Editing Humin (section)

==Humins in soil chemistry==
Soil consists of both mineral (inorganic) and organic components. The organic components can be subdivided into fractions that are soluble, largely [[humic acid]]s, and insoluble, the humins.  Humins make up about 50% of the organic matter in soil.<ref>Rice, James A. "Humin" Soil Science 2001, vol. 166(11), pp. 848-857. {{doi|10.1097/00010694-200111000-00002}}</ref>

Due to their very complex molecular structure, humic substances, including humin, do not correspond to pure substances but consist of a mixture of many compounds that remain very difficult to characterize even using modern analytical techniques.<ref>{{citation|title=The contentious nature of soil organic matter | first1 = J. | last1 = Lehmann |last2 = Kleber | first2 = M. | journal = Nature | volume = 528 | issue = 7580 | pages = 60–68 | date = 2015-12-03 | doi = 10.1038/nature16069| pmid = 26595271 | doi-access = free | bibcode = 2015Natur.528...60L }}</ref>