Dissolved organic carbon

Soil dissolved organic carbon (DOC) is a small but important fraction of total soil carbon that is involved in an enormous variety of important interactions with plants, microbes, and minerals. DOC is composed of thousands of individual compounds with differing sizes, reactivities, and functions, and is fundamental to soil forming processes. The reactivity of DOC with mineral surfaces changes depending on each molecule's functional groups, shape, and the composition of the soil solution. Adsorption is a dominant fate of DOC, but adsorption reactions are reversible and aged DOC may be released and exported from soils to groundwater and fluvial networks.