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 #40
I’ll never forget the sage words an old farmer told me when I announced my intention to start farming in the late 1990s. I explained that I was not leaving my marketing job and that I was also doing a fair amount of freelance consulting work. He told me, “It’s funny how many other jobs you need...
Univ. of Calif.: Huma Gro® Increases Strawberry Yields 30%
Huma Gro® Ultra-Precision™ Blend Plus Root Dip Increases Strawberry Yields 30%, Univ. of Calif. Conducted by: Surendra K. Dara, PhD, University of California Huma Gro® Products: Ultra-Precision™ Blend; plus root dip of Breakout®, Promax®, Vitol®, and Zap® OBJECTIVE The purpose of this research project was to evaluate how a special blend of fertilizer solution and...
Earth Week: Celebrating All Creatures Small and Great
No matter how small the acts, or how small the actors, everything in our natural world connects, and everything makes a difference. I spend a lot of time reading to my granddaughters, and I’ve found that there are now many kid books about how to help the Earth (I’ve selected a few at the end...