1. Autumn planting time: sow in early September of the first year, overwinter with seedlings, sow in the first half of May of the second year, harvest before winter, overwinter in cellar or open field, draw lots for flowering in the third year, and harvest seeds in the second season. From early May to late June, the seedlings planted can be classified as shallots; It can also be used to plant furrow onions in flat beds (pinch onions) or narrow row spacing, which can be used as autumn onions before and after long summer, or as early spring croissants after wintering.
2. Spring planting time: Sow in early spring after soil thawing, supply as shallots before hot summer, or harvest as dried shallots or furrows in the year after planting. It can also be used as a horny onion or as a seed plant to keep in winter.
3. Summer planting time: it is usually planted from late July to early August, so it is also called green onion. The plants were larger when overwintering that year. The vernalization process is easy to complete in the next spring, with early germination and fast bolting and flowering. Generally, chopped green onion is listed after it is collected.
Second, the planting method of green onions
sow seeds
Onion is one of the onion vegetables, which has high yield, easy cultivation, less pests and diseases and is resistant to storage and transportation. It is a very popular vegetable and an important condiment, which not only sells well all over the country, but also can be exported in large quantities to earn foreign exchange.
Welsh onion has small seeds, thick seed coat, unearthed cotyledons, slow seedling growth and long seedling stage. In order to shorten the occupation time and facilitate management, seedlings were transplanted. Seedbeds should not be replanted. After the previous crop is harvested, it should be deeply ploughed and fertilized, and generally made into a high border with a width of1.4m.. The seedbed should be carefully arranged, the bed surface should be soaked with water before sowing, and new seeds should be used for sowing. The seed dosage per mu is 75-100g. After sowing, cover 2 cm with soil, and then cover with straw or film to increase temperature and moisture and speed up seedling emergence.
Pest control of scallion
1, pest
The onion pests cultivated out of season mainly include leaf miner, onion thrips, beet armyworm and so on. Control method: at the peak of nymph occurrence, spray 10% imidacloprid wettable powder with 2 000 ~ 2 500 times of solution, and spray 1 time every 7 ~ 10 days for 2 ~ 3 times continuously. At the early stage of adult occurrence and the peak period of larval damage, spray 1.8% avermectin EC with 2 000 ~ 3 000 times of solution every 7 ~ 10 d for 2 ~ 3 times continuously.
2. Illness
The main diseases are purple spot, downy mildew and virus disease.
1) purple spot disease: pull out diseased plants or remove diseased leaves and stems in time, and bury or burn them; Spraying 75% chlorothalonil, 500-600 times wettable powder, 500 times 70% mancozeb wettable powder or 500 times 64% antiviral alum wettable powder alternately at the initial stage of the disease, and spraying 65,438+0 times every 7-65,438+00 days for 2-3 times continuously.
2) Downy mildew: spray 25% metalaxyl wettable powder or 75% chlorothalonil wettable powder 500-600 times at the initial stage of the disease, and spray 1 time every 7 days for 3-4 times.
3) Viral diseases: early detection of diseased strains, timely removal, centralized burial or incineration. Strengthen fertilizer and water management and prevent aphids in time. At the beginning of the disease, 20% virus A wettable powder with 500 times solution was sprayed continuously for 2 ~ 3 times. ? [7]
Second, the law of fertilizer demand for green onions
China is a country with a large population and relatively insufficient cultivated land resources. The increase of agricultural yield mainly depends on the increase of yield, and the application of fertilizer plays an important role in the increase of crop yield. However, for a long time, the phenomenon of blind fertilization in rural areas in China has been serious, which not only caused an increase in agricultural production costs, but also brought serious environmental pollution, threatened the quality and safety of agricultural products and affected the further improvement of agricultural quality. Therefore, it is particularly important to master the law of plant fertilizer demand and balance fertilization.