Generally, it is recommended to choose varieties with high heat resistance, insect resistance and good quality, such as Xichun Kang Wang AC-3, Jiaocheng Chengza No.5, Heat Resistance No.50 and Qingza No.5. When selecting varieties, we should pay attention to the collocation of early, middle and late varieties, so as to sow in batches at the appropriate sowing date, stagger the supply and extend the time to market.
Before sowing, soil preparation should be carried out in sunny days, and the soil should be raked to the wall. Generally, Chinese cabbage planted in summer must be cultivated with high ridges and narrow walls, which is beneficial to flood control, irrigation and drainage, ventilation and light transmission, and pest control. 1 10cm can be used to open the wall, with a ditch width of 40cm and a wall width of 70cm, and two ponds can be planted in each row. Because it is difficult to apply fertilizer in rainy season, it is necessary to apply base fertilizer again, and apply decomposed farmyard manure 52.5-60t/hm phosphate fertilizer 600kg/hm potassium fertilizer 450-600kg/hm compound fertilizer 375-450kg/hn? -secondary application to ensure that Chinese cabbage does not lack fertilizer during the growth period and enhance the plant's ability to resist pests and diseases.
Due to the high density, the sowing amount of early-maturing seeds is about 2.25kg/hm2, while the sowing amount of high-density sowing is about 1.5kg/hn. Used for middle and late maturing seeds, 6-8 seeds per pool.
Soak the seeds with warm soup before sowing, or wrap the seeds with carbendazim, metalaxyl, manganese zinc or chlorothalonil when sowing. Will not immediately affect the germination rate.
The sowing period is from late May to July and from July to 10 every year. The planting specifications are generally 35cm×40cm and 40cm×40cm, and the planting density is 45000-5 1000 plants /hn?
Water thoroughly before sowing, and sow after the soil absorbs enough water. After sowing, cover 0.3 cm thick with decomposed fine fertilizer. After watering, it is recommended not to expose the seeds. Too thick to see. Then spray insecticide. All pesticides should be low toxic and harmless to seedlings.
Black film should be used in summer to prevent weeds and reduce the surface temperature of soil, which is beneficial to the growth of Chinese cabbage. Three days after sowing in summer, seedlings can emerge. When two leaves are exposed, the membrane must be broken in time. The diameter of the membrane hole is 0.8- 1cm, and the membrane hole will gradually tear with the growth of seedlings. If there is no pond, replant it in time and water it thoroughly after replanting to facilitate the emergence of seedlings.
When the seedlings grow to 2-3 leaves, they should be thinned first, leaving 4-5 plants in each pool; When the seedlings grow to 4? When there are 5 leaves, the second thinning, 2 leaves per pool? 3 plants; When the seedlings grow to 6 to 7 leaves, fix the seedlings and keep one. The principle of each refinement and decision is to delete weaknesses, maintain strengths, delete impurities and delete purity.
Chinese cabbage likes wet soil and climate. Keep it moist throughout the growing season. In rainy season, ditches should be cleaned in time and soaked in water. In high temperature period, it is suggested to water in the morning and evening, inject a small amount of water, irrigate quickly and drain quickly.
Fertilization for the first time 1 time: urea 120kg/hn is used after the seedlings are fixed. Add compound fertilizer 150kg/hn? Pour water on it; The second fertilization was carried out at the tree-clumping stage, and urea 150kg/hm compound fertilizer 300kg/hm potassium sulfate 120kg/hm2 was mixed with water; At the beginning of the third fertilization, urea 150kg/hm 2 compound fertilizer 375kg/hm 2 potassium sulfate 150kg/hm2 was added with water. In the middle stage of nodulation, 1: 250 potassium dihydrogen phosphate was used as the foliar spray outside the root, every 7 days 1 time.
In the production of pollution-free agricultural products, pest control should follow the plant protection policy of "prevention first, comprehensive management" and adhere to the principle of "agricultural control, physical control and biological control first, supplemented by chemical control".
Downy mildew of Chinese cabbage is a fungal disease caused by downy mildew of flagellate subspecies. The main victims are leaves, followed by stems, pedicels and seed pods. The disease occurred at seedling stage, with white mold layer on the back of cotyledons and no obvious symptoms in front of leaves. Seedlings of early and serious diseases usually wither and die. Adult plants are damaged from the outside leaves. Small green to yellowish spots appear on the front of the diseased leaves. After expansion, it becomes yellowish brown and is bound by veins, forming polygonal lesions. When the weather is wet, it will appear on the back of the disease. A layer of white mold. Chinese cabbage enters heading stage. If the conditions are suitable for the disease, the disease spots on the leaves will increase and connect with each other, and a large number of external leaves will die, and the disease will develop from the outside to the inside.
Selecting disease-resistant varieties; Sow in time; Clear the garden: the disease occurs at the seedling stage, and the diseased seedlings should be pulled out when thinning and fixing the seedlings. After harvesting Chinese cabbage, the diseased plants with diseased leaves should be moved to the field to be buried or burned, and the soil should be deeply cultivated. It can reduce the spread of pathogens in the field; Strengthen water and fertilizer management: apply base fertilizer and increase phosphorus and potassium fertilizer; Chemical control: trimethoprim, encore, disinfectant, Jingao, facial cleanser and other reagents are used alternately, and sprayed 1 time every 7 days, for a total of 3 times.
Soft rot of Chinese cabbage is a bacterial disease caused by Erwinia. Soft rot of Chinese cabbage is also called "rot disease" and "deprivation disease". Most diseases begin at the heading stage of Chinese cabbage. At the early stage of the disease, the outer leaves of plants wither, and when the sun is strong at noon on a sunny day, the withering is obvious and can be recovered sooner or later. In severe cases, the leaves can't wither, the outside leaves lie flat on the ground, the head is exposed, and the pulp of the roots and rhizomes of the petiole is completely rotten, giving off an unpleasant smell.
Select disease-resistant varieties: in seriously ill areas, choose green soft rot varieties; Implement crop rotation in the affected areas and replant crops such as beans, wheat and rice; Timely control underground pests, yellow beetles, Pieris rapae, Plutella xylostella and other pests to reduce pests; Dig out the diseased plant in time and sprinkle quicklime to disinfect the affected area. Chemical control: 72% of household streptomycin soluble powder is 4000 times, and 77% can kill WP800. Alternately use drugs such as double solution and 72% streptomycin sulfate soluble powder 3000-4000 times, spray once every 7- 10 day, and spray continuously for 2? Three times.
Black rot of Chinese cabbage usually occurs at the same time as soft rot, forming a compound infection of the two diseases. Chinese cabbage will get sick at all stages. When it began to grow seedlings, the edges were unclear, black and withered quickly. After adult infection, the leaf spot usually extends inward from the leaf edge, forming a "V"-shaped dark brown spot, which turns yellow around and the reticular veins in the spot turn brown or black. The lesion expands, causing some or most leaves to rot and die. Petiole disease, the pathogen grows up along the vascular bundle, which can form brown dry rot, with the leaves tilted to one side and half of them yellow. The stem is shortened and rotted, the vascular bundle is discolored and there is a circle of black spots. Severe pulp is hollow, black and dry.
Disinfection of seeds: when soaking in warm soup, the seeds are pre-soaked with cold water for 10 minute, and then with 50-7 hot water for 25-30 minutes. Potassium permanganate can be used for chemical treatment, 77% can kill 800 times of suspending agent and 300 times of 45% Morinda citrifolia solution, and the soaking time is 20 minutes. Soaked seeds should be fully washed with water and dried before sowing. Implement two-year rotation of host crops to avoid continuous cropping of cruciferous vegetables; Clean the courtyard, remove the diseased body in time, plough after late autumn, decompose farmyard manure after fertilization, sow in time, plant with reasonable density, irrigate reasonably, prevent insects in time and reduce the spread of bacteria. Drug control: at the initial stage of the disease, agricultural streptomycin, neomycin, keratin, starcom and bacterial Turk can be sprayed alternately.
Chinese cabbage virus disease is mainly caused by radish mosaic virus infection. After the seedlings were injured, the veins of the heart leaves looked translucent, and the green of the veins gradually turned into light green and dark green mosaics along the veins. The leaves atrophy unevenly, the heart leaves twist and grow slowly. Sometimes brown necrotic spots or stripes are produced on veins. In severe cases, diseased plants will die prematurely. At the adult stage, the leaves are atrophied and uneven, with yellow-green mosaic, brown necrotic spots or stripes on the veins, the leaves become brittle and hard, the color gradually turns yellow, and the diseased plants become shorter. When the disease is serious, the diseased plant stops growing, can't form a normal spherical shape, the root system is underdeveloped, and the cross section of the diseased root is yellowish brown. Although Chinese cabbage can coagulate late, there are still many gray necrotic spots on the spherical leaves.
Phenolic insects are the main vectors of viral diseases. Therefore, to prevent and control viral diseases, we must first prevent and control phenolic insects. Drug control: the application of antivirus star, Junduling, Tektronix, Du Xiao and virus control.
Chinese cabbage clubroot is a fungal disease, which is caused by rhizobia of Myxomycetes. The disease occurs at the root. It may be injured at seedling stage, and in severe cases, it will lead to seedling death. In adulthood, the symptoms of the ground were not obvious at first, and then the growth gradually slowed down, became shorter, the leaves faded, and there were symptoms of water shortage. Basal leaves often wither at noon and recover sooner or later. Later, the basal leaves turned yellow and withered badly. When the whole plant dies. The root of the diseased plant is swollen and tumor-like, with many tumors on the main root, many tumors on the lateral root and many tumors on the fibrous root. The tumor was milky white in the early stage and turned brown in the middle and late stage. The surface is rough, cracked, and finally decays and stinks.
Strict implementation of plant quarantine measures. It is forbidden to transport cruciferous vegetable seeds, seedlings and vegetable products with roots and soil from epidemic areas; Rotation with non-cruciferous vegetables, preferably dry rotation, with a rotation period of 4? More than five years. Adjust the pH value of the soil. Combined with the application of quicklime 1500-2250kg/hn? Wash the pond with 1% quicklime water during soil preparation or before planting; Selecting disease-resistant varieties; Planting high dominant tree species and strengthening field management; Check the planting site regularly, pull out the plants in time when diseases are found, transport them out of the field for deep burial or incineration, and then water the diseased spots with 15% lime water. For fields with serious root edema, in order to prevent diseases spread by tap water, do not water the whole field, it is best to water it; Drug prevention and treatment: At the initial stage of the disease, Pujunte, Genzhangling, Genbizhi, Gendou and Genjunling were irrigated once every 10 day, and three times in a row.
The common pests of Chinese cabbage are Pieris rapae, Plutella xylostella, alfalfa, Chinese cabbage, Pieris rapae, Tongguchang and Hanluo # H. In the process of control, biological pesticides and new pesticides with high efficiency, low toxicity and low residue are used.
Use BT emulsion 500- 1000 times, 10% chlorpyrifos 2000-3000 times, avermectin, moth, emamectin benzoate, poisonous maid and 2.5% kungfu EC 3000-4000 times to control Pieris rapae.
Control Phytophthora. Use 1.8% avermectin emulsion with 3 1000 times solution, 1.8% Pseudomonas aeruginosa emulsion with 2500-3000 times solution, 20% spot latent cleaning emulsion with 1500 times solution and 2000-/kloc-0.
Prevention and control of wax and snails. Prevention and treatment with drugs such as Meta and MIDA. When the leaf ball is formed, more than 80% of the leaves have been entangled together, which has a certain firmness. The leaves outside turn to yellow stone and can be harvested. Harvest in time in rainy season, otherwise it will rot. The harvest must be clean and tidy, classified and packaged to prevent extrusion damage and keep fresh and beautiful.