Detailed explanation of the key points of pollution-free cultivation techniques for spring and autumn Chinese cabbage, with an introduction to pollution-free vegetables

There are many varieties of cabbage. Northern Chinese cabbages include Shandong Jiaozhou Chinese cabbage, Beijing Qingbai, Qing Tianjin Maye Chinese cabbage, Northeast short-stalked Chinese cabbage, Yutian Chinese cabbage, Shanxi Yangcheng large fringed-leaf Chinese cabbage, and others. Green pollution-free food is what people have been pursuing in recent years, and Chinese cabbage has high nutritional value, so more and more people are growing it. So what are pollution-free vegetables? How do you grow pollution-free Chinese cabbage? What cultivation techniques do you need to master?

I. What are pollution-free vegetables?

Pollution-free vegetables are edible agricultural products, whether processed or primarily processed, whose production area environment, production process and product quality meet the requirements of relevant national standards and specifications, which have passed certification and obtained a certification certificate, and which are permitted to use the pollution-free agricultural product mark.

II. Pollution-free Chinese cabbage cultivation techniques

1. Pollution-free cultivation techniques for spring cabbage

(1) Sowing

The two methods, direct sowing and seedling transplanting, are generally determined by how early or late the previous crop is harvested. If the previous crop is harvested early and the land can be prepared and beds made in time, the direct sowing method can be used. Otherwise, the seedling transplanting method is used. Direct sowing is done 5~6 days later than seedling transplanting. Chinese cabbage is generally cultivated using two patterns: high ridges and flat beds. High ridges generally carry one row per ridge, with a ridge height of 12~15 cm; flat beds carry two rows per bed, with bed width determined by the variety.

Direct sowing has two methods: hill sowing and drill sowing. Hill sowing means opening holes within the row or on top of the ridge at a certain plant spacing. Drill sowing means opening a furrow 5~10 cm deep according to the row spacing, evenly scattering the seeds in the furrow, and covering with 1 cm of fine soil. The seeding rate is about 0.3 kg per mu. For directly sown Chinese cabbage, after the young sprouts emerge, water lightly frequently to keep the ground moist and lower the surface temperature.

(2) Seedling stage management

After the seedlings emerge completely, thin them at the 3~4 leaf stage. Remove twin, overly dense, crowded, diseased, pest-damaged, weak and deformed seedlings. After thinning, cultivate in a timely manner after watering or rain, which both prevents soil compaction and removes weeds, loosens the soil and maintains soil permeability. At the 5~6 leaf stage, final thinning is done with a plant spacing of 10 cm. In hot and dry years, final thinning should be appropriately delayed so that the dense seedlings cover the ground, lower the ground temperature and thereby reduce the occurrence of disease. After final thinning, timely cultivation should also be carried out to eliminate weeds and preserve moisture; be sure not to cultivate too deeply this time. After each thinning and final thinning, water immediately to prevent wilting caused by disturbance of the seedling root system.

(3) Transplanting and setting out

The seedling age is generally 15~20 days, and when the seedlings have 5~6 true leaves it is the best time for transplanting. Transplanting is best done in the afternoon. Water immediately after transplanting. After that, water once each morning and evening for 3-4 consecutive days to help the seedlings recover.

(4) Reasonable topdressing

Topdressing should be decided according to the different growth stages and the condition of the seedlings. Generally no topdressing is applied at the seedling stage. If the base fertilizer is insufficient, the first application can be seedling-promoting fertilizer at the 3~4 true leaf stage, broadcasting 10 kg of compound fertilizer per mu on both sides of the seedlings and watering immediately; the second is 15~20 kg of compound fertilizer per mu as a plant-developing fertilizer after final thinning or seedling transplanting, applied in furrows opened on both sides of the ridge; the third is the major topdressing during the continuous cropping period, applying 15~20 kg of urea and 10~15 kg of superphosphate per mu, placing the fertilizer into furrows or holes, then adding a little soil to support the ridge and watering; the fourth is the heart-filling fertilizer applied in the middle of head formation, applying 10~15 kg of urea per mu, which can be washed in with water.

 (5) Reasonable watering

From the rosette stage to the rosette stage, the temperature gradually drops and the weather is mild, so watering can be done appropriately during this period. At the end of the rosette stage, water can be appropriately controlled for several days, and watering resumes after the third topdressing. After Chinese cabbage enters the head formation stage, it needs the most water, so as soon as the seedling hardening period ends, give one thorough watering. Then after 2~3 days, give a second watering. After that, water generally once every 5~6 days to keep the soil moist.

2. Pollution-free cultivation techniques for autumn cabbage

(1) Reasonable crop rotation

For rotating crops when planting autumn cabbage, scallion, garlic and wheat stubble are generally better, and melon or potato plots can also be chosen as the previous crop for planting autumn cabbage. Generally, vacant land or vacant ridges are left for planting autumn cabbage. When growing cabbage, reasonable crop rotation is required; it cannot be continuously cropped, nor can other cruciferous crops be chosen for rotation. This is the key measure to prevent the occurrence and harm of diseases and insect pests in autumn cabbage. Autumn cabbage likes water and fertilizer, so plots with high fertility, irrigation conditions and good drainage should be chosen for planting autumn cabbage. Land preparation should be fine, with fine soil and no clods, which is beneficial to the good development of the autumn cabbage root system.

(2) Selecting excellent seeds

The key to the yield of autumn cabbage and the severity of disease and insect pest occurrence is excellent varieties. Good seeds with strong stress resistance should be selected, and early, middle and late varieties should be reasonably matched to give full play to the role of “making the best use of the seeds and the land.” After the seeds are selected, they should be screened to remove inferior and mixed seeds, improving seed purity (above 98%) and cleanliness (above 99%). Before sowing, treat the seeds: first soak the seeds in cold water for 10 minutes, then remove them and soak them in 50°C water for 30 minutes to achieve the purpose of disinfection and sterilization, ensuring a full stand from one sowing.

(3) Early sowing at the right time

Generally, the suitable sowing period for early-maturing varieties is July 20~25, for mid-maturing varieties July 15~20, and for late-maturing varieties July 12~15. Grasping this period for sowing means hitting the sweet spot and planting in the high-yield period. The sowing quality should be improved. For plots with good subsoil moisture and poor surface moisture, push away the dry soil layer and sow the seeds on the moist soil; for plots with poor subsoil moisture and also poor surface moisture, sow with water in the hole and use precision sowing, sowing 4~5 seeds per hole (hill), with a seeding rate of 75~100 g per mu and a target stand of 3200 plants per mu.

(4) Field inspection and reseeding

After sowing, field inspections should be carried out frequently. Where missing seedlings or gaps are found, reseeding should be done promptly to achieve full seedlings in every ridge and full plants in every hole, with a complete and strong stand.

(5) Scientific fertilization

Cabbage has a very high fertilizer requirement. The base fertilizer should be mainly decomposed organic fertilizer, applied at about 5000 kg per mu, or 1000 kg of decomposed and harmlessly treated fresh chicken manure. Applying sufficient nitrogen fertilizer is the key to high yield in autumn cabbage. In the later period, sufficient phosphorus and potassium fertilizers should be applied, and the application of trace elements is also very necessary. Topdressing should be done early. From the rosette stage to the head formation stage, autumn cabbage enters a stage of rapid growth, and during this period the demand for water and fertilizer is especially large. Generally, topdressing is applied once each at the rosette stage and the head formation stage, mainly nitrogen, together with a certain amount of phosphorus and potassium fertilizer, to meet the nutrient needs of autumn cabbage at different growth stages.

(6) Strengthened management

First, thin seedlings early and set the stand early to promote early and rapid seedling growth; second, hoe and ridge frequently and carefully to promote standing up; third, irrigate reasonably, watering in drought and draining in waterlogging, especially watering well at the rosette stage and the head-filling stage; fourth, prevent disease and eliminate insects, with prevention as the main approach and treatment as the supplement, combining prevention and treatment and using integrated management, mainly adopting biological measures to control downy mildew, soft rot and other diseases and insect pests.