Humic Acid: A Beneficial Adjuvant for Herbicide Reduction
Humic acid is a workhorse for building healthy soils. It is a naturally found chemical compound in soil humus, and binds soil nutrients to hold them in the soil for plant use. Like a natural fertilizer, it helps to enhance nutrient availability and stimulates healthy growth in plants.
How do Humic Acids Help in Habitat Restoration?
Humic acid is not widely used in habitat restoration projects, but it is on farms. For over a decade, farmers have used humic acid for two reasons:
- Increased soil health with moisture retention and nutrient availability
- Stimulate increased plant uptake of nutrient fertilizers
The second reason is key: humic acid not only binds and holds nutrients, it also chelates them (changes them into plant-available forms for plants to use immediately and stimulate growth). So humic acid leads to better nutrient uptake!
Knowing this, farmers are able to add humic acid to nutrient fertilizers and reduce the total concentration of fertilizers by as much as 50%. This is because less fertilizer is needed for plant growth when it is absorbed more efficiently and effectively.
Can Humic Acid also Reduce Herbicide?
Since humic acid stimulates nutrient absorption in plants, Phoenix Regen hypothesized that it may also help to stimulate herbicide absorption. If true, this has the potential to increase herbicide effectiveness, and reduce the total amount of herbicide that may be needed for successful results.
In 2024, Phoenix Habitats began field trials with humic acid on habitat restoration projects. We found that herbicide reductions of 50% yielded similar or better results than fully concentrated herbicide mixes without humic acid. This article has more information about those successful spray experiments!
Further study is needed, but humic acids might be the safest, most beneficial technology available to reduce herbicide usage for invasive weed control.
How do I use Humic Acid adjuvants?
Since humic acid is a popular farming product, it is readily available in powdered and liquid formulations. At Phoenix Habitats, we have trialed BioAg products that are liquid and tank mixable. A very small amount is needed per backpack spray tank, around 0.5 ounces or 0.1% of the total mix concentration. Considering the cost savings from reduced herbicide product usage, this may also be part of cost reduction strategy for increasingly expensive restoration projects.
Humic Acid Benefits for Soil
In addition to reducing herbicide concentrations in soils, the benefits of humic acid for soils are extensive. It improves soil structure, helping bind soil particles together into stable aggregates. This, in turn, enhances water infiltration and retention, which is critical for drought resilience. It also boosts the soil's cation exchange capacity (CEC), acting like a nutrient savings account, preventing valuable minerals from leaching away. For plants, humic acid stimulates root growth, improves nutrient uptake by making minerals more soluble, and can even help plants tolerate environmental stresses.
For the reasons above, we believe that using humic acid as a spray adjuvant or separate soil inoculant will both have positive benefits for soil health in habitat restoration projects.