A process involving the decay of plant and microorganism matter to produce thenatural organic matter (NOM) as found in some soils, sediments, peats, coals, and shales. Plantlignin, related transformation phases, polysaccharides, melanin, cutin, proteins, lipids, nucleic acids, and fine char particles, are materials involved in humification.
Cf., fulvic acid, humic acid, humic substances, humin