ABSTRACT
Soil organic matter (SOM) is a complex mixture of animal and plant residues, fresh and at all stages of decomposition, living and decaying microbial tissue and heterotrophic biomass, and the relatively resistant humic substances. It has a series of beneficial properties for soils, even at low percentage levels. Organic matter (OM) is one of the most complex, dynamic and reactive soil component. The various organic fractions have different properties which affect the soil behavior and fertility. Unfortunately, it is difficult to separate and quantify those fractions in order to be able to correlate soil constituents and plant productivity.
