ABSTRACT
The chemical composition of plant remains entering the soil is very diverse. Detection of a definite set of structural units, at least kinds of carbon framework, in humic substances provides direct information regarding the pathways of humification. The chemical composition of plant remains entering the soil is very diverse. Detection of a definite set of structural units, at least kinds of carbon framework, in humic substances provides direct information regarding pathways of humification. During the process of decomposition of biopolymers partial transformational changes are unavoidable, giving monomers or oligomers. Hence for comparing the composition of initial substances and formed humic substances the carbon framework of compounds or definite classes are more convenient than specific individual substances. In humus chemistry it is customary to present nomenclature as a definite hierarchic system which is often used as a classification scheme. Finally, all specific humic substances are unavoidably subjected to partial destruction alkaline or acid hydrolysis during analytical division and preparative separation.
