The nitrogen-deficient plants were light green, with yellowing of the base leaves, brownishness on drying, short and fine stems, few branches (branches), and premature aging. The potassium-deficient stems are easy to fall over, and the edges of the leaves are yellow, scorch, and fragmented. There are necrotic spots between the veins. The entire leaf is sometimes rolled or shrunken, with many brown roots. Grain crops and other crops with high sugar content require large amounts of potassium at the later stages of growth, such as cereals and potatoes, sweet potatoes, watermelons, and grapes. The magnesium-deficient leaves turn yellow and the veins are still green but turn yellow between veins, sometimes purple, and necrotic spots appear. The chlorosis of iron-deficient veins shows a clear reticular pattern. In severe cases, the entire leaf (especially the young leaves) is pale yellow or even white. Phosphorus-deficient plants are dark green, often red or purple, dark green when dry, stems short and fine, the base leaves yellow, the flowering phase is delayed, and the seeds are small and not full. The lack of boron is manifested as the phenomenon of stopping growth at the top. The young leaves are deformed and shrunk. Irregular retreats between veins, such as "flowers but not realities" of rapeseed, and "bud but not flowers" of cotton, are all due to shortages. Boron caused. Zinc deficiency is characterized by small clusters of leaves, spots on both sides of the leaves, short plants, shortened internodes, delayed growth period, such as white flowering corn seedlings. The lack of copper leaves the chlorosis of the new leaves, the white tip of the leaf is curled like a paper cocoon, and the leaves show necrotic spots, which then wither and die. For example, cereals show clusters of plants and their tops turn white. When they are severe, they do not produce headings and are not strong. There was a small necrotic spot between the manganese veins and dark veins and ribs in the veins. For example, manganese deficiency in citrus. Fei County Mingtao Electronic Co.,Ltd , https://www.yourbeautyassistant.com