humic

Humic refers to a broad group of naturally occurring organic molecules known as humic substances, produced by the microbial and chemical breakdown of plant and animal material. They are a major component of humus, the dark organic matter that enriches soil and sediments over time.

Humic substances are heterogeneous mixtures that include humic acids, fulvic acids, and humin. Fulvic acids are soluble in water across all pH levels, while humic acids are soluble in basic solutions and precipitate under acidic conditions; humin is not soluble in water. These compounds form through the disproportionate and long-term degradation of lignin- and polyphenol-rich materials and can also originate from coal, peat, and other fossil or sedimentary sources. They are typically rich in acidic functional groups such as carboxyl and phenolic groups, which enable metal binding and contribute to chemical reactivity.

In soils, humic substances influence physical and chemical properties by increasing cation exchange capacity, improving water retention, and promoting soil structure through interactions with minerals and microorganisms. They also play a role in nutrient availability and microbial activity. In natural waters, humic substances affect color and quality and can bind metals or organic contaminants, influencing mobility and bioavailability. They are widely studied in environmental science and agriculture for their perceived effects on soil fertility and pollutant dynamics.

Applications range from use as soil amendments and conditioners in agriculture to being a component of natural organic matter in water treatment discussions. The topic includes ongoing research and market controversy, as product claims vary and the chemical complexity of humic substances makes standardization challenging.