The first reason is that the amount of calcium needed for vegetables is much larger than that of ordinary field crops. According to research, the calcium intake of vegetable crops is more than five times higher than that of wheat. Among them, radish is 10 times more than wheat, and cabbage is more than 25 times higher than wheat. Therefore, calcium deficiency in field crops is rare, while vegetable crops are the most vulnerable to calcium deficiency. For example, the dry heart of Chinese cabbage, leaf char of lettuce, and the umbilical rot of tomatoes and sweet peppers are all caused by calcium deficiency. Second, it must be clear that the symptoms of calcium deficiency occur in vegetable crops, not because of calcium deficiency in the soil, but in the late stages of vegetable growth, physiological calcium deficiency that occurs due to obstacles in the transport of calcium in the body. Calcareous soils generally contain more calcium carbonate. According to soil analysis of 14 vegetable plots in the suburbs of Beijing, the soil calcium content was 0.17% to 0.57% with an average of 0.46%. In theory, these calcium are sufficient for vegetable absorption and utilization, but in fact it is difficult for vegetables to absorb and utilize. For this physiological calcium deficiency, the use of calcium fertilizer to the soil has little effect, while the spraying of 0.3% to 0.5% calcium chloride solution on the foliar, and even spray a few times have a certain effect. HEBEI PINGLE FLOUR MACHINERY GROUP CO., LTD , https://www.plrollermill.com