1、Humic acid

Its structure is unlike that of proteins or carbohydrates, the two most common organic polymers found in biological material; instead, humic acid can be characterized as a loose assembly of aromatic polymers of varying acidity and reactivity.

2、Humic Acid

Humic substances are the major fraction of soil organic matter. HA arise from the decay of plants and animals and represent about 50–80% of the organic matter in water coming from terrestrial sources, lakes and rivers [1].

3、What Is Humic Acid?

Humic acids are an excellent natural and organic way to provide plants and soil with a concentrated dose of essential nutrients, vitamins and trace elements. Compared to other organic products, Leonardite enhances plant growth (biomass production) and fertility of the soil.

Amino acid, fulvic acid, humic acid: the role and difference

Humic Acid (Humic Acid, abbreviated HA) is a type of organic matter that is the remains of animals and plants, mainly plant remains, after the decomposition and transformation of microorganisms, as well as a series of complex geochemical reaction processes and accumulation.

Properties of Humic Acid Substances and Their Effect in Soil Quality

Humus is categorised according to their molecular weights and solubility into humus, humic acids and fulvic acids. Humic substances are the organic material naturally present in soil.

Soil organic matter, humus substance, humic acids and humates

Organic matter in the soil includes the entire organic mass, including humus and undegraded residues of plants and animal organisms.

Humic Acid: What is Humic Acid?

Humic acid is a complex organic substance that occurs naturally in soil, peat, and coal. It is formed through the decomposition of plant and animal matter over thousands of years.

Humic acids: Structural properties and multiple functionalities for

Humic acids (HAs) are macromolecules that comprise humic substances (HS), which are organic matter distributed in terrestrial soil, natural water, and sediment.

Humic Acid: The Science of Humus and How it Benefits Soil

Humic acid: a dark-brown humic substance that is soluble in water only at higher soil pH values and is of greater molecular weight than fulvic acid. Humic acid may remain for centuries in undisturbed soil.

What is Humic Acid? — Earthgreen Products

They're long-chain molecules that are high in weight and dark brown in color. They are not a single acid. Rather, "humic acid" is a broad term that refers to a complex mixture of many different acids that are soluble in alkaline solutions. They exist naturally as part of nature's life cycle in soils, oceans, and streams.

Humic acid is an organic substance primarily formed through the decomposition and transformation of animal and plant residues under microbial action. It not only contains abundant nutrients but also exhibits excellent soil-improving properties. The following sections provide a detailed introduction to its composition, properties, and functions:

I. Composition of Humic Acid

1. Main Components: Humic acid is a complex organic compound composed of elements such as carbon, hydrogen, oxygen, and nitrogen. Its molecular structure includes various functional groups, such as carboxyl, phenolic hydroxyl, and quinone groups, which give it unique chemical properties.
2. Trace Element Content: Humic acid contains multiple trace elements, including iron, manganese, copper, zinc, boron, and molybdenum, which are essential for plant growth and soil health.
3. Amino Acids and Proteins: It contains a certain amount of amino acids and proteins, providing essential nutrients for plants.
4. Saccharides: Humic acid also includes sugars like glucose and fructose, which supply energy to plants.
5. Other Organic Compounds: It may contain additional organic compounds, such as polycyclic aromatic hydrocarbons and phenolic compounds, which promote plant growth.

II. Properties of Humic Acid

1. Physical Properties: Humic acid is a viscous substance with significant adhesion and plasticity. It has a relatively low melting point (around 180°C) and exhibits hygroscopicity and thermal stability.
2. Chemical Properties: The functional groups in humic acid enable diverse chemical reactivities, including redox reactions and hydrolysis. These reactions allow interactions with other substances, influencing its applications.
3. Biological Activity: Humic acid promotes plant growth and development by regulating hormone balance, enhancing root development, and improving disease resistance.
4. Environmental Adaptability: It remains stable across diverse environments, including acidic, alkaline, and saline-alkali soils, where it effectively improves soil conditions.

III. Functions of Humic Acid

1. Improving Soil Structure: Humic acid increases soil porosity, water retention, and air permeability, benefiting root growth and nutrient absorption. It also adsorbs harmful substances, reducing heavy metal toxicity.
2. Enhancing Soil Fertility: Rich in nutrients, humic acid directly nourishes plants. Additionally, it accelerates microbial decomposition of organic matter, boosting soil fertility.
3. Strengthening Plant Stress Resistance: Its functional groups and organic components enhance disease resistance, drought tolerance, and cold resilience. For example, phenolic compounds inhibit pathogen growth, while polycyclic aromatic hydrocarbons improve photosynthetic efficiency.
4. Promoting Plant Growth: Saccharides in humic acid provide energy, while hormone regulation supports root development and stress resistance.
5. Protecting Ecological Environments: By adsorbing pollutants and reducing heavy metal toxicity, humic acid safeguards ecosystems. It also stimulates microbial activity and biodiversity, further protecting soil health.

humic acid is a complex organic substance derived from the microbial breakdown of animal and plant residues. Its rich nutrients and soil-improving capabilities play vital roles in agriculture and environmental protection.