The first step is to select humic acid fertilizer according to the application method. If it is used for flushing, irrigation or leaf surface spraying, it is recommended to use potassium humate, ammonium humate or potassium humate, ammonium fulvic acid. If it is used for base fertilizer application, It is recommended to select chemical fertilizers such as ammonium humate or ammonium nitro humate, and pay special attention to burying them in the soil when applying. Since ammonium humate is the product of the combination of humic acid and ammonium bicarbonate, it is easy to evaporate, so it is not recommended Flushing or foliar spraying. In addition, sodium humate should not be applied in soil layers with a high pH value (saline soil).

Part 2: Select humic acid fertilizers according to crop hobbies and growth and development nodes. Taking fruit trees as an example, fertilizers are mainly applied to phosphorus and potassium fertilizers in autumn, and nitrogen fertilizers are mainly applied to fertilizers in early spring. During the period, nitrogen fertilizers, potassium fertilizers, calcium fertilizers and micro-fertilizers must be mainly applied. In addition, fertilizers should be applied in combination with the hobbies of crops. For example, fruit trees, eggplants, cigarettes, sweets and so on are potassium-loving crops. Potassium humate fertilizer works better.

Part 3, Selection of humic acid fertilizers according to crop types and inputs. Humic acid fertilizers can be divided into humic acid simple chemical fertilizers, humic acid compound (mixed) fertilizers, humic acid organic fertilizers, humic acid organic fertilizers, Acid organic-inorganic compound fertilizer, micro-element fertilizer in humic acid, etc.

For farmland crops, it is recommended to choose humic acid compound (mixed) fertilizer, which is easy to use, cost-effective and high; for vegetables and fruit trees, humic acid organic fertilizer, humic acid organic-inorganic compound fertilizer or humic acid organic fertilizer can be selected. Fertilizer with micro-elements in acid, the organic matter in this fertilizer can reach 20%-45%, which can reasonably improve the taste and color of crops.

If it is used for flushing or spraying on the surface of leaves, it is recommended to choose water-soluble chemical fertilizers containing humic acid or fulvic acid. Although these types of fertilizers are expensive, they are effective and fast, so they are mostly used for crops with higher use value. .Although humic acid can be applied in the whole growth period of crops, due to economic development considerations, it can be applied 1-2 times in each of the four critical periods of crop transplanting, before flowering, fruit setting, and color change. It will be better to combine the spraying effect with the color change period.