Potassium lignosulfonate is a lignosulfonate in which potassium is the main counter-ion. In agriculture it is evaluated as a binder in fertilizer granulation, a dispersant or complexing component in liquid and foliar nutrient formulations, and a potassium-bearing input. The potassium counter-ion gives the material a measurable K2O content. By itself, that does not establish plant availability, potassium-use efficiency, crop safety or yield response. This page sets out the current grade data, the technical points the counter-ion introduces, and how to qualify a grade.
For ammonium grades and the published soil research, see ammonium lignosulfonate in agriculture; for all salt forms, see the lignosulfonates in agriculture guide.
Current grade data: powder and liquid
Values from Green Agrochem’s current technical data sheets for Potassium Lignosulfonate, Agri Grade (GAC-KLS, Rev. 1.0) and Liquid Potassium Lignosulfonate (GAC-KLS-L, Rev. 2.0). Both describe these as typical production results; the COA issued with each shipment reports batch values.
| Parameter | GAC-KLS (powder / granules) | GAC-KLS-L (liquid) |
|---|---|---|
| Appearance | Yellow-brown powder / granules | Black liquid |
| pH | 4–7 | 4.0–7.0 |
| Dry matter / solids | Dry matter 95% min | Solid content 45% min |
| K2O | 8% min | 8–10% |
| Lignosulphonate content | 55% min | 45% min |
| Sulphate | 2% min | Not stated |
| Water-insoluble matter | 1.0% max | 2.5% max |
| Reducing matter / sugar | Total reducing matter 7% min | Reducing sugar around 4% |
| Density | 0.532 g/cm³ | 1.20–1.30 g/ml |
| Moisture | 5% max | Balance to solids (55% max) |
| Packaging / shelf life | 25 kg bags or 500–600 kg FIBC; 24 months | Flexitank or IBC; 12 months; protect from freezing |
These are product-characterization values. Before a K2O figure appears in a nutrient declaration, confirm whether it is total or water-soluble K2O, the analytical method, the basis (as-supplied or dry), the tolerance and the labelling rules of the destination market. The liquid grade is also positioned for construction and ceramics. For agricultural use, confirm that the lot, SDS and COA match an agricultural specification.
What the potassium counter-ion changes
| Aspect | Technical point | What to check |
|---|---|---|
| Potassium contribution | At 8–10% K2O the material is a minor potassium source compared with potassium chloride, sulphate or nitrate. | Calculate delivered K2O on the same basis as the rest of the formula. |
| Chloride and sodium | A potassium lignosulfonate adds potassium without chloride from the counter-ion, but residual chloride or sodium depends on the process. | Request chloride and sodium results if the crop or market is sensitive. |
| Compatibility | Potassium is monovalent, so the grade does not add the divalent ions that drive some precipitation with phosphates or sulphates; other ingredients still can. | Precipitation, viscosity and pH drift in the complete formula and actual water. |
| What it does not prove | The counter-ion does not demonstrate slow release, nitrogen-efficiency enhancement, soil neutralization, growth stimulation or yield response. | Each requires its own controlled evidence. |
Formulation roles to evaluate
Fertilizer granulation and binding
The powder grade may be screened as a binder or processing aid. Compare candidates on an equal dry-lignosulfonate basis and measure granule formation, crushing strength, attrition, caking and redissolution under the actual moisture, recycle ratio and drying profile.
Liquid, foliar and fertigation formulations
Lignosulfonates may help disperse solids or complex metal ions. Test dissolution of the powder or dilution of the liquid in the actual water, then precipitation, viscosity, storage stability and nozzle or emitter passage in the complete formula. Leaf safety must be tested separately for foliar use. Insoluble matter (1.0% max powder, 2.5% max liquid) matters for filtration and drip systems.
Potassium-bearing input
If the potassium content is part of the value proposition, treat it as a nutrient claim. That means market-specific analysis, labelling and, where needed, registration.
Qualifying a grade
| Question | What to measure | Minimum comparison |
|---|---|---|
| Does it improve formulation handling? | Dissolution, precipitation, viscosity, storage stability, filtration | Same formula without lignosulfonate, and the incumbent additive |
| Does it improve granule quality? | Crushing strength, attrition, caking, redissolution | Incumbent binder at equal dry dose |
| Does it affect potassium availability or crop response? | Extractable K, tissue K, biomass, marketable yield, crop safety | Equal-K2O control from a conventional potassium source |
- Define one primary formulation or agronomic objective.
- Calculate dry lignosulfonate and K2O delivery from verified analysis, stating the basis.
- Include an untreated control and an equal-K2O or commercial benchmark.
- Test compatibility, storage and processing before crop work.
- Run replicated trials with predefined endpoints, and monitor phytotoxicity as well as the intended effect.
- Approve the exact grade and test basis before any commercial recommendation.
Neither potassium TDS gives an application rate. Any starting rate must be developed for the specific formulation and stated as a recommended starting trial range with its calculation basis.
Documents to request
- TDS for the exact grade code, with revision.
- SDS for handling, storage and transport.
- COA with batch values, units and test methods, including K2O method and basis.
- Chloride, sodium and contaminant results where the crop or market requires them.
- Market-specific regulatory evidence for any fertilizer or nutrient claim.
Claims that should not be assumed
Do not describe potassium lignosulfonate as a slow-release fertilizer, nitrogen-efficiency enhancer, soil neutralizer, growth stimulant, stress-tolerance agent, soil-microbiome enhancer, non-toxic, biodegradable, organic-compliant or yield-improving without product-specific evidence and a market-specific regulatory review.
Related resources
- Potassium lignosulfonate product page
- Liquid potassium lignosulfonate: data and agricultural trials
- Ammonium lignosulfonate in agriculture
- Lignosulfonates in fertilizer formulation
- Lignosulfonate as a foliar spray adjuvant
Send the intended formulation, target K2O analysis, water quality, process, crop, destination market and test plan to info@greenagrochem.com for exact-grade documents and samples.