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 (click on the image)
We will discuss the interrelationship of soil, pH, and humic substances in Humic Corner #4.
Related Posts
This Week in Ag #14
You never get a second chance to make a first impression. That popular saying could just as easily apply to planting corn. It’s impossible to recover from planting time mishaps. Don’t believe it? Try this. Walk into a cornfield where plants have recently emerged. Identify a plant that’s shorter than the rest (some call these
A Farmer’s Fourth of July: The Fireworks Waited
This Week In Ag #122: A Farmer's Fourth of July: The Fireworks Waited For many Midwest farm families, the Fourth of July wasn’t about fireworks or cookouts—it was wheat harvest season. In this personal reflection, Fred recalls a time when the combine came first, soybeans followed close behind, and the only bangs came from the grain bin, not the sky.
Reaching Crop Milestones
Raising a crop takes more than seed and soil—it takes faith. Just like raising kids, farming is full of stages that bring joy, stress, hope, and awe. From emergence to canopy and tasseling to harvest, each milestone tells a story of patience, persistence, and purpose. Here’s a look at the defining stages that make farming not just a job, but a calling.
