Organic matter and composting

Organic matter

Organic matter consists of a complex system of substances, whose dynamic is determined by the incorporation to the soil of organic residues, principally of vegetal although also, to a lesser extent, of animal origin, and by their continuous transformation under the influence of biological, chemical and physical factors. For this reason, soil organic matter is formed of recently incorporated organic residues, by these residues in different states of decomposition, products of the metabolism of the micro-organisms which use these residues as energy source, secondary synthesis products in the form of bacterial plasma and humic substances (Kononova, 1965).

Organic matter can be divided into two overall groups: non-humic and humic substances (humus). The first group is composed of well-defined chemical compounds which are generally colorless and not distinctive to the soil. They are simple compounds of low molecular weight, which are used by microorganisms as substrate and...