1. Urea has a high nitrogen content and is a neutral fertilizer that is easily absorbed by the leaves. The appropriate concentration in wheat, rice and other gramineous crops is 1.5% to 2%, the suitable concentration in cruciferous vegetables is 1%, 0.5% in watermelon, eggplant, sweet potato, peanut, and 0.5 in fruit trees. %, generally 0.2% to 0.3% in greenhouse vegetables. Spray once every 7-10 days, usually spray 2 or 3 times, spray time is appropriate in the morning or evening. 2. Potassium dihydrogen phosphate is a multi-component compound fertilizer. The effective composition of phosphorus and potassium is high, and it is easily soluble in water. The appropriate concentration for spraying is 0.2% to 0.3%. Cereal crops from jointing to flowering, cotton, peanuts, potatoes in full bloom, vegetables in the late growth stage, spraying 1 or 2 times. 3. The application of boron fertilizer is more borax, the solution concentration is generally 0.05% to 0.2%, and the amount of 667m2 (1 mu) is generally about 100g. In the leguminous and cruciferous as well as potato, cotton, watermelon, cucumber, grapes and other crops on the effect is more significant. 4. The main application of zinc fertilizer is zinc sulfate, spray concentration is generally 0.05% to 0.1%. Maize, rice, cotton, beans, and fruit trees require more zinc, which increases production significantly. The fruit trees were deficient in zinc and sprayed at a concentration of 0.01% to 0.05% when there were leaves. The concentration of sprayed shoots was 0.3% when there were no leaves. The spray concentration of corn and rice was 0.1% to 0.2%. 5. Ferrous sulphate is often used in ferrous sulphate. Because ferrous sulphate is rapidly converted into insoluble iron in the soil and fails, it is mostly sprayed. The concentration is generally 0.2% to 1%. Fruit trees are mostly sprayed before sprouting. Need more iron-sensitive crops are beans, sorghum, spinach, tomatoes, peaches, apples and so on. covid19 Anesthesia Medical Co., Ltd. , https://www.sinoanesthesia.com