For the four seasons, we must choose cold-tolerant, drought-tolerant, heat-resistant, adaptable, long-lasting, long-stemmed, non-differentiated varieties, such as Chinese giant onions, Zhangqiu scallions (high white) or local farm varieties whip pole onions. Onion varieties not suitable for four seasons cultivation.
2. Cultivation methods
(1) From January to March, sowing in simple solar greenhouses, sowing in flat rice, and marketing of small shallots from March to May.
(2) In the middle and late March of the year, planting in small arch sheds, sowing in flat rakes, and listing in June. It can also be transplanted in mid-June and marketed or stored in winter from October to November.
(3) Seedlings were sown in the open field in early April, and planted in the middle and late June. The winter was exposed in the open season. The flower buds were removed from March to April in the following year, and green onions were available from April to May.
(4) Seedlings are planted from July to August, transplanted from early September to early November, planted (plant spacing 3cm), wintered in open field, buds removed from March to April in the following year, and spring onions from May to July.
(5) Sowing seedlings in mid-to-late September, wintering in seedbeds, and marketing of small green onions from March to April in the following year.
(6) Sowing seedlings in the middle and late September, transplanting in mid-April of the following year, harvesting shallots from July to August, or transplanting in June, harvesting and winterization from October to November.
(7) Sowing in greenhouses from late August to early September, sheds in mid-October, and small scallions from December to February.
3. Management technology
(1) Winter and spring seedbed management
Before wintering, the seedlings should have 2 to 3 leaves. According to the temperature and soil moisture, one overwintering water should be poured before freezing, and then a layer of decomposed farmyard manure should be covered to ensure the safety of the seedlings. In the spring, the temperature rises, and the seedlings enter a period of rapid growth. The first time is between 1 and 2 seedlings, and the seedling distance is about 3 cm. The second is combined with water 2 to 3 times topdressing available nitrogen fertilizer or ternary compound fertilizer, each 10 ~ 15kg/667 square meters, to promote the rapid growth of seedlings, or small green onion market or cultivate robust seedlings for transplanting.
(2) Summer Bed Management
Summer nursery is in high temperature and rainy season, the key to management is to do a good job in the three preventions, one to prevent pests and diseases, the second to prevent grass damage, prevent grass seedlings. Before sowing, after sowing, every 667 square meters with 33% weeding through 100ml spray closed soil, combined with artificial weeding 2 to 3 times, completely eliminate weeds. Three waterproof stains, seedlings to do drought can be poured, can be arranged, can not be seedbed water.
(3) Transplanting
Before transplanting, adequate base fertilizer should be applied. Every 667 m2 of farmland should be bred with 6,000 kg of quality farmyard manure, 30 kg of phosphate fertilizer and 50 kg of ternary fertilizer, and 1/3 of the total amount of basic fertilizer should be withdrawn. When transplanting, seedlings should be graded. Large and small seedlings cannot be mixed. Shallots can be properly planted, row spacing 60 ~ 70cm, spacing 3 ~ 4cm, made of onion market, then spaced 80cm, spacing 5cm. After transplanting, timely cultivating loose soil and flat ridge should be adopted, and the compaction should be promoted to promote root growth. Combined with water-saving topdressing NPK fertilizer, top-dressing 30 kg at 667 m2 can be cultivated in a timely manner depending on the growth of seedlings to promote the formation of light blue.
4. Pest Control
(1) Underground pests
There are mainly oysters, scallions, and green onion, combined with basic fertilizer before soil tillage, 667 square meters with 3% phoxim granules 3kg, concentrated in the planting ditch when transplanting. The duration of the damage caused by green onions is generally from mid-April to early June and early September to early November. The larvae can be used to irrigate the roots with 50% phoxim 1000 times solution, which is very effective.
(2) Ground pests
There are mainly cabbage caterpillars, green onions thrips, leaf miners and red spiders. The control of cabbage caterpillar can be used 10% cypermethrin EC 20 ~ 40ml, 2.5% EC killing EC 15 ~ 25ml, 20% speed kill Ding EC 10 ~ 30ml, spraying water. Control onion thrips, leaf miner can use 50% Dimethoate EC 1000 times or phoxim 1000 times liquid, extermination and killing 4000 times liquid, speed killing Ding 1500 times liquid spray. Prevention of spider mites killing with 1000 times liquid spray. 10 days before the start of the market, stop the medication.
(3) Diseases
Onion diseases mainly include rust, purple spot, downy mildew, gray mold, black spot, etc. The main prevention and control measures include increasing farmyard manure and phosphorus and potassium fertilizers to ensure the plants grow robustly. Diligently cultivating and loosening the soil, spreading moisture, and draining water in time after rain, regulate the microclimate in the field. Small water pouring, to prevent flooding irrigation. Control methods: rust use 25% Triadimef 2000 times; purple spot use 50% carbendazim 500 times; downy mildew use 25% metalaxyl 800 times or chlorothalonil 500 times; gray mold use 20% Dakling 1000 times or 50% fluocin 800 times; black spot use 50% carbendazim 800 times or 70% thiophanate 1000 times. Spray every 5-7 days, 2 or 3 times in a row.
5. Heavy soil treatment technology
Scallion should not be replanted, otherwise it will seriously affect the yield. If it is planted, the soil must be treated.
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