Soil is a complex, dynamic, and heterogeneous system, composed of mineral and organic matter, as well as water and air. It is of biogeochemical relevance because it provides a reservoir of resources, such as carbon, nitrogen, and water, which are essential for life. Soil organic matter (SOM) refers to the total amount of organic material in the soil. Although SOM represents only a small percentage of most top soils, it plays a central role in the global cycling of carbon . The classification of SOM can be subdivided depending on the origin and degree of decomposition of plant and animal residues. The term "raw organic matter" is often used to describe the organic material that is found at the initial stages of decomposition. At the final stage of this process the so-called "humus" remains, which is the dead part of SOM . Humic substances (HSs) can be categorized into fulvic acids, humic acids (HAs), and humin. This definition is based on the extraction methods used for these substances. From a chemical point of view, SOM is one of the most heterogeneous substances, containing a wide spectrum of molecules such as carbohydrates, proteins, lipids and others. This also results in the presence of a multitude of functional groups, often including aromatic and aliphatic ones, as well as functional groups composed of different elements such as oxygen, nitrogen or sulphur.