Potassium Magnesium Sulphate (granular)
A straight potassium fertiliser specified under the Fertiliser Control Order, 1985 (Schedule I, Part A, 1(c), item 7). Key notified values: Magnesium as MgO 10.0 min; Potash as K₂O 30.0 min; Sulphate Sulphur as S 17.0 min. Added by S.O. 2126(E) of 31 May 2021.
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Specification
As notified in the Order, line by line. Values are per cent by weight unless the line says otherwise.
How to read this table
- Minimum means the product must contain at least this much; maximum means not more than this (moisture, impurities and heavy metals have a maximum).
- Per cent by weight means grams in every 100 g of product: 0.5 per cent zinc is 5 g of zinc in every kg.
- P₂O₅ and K₂O: phosphorus and potassium are declared as their oxides. To get the element, multiply P₂O₅ by 0.436 and K₂O by 0.830.
- Tolerance: a lab result may fall slightly short of the notified value before the sample is called non-standard; the limits are in Schedule I, Part B.
- S.O. … (E) is the number of the Gazette notification that made a change; “in force” (w.e.f., with effect from) is the date it started to apply.
| Parameter | Notified value | |
|---|---|---|
| (i) | Moisture per cent. by weight, minimum | 0.5 |
| (ii) | Magnesium as MgO per cent. by weight, minimum | 10.0 |
| (iii) | Potash as K₂O per cent.by weight, minimum | 30.0 |
| (iv) | Sulphate Sulphur as S per cent. by weight, minimum | 17.0 |
| (v) | Total Chlorides per cent. by weight, maximum | 2.5 |
| (vi) | Particle Size 90% of the material shall be retained between 5 mm IS sieve and on 2 mm IS sieve |
Tolerance: how far a sample may fall short of a declared value is set in Schedule I, Part B; see the tolerance limits.
Test methods (Schedule II, Part B): method 2: Moisture (oven dry method); method 5: Potassium (sodium tetraphenylboron method); method 20: Particle size; method 24: Total sulphur.
Check a lab report
Compare the results of a lab test with this specification, line by line, including the tolerance allowed in Part B. Enter each result as on the report (per cent by weight unless the line says otherwise). A guide only: the report of a notified laboratory decides whether a sample is standard.
| Parameter | Notified | Lab result | Result |
|---|---|---|---|
| (ii) Magnesium as MgO | 10.0 mintolerance 0.5 units | ||
| (iii) Potash as K₂O | 30.0 mintolerance 0.5 units | ||
| (iv) Sulphate Sulphur as S | 17.0 mintolerance 0.5 units | ||
| (v) Total Chlorides | 2.5 max | ||
| (vi) Particle size | 90% of the material mintolerance 7 units |
Not checked here: Moisture.
Notification history
- 31 May 2021S.O. 2126(E): entry inserted (in force 1 Jun 2021)
Before you make, label or buy it
- Manufacturers and importers: each declared value on the label must meet the limit above; samples are tested by the notified method.
- Dealers and farmers: check that the product name and declared contents on the pack match this specification, and keep the bill with the batch number.
- Doses are not part of this specification: follow the label and local agricultural advice.
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Consolidated by NanoKheti from the Fertiliser (Inorganic, Organic or Mixed) (Control) Order, 1985, as amended up to the Ninth Amendment Order, 2026 (S.O. 4045(E), 22 Jul 2026), for reference. The Gazette text is authoritative; this page is not legal advice. Check the notification before labelling, licensing or buying. Checked for later changes on 20 October 2026.