Langbeinite

Langbeinite is a naturally occurring double sulfate of potassium and magnesium, processed from mined ore. Because all three of its nutrients are supplied as sulfates, it contains no chloride, distinguishing it from muriate of potash.

Mineral composition

Potassium magnesium sulfate (K₂SO₄·2MgSO₄)

Potassium content

About 22% K₂O

Magnesium and sulfur

Roughly 11% magnesium and about 22% sulfur, as sulfate

Chloride

None; a chloride-free potassium source

Langbeinite supplies potassium, magnesium, and sulfate-sulfur, all in soluble forms that dissolve to release plant-available ions. Because it carries no chloride and has a comparatively low salt index, it is gentler on chloride-sensitive crops and near-seed placement than some other potassium sources.

• Potassium, magnesium, and sulfur are released together as the mineral dissolves
• Contains no chloride, unlike muriate of potash
• Has a relatively low salt index for a soluble potassium source

Langbeinite is chosen where a crop or soil needs potassium and magnesium together, or where chloride is a concern for crop quality or salinity. It suits chloride-sensitive crops and magnesium-deficient soils, and its combined analysis can simplify a fertilizer program that would otherwise need separate magnesium and sulfur sources.

• Well suited to chloride-sensitive crops and magnesium-deficient soils
• Supplies magnesium and sulfur without needing separate products
• Its near-neutral reaction avoids a strong effect on soil pH

Langbeinite provides a fixed ratio of potassium, magnesium, and sulfur, so it fits situations where those proportions match the crop and soil need; where much more potassium than magnesium is required, a straight potassium source may be more economical. It is also typically more costly per unit of potassium than muriate of potash.