How to plant it in Northeast Natsuna?

1, variety selection. When planting Chinese cabbage in summer, we must choose varieties that are heat-resistant and can form tight leaves in summer because of the weather, and at the same time, we must take into account varieties that are early-maturing, short in growth cycle and fast in growth. At present, the main varieties on the market are Xiayou No.2, Xia Tian 1, Xiabai 45, Xia Feng, Youxiawang, Heat Resistant King and Xiabao.

2. Sowing conditions. Northeast China has a large land area, and the climate conditions and farming habits in the three northeastern provinces are slightly different. When determining the sowing date, we should fully combine the local meteorological data and the actual sky conditions, choose the best sowing date, and meet the environmental conditions needed for the growth of Chinese cabbage to the greatest extent, which is also the key to whether Chinese cabbage can get a bumper harvest in summer. In Shenyang, the sowing time of summer Chinese cabbage can be from late May to late July, while in Harbin, the best planting time of summer Chinese cabbage is from mid-June to early August.

3. Live broadcast. In summer, Chinese cabbage can be directly planted or raised, but direct seeding is the most commonly used method for planting large-scale open-air Chinese cabbage in summer. Direct seeding is divided into two types, but from the point of view of efficiency and later field management, line seeding has more advantages. Sowing 150-200 grams of Chinese cabbage seeds per mu is enough. The optimum planting density is 50cn row spacing, 40cm plant spacing and about 3000 plants per mu. In summer, Chinese cabbage should be irradiated with strong light after emergence, and shading measures should be taken when necessary. In summer, Chinese cabbage must be watered before sowing to keep the land moist, which is beneficial to the excavation of Chinese cabbage seedlings. After the seedlings are unearthed, they should be interplanted in time. Generally, according to germination density and growth state, interplanting is divided into two times. The first time is when Chinese cabbage seedlings grow to 1-2 leaves, and the second time is when Chinese cabbage seedlings grow to 3-4 leaves. Generally, in summer, when Chinese cabbage seedlings grow to 5-6 leaves, strong seedlings should be planted. When planting seedlings, avoid the high temperature at noon. It is best to choose before 9: 00 am and after 4: 00 pm, and about 3000 seedlings can be protected per mu. After 3-4 days of planting, remember to check the seedlings in time.

4. On-site management. Before sowing Chinese cabbage, the selected farmland to be planted with Chinese cabbage should be deeply ploughed with a rotary tiller, and sufficient fertilizer should be applied at the same time. Under normal circumstances, 3500-4000 kilograms of farmyard manure and 60-80 kilograms of ternary compound fertilizer are applied per mu, and 20 kilograms of calcium superphosphate can be added per mu of summer cabbage for farmers with conditions. Because the growing period of Chinese cabbage in summer is in summer, the weather is hot and dry, the evaporation of water in the cabbage field is large, and the demand for water in Chinese cabbage is also great. If the water content of Chinese cabbage does not keep up in summer, it will lead to loose leaves, lower yield and lower quality. Therefore, when planting Chinese cabbage in summer, it is necessary to keep the vegetable field moist, and it must wait until the topsoil turns white before drying, so as not to lack seedlings or burn the newly grown Chinese cabbage seedlings. Because the growth cycle of Chinese cabbage planted in summer is generally short, we generally don't squat down the seedlings of Chinese cabbage in summer, but choose fertilizer and water to promote it to the end. When the weather is dry and there is no rain, you should always water the summer cabbage to ensure that it is moist. If there is water in the field due to heavy rain, it should be drained in time to prevent the roots of Chinese cabbage from rotting and getting sick. In summer, urea 15 kg should be applied to each mu of Chinese cabbage after planting, and the second topdressing should be carried out at the harvest time of Chinese cabbage. At this time, 20-25 kilograms of compound fertilizer can be applied per mu.

5. Due to the planting season and climate, the incidence of diseases and insect pests of Chinese cabbage in summer is still relatively high. At this time, it is necessary to strengthen inspections, early detection and prevention in advance. Downy mildew and soft rot are the most common diseases for planting Chinese cabbage in summer. To prevent downy mildew, 50-600 times of 50% interlayer wettable powder and 200-300 times of 40% triethylaluminum wettable powder can be sprayed at the early stage of Chinese cabbage disease. When controlling soft rot, agricultural streptomycin can be sprayed 2-3 times during the onset of Chinese cabbage, and diluted 3,000-4,000 times with 72% agricultural streptomycin sulfate soluble powder before or at the beginning of the onset. When spraying, we should focus on mild plants and their surrounding plants, and spray them near the petiole and stem base on the ground, so as to remove the diseased plants in time, reduce the spread of bacteria and prevent the spread of diseases. The main pests of Chinese cabbage in summer are aphids and cabbage caterpillar, and 4.5% beta-cypermethrin can be diluted 1000- 1500 times for spray control. It should be emphasized that aphids should be strictly killed in Chinese cabbage in summer to prevent the occurrence of virus diseases.