A fertilizer analysis expressed as MgO equivalents should not be compared numerically with elemental Mg. Convert both offers to one basis before calculating cost per kilogram of magnesium.
The factor comes from the formula mass
Using rounded masses Mg = 24.305 and O = 15.999, MgO has formula mass 40.304. The elemental-Mg fraction is 24.305 / 40.304 ≈ 0.6030. A hypothetical analysis of 16.0% MgO equivalents therefore corresponds to approximately 9.65% Mg. It does not mean that the magnesium sulfate contains free MgO at that level.
| Illustrative field | Common-basis result |
|---|---|
| 16.0% MgO equivalents | Approximately 9.65% Mg |
| USD 0.20/kg material at that analysis | 0.20 / 0.09648 ≈ USD 2.07/kg Mg |
| Another offer reporting elemental Mg | Use that stated Mg fraction directly on its defined basis |
Confirm the actual product and reporting convention
The K+S magnesium sulfate product page is a producer example of a defined fertilizer analysis. Request ENVO’s actual offered grade documents and read whether each field is elemental or an equivalent expression. Do not fill a missing field from the product’s hydration name alone.
The worked values are hypothetical and exclude freight differences, unusable quantity and process costs. They do not rank grades with different mandatory quality requirements as equivalent. Keep the sulfur contribution and actual solution-feeding criteria in the broader decision.
Send ENVO the preferred analysis basis, intended use and destination. A common unit makes the price comparison valid; it does not by itself establish agronomic suitability or the required crop programme.
Related decisions
- Magnesium sulfate adds sulfur too: keep a two-nutrient ledger
- Magnesium sulfate for solution feeding: specify the water-insolubles method
Review Magnesium sulfate product identity and purchasing requirements. For the decision above, send ENVO your application, acceptance criteria, quantity and destination. Confirm the offered grade and available documents before ordering.
Technical references support the stated material or test method. Confirm the offered grade and current acceptance criteria for your application. Quality and document guidance
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