1 cultivate strong seedlings Green onions are vegetables that are not allowed to be continuously cropped. Miaodi should choose high-pit areas of non-scallion garlic crops before and after, and avoid choosing wild grassland. After the first crop was harvested, it was sun-dried twice and left idle for about 20 days. The onion seedling period is up to 50 days, and the organic fertilizer is 6000kg/hm, the superphosphate is 750kg/hm, and the imported compound fertilizer is 225~300kg/hm. The level of the flat and wide trench is 1.5m, and the land is finely ground. In order to prevent the harm of underground pests, 150kg/hm of 3% phoxim granules were applied during the preparation of the ground, and the ditch system was opened around Putian. The main varieties of green onions are Changbao, Changyue and Mingyan. For every 100g of seed, the seedbed bed is 35~40m, and 666.67m field can be transplanted. Early-maturing varieties were sown from March 10 to 25, and mid-late cultivars were sown from the end of March to April 10. Before the sowing, the soil is not enough, so you can water it first. Generally, it is spread evenly. After seeding, it is gently watered on the surface of the clam. After watering, the dried soil is covered with 0.5cm thick. After the soil is covered, it can not be watered to prevent the soil from squashing. Then cover the mulch and take a small arch shed. It is good for warming, moisturizing and preventing rain from causing soil compaction, but it is necessary to prevent high temperature burning. The green onion seeds sprouted at the fastest temperature around 18 °C, and they can emerge after 5~6 days. After 60% of the seedlings were released, the mulch film was removed in time, and the film was released too late, resulting in weak seedling growth. Cover the film on the small ring shed before the rain, and peel off the film after the rain. According to the soil moisture, the seedling stage can be poured 1~2 times of small water, and the water should not be too much, so as to avoid the seedlings being long. The whole seedling stage is topdressed 3~4 times, the quick-acting organic fertilizer and the imported compound fertilizer are used alternately, and the chemical fertilizer concentration does not exceed 0.5%, which promotes the growth of the seedlings. During the nursery period, if there is a seedling dew root, it is necessary to cover the dry fine soil in time, and the seedbed bed should be weeded in time to prevent pests and diseases. 2 Site preparation The green onions are suitable for growing in the loam with good drainage and deep and fertile soil. Sandy loam is easy to insert onion, loose soil and soil, good ventilation and easy to obtain high yield. After the previous harvest, immediately turn over the land 25~30cm, ploughing and whitening, combined with the high-quality decomposed organic fertilizer 30t/hm, and the soil fertility of the rice paddy field, the amount of organic fertilizer should increase accordingly. After the rotary tillage and mixing, the ditch is ditched, the ditch depth is 30 cm, the width is 20 cm, and the distance between the two grooves is 1 m. The ploughing is carried out in the ditch, the depth is 20cm, the base fertilizer is applied at the bottom of the ditch, and the organic fertilizer is mainly used to make the soil mix with the fertilizer, and the soil in the ditch is required to be loose. The back of the ditch should be more than 30cm above the bottom of the ditch, and the planting ditch should be north-south, so that the light is evenly distributed, and the northward strong wind of the autumn and winter seasons can be reduced to cause the green onions to fall. The ditch around the Daejeon is equipped with a waist groove at intervals of 20~30m, which is good for drainage. The colonization time is generally from late May to mid-June. Before planting, the size of the seedlings was graded, and the diseased seedlings, weak seedlings, over-small seedlings and obviously curved seedlings were removed. The plant spacing was 2.5~2.8cm, the row spacing was 1m, and the planting was about 345,000 plants/hm. Avoid colonization of onion when planting, the depth of planting should not be buried in the heart, it is not suitable to seedling too deep, too shallow to affect the length of the scallion. The planting tool can use a garden iron or garden wood rod 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 it up slightly, so that the roots should be rolled down and keep the onions straight. After planting, the loose soil on both sides of the onion plant is compacted, and then the root water is poured. 3 seedling management The green onion seedlings are not drought-tolerant, and it is necessary to keep the soil moist. Otherwise, the growth is slow and uneven. 30 days after sowing, seedlings, weeding, and watering seedlings were carried out, 1 or 2 times, and the seedling distance was about 10 cm. 1 leaf 1 heart to 2 leaves 1 heart with water to apply quick-acting nitrogen fertilizer, 5-10 kg per mu of urea; at the same time do a good job in the prevention and control of seedling pests and diseases, with Miao Biaoling 1-2 times. Control the nitrogen seedlings before transplanting and planting, and promote the seedling roots to be more robust. 4 Nutritional characteristics and nutrient absorption of green onions Green onions are fertile crops with long growth period, high yield, large amount of fertilizer, and increased fertilizer requirements as production increases. According to research, the yield of high-yield cultivation of onion can reach 80~90t/hm, and each production of 1t green onion needs pure N2.7~3.3kg, P2O50.5~0.6kg, K2O3.3~4.0kg, and the absorption ratio of NPK is 1 : 0.4:1.3, potassium is the most, nitrogen is the second, phosphorus is the least, the demand for nitrogen and potassium is large, and it is sensitive to potassium nutrition. The growth stage of green onion can be divided into five stages: germination stage, seedling stage, slow seedling stage, vigorous whitening growth period and flowering and fruiting stage. Among them, the growth of green onion in seedling stage and planting slow seedling stage is slow, the accumulation of dry matter is less, and the nutrients absorbed are also less. The nitrogen, phosphorus and potassium three elements absorb more nitrogen and potassium. In the vigorous growth period of the stalks, the green onions accumulated quickly, and the nutrients absorbed were the most. The amount of nitrogen and phosphorus absorbed was as high as 68.4% and 46.4% of the total growth period. During the late growth stage of green onion, the dry matter accumulation was slower, and the absorbed nutrients were also less, but the proportion of absorbed phosphorus and potassium was significantly increased, accounting for 44.1% and 34.6% of the total absorption during the whole growth period. 5 large onion fertilization technology 5.1 Fertilization amount On the basis of applying high-quality organic fertilizer 30t/hm, in moderate fertility plots, the suitable fertilization amount is: nitrogen fertilizer (N) 350~450kg/hm, phosphate fertilizer (P2O5) 90~120kg/hm, potassium fertilizer (K2O) 300~450kg /hm, equivalent to urea about 750~1000kg/hm, ordinary calcium phosphate (effective phosphorus content 12%) 750~1000kg/hm or diammonium phosphate (effective phosphorus content 46%) 200~260kg/hm, potassium chloride (effective Potassium content 60%) 500~750kg/hm. When the soil fertility is low and the organic fertilizer is lacking, higher fertilization amount can be considered; on the contrary, when the soil fertility is high and the soil fertility foundation is good, the fertilization amount can be appropriately reduced. When diammonium phosphate is applied, the amount of urea can be reduced by 10% to 15%. 5.2 Fertilization method Before transplanting the onion, 40% of the nitrogen and potassium fertilizers and all the phosphate fertilizers were mixed and used as the base fertilizer to spread the soil and deep into the soil. The remaining 60% of the nitrogen and potassium fertilizers are used for topdressing, and the combination of the soil is applied twice in mid-September and mid-to-late October. 6 pest control The prevention and control of green onion pests and diseases must adopt the strategy of "prevention first, comprehensive prevention" to strengthen agricultural control. In the critical period, timely spraying and prevention, in order to effectively control the occurrence of pests and diseases. The agents used are high-efficiency, low-toxic, low-residue pesticides or biological pesticides, and the safety intervals of pesticides are strictly controlled. The diseases of the onion mainly include purple spot disease, downy mildew and soft rot. In the early stage of the disease, 64% anti-virus cockroach, onion garlic powder, agricultural streptomycin and the like can be used for prevention and treatment. Insect pests should be treated early, and mites, thrips, and leaf miners should be used in the stage of spotting hazards, such as net, good winter, flies, etc.; Spodoptera litura, etc., when 1-2 instar larvae, use translucent leaves to kill, etc. Chemical control. (1) Onion horses and leaf miners are sprayed with 40% dimethoate emulsion or 80% dichlorvos emulsion 1000-1500 times. (2) Onion fly is rooted with 90% trichlorfon plus water 1000 times. (3) Downy mildew can be sprayed with 75% chlorothalonil 600-1000 times solution. 4 purple spot can spray 1:1:200 Bordeaux mixture. Or 65% Daisen zinc 600 ~ 700 times liquid, or 65% Fumei zinc 600 ~ 700 times liquid control. 7 large onions storage The harvesting period of green onions is due to regional climate differences. In principle, green onions should be harvested before freezing (before and after small snow), or listed in advance (depending on the market), or after the winter, the buds are listed, which is also the product of green onion. A big advantage (flexible planning period). The green onions harvested before freezing are shaken to the soil, bundled in bundles, and stored in a cool, dry place. The roots are placed straight down to supply the market at any time. Disclaimer: Some articles on this website are transferred from the Internet. 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