Effects of Humic Substances on Soil Microbes

By Richard Lamar, PhD
Senior Director of Humic Research
Bio Huma Netics, Inc.

Most of the work on agricultural applications of humic substances (HS) has focused on their biostimulant effects on plants. Far less work has been conducted on the effects of HS on soil microbial populations. It’s not surprising to learn, from the few studies that have been published, that HS also stimulate the growth of soil bacteria, even the bacteria that inhabit earthworm digestive tracts. One of the most important discoveries is that many species of soil bacteria are able to grow on humic acid (HA) as their sole carbon source (Tikhonov et al., 2010).

These findings have important implications for the roles played by soil bacterial communities—including those residing in the guts of soil fauna, such as earthworms—in the humification process (i.e., the process of conversion of dead plant tissues to humic substances). This means that these bacteria are consuming HS and modifying HS by metabolizing humic molecules and using the metabolized molecules to produce proteins, fats, and other types of molecules. When the bacteria die, they are in turn consumed by other microbes and those molecules created from metabolized humic molecules wind up being included as HS.

The other important piece of information that has come out of the work on bacterial-HS interactions is that, in addition to being potential carbon sources, HS can also act as soil bacterial growth stimulants or growth regulators (Tiknonov et al., 2010). This was demonstrated in a study in which a number of soil isolated bacterial species were grown on a medium that contained glucose as the carbon source (10 mg/ml) and humic acid (1 mg/ml). Thus, the humic acid was 10X lower than the glucose. Growth of the bacteria on this medium was compared with the growth of bacteria on a medium that did not contain the humic acid. The growth of 41% percent of the bacterial species (these were isolated from earthworm digestive tracts) were stimulated by the inclusion of the humic acid. The authors of the study concluded that, because the concentration of glucose was so high and the increase in available carbon from the addition of 1 mg/ml humic acid was insignificant, the humic acid acted as a growth stimulant to the 41% of bacteria whose growth was increased.

These types of studies have demonstrated that HS can stimulate the growth of plant-growth-promoting rhizobacteria (aka PGPR bacteria, for which the “rhizo” stands for rhizosphere or the area of soil that is intimately associated with plant roots). One of the most well-known PGPR bacteria are Pseudomonads, strains of which have been found to be able to solubilize phosphate, produce siderophores (important for Fe uptake), ammonia, and the plant-growth-regulator auxin (Gupta, 2008; Selvakumar et al., 2009).


Gupta, A. and M. Gopal. 2008. Siderophore production by plant growth promoting rhizobacteria. Indian J. Agric. Res. 42(2):153–156.

Salvakumar, G., P. Joshi, S. Nazim, P. K. Mishra, J. K. Bisht and H. S. Gupta. 2009. Phosphate solubilization and growth promotion by Pseudomonas fragi CS11RH1 (MTCC8984), a psychrotolerant bacterium isolated from a high-altitude Himalayan rhizosphere. Biologia, 64(2)239-245

Tikhonov, V. V., A. V. Yakushev, Y. A. Zavgorodnyaya, B. A. Byzov, and V. V. Demin. 2010. Effect of humic acids on the growth of bacteria.  European Soil Science, 43 (3):305–313.

Rutgers Univ.: Huma Pro® Stimulates Root Growth

Huma Pro® Stimulates Rhizophagy Cycle of Microbes to Increase Root Growth, Rutgers Univ.

Conducted by: James White, PhD, Rutgers University

Huma Gro® Products: Huma Pro®


The purpose of this research project was to evaluate how humic acids stimulate microbial activity and initiation of the rhizophagy cycle (in which plants cultivate microbes on their roots and then absorb them to extract their nutrients). Huma Gro® Huma Pro®, a liquid 6% humic acid product, was used as the humic acid biostimulant source.


Huma Pro®, a 6% liquid humic acid, was incorporated into agarose at concentrations of 0%, 0.01%, and 0.10% humic acids. Seeds of tall fescure, annual bluegrass (Poa annua), and beefsteak tomato were surface disinfected in 3% NaOCl for 30 minutes to reduce microbial load on seedlings. Seeds were germinated and grown for 6 days on agarose (a polysaccharide derived from seaweed) with and without the Huma Gro® product.


Huma Pro® promotes seedling development in the seedlings tested. Root length in seedlings treated with Huma Pro® increased 73% (tomato) to almost 300% (tall fescue), roots growing downward increased 7 percentage points (tomato) to almost 75 percentage points (bluegrass), and shoot length increased 80% for tall fescue. Huma Pro® acts to stimulate the root microbiome and shows evidence of stimulating the rhizophagy cycle. Stimulation of the rhizophagy cycle in plants should result in increased nutrient absorption in plants.

Click HERE to read the full report.

The Value of Humic Substances in the Carbon Lifecycle of Crops: Humic Acids, Fulvic Acids, and Beyond


By Larry Cooper, with Rita Abi-Ghanem, PhD

Humic substances play an important role in soil fertility and crop yield. This article provides a basic overview of what humic substances are, how they are created, and how they work. Discussion is provided on how to add humic content to crop soil, including the use of commercial products such as the Huma Gro® line of carbon-rich organic acids.
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Bio Huma Netics, Inc. y Mesa Verde Resources forman una alianza estratégica

Bio Huma Netics, Inc. (BHN), una empresa de Arizona que fabrica productos de las marcas Huma Gro®, Huma Gro® TurfProbiotic Solutions®, recientemente formó una alianza con Reid Enterprises LLC, que opera como Mesa Verde Resources en Nuevo México. Mesa Verde Resources es una empresa minera de sustancias húmicas que produce, fabrica y vende productos de ácidos fúlvico y húmico.

Además de acceder a una variedad más amplia de productos, los clientes de ambas empresas no notarán mayores cambios en las operaciones diarias. No habrá cambios inmediatos en el personal de ninguna de las empresas y ambas continuarán operando por separado con denominaciones distintas en el futuro cercano.

Se espera que esta alianza propicie una relación sinérgica entre las líneas de productos de agricultura, campos de golf y remediación de suelos/aguas residuales de BHN, y la línea de productos de ácidos fúlvicos y húmicos de Mesa Verde Resources tanto en el mercado nacional como internacional. Si bien hasta el momento BHN se había enfocado en una parte de las sustancias húmicas para extraer la tecnología Micro Carbon Technology® que se utiliza como base para todos sus productos líquidos, la fusión de empresas ofrecerá a sus clientes una variedad de productos secos y líquidos aún mayor, incluidas las distintas formulaciones de ácidos fúlvicos y húmicso de Mesa Verde Resources.

Durante los últimos 10 años, Bio Huma Netics ha experimentado un crecimiento promedio del 20 % anual. Gracias a la alianza con Mesa Verde, se espera que las ventas de la compañía fusionada aumenten un 30 % en 2017.

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Acerca de Mesa Verde Resources

Mesa Verde Resources (MVR) extrae y fabrica humatos de alta calidad en Nuevo México, con productos de ácidos fúlvicos y húmicos que incluyen productos granulados, polvos para soluciones y suspensiones y ácidos fúlvicos y húmicos líquidos. Los humatos de MVR, extraídos de la formación Fruitland de la cuenca de San Juan en el noroeste de Nuevo México desde 1975, son ampliamente utilizados para mejorar la producción y la calidad de los cultivos, y para mejorar y reabastecer los suelos degradados. Obtenga más información en www.humates.com.

Acerca de Bio Huma Netics, Inc.

Fundada con el nombre de Sunburst Mining Company, Inc. en Mesa, Arizona en 1973, Bio Huma Netics, Inc. (BHN) es líder mundial en el suministro de soluciones sustentables para los problemas medioambientales del mundo en las áreas de agricultura (HUMA GRO®); horticultura, campos de golf y plantas ornamentales (HUMA GRO® TURF); y remediación de aguas residuales y suelos (PROBIOTIC SOLUTIONS®) a través de nuestra exclusiva tecnología Micro Carbon Technology®. Obtenga más información en www.bhn.us.

Contacto de cliente/prensa: 1-800-961-1220

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Bio Huma Netics, Inc., and Mesa Verde Resources Form Strategic Alliance

Bio Huma Netics, Inc. (BHN)—an Arizona company that produces products under the Huma Gro®, Huma Gro® Turf, and Probiotic Solutions® brands—has recently formed an alliance with Reid Enterprises LLC, which does business as Mesa Verde Resources in New Mexico. Mesa Verde Resources is a humic substance mining company that produces, manufactures, and sells humic-acid and fulvic-acid products.

Other than access to a greater range of products, customers from the two companies should see no change in day-to-day operations. There will be no immediate change in personnel at either company, and the two companies will continue to operate separately under separate names for the immediate future.

This alliance is expected to facilitate a synergistic relationship between the BHN lines of agriculture, turf, and wastewater/soil remediation products and the Mesa Verde Resources line of humic and fulvic products for both domestic and international markets. While BHN has previously focused on a fraction of humic substances to extract the Micro Carbon Technology® used as a base for all its liquid products, the combined company will now offer its customers an even greater selection of dry and liquid products that includes MVR’s various formulations of humic and fulvic acids.

Bio Huma Netics has averaged over 20% growth per year over the last 10 years. With the Mesa Verde alliance, combined company sales are expected to increase by 30% in 2017.

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About Mesa Verde Resources 

Mesa Verde Resources (MVR) mines and manufactures high-quality New Mexico humates, with humic and fulvic acid products including granular products, powders for solution and suspension, and liquid humic and fulvic acids. MVR humates—mined from the Fruitland Formation of the San Juan Basin in Northwest New Mexico since 1975—are used extensively to increase crop quality and production and to improve and replenish depleted soils. Learn more at www.humates.com.

About Bio Huma Netics, Inc

Founded as Sunburst Mining Company in Mesa, Arizona in 1973, Bio Huma Netics, Inc., (BHN) is a global leader in providing sustainable solutions to the world’s environmental challenges for agriculture (HUMA GRO®); horticulture, turf & ornamentals (HUMA GRO® TURF); and soil & wastewater remediation (PROBIOTIC SOLUTIONS®) through its constantly improving proprietary Micro Carbon Technology®. Learn more at www.bhn.us.

Media/Customer Contact: 1-800-961-1220

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