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 one of the richest natural sources of humic substances. SoilBoost EA is a Leonardite-derived soil conditioner containing 96.55 percent humic acid, used to support nutrient uptake, soil structure and water-holding capacity in tropical plantations.
Product status. SoilBoost EA is a soil conditioner. It is not a fertiliser and not a substitute for one, and it is not a fungicide or pesticide. It is intended to be used alongside a balanced fertiliser programme, not in place of it.
Manufactured exclusively for Chemiseed Sdn. Bhd. and Kudzu Seeds Trading.
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 useful: it raises the proportion of humic and fulvic substances well above ordinary lignite, peat or compost. Where compost typically contains only a few percent humic substances, Leonardite is among the most concentrated natural sources available, which is why it is the usual 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 containing 96.55 percent humic acid, delivering humic substances directly to the root zone. It is a soil conditioner, not a fertiliser and not a substitute for one: it is intended to influence how the soil holds and releases nutrients rather than to supply NPK itself, and it is used alongside a balanced fertiliser programme.
Composition
The values below are the cleared specification figures for SoilBoost EA.
| Property | Value | Notes |
|---|---|---|
| Humic acid (from Leonardite) | 96.55 percent | The active humic fraction of the product |
| Sulphur | 0.45 percent | Secondary nutrient; sulphur is involved in protein and chlorophyll formation |
| pH | 3.84 | The concentrate is acidic. It is applied at low rates and is not intended as a soil pH amendment |
| Source material | 100 percent Leonardite ore | One of the richest natural sources of humic and fulvic substances |
Figures other than those listed above are not part of the cleared specification. Humic substances are conventionally described as comprising humic and fulvic fractions, and SoilBoost EA is standardised on its humic acid content only; no fulvic acid or micronutrient content is declared.
How humic substances are understood to work
The mechanisms below are the ones generally described in the soil science literature for humic substances. They describe how humic materials are understood to behave in soil, not a guaranteed outcome in any particular block.
Nutrient chelation
Humic and fulvic molecules can form stable, water-soluble complexes with iron, zinc, copper and other micronutrients already present in the soil, which is associated with keeping them available to roots rather than precipitating out.
Cation exchange capacity
Humic acid is a high cation-exchange material and its addition is generally associated with improved retention of potassium, calcium, magnesium and ammonium, which may reduce leaching losses under heavy tropical rainfall.
Root-level nutrient signalling
In research settings, humic substances have been associated with upregulation of nitrate-uptake activity in roots. Whether this translates into measurable field nitrogen efficiency varies by site.
Organo-mineral complexation
Humic molecules bind with soil minerals and can slow the breakdown of labile carbon, a mechanism associated with longer-term soil organic matter and structure.
What the research shows, and where it does not apply
The most directly relevant synthesis is Ma et al. (2024), “The Impact of Humic Acid Fertilizers on Crop Yield and Nitrogen Use Efficiency: A Meta-Analysis”, Agronomy 14(12):2763. It pools results from many published trials of humic acid fertilisers as a class. It did not test SoilBoost EA. Its averages therefore describe that input category, not this product — and note that the paper studies humic acid fertilisers, whereas SoilBoost EA is a soil conditioner, so the read-across is imperfect in that respect too.
Within that framing, and attributed to the paper rather than to us, Ma et al. report pooled mean increases of roughly 12 percent in crop yield, 27 percent in nitrogen use efficiency and 17 percent in nitrogen uptake across the trials analysed. Those are the meta-analysis’s averages across many crops, soils and climates, with wide variation between individual studies. They are not a result that SoilBoost EA delivers or that we predict for any particular plantation, and we do not publish a yield uplift figure for SoilBoost EA.
An older synthesis, Rose et al. (2014, Advances in Agronomy), points in the same direction, reporting that humic amendments are on average associated with improved shoot and root growth, again with a wide spread of individual results and generally stronger responses under stress conditions.
An important caveat for tropical growers: the same Ma et al. meta-analysis finds that responses to humic substances are strongest in soils in roughly the pH 6 to 8 range and diminish outside that band. Many tropical plantation soils are considerably more acidic than that. The figures above should therefore not be read across to Malaysian or Indonesian plantation conditions without local verification. Verify against your own soil and leaf analysis rather than assuming a fixed fertiliser credit.
Frequently asked questions
What is the humic acid content of SoilBoost EA?
SoilBoost EA is 96.55 percent humic acid, from 100 percent Leonardite ore, with 0.45 percent sulphur and a pH of 3.84. It is a soil conditioner, not a fertiliser.
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 96.55 percent humic acid.
What is the difference between humic acid and fulvic acid?
Both are fractions of the humic substances found in Leonardite. Humic acid is the larger, less mobile fraction generally associated with soil structure, cation exchange capacity and organic matter. Fulvic acid is smaller and more mobile and is generally associated with micronutrient transport and uptake.
Does Leonardite humic acid replace fertiliser?
No. SoilBoost EA is a soil conditioner and is not a fertiliser or a substitute for one, and it is not a fungicide or pesticide. It is used alongside a balanced fertiliser programme. Verify results against your own soil and leaf analysis rather than assuming a fixed fertiliser credit.
Why is Leonardite used instead of compost as a humic source?
Leonardite is far more concentrated in humic and fulvic substances than compost, peat or generic humates, so a small application rate delivers a consistent, standardised dose of humic substances.
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