The common physiological disease of Chinese cabbage is dry heart disease. The incidence of dry-heart-burning disease is the highest when the soil is dry and the amount of nitrogen fertilizer is excessive. The diseased plants have high nitrogen and low calcium, and the ratio of nitrogen to calcium is small. The main reason is that the content of available nitrogen in the soil solution is too high when the soil is dry, which affects the absorption of calcium. Excessive watering can also lead to a large loss of effective calcium in the soil, and thus, the importance of calcium for the growth of Chinese cabbage. Cabbage requires more boron, outer leaf content of less than 15 mg? Kilograms easy to produce symptoms of boron deficiency, growth point growth blocked or atrophy, hard and shriveled leaves, petiole often corked brown plaque, petiole appeared horizontal , Can not be normal ball or ball is not tight, seriously affecting the yield and quality of Chinese cabbage. Therefore, boron fertilizer is applied to boron deficient soil (the soil available boron is less than 0.5 mg?kg). Http:// Palm Recognition Access Control Chongqing Huifan Technology Co., Ltd , https://www.huifantech.com