Humic acids and fulvic acids play different but complementary roles in soil health, with humic acid helping condition soil while fulvic acid supports nutrient transport, availability, and plant uptake. Understanding how these substances work can help growers incorporate both substances into a long-term soil fertility and crop nutrition program.

When you’re working to improve soil health, you’ll inevitably run into humic acid and fulvic acid. The two are often mentioned together, but they are not interchangeable. You need both to benefit your crops and your soil health in the long term.

Let’s take a closer look at these important substances and how they benefit your crops.

What Is Humic Acid?

Humic acid is a hydrophobic, organic substance that is used as a soil conditioner. It builds soil organic matter, which feeds your soil biology and in turn, your crops. It also improves your soil’s water-holding capacity and helps soil hold onto nutrients.

These characteristics make humic acid valuable as part of your long-term soil health program. Rather than simply providing nutrients to the plant, humic acid improves the soil environment where roots and soil microorganisms interact.

What Is Fulvic Acid?

Fulvic acid is a hydrophilic, organic substance that can be used as a foliar or soil application. It has a smaller molecular structure that allows it to move readily through soil and the plant, attracting and carrying ions as it goes. Fulvic acid is an excellent nutrient transporter and powerful natural chelator, especially of micronutrients.

Furthermore, fulvic acid opens cell membranes in plants so they are more permeable. This helps plants absorb the nutrients they need, fast. In this way, fulvic acid acts as a biostimulant, triggering physiological responses in plants.

Here are some of the main characteristics of humic and fulvic acid compared side by side:

	Humic Acid	Fulvic Acid
Molecular size	Larger	Smaller
Solubility	Less soluble	Highly soluble
Primary role	Soil building and conditioning	Nutrient transport and availability
Soil benefits	Structure, CEC, water holding, nutrient retention	Nutrient movement and availability
Plant benefits	Supports the root environment	Supports nutrient uptake and movement
Application focus	Soil	Soil and foliar applications

As you can see, humic and fulvic acids do not serve completely separate functions. In fact, they can work together as part of your larger soil and plant nutrition program.

C-Cat Carbon Catalyst: Best-in-Class Fulvic Acid

For a high-quality fulvic acid input, the ST Biologicals mentors often recommend TEVA’s C-CAT carbon catalyst chelating compound. Its proprietary formulation is extracted from humic acid and double-filtered to produce an extremely powerful natural chelating compound that releases tied up phosphate and potassium, boosts nitrogen uptake, and releases micronutrients. It enhances stomata opening and transpiration so nutrients are readily absorbed through foliage or roots and moves through the plant.

C-CAT has a very high CEC, which makes the formulation behave like a magnet for nutrients, attracting ions and moving them to the plant root zone in plant-available forms. As a result, plants that receive C-CAT are vigorous, well-balanced, high-quality, and high-yielding. 

The ST Biologicals mentors can help you incorporate C-CAT as well as humic acid at your operation. Get in touch with us today to design your soil fertility and crop nutrition program. We’re here to help you succeed. When soil speaks, we listen.

---

Fulvic Acid FAQs