Humic substances are organic compounds that are important components of humus, the major organic fraction of soil and peat.

Humic acids physical effects

Humic acids physically modify the structure of the soil, with benefits such as:

• Improved structure of soil: Prevents high water and nutrient losses in light, sandy soils,
simultaneously converting them into fruitful soils by way of decomposition. In heavy and compact
soils, aeration of soil and water retention is improved; cultivation measures are facilitated.
• Prevents soil cracking, surface water runoff and soil erosion by increasing the ability of colloids to
• Helps the soil loosen and crumble, and thus increases aeration of soil as well as soil workability.
• Increases water holding capacity of soil and thus helps resist drought.
• Darkens the color of the soil and thus helps absorption of the sun’s energy

Humic acids biological effects

Humic acids biologically stimulate the plant and the activities of micro-organisms.

• Stimulates plant enzymes and increase their production.
• Acts as an organic catalyst in many biological processes.
• Stimulates growth and proliferation of desirable micro-organisms in soil
• Enhances plant’s natural resistance against diseases and pests.
• Stimulates root growth, especially vertically and enable better uptake of nutrients.
• Increases root respiration and root formation.
• Promotes the development of chlorophyll, sugars and amino acids in plants and aid in
• Increases vitamin and mineral content of plants.
• Thickens the cell walls in fruits and prolongs storage time.
• Increases germination and viability of seeds.
• Stimulates plant growth (higher biomass production) by accelerating cell division, increasing the
rate of development in root systems and increasing the yield of dry matter.
• Increases the quality of yields; improves their physical appearance and nutritional value.

Humic acids chemical effects

Humic acids chemically change the fixation properties of the soil, with benefits such as:

• Neutralizes both acid and alkaline soils; regulates the pH-value of soils.
• Improves and optimizes the uptake of nutrients and water by plants.
• Increases buffering properties of soil.
• Acts as natural chelator for metal ions under alkaline conditions and promote their uptake by the
• Becomes rich in both organic and mineral substances essential to plant growth.
• Retains water soluble inorganic fertilizers in the root zones and reduces leaching.
• Possesses extremely high cation-exchange capacities.
• Promotes the conversion of nutrient elements (N, P, K + Fe, Zn and other trace elements) into forms
available to plants.
• Enhances the uptake of nitrogen by plants.
• Reduces the reaction of phosphorus with Ca, Fe, Mg and Al and liberates it into a form that is
available and beneficial to plants. The productivity of particular mineral fertilizers is increased
• Liberates carbon dioxide from soil calcium carbonate and enables its use in photosynthesis.
• Helps to eliminate chlorosis due to iron deficiency in plants.
• Reduces the availability of toxic substances in soils.