Leonardite Humic Acid: Source, Composition, and How It Works
Leonardite Humic Acid: Source, Composition, and How It Works
Leonardite is the naturally oxidized form of lignite (brown coal) and the richest natural source of humic substances. SoilBoost EA is a Leonardite-derived humic acid soil conditioner containing 60.6 percent humic acid (CDFA method), used to improve nutrient uptake, soil structure, and water-holding capacity in tropical plantations.
What is Leonardite?
Leonardite is a soft, waxy, dark-brown to black material formed over millions of years as lignite weathered and oxidized near the surface. That natural oxidation is what makes it valuable: it raises the proportion of humic and fulvic acids far above ordinary lignite, peat, or compost. Where compost might contain a few percent humic substances, Leonardite is among the most concentrated natural sources available, which is why it is the preferred feedstock for commercial humic acid soil conditioners.
From Leonardite to SoilBoost EA
SoilBoost EA is produced exclusively from 100 percent Leonardite ore. The humic and fulvic molecules are extracted and concentrated into a soil conditioner that delivers active humic substances directly to the root zone. It is a soil conditioner, not a fertilizer: it improves how the soil holds and releases nutrients rather than supplying NPK itself, and works best alongside a balanced fertilizer program.
Composition and key ingredients
The values below are the cleared specification figures for SoilBoost EA.
| Ingredient / property | Value | What it does |
|---|---|---|
| Humic acid (from Leonardite) | 60.6% (CDFA method) | Chelates nutrients, raises cation exchange capacity, builds soil organic matter |
| Fulvic fraction | Present (low molecular weight humic substances) | Highly mobile, carries micronutrients into the plant and improves uptake |
| Sulphur | ~0.45% | Secondary nutrient supporting protein and chlorophyll formation |
| pH | 3.84 (acidic concentrate) | Helps solubilise and release locked nutrients in the root zone |
| Chelated micronutrients | Iron, zinc, copper and others (complexed) | Kept bioavailable rather than precipitated and lost |
| Source material | 100% Leonardite ore | Richest natural source of humic and fulvic acids |
How the ingredients work
Nutrient chelation
Humic and fulvic molecules form stable, water-soluble complexes with iron, zinc, copper, and other micronutrients, keeping them available to roots instead of precipitating in the soil.
Cation exchange capacity
Humic acid increases the soil's CEC, so potassium, calcium, magnesium, and ammonium resist leaching during heavy tropical rainfall.
Root-level nutrient signalling
Humic substances are associated with upregulation of nitrate-uptake activity in roots, improving how efficiently applied nitrogen is absorbed.
Organo-mineral complexation
Humic molecules bind with soil minerals and protect labile carbon from rapid breakdown, building longer-term soil fertility and structure.
What the research shows
A 2024 meta-analysis (Ma et al., Agronomy, MDPI) across multiple crops and environments found humic acid amendment delivers on average a 12 percent crop yield uplift, a 27 percent improvement in nitrogen use efficiency, and a 17 percent increase in nitrogen uptake. A landmark meta-analysis (Rose et al., 2014, Advances in Agronomy) across hundreds of studies reported average shoot dry weight increases of about 22 percent and root dry weight increases of about 21 percent in response to humic substances, with stronger responses under stress conditions. Responses are strongest in soils with moderate pH, rainfall above 300 mm, and low baseline nitrogen, conditions typical of tropical plantation agriculture.
Frequently asked questions
Is Leonardite the same as humic acid?
No. Leonardite is the raw, naturally oxidized lignite ore. Humic acid is one of the active fractions extracted from it. SoilBoost EA is the Leonardite-derived product, standardised at 60.6 percent humic acid by the CDFA method.
What is the difference between humic acid and fulvic acid?
Both come from Leonardite. Humic acid is the larger molecule that improves soil structure, cation exchange capacity, and long-term fertility. Fulvic acid is smaller and more mobile, so it carries micronutrients into the plant and aids uptake. SoilBoost EA contains both.
Does Leonardite humic acid replace fertilizer?
No. SoilBoost EA is a soil conditioner that helps fertilizer work harder by improving nutrient retention and uptake. It is used alongside a balanced fertilizer program, not as a replacement for it.
Why is Leonardite better than compost as a humic source?
Leonardite is far more concentrated in humic and fulvic acids than compost, peat, or generic humates, so a small application rate delivers a large, consistent dose of active humic substances.
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