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WHAT ARE HUMIC AND FULVIC ACIDS?

Humic Substances occur naturally in our environment and are the remains of a process called humification, which is the biodegradation of biomatter that then recombines and synthesizes into dark coloured complex compounds with no definite chemical structure. Humic Acids and Fulvic Acids are extracted from Humic Substances. These organic compounds are differentiated according to their solubility in either acidic or basic solutions. They also vary in molecular size, carbon-hydrogen-oxygen-nitrogen content, and their function in biological systems. Various scientific studies have shown that the humic acids content in soil is a significant contributor to soil fertility. Improved soil fertility and plant growth are positively influenced by these substances due to their effect on the cation-exchange capacity (CEC), the oxygen content and above average water holding capacity. Humates’ most important feature is their ability to bind insoluble metal ions, oxides and hydroxides, and to release them slowly and continually to plants when required. These properties result in physical, chemical and biological benefits in soils which in turn translate to ecological and economic benefits.


Humic Acids (HA) is a broad term used in commerce and science to identify a class of isolated compounds that can be extracted from natural humic substances in a number of ways, typically with alkali solutions, and then precipitated from the alkaline aqueous solutions by acidification. HA has less functional groups or ionic charges and a lower chemical reactivity than FA. It has an alkaline solution at a pH of approx. 10 and has fairly large molecules (150 – 300nM in size). Roots or plant leaves cannot absorb it and it is unable to transport nutrients into the plant. HS is known to improve the cation exchange capacity (CEC) of soil.

Fulvic Acids (FA) is a broad term used in commerce and science to identify a class of isolated compounds extracted from natural humic substances that are soluble in both alkali and acidic aqueous solutions. FA has a higher number of functional groups or ionic charges and a higher reactivity than HA. It is water soluble at any pH and has fairly small molecules (80 – 100nM in size). Plant roots and leaves can absorb it and it transports nutrients into the plant. FA promotes the use of available mineral nutrients and improves the CEC of the soil.