Symptoms When the plant lacks calcium, the growth and development of cabbage leaves is blocked. The leaves are rolled up slightly and then die, commonly known as "leaf burning" and "dry burning." The dried, yellow and leafy leaves of individual leaves within the leaf were dry paper-like, and the value of the commodity was significantly reduced. ã€cause】 First, less calcium in the soil; second, due to excessive nitrogen fertilizer application, inadequate irrigation, or poor irrigation water quality, the concentration of cations in the soil solution is too high, reverse osmosis occurs, and calcium absorption is inhibited, resulting in the formation of calcium deficiency. The third reason is the lack of calcium in the inner bulb of the plant. [control methods] Before the site preparation, 100-150 kilograms of slaked lime were spread per acre, and they were turned into soil with the fertilizer. Can also be sprayed before and after the onset of 3% of superphosphate calcium fertilizer (adhesive should be added) 2-3 times. For drought-caused calcium deficiency, ground water and good water quality to ensure the soil moisture reaches 70%. Apply as many organic fertilizers as possible, reduce inorganic fertilizers, increase soil water retention, use organic fertilizers for top dressing, and topdressing, do not apply single or excessive topdressing nitrogen fertilizers. Apply watering, apply topdressing phosphate and potash fertilizers in order to prevent dry heartburn. occur.