Paying attention to nitrogen fertilizer and neglecting potash fertilizer Chinese cabbage needs balanced fertilization for growth

Fertilization of Chinese cabbage should achieve the dual goals of high yield and high yield. The demand ratio of nitrogen, phosphorus and potassium in Chinese cabbage was 1 ∶ 0.5 ∶ 1.2, and the amount of potassium required was greater than that of nitrogen. But in the actual production, generally only pay attention to nitrogen fertilizer, ignore the supplement of potash fertilizer.

Fertilization of Chinese cabbage

First of all, the application of nitrogen fertilizer should be appropriate. Practice has proved that the production of 1000 kg of Chinese cabbage needs to absorb about 2 kg of pure nitrogen from the soil, and the production of 10,000 jin of Chinese cabbage needs to absorb 22 kg of nitrogen. The nitrogen needed for Chinese cabbage can come from soil, organic fertilizer and chemical fertilizer. Under the condition of applying a large amount of organic fertilizer, the amount of chemical nitrogen fertilizer should be reduced appropriately. The application of appropriate amount of nitrogen fertilizer is beneficial to the growth and photosynthesis of Chinese cabbage and realize the high yield of Chinese cabbage. At present, the actual amount of nitrogen application in most areas exceeds the demand, and excessive application of nitrogen fertilizer not only thickens the outer leaves of Chinese cabbage, has poor core, low yield and quality, but also has high leaf water content, is not resistant to storage and is easy to rot after harvest, and is vulnerable to diseases and insect pests in the later stage of growth.

Therefore, in addition to the appropriate amount of nitrogen fertilizer, the period of use should also be appropriate. In the whole growth period of Chinese cabbage, the amount of nitrogen uptake was also different at different stages. The seedling stage is very little, accounting for about 2% of the total; the rosette stage increases to about 28%; the pericardium stage is the most, accounting for about 70% of the total, so the application of nitrogen fertilizer should be applied in stages, reflecting that the first is light and the second is heavy. Chinese cabbage has a long growth period and should be fully fertilized. In the aspect of topdressing, Chinese cabbage should control water and fertilizer (mainly nitrogen) from seedling stage to rosette stage, except for special circumstances. Generally squatting seedlings in the rosette stage, first, the growth of the outer leaves of the ground is robust, and the other is to promote root growth and tie down, laying the foundation for rapid growth and absorption of a large amount of nutrition and water in the later stage. The first topdressing was in the rosette stage. Topdressing available nitrogen and potassium fertilizer is suitable, irrigation at the same time, water and fertilizer will enter the pericardium stage. The second topdressing is in the early and middle stages of pericardium, mainly applying nitrogen fertilizer, at most twice, to control the amount of nitrogen. In the later stage of wrapping, stop topdressing nitrogen fertilizer.

Second, increase the proportion of phosphorus and potassium fertilizer. In base fertilizer and topdressing, the increase of potassium fertilizer is beneficial to the heart of Chinese cabbage and enhance the disease resistance. Topdressing in the early stage of wrapping heart, pay attention to the application of potash fertilizer, Chinese cabbage in the heart stage, such as insufficient phosphorus and potassium fertilizer, it is not easy to set balls. At present, the application of potash fertilizer is often ignored in production. The suitable amount of potassium application is generally 12 kg potassium chloride or 16 kg potassium sulfide per mu. It is best to apply base fertilizer and topdressing twice, base fertilizer is applied at the bottom of the hole when planting, topdressing is carried out at the end of rosette stage, combined with nitrogen fertilizer and irrigation at the same time.

Third, we should pay attention to the supply of calcium fertilizer. The dry heartburn disease of Chinese cabbage can be effectively prevented by applying calcium superphosphate and supplementing calcium nutrition. Chinese cabbage likes calcium, and calcium deficiency, especially excessive nitrogen application, is easy to cause dry burning heart disease. Controlling nitrogen fertilizer and supplementing calcium nutrition is the key to prevent "dry heartburn" disease of Chinese cabbage. The method of calcium supplement, in addition to applying calcium fertilizer in the soil, can also be foliar supplement, spraying 0.1%-0.3% calcium chloride or calcium nitrate, or spraying calcium glycolate and calcium amino acid, spraying 2 times 3 times at the rosette stage.