Why Are Humic Substances Called Acids?

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

We are accustomed to seeing humic substances (humic and fulvic) in dry/granular form, and we tend to think of acids as liquids. So why are humic and fulvic substances called acids?

All substances, solid AND liquid, have a chemical makeup. An acid is a chemical that can donate a proton (H+) to a water molecule (H2O, which would form H3O+) or to another chemical such as ammonia (NH3, which would form NH4+).

Organic acids are generally weak acids that do not completely dissociate (i.e., donate a proton) in water in the way that strong mineral acids do, such as in the case of hydrochloric acid (HCl). The most common organic acids are carboxylic acids, sulfonic acids, phenols and alcohols (Figure 1).

Organic acids can be aliphatic (structured as open chains rather than aromatic rings), such as acetic acid (Fig. 1A) or ethanol (Fig. 1E). Organic acids can also be aromatic (made up of ring structures, originally named so because of their fragrant properties), such as benzoic acid (Fig. 1B), benzene sulfonic acid (Fig. 1C) or phenol (Fig. 1D).

All of these structures can be found in humic and fulvic acids, sometimes all in the same molecule. For example, one humic acid or fulvic acid molecule might contain a benzoic acid, a phenol, an alcohol, and an aliphatic carboxylic acid (Figure 2). All of these functional groups can ionize (i.e., lose their H+ atoms and contribute to acidity) (Figure 3). The primary factor affecting ionization of organic acids is pH.

Figures 1–3. Chemical structures found in organic acids

We will discuss the interrelationship of soil, pH, and humic substances in Humic Corner #4.

The Value of Humic Substances in the Carbon Lifecycle of Crops:

Humic Acids, Fulvic Acids, and Beyond.

A New White Paper from Huma Gro®

This white paper is based on an article by Huma Gro® staff originally published in the January 2017 issue of AgroPages Magazine.

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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For more information on Huma Gro® Carbon-Rich Organic Acids, go to https://humagro.com/huma-gro-products/organic-acids/.

To view an online version of the complete Huma Gro® Product Catalog, go to http://bit.ly/HumaGroCatalog2017.

Southwest Ag Summit

SWAgSummit

Come see us at the Southwest Ag Summit at Arizona Western College in Yuma, Arizona, on February 25–26. Ray Speakman and Nathan Smith will be there in Booth 52 to answer all of your Huma Gro questions. For more information, go to www.swagsummit.com.

20th Annual Commodity Classic

Blazing-to-Success

Come see us at the 20th Annual Commodity Classic at the Phoenix Convention Center in Phoenix, Arizona, on February 26–28. Alan Merrill and Johann Buck, PhD, will be there in Booth 1438 to answer all of your Huma Gro questions. For more information, go to www.commodityclassic.com.

Solving Agricultural Challenges with HUMA GRO®

This video is about solving the challenges of modern agriculture & crop fertility with HUMA GRO® product line: Sustainable Soil Fertility & Carbon-Rich Organic Acids, Optimal Growth Managers, Ultra-Efficient Crop Nutrition, and Zero-Residue Crop Protection.  With HUMA GRO®, growers can apply less and see more benefits from our Micro Carbon Technology®. HUMA GRO® enhances fruit quality and increases yields while being environmentally sustainable. Watch this video featuring Lyndon Smith, President/CEO.

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