Humic acid and Humic substance formation is caused by the microbial degradation of dead plant matter, such as lignin. They are very resistant to further biodegradation. The precise properties and structure of a given sample depend on the water or soil source and the specific conditions of extraction. Nevertheless, the average properties of humic substances from different sources are remarkably similar.
Humic Acid Substance components
Humic substances in soils and sediments can be divided into three main fractions: humic acids, fulvic acids, and humin. The humic and fulvic acids are extracted as a colloidal sol from soil and other solid phase sources into a strongly basic aqueous solution of sodium hydroxide or potassium hydroxide.
Humic acids are precipitated from this solution by adjusting the pH to 1 with hydrochloric acid, leaving the fulvic acids in solution. This is the operational distinction between humic and fulvic acids. Humin is insoluble in dilute alkali. The alcohol-soluble portion of the humic fraction is, in general, named ulmic acid. Gray humic acids (GHA) are soluble in low-ionic-strength alkaline media; brown humic acids (BHA) are soluble in alkaline conditions independent of ionic strength; and fulvic acids (FA) are soluble independent of pH and I.
Chromatography and liquid-liquid extraction can be used to separate the components that make up a humic substance. Substances identified include mono-, di-, and tri-hydroxy acids, fatty acids, dicarboxylic acids, linear alcohols, phenolic acids, and terpenoids.
Humic acid and related origin
Organic matter ,humic substance,humic acid ,humate and fulvic acid are closely related,all are come from the natural process of decaying plants and animals body.Organic matter is defined that all the organic substance in the soil with Hydrocarbonated base(containing hydrogen, carbon and oxygen).
Humic substance is pure substance from process of humification with stronger Cation Exchange Capacity than clay.Humic acids is the fraction of humic substance that is not soluble in acidic condition and soluble in higher PH solution with high molecular weight.Humate is humic acid salt is completely soluble in water extracted from humic acid after treating with high PH alkaline agentlike NAOH,KOH.Fulvic acid is defined as lower molecular weight soluble in both acidic and alkaline condition.
All of them are soil food and storage of mineral and water.For example,most dark color soil is much more fertile than light color soil,like most northeast part of China,they have a lot of dark color soil and most local peasant call it black soil.As black soil are from decaying plants mostly is humic substance has strong cation exchange capacity,easy to hold minerals and water.
Humic acid and its source
Mostly the raw material of humic acid is leonardite and oxidized lignite.Also in some place like Russian is extracted from peat.
Benefits of humic substance
Largely promote the buffering power and fertility of soil by improving the structure.
In sandy soil, humic acid will help to increase fertility of soil through its cation exchange capacity to retain water and beneficial micro nutrient .In heavy and compact soil ,Humic acid will work with fungi to construct a crumb structure root to absorb water oxygen and nutrient also improve root penetration.
Neutralize both acidic and alkaline soil to release the beneficial metal ions, thus promote absorption by plants.
In alkaline soil, beneficial ion and other trace elements can not be absorbed by plants,humic acid can buffer the pH and convert the nutrients and trace elements into absorbable form and promote their uptake by the roots.
In acidic soil, humic acid will largely reduce the toxins such as the ally aluminum and heavy metals, which will be bonded firmly and immobilized ,thus their toxicity is reduced and phosphate is bonded by aluminum is released.
In salinalised soil, Salts are split up by the high cation exchange capability, cation (eg.Ca, Mg) are bonded and chelated.
Largely optimized the absorption of beneficial ion by plants thus increase plants growth accordingly increase the yield and fruits quality .
Humic acid stimulates the membrane of seeds to form a strong roots, which is decisive to increase the capacity of root to take up both micro and macro nutrients. Based on improved structure by humic acid N is largely stored and slow released, P is release from AL +in soil,also other microelement is in the form of easy-available by plants, meanwhile the beneficial fungi is active to produce different kind enzymes. with the above joint effort, the yield will be increased at lease 30%.
Enhanced cell assimilation as well as photosynthesis increase the plant’s sugar and vitamin content, thus the quality of their seeds will be largely increased.
Enhance plants’ ability to counter stressed conditions.
Humic acid can mobilize K absorption to regulate the stomata open and close on the leaves also promote metabolism, thus increase the plants’ ability under stressed conditions.
Natural nitrogen stabilizer.in Soil if these sufficient humic substance there will be at least 35% of soluble nitrogen applied and held in the soil in the form of organic ,then convert into stable form ,finally bioavailable form.
Strong ability to release the lock up Phosphorus in soil,as humic substance has stronger CEC that will greatly chelate the cation from phosphate and release anion phosphate radicals.
How to ues these humic acid?
It is advised to use humic acid to mix with other chemicals ,or compost,manure fermentation,also additives to pesticide.