Potassium sulfate may also be source of sulfur when sulfur is required. If may also be used as a source of sulfur. Potassium hydroxide, also known as caustic potash, is used to a limited extent in the production of liquid mixed fertilizers. The present cost of producing potassium hydroxide has limited its use in the fertilizer industry, even though it is a very desirable product due to high solubility and low salt index. It has a low salt index and provides nitrate N which may be desirable for these specialty crops.
Production costs have limited general use for most agronomic field crops.