Spraying foliar fertilizers on crops is a fertilization measure that can intensify the nutrition of crops and prevent certain disease-deficient conditions. It is also an effective fertilization technology that can increase the utilization rate of fertilizers. However, improper spraying will produce little or counterproductive results. Therefore, in order to improve the spraying effect of the foliar fertilizer, it is necessary to grasp the following technical requirements: 1. The spray concentration requirement is suitable. Different foliar sprays have different concentrations; different types of crops have different spray concentrations; the same crops have different spray concentrations at different growth stages. Therefore, when applying foliar spray fertilizer, it is necessary to flexibly grasp the specific circumstances and formulate suitable concentrations. Otherwise, if the concentration is too low, the effect is too low. If the concentration is too high, the stems and leaves will be damaged. 2, fertilizer solution to mix well. Some trace element fertilizers such as borax are not easily soluble in cold water, and are easily dissolved only when the water temperature is above 40°C. In the preparation of borax solution should be dissolved with a small amount of warm water and then diluted with water to the required concentration, so that fertilizer can be uniform. Fertilizer should be sprayed in time after being formulated to prevent re-precipitation after long-term storage. 3, spraying parts to be comprehensive. Many farmers tend to spray only the fertilizer solution on the front of the blade while neglecting the back of the leaf. The result is often not satisfactory. Because the foliar fertilizer is mainly absorbed by the leaves through the stomatal diffusion, and the stomata is distributed on the leaf, the back side of the leaf is generally more than the front side of the leaf. Therefore, when spraying the leaf surface fertilizer, it is necessary to pay attention to the positive and negative sides of the leaves to be sprayed to expand. The absorption surface, especially the dicotyledonous plant, should pay more attention to the back of the wet leaf. 4, the number of spraying should be appropriate. After nitrogen and potassium fertilizers are absorbed by the foliage, they are transported quickly and can reach all parts of the crops quickly. Therefore, it is sufficient to spray once during the critical period of fertilizer application. Phosphate fertilizers and other trace elements move slowly, generally spraying 2 or 3 times, spraying once every 7 days to 10 days, can have better results. The mobility of trace element iron is even worse. It is advisable to spray iron-containing fertilizers on fruit trees for 3 to 4 times, spraying once every 5 days to 7 days. 5, spraying should be appropriate. The longer the fertilizer solution stays on the leaves of the crop, the more beneficial it is to the absorption of fertilizer components by the leaves, thereby increasing the utilization rate. The spraying effect of foliar fertilizer is affected by factors such as high temperature, light intensity, rain, etc. Spraying should be carried out on a cloudy and sunny day with no wind, especially in the evening, because the light is not very strong and the temperature is low. After application, the leaves are wet for a long time, which is beneficial to absorption and increase fertilizer efficiency. Be sure to avoid the noon on sunny days, especially the hot days, and avoid the evaporation of fertilizer solution in a short time, which will affect absorption. Do not spray foliar fertilizer before the rain to prevent the fertilizer from being leached out of the rain. It is worth noting that foliar fertilization cannot fully replace the rhizosphere of the crop, because the crop root has a larger and more complete absorption system than the leaf, and only when the rhizosphere fertilizer is reasonably applied, the foliar fertilizer is applied in combination. In order to give full play to the role of foliar fertilizer production and quality enhancement.