Comparing Potassium Sources for Crops | Protassium+®


What Does Your Potash Bring to the Table?

Protassium+ premium sulfate of potash (SOP) is the richest source of low-chloride potassium, providing the equivalent potassium content of 50% K2O, commonly referred to as potash. When comparing K sources, you must keep in mind chloride level, salt index and the addition of value-added nutrients.

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Minimize the Harm

Compare Chloride Levels

Because Protassium+ SOP is low in chloride (less than 1%) compared with many other potassium fertilizers, it minimizes the harmful impact chloride can have on your crops. Excess chloride can reduce the uptake of vital nutrients, resulting in poor crop health, reduced yields and lower harvest quality.

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Avoid the Burn

Reference the Salt Index

SOP has the lowest salt index per unit of K2O of all major potassium sources. A low salt index minimizes adding to the salinity of soil water and helps avoid crop development and soil system issues including:

  • Poor germination
  • Water and nutrient imbalances
  • Seedling injury and "Tip Burn"
  • Stunted root and shoot growth


Potassium fertilizer is often applied at greater than 100 lbs/ac total K2O

  • Some low chloride fertilizers also have low potassium analysis
  • Fertilizer application rates needed to satisfy the K2O needs of the crop can result in excess chloride being applied with some low chloride fertilizers

Consider the Source

Value-Added Nutrients

Other K sources like muriate of potash (MOP or KCl), potassium thiosulfate (KTS), potassium nitrate (NOP) and polyhalite (Poly) contain high levels of unneeded and/or potentially damaging nutrients. Protassium+ SOP is a unique dual-nutrient source, offering 50% potassium and 17% sulfur in the plant-available sulfate form—an essential secondary nutrient key to plant health.


Support Sustainability

An Eco-Friendly Choice

Once the nitrogen (N) needs of the plant have been satisfied, it is critical to discontinue applications of nitrogen, including potassium sources containing nitrogen. Over-application of nitrogen can result in poor produce quality and low yields. Additionally, unused nitrate may leave the root zone and potentially create environmental concerns. SOP does not contain nitrate.

Nearly 90% of Protassium+ SOP is sustainably produced through a natural solar evaporation process from the Great Salt Lake of Utah in the United States, and the remainder is produced through two unique processes―ion exchange and glaserite methods―at Big Quill Lake in Saskatchewan, Canada. In each of these processes, the water or natural elements remaining after the extraction process are returned to the lakes for future reuse.

Some organic grades of Protassium+ premium sulfate of potash meet the requirements for organic use under the U.S. National Organic Program and are certified by both the Organic Materials Review Institute (OMRI) and the California Department of Food and Agriculture (CDFA).  Some organic grades are also approved by Ecocert for use in organic agriculture production conforming to the Canadian Organic Standard.