Fulvic Acid Definition

Fulvic acid is one of the constituents of humus, the dark-brown organic layer of soil. Dry soil, swamps and geologic deposits such as coal, fossil fuel and lignite all contain humus. Fulvic acid is a soluble mixture of organic acids extracted primarily from water-based humus. Agriculture makes use of fulvic acid for plant growth. Fulvic acid is also available as a dietary supplement; talk to your doctor, however, before adding any supplements to your diet.

Humus

Humus is nutrient-rich and consists of partially decomposed plant and animal remains. It has three main parts -- humic acid, fulvic acid and the insoluble humin. Humus at the bottom of lakes or seas is mostly humic acid. On the other hand, humus from poorly drained areas such as bogs and swamps is mostly fulvic acid. Black water from the Okefenokee Swamp, the Satilla River and the Ohoopee River in the United States has a fulvic acid to humic acid ratio of 2.6, meaning that there is more than twice the concentration of fulvic acid in this aquatic humus. Humus from geologic deposits such as lignite is composed of up to 99 percent humic acid with only 1 percent fulvic acid.

Extraction

You can extract humic acid from humus by first mixing the humus with a dilute alkali and then precipitating the humic acid out of solution by acidifying the mixture to a pH of 1 to 2. The fulvic acid, which is soluble at all pH levels, remains in the acid solution. It is yellow to brownish black in color. Recovering fulvic acid from land-based humus can be difficult. The extract contains inorganic impurities and sodium chloride, which results in a low net yield of fulvic acid. Aquatic humus, however, is predominantly fulvic acid and so is the preferred source for fulvic acid extraction.

Composition

Further purification of fulvic acid leads to four fractions. Fraction A contains sugars and amino acids. Fraction B is deep yellow and contains tannins or phenolic glycosides. Fraction C is the smallest fraction and contains polyuronides and sugars. Fraction D is reddish in color and rich in nitrogen, organic phosphates and polysaccharides.

Agricultural Use

Fulvic acid has a water bridging ability. It attracts water molecules, helping the soil to remain moist and aiding the movement of nutrients into plant roots. The small molecular size of fulvic acid allows it to enter the vascular system of plants. Fulvic acid easily binds to minerals such as iron, calcium, copper, zinc and magnesium. As it moves through the roots, stem and leaves, it takes these minerals to metabolic sites within the plant (see reference 2). The ability of fulvic acid to bind to trace minerals makes it an effective organic chelating compound. Sprayed on plants, fulvic acid is a non-toxic mineral additive and water binder that maximizes the plant's productivity.

Dietary Supplement

Marketers promote fulvic acid as a dietary supplement that improves mineral absorption and boosts the immune system; however, human studies have not validated these claims (see writer notes). Caution should be used with fulvic acid supplements as Kashin-Beck disease, a degenerative bone disease found in China, is caused by drinking water with a naturally high level of fulvic acid while eating a diet that is low in selenium. Selenium acts to prevent the free radical damage caused by fulvic acid, according to an April 1999 study published in the journal "Environmental Health Perspectives." Before taking fulvic acid supplements, discuss it with your doctor.