Detailed Explanation of Key Techniques for High-Yield Cultivation of Chinese Cabbage

I. Select good varieties and avoid continuous cropping. For Chinese cabbage, disease-resistant, moisture-tolerant, high-yield F1 hybrids should be selected, such as the Fengkang series, Yuxin No. 1, No. 2, No. 6, Tokyo No. 5, Xinxiang Xiaobao 23, Xinxiang 90-3, Zhongbao 75, Jincai No. 3, etc. At the same time, avoid continuous cropping with cruciferous vegetables; rotation can be done with alliums, melons and legumes, solanaceous fruits, and grain crops. II. Clear the stubble and prepare the land, apply sufficient base fertilizer. The root system of Chinese cabbage is relatively shallow, and it has high demands for soil water and fertilizer, so early stubble clearing and early plowing should be pursued. Generally, about 15 days before sowing, plow deeply about 20 cm, and through summer sun exposure to sterilize and kill eggs, make the soil loose, ready for sowing. Chinese cabbage is a vegetable with high fertilizer demand, and sufficient base fertilizer is needed to meet its growth and development needs. Therefore, generally when preparing the land, apply 3000 kg of decomposed organic fertilizer per mu or 500 kg of high-quality commercial organic fertilizer.

III. Sterilize seeds and sow at the right time. Before sowing, mix seeds with zineb or thiram to sterilize and disinfect the seeds, with the amount of pesticide being 0.4% of the seed amount. Because high temperatures easily cause the occurrence of cabbage viral disease, in Laizhou the sowing period should be appropriately delayed, and sowing can be done on August 15-20 (End of Heat). This can both avoid viral disease and ensure timely head formation of Chinese cabbage. The sowing method should preferably be drilling or hole drilling. In order to prevent the soil surface from drying out and strong sunlight from scorching the seedlings after emergence, covering can be done after sowing, with a covering thickness of about 3 cm.

IV. Master density, thin and finalize seedlings. For Chinese cabbage planting density, early-maturing varieties should be 3200 plants per mu, and mid-to-late-maturing varieties 2300-2400 plants per mu. Thinning and finalizing seedlings should be carried out in a timely manner to prevent crowding of seedlings and promote robust growth. Thinning is generally carried out in stages. The first time, at the cross stage, eliminate small seedlings that emerged too late, inferior seedlings with abnormal cotyledon shape, and inferior seedlings that have fallen over on the ground; the second time, when the seedlings have 4-5 true leaves, thin according to a plant spacing of 10 cm for drilling, and 7 cm for hole drilling, selecting and keeping seedlings that grow strongly and have the characteristics of this variety, and pulling out mixed and diseased seedlings; when the seedlings have grown for 20-26 days and entered the rosette stage, thin according to the predetermined plant spacing.

V. Strengthen field management and control fertilizer and water. During the seedling stage, water frequently with small amounts to retain moisture and lower temperature; during the rosette stage, keep it somewhat dry but not drought-stressed, so as to appropriately restrain growth and promote deep rooting. In the early rosette stage, apply 15 kg of urea per mu, cover with soil, and water. In the late rosette stage and early head-forming stage, apply 20-25 kg of potassium-containing compound fertilizer per mu, and pay attention to appropriately controlling moisture. Before closing the rows, pesticide should be applied carefully and thoroughly to eliminate aphids and cabbage caterpillars, and prevent downy mildew and soft rot. During the head-forming stage, chemical fertilizer can be applied 2-3 times as a top dressing; in the later stage, water should be controlled, and when the heads are firm, attention should be paid to drainage to facilitate harvest. Before frost, bundle the cabbage, and when the temperature drops to 0°C, harvest and store in time.

VI. Prevent and control diseases and pests to strive for high yield. During the seedling stage, focus on preventing aphids, while also controlling cabbage webworm, cabbage caterpillar, and diamondback moth, spraying pesticides such as acetamiprid or Caixi. During the rosette stage, focus on preventing downy mildew and soft rot. For downy mildew, use pesticides such as Duofan or Jinlei. From the rosette stage to the head-forming stage, it is highly susceptible to soft rot, and agricultural streptomycin or copper abietate can be used for prevention. Bai Xianhua