(1) It can increase soil nutrition. Humic acid has a strong ability to enrich nutrients in soil and can protect and store nutrients. (2) It can improve the plant's resistance to diseases and insect pests. The salicylic acid structure and phenolic structure in humic acid have antibacterial properties, preventing plants from being harmed by germs. At the same time, humic acid can improve the metabolic function of plants and improve the activity and immunity of certain enzymes in plants. (3) Increase soil moisture content. Humic acid can increase soil water holding capacity by 5 to 10 times. (4) Improve the soil. The structure of humic acid is a weak acid-alkaline system, which can adjust and buffer soil pH. (5) Promote soil microbial activity. Humic acid can provide most of the energy source for microbial activities in the soil and improve the microbial population in the soil.