What are humic substances?
Humic substances are found in all soils and waters and arise from the decomposition products of plants. They are separated by extraction into humin, humic acid and fulvic acid. Their salts are called humates and fulvates.
Humic and weed substances:
- Humic substances, highly transformed, high-molecular substances without recognizable tissue structures.
- Dispersing substances that are not transformed or only slightly transformed and in which tissue structures are still largely morphologically visible. These include above-ground dead plant residues, as well as dead roots and soil organisms or their components. These substances, often called non-humic substances, mainly contain lipids, lignin and polysaccharide fragments.
Simply put, humus consists of nutrient humus and permanent humus. While nutrient humus in the form of organic matter biomass added to the soil (i.e. essentially biomass consisting of carbohydrates, lipids, proteins and lignins) can still be largely biodegraded with the release of important nutrients, permanent humus in the form of high molecular weight humic substances is largely resistant to biological degradation.
This is probably due, on the one hand, to the complex macromolecular structure of humic substances, and on the other hand, to their ability to bind tightly to the surrounding inorganic soil matrix in the form of stable clay-humus complexes.
By linking the nutrient humus with the degradation-resistant permanent humus, microbial degradation is significantly slowed down, resulting in a larger portion of the nutrient humus being converted into permanent humus, and at the same time, due to the slow metabolism of the nutrient humus, CO2 emissions from agricultural land are significantly reduced.
