Muriate of Potash

Muriate of potash (MOP) is the most common form of potash. It is particularly effective when used in the commercial cultivation of the carbohydrate crops including wheat, oats, and barley. MOP is composed of potassium and chloride in the forms of charged atoms, and therefore in the form of a salt which is soluble in water. MOP has a total global market size of approximately 60 million short tons.

Sulfate of Potash

Sulfate of potash (SOP) is the second major form of potash, with a chemical formula of K2SO4.  It is particularly effective in the cultivation of fruits, vegetables, potatoes, tobacco and tree nuts. SOP has a total global market size of approximately 5.5 million short tons.

SOP provides the potassium needed to nourish and strengthen plants, ward off disease, improve transportability and add flavor. SOP improves crop yield and provides sustainable food supplies for the rapidly expanding global population, growing middle-class, and shrinking agricultural land.


SOP is superior to MOP because it does not contain chloride, which has a toxic impact on many food plants, especially fruits and vegetables. When MOP is used, soils fall victim to increasing levels of chloride salt which hurt plant yields. Chloride-free fertilizer enhances plant health, so the demand for SOP has increased. An abundance of research has concluded that the demand for specialty fertilizers, particularly SOP, has averaged a substantial annual growth over the last five years.

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Chloride is detrimental to many fruits

Chloride is detrimental to many vegetables

Chloride in plants increases osmotic potential

SOP sells at a significant premium over MOP

In addition, SOP has a lower salinity index than MOP. The higher salinity of MOP can cause plants to have difficulty absorbing water and nutrients from the soil thereby diminishing the quality and yield of the crop. SOP has a salinity index of 46, the lowest of the potassium fertilizers, while MOP has a salinity index of 116. For these reasons, producers of high value crops use SOP over MOP. The photos below visually depict the benefits of using SOP on oranges.