Humic acid (HA) is a macromolecular organic substance that is widely used in agriculture, forestry, animal husbandry, chemical industry, building materials, medicine, environmental protection, and a number of other fields. However, the production of chemical HA in the market relies on non-renewable resources, such as peat, lignite, and coal, which require long periods to form. And the extracted HA yield depends on the type and quality of fossils.
