1. What are Humic Acids? | 

Organic matter is formed through the chemical and biological humification of plant and animal matter and through the biological activities of microorganisms. Not all organic matter is humus. Humus, is a transformation product from animal and plant organisms that were more resistance against decomposition than the first living matter.

When organic matter decomposes to the point that it becomes humus, then it can be defined as humic, which is the soluble portion of humus. The greater the humification index (proportion between humified and not humified parts of a given organic substance) is, the greater part of the organic substance has been transformed into humic acids. Humic acids is the collective term for humic acid and fulvic acid, which make up the main fraction of natural humic matter.

Although even the International Humic Acid Society has not exactly defined several terms related to humic acids, they (both humic acid and fulvic acid) are accepted as part of humified vegetable substance and the biological center of natural humic matter. The insoluble portion of humus is non humic and called humin.

Humic acids are an excellent natural and organic way to provide soils and plants with a concentrated dose of essential nutrients, vitamins and trace elements. Not only in agriculture, humic acids are also used in the industry and for environmental applications such as wastewater treatment or erosion control.

2. Sources of Humic Acids | Top

Humic acids are complex molecules that exist naturally in soils, peats, oceans and fresh waters. The best source of humic acids are the sedimentation layers of soft brown coal, which are referred to as Leonardite. Humic acids are found particularly in high concentration in these layers. Leonardite is organic matter, which has not reached the state of coal and differs from soft brown coal (lignite) by its high oxidation degree and high humic acids content as well as higher carboxyl groups. It is often defined as naturally occuring oxidized lignite.

Compared to other organic products, Leonardite is very rich in humic acids. While Leonardite is the end product of a humification process lasting 70 million years, the formation of peat, to give an example, is completed within only a few thousand years. Similarly, composts and organic dungs have a litte content of humic acids.

One of the most important characteristics of the earthy life is that the increasing reproduction of the living matter is decisively enabled by the solid decomposition products of the living matter. Humus gives the essential medium (environment) for reproduction of the continental biomass, which is the accumulative mass of all organic substances on the continents.

In fact, humic acids themselves have all the positive effects and produce all the positive results attributed to humus and humus bearers in the agricultural and therapeutical praxis.

Decomposition process of the earthy biomass can be divided into two phases: humification and carbonisation. The so called recens humic substances have been formed during the humification and the fossil humic substances during the carbonisation process. Dead plant matter that has been transformed during chemical-biological oxidation and reduction processes is the origin of the formation of humic acids.

In the starting phase of decomposition of organic substance, first an aerobic and then an anaerobic biochemical oxidation takes place. Within this dynamic balanced process, the basic components of humic acids have been formed, originating from hardly decomposed compounds (lignin, tannin, flavonids, glycocides and their derivatives). Other parts of plant matter - proteins, cellulose, carbonhydrate - leave the biomass in form of NH₃, CO₂, H₂S, CH₄, H₂O, etc. Some of their derivatives become part of humus forming compounds with humic acids.

Such non-decomposing compounds like waxes and resins make up the greater part of the bituminous substances. In a later phase of humification, the hydroxyl-aromatic molecules complement themselves with oxycom-carboxyl groups and undergo polymerization and micelle forming processes.

Thus, the molecules forming plant matter undergo a decomposition process and make up the essential components of humic acids during this process. Humic acids are created from these compounds.

When the decomposing organic substance and an organic minerals are covered by soil layers, the carbonisation process (coal formation: soil-peat-coal) starts. During this process the former oxidative environment becomes reductive. Temperatures and pressure increase. The biological processes practically stop in this phase and chemical processes such as water withdrawal, decarboxylizing and hydrogen removal become characteristic. Relative carbon content of the organic substance increases and the molecules connecting aromatic C-O-C bonds change into C-C (anthracen) bonds.

Under special geological circumstances the carbonisation process can slow down or even turn back in such a way as to let air and water enter between layers or the given layers get on the soil surface, for instance as a result of pressures from below. These sedimentation layers on the surface contain the so-called naturally oxidized coals - the only sources of humic acids that are attainable and economically profitable for industrial production. However, there are only a few places on earth where such sedimentation layers exist and humic materials vary in composition depending on their source, location and method of extraction.

3. Chemical-Biological Properties of Humic Acids | 

Humic acids contain the humic acid and the fulvic acid. While the former are very complex organic compounds, the latter are compounds with a relatively low molecular weight. Fulvic acids are those organic materials that are soluble in water at all pH values. Humic acids are those materials that are insoluble at acidic pH values (pH<2) but are soluble at higher pH values. Humin is the fraction of natural organic materials that is insoluble in water at all pH values.

3.1. Composition and Properties of Humic Acids | 

Both humic acid and fulvic acid have a pretty similar structure: their carbon content ranges between 40 and 60% (being higher in the humic acid) and their content in oxygen ranges between 30 and 50% (higher in the fulvic acid). Both the humic and fulvic acids also contain nitrogen, around 5% in the humic acid and less than 1% in the fulvic acid.

The major functional groups of humic acids are carboxylic acid, phenolic and alcoholic hydroxyls, ketone and quinone groups. Most of the chelating power of the humic and fulvic acids is due to the carboxylic and hydroxyacid groups. Fulvic acids are richer in carboxylic acid, phenolic and ketone groups. This is the reason why they have a higher solubility in water at all pH values.

Among humic substances only the fulvic acid is watersoluble. The greater the molecule is, the more difficult it can be dissolved in water, as the number of active hydrophilic groups (COOH, OH) specifically decreases with the increase of molecule measurements.

Another reason is the lactone ring in the molecule that closes in neutral or acidic environment. This lactone ring opens in alkaline environment and thus the number of hydrophilic groups increases . That is the reason why the humic acids are soluble in alkaline environment.

In terms of their biological, chemical and physical properties, it can in general be said that the humic acid acts mainly on the physical and chemical reactions and the fulvic acid acts more on the biological and chemical reactions.

3.2. Biological Activity of Humic Acids | 

Biological activity of humic acids is a well-known fact in the chemistry. The biological activity of humic acids was first discovered by a Russian scientist, Prof. Lydia Khristeva about fifty years ago.

This biological activity results from the property of humic acids to behave as electron and oxygen transfer molecules. This ability enables them to take part in cell-breathing processes as catalysts, similarly to FAD and NADH coenzymes. This electron transfer property of humic acids occurs due to the cyhnon-carboncyhnon structure and the delocalized electron structure.

The biological activity of natural humic acids is weak as their solubility in water is low. By alkaline extraction of natural humic acids, humic acids are made soluble as potassium and sodium salts.

As a result of the alkaline extraction, the hydrogen atoms in the carboxyl and hydroxyl groups are replaced by the alkaline metal ions. The humate has a molecular weight as a result of the continuing separation. These weights are localized along the molecular chain. The force of repulsion of the weights enables the molecules of humic acids to become soluble without forming a sphere. As a result, humic acids become biologically active.

To give an example, the carboxyl (NIII) and phenolic (OH) groups create chelate complexes with microelements and carry them to the plants. These groups are also responsible for the high ion exchange capacity of humic acids. Other groups such as cyhnons (NI=N I=IN) contain not localized weights that collect the sun energy. These functional groups of humic acids are localized as such so as to provide an optimum interaction of humic acids and metals ions for the plant. Scientists suggest that humic acids are the binding ring of a chain in the evolution of living and dead matter.

As catalysts humic acids accelerate the cell-breathing process and thus increases the energy production of the citrate circle. As a result, more energy is released in the cells.

The decisive chemical parameter of this process is the concentration of free electrones and not the molecule measurements or the total acidity. This means that the greater the humic acid molecules are, greater bio-stimulant effect they have. Consequently, it can be said that the fulvic acid is not as bio-active as the humic acid.

Humic acids always have an optimal concentration. In different living organisms this optimum can be different, but is to be realized in every case. It follows from this that an overdose does not produce any better results.

3.3. Reactivity of Humic Acids |

Reactivity of humic acids is also a well-known fact. Humic acids enter into reaction with practically all compounds occuring in biological systems.

Organic cations can be fixed by humic acids by ionic, complex, chelate and polar adsorbtion bonds. Main reaction partners are the acidic carboxyl and hydroxyl groups here, but carbonyl and semichynon groups may react as well.

Anorganic anions cannot be immediately bound with humic acids, but under certain circumstances it is possible to create bonds with good effectiveness.

Reactions of organic compounds depend upon the molecule structure (aromatic, aliphatic, ionic). Tests show that humic acids can enter into reactions with almost all different molecule structures (xenobiothics, proteins, enzymes).

Humic acids are natural complex generators. All essential microelements having variable valency metals form chelate complexes with humates. Humates form unsoluble complexes with heavy metals that hinder their penetration to the cells. Another important property of humates is their ability to bind iron and aluminium ions to form complexes. Tests show that humates neutralize the negative effects of pesticide residuals.

The fact that humic acids promote and strengthen the metabolic processes in plants has also implications for animal organisms. Various tests conducted worldwide (including in Germany, the USA, Turkey, Hungary and the Netherlands) showed that used as an animal feed additive, humic acids strengthen the immune system and increase the animal's resistance against most important diseases as well as increasing the live weight of the animal. For instance, tests done with poultry have revealed an increase of about 10% in the live weight of animals and an increase of 5-7% in the resistance against diseases.

Other tests have demonstrated that added to human feeds of sheep in a ratio of 1%, humic acids increased the general effectiveness of the feeds about 10-20%. This increase was related to the increase in the redblood cells in sheep. Added to animal feeds for cattle, humic acids improved the metabolism of the animals and increased the hemoglobin level in blood by 11.5%, phosphorus level by 6.7%, albumin level by 24.3% and the beta-globulin level by 32% in the animals.

These results indicate a new direction in the use of humic acids, namely the pharma industry. Some scientific research has been done so far in the field and the anti-toxic and therapeutical effects of humic acids have already been detected.