What is the appropriate concentration of foliar fertilizer?

What is the appropriate concentration of foliar fertilizer? It is hoped that experienced netizens can help introduce that foliar fertilizer is an effective way to quickly supplement nutrition, relieve the physiological diseases of crops due to lack of nutrients, promote crop robust growth and increase yield. However, the concentration of foliar fertilizer will not often lead to crop damage, so the farming network collates the concentration of commonly used foliar fertilizer, which is listed in detail below for netizens' reference. 1. The concentration of urea as foliar fertilizer: the commonly used spraying concentration is 1%-1.5% (that is, 100 kg water plus 1-1.5 kg urea); within this range, the concentration of dicotyledonous plants can be appropriately lower; Monocotyledonous plants, the concentration can be appropriately higher; seedling stage, the concentration can be appropriately lower; seedling stage, the concentration can be appropriately higher. 2. The concentration of calcium superphosphate as foliar fertilizer: the commonly used spraying concentration is 2%-3%; the fertilizer should be fully stirred after adding water, and filtered after 24 hours, and the clear liquid is sprayed. 3. The concentration of potassium dihydrogen phosphate as foliar fertilizer: the commonly used spraying concentration is about 0.3%; the preparation method is to take 300 grams of potassium dihydrogen phosphate plus 100 kilograms of water, fully dissolved and sprayed. 4. The concentration of potassium sulfate as foliar fertilizer: the commonly used spraying concentration is 1%-1.5%. 5. The concentration of zinc sulfate as foliar fertilizer: the commonly used spraying concentration is 0.1%-0.2%; spray after adding a small amount of lime liquid to the solution. 6. The concentration of borax (or boric acid) as foliar fertilizer: the commonly used spraying concentration is 0.2%-0.3%; when preparing the solution, dissolve borax with a small amount of 45 ℃ hot water, and then mix it with enough water. 7. The concentration of plant ash as foliar fertilizer: the commonly used spraying concentration is 3%-5%; stir with plant ash after adding water, stand for 15 hours and then filter and reuse. What are the advantages of foliar fertilizer? What are the methods of foliar fertilization