Humic Substances: An Introduction

How humic substances form

Humic substances form over long periods of time as dead plant material is broken down and transformed by microorganisms. The result is a group of complex organic compounds that are more stable than the original material. They occur in soils, in water and in natural deposits such as peat or lignite (leonardite). These deposits are common raw materials for humic products in agriculture. Vitagumin is derived from lowland peat.

The fractions

Humic substances are not a single uniform substance. They are commonly divided into fractions according to their solubility:

Humic acids

Soluble in alkaline solution, precipitating under strongly acidic conditions. They often make up the largest share of humic substances.

Fulvic acids

Soluble at all pH values. They consist of smaller molecules with many acidic groups.

Hymatomelanic acids

The alcohol-soluble part of the humic acids, often reported separately in the literature.

Humin

The fraction that is insoluble at any pH. It remains closely bound to mineral soil components.

The role soil science attributes to humic substances

In soil science literature, humic substances are mainly associated with the following soil properties:

Soil structure: they are involved in the formation of stable soil aggregates.
Water balance: soil organic matter can bind and retain water.
Exchange capacity: their acidic groups can bind nutrient cations and release them again.
Complexation: humic substances can bind metal ions, including trace elements.
Buffering: they help to moderate fluctuations in soil pH.

How strongly such properties come into play in a given case depends on soil, climate, crop, management and the specific product.

This page describes humic substances as a group of substances. It does not describe proven effects of Vitagumin. Information on the product is available on the product page and in the documentation we provide on request.

Humic substances – an introduction