German technology
Humic Substances Based Products
Humintech GmbH
Am Pösenberg 9-13
D-41517 Grevenbroich

Telefon: +49 2181 70 676 - 0
Fax: +49 2181 70 676 - 22
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Frequently Asked Questions

What is Leonardite?

Leonardite is a low rank coal derived from prehistoric plant matter. It is found as outcropping of lignite deposits, usually very close to the surface. It differs from lignite by its high oxidation degree and the higher carboxy groups. Due to the large amount of living bacteria, Leonardite was formed instead of coal in certain sedimentation layers. Being a highly decomposed compressed natural organic humus that has been further processed by microbial activity, Leonardite has a high humic acid content which is one of the most bio-chemically active elements. The composition of Leonardite will show on average organic matter 75-90%, aluminum, nitrogen, phosphorus, potassium, sulfur, iron and calcium less than 1%. Since Leonardite is a naturally mined material, the composition of Leonardite differs slightly throughout the deposit and from deposit to deposit.

What are Humates?

The sodium, potassium and ammonium salts of humic acids derived from Leonardite through alkaline extraction are referred to as humates. While sodium humates have usage in various industries such as printing inks, potassium humates are used extensively in agriculture. Only potassium humates are approved for organic agriculture by OMRI (Organic Materials Review Institute).

What are Humic Acids?

Humic acids are complex organic molecules formed by the breakdown of organic matter in soil. They are the main fraction, the biological center, of natural humic matter. It is the collective term for humic acid and fulvic acid.

How does a humic acid work?

Humic Acids stimulate and promote plant development, resulting in higher yields. Humic Acids improve the structure of soil and increase water retention, seed germination, root growth and quality of yields. For soils to remain fertile, humus must either be replaced or added. Applying Humic Acids does this and increases the natural fertility process in the soil.

How is this accomplished?

The most important feature of Humic Acids is their ability of binding ions which produces bio-chemical reactions known as chelation. This makes the nutrients more readily available to the plants for the proper growing process. As a result, Humic Acids produce three types of effects on soil and plant: They physically modify the structure of soil, they chemically change the fixation properties of the soil and they biologically stimulate the plant and the activities of microorganisms.

Are Humic Acids Chelating Agents?

Yes, Humic Acids act as a natural chelator for trace elements and nutrients in the soil and promote their uptake by plants by converting them into forms available to plants. In the absence of chelates, iron, copper, zinc, manganese and other trace elements are converted to insoluble hydroxides. Humic Acids keep these trace elements in solution and available for plants.

Do humic acids change mobility of metals in soil?

Heavy metal and rock: Humic acid (HA) in natural clays can play an important role in the (im)mobilization (complexation) of toxic metal ions such as radionuclides in the deep geological disposal of high-level radioactive waste. To better understand the influencing factors, the sorption behavior of Eu3+ and Gd3+ ions, as homologues of the actinides Am and Cm, was studied under various conditions. (Waste Disposal in Clay Formations: Influence of Humic Acid on the Migration of Heavy-Metal Pollutants; Ralf Kautburger; Horst P. Beck)

Effect of humic matter on metal adsorption onto clay materials was examined
The results revealed that desorption of metals from clay barriers, occurring in consequence of acidification processes, is generally counteracted in the presence of humic matter. For all clay materials under study, adsorption of metals were found to be enhanced in neutral and acidic systems with humic acid, which is explained by additional adsorption of humic-bound Metals. A commonly used composite approach (linear additive model) was tested for suitability in reconstructing the solid-liquid distribution of metals in ternary systems (metals/humic acid/clay) on the basis of data determined for binary subsystems. The model can qualitatively explain the influence of humic acid as a function of pH, but it failed to reproduce our experimental data quantitatively. It appears that the elementary processes (metal adsorption, metal-humate complexation, humic acid adsorption) cannot be considered to be independent of each other. “Effect of humic matter on metal adsorption onto clay materials: testing the linear additive model.” Lippold H1, Lippmann-Pipke J

Influence of humic acids on the migration behavior of radioactive and non-radioactive substances under conditions close to nature
The interaction behavior of humin; acids with uranium(V1) and the influence of humic substances on the migration behavior of uranium was investigated. A main focus of this work was the synthesis of four different humic acid model substances and their characterization and comparison to the natural humic acid from Aldrich. A radiometric method for the determination of humic acid functional groups was applied in addition to conventional methods for the determination of the functionality of humic acids. The humic acid model substances show functional and structural properties comparable to natural humic acids. Modified humic acids with blocked phenolic OH were synthesized to determine the influence of phenolic OH groups on the complexation behavior of humic acids. A synthesis method for 14c-labeled humic acids with high specific activity was developed. The complexation behavior of synthetic and natural humic acids with uranium(V1) was investigated by X-ray absorption spectroscopy, laser-induced fluorescence spectroscopy and FTIR spectroscopy. The synthetic model substances show an interaction behavior with uranium(V1) that is comparable to natural humic acids. This points to the fact that the synthetic humic acids simulate the functionality of their natural analogues very well. For the first time the influence of phenolic OH groups on the complexation behavior of humic acids was investigated by applying a modified humic acid with blocked phenolic OH groups. The formation of a uranyl hydroxy humate complex was identified by laserspectroscopic investigations of the complexation of Aldrich humic acid with uranium(V1) at pH 7. The migration behavior of uranium in a sandy aquifer System rich in humic substances was investigated in column experiments. A part of uranium migrates non-retarded through the Sediment, bound to humic colloids. The uranium migration behavior is strongly influenced by the kinetically controlled interaction processes of uranium with the humic colloids. The influence of humic acids on the sorption of uranium(V1) onto phyllite was investigated in batch experiments using two different humic acids. The uranium(V1) sorption onto the phyllite is influenced by the pH-dependent sorption behavior of the humic acids Authors: Susanne Pompe, Marianne Bubner, Katja Schmeide, Karl Heinz Heise, Gert Bernhard, Heino Nitsche

Are Humic Acid Products Fertilizers?

No, they are not fertilizers, but complement normal fertilizers and a well balanced fertility programme. Humic Acids do not supply nutrients in the conventionel sense, but increase their availability. They are not a solution in themselves, but part of a balanced programme.

Why should manufacturers use Humic Acids?

When Humic Acids enter plants at early stages of development, they result in increased cell division, root development and eventually dry matter, they act as respiratory catalyst, act as natural chelator for metal ions under alkaline conditions, convert nutrients into forms available to plants, protect plants from chlorosis and increase the permeability of plant membranes. They also decrease plant stress and increase the quality of yields.

What crops will Humic Acids help?

Tests have shown that Humic Acifs benefit all types of agricultural crops and horticultural plants. As in nature, results will of course vary according to soil and weather conditions.


Humintech is a biotech company based in Grevenbroich, Germany. We are primarily focused on the research, development and industrial production of humic matter and humic acids for the agricultural sector. Our products find further use in pharmaceutical, construction industry, for ecological purposes such as water purification and soil decontamination.


Humintech GmbH

Am Pösenberg 9-13
41517 Grevenbroich / Deutschland 

Phone: +49 2181 70 676 - 0
Fax: +49 2181 70 676 - 22


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