and autumn.
2. Lighting. Onion does not require high light intensity. The light compensation point is 2500 lux and the saturation point is 25000 lux. The strong growth of onion needs good lighting conditions, and it is not tolerant of shade and does not like strong light.
3. Moisture. The leaves of onion are tubular and the surface is waxy, which can reduce water transpiration and resist drought. However, the absorption capacity of root system is poor, so it is necessary to supply appropriate water in each growth and development period. There are many requirements for water in the vigorous growth period of onion seedlings, vigorous growth period of leaves and flowering and fruiting period, so high soil moisture should be maintained. Onion is not tolerant to waterlogging, so attention should be paid to timely drainage and waterlogging prevention in rainy season to prevent root retting. Too much water at bolting stage is easy to lodging.
4. Soil nutrition. Onion has strong adaptability to soil, especially sandy loam with deep soil layer, good drainage and rich organic matter. Soil ph value is 6.9 ~ 7.6, which is suitable for the growth of onion. Too low or too high can inhibit seed germination and plant growth.