What’s your grade? Agricultural or solution?

Agricultural or solution? When reading marketing literature about gypsum, we often see gypsum referred to as solution grade gypsum. This product is primarily targeted for the irrigation market. Is solution grade gypsum any different than conventional gypsum?

Gypsum is sold as either powdered ag-gyp or pelletized gypsum. However, ag-gyp can be marketed as a regular commodity, or it can be processed and screened so that it solubilizes in water and can be put through irrigation systems, including drip systems, sprinklers and sprayers.

Flower farm in Holland
Dutch flower farm

Solution grade gypsum has to have a purity of 95%. Impurities (other minerals) in mined gypsum could impact solubility as well as plug orifices. It also has to be screened with a mesh finer than 300. A typical analysis is that 100% passes through 100 mesh, nearly 100% passes through 200 mesh, and 95% passes through 300 mesh.

The high purity and fine grind of solution grade gypsum allow it to be applied through sprayers, irrigation or top dressed or spread and incorporated in the soil. Its purity and solubility (fineness of grind) increases in solubility and mobility in the soil and keeping calcium and sulfur levels readily available to plant roots and soil microbes. It is more reactive, and you can apply less often than regular ag-gyp.

Solution grade gypsum costs more to process than conventional ag-gyp because of it fine grind and high purity. But these two features provide these additional benefits:

  • Faster water penetration and retention
  • Use in sprinkler, drip, flood, furrow or pivot irrigation systems

Solution grade, like conventional ag-gyp and pelletized gypsum will:

  • Improve soil tilth
  • Remediate sodic soils
  • Increase nutrients availability in the soil
  • Help remediate salinity
  • Supply calcium and sulfur

Remember, solution grade gypsum is primarily targeted for the irrigation market when fineness of grind and purity are important. For the regular agriculture market when material is broadcast, conventional ag-gyp or pelletized gypsum work just fine.


Dr. Davidson posts articles on soil management and subjects to gypsum. If you have suggestions for topics or questions, feel free to contact him at [email protected] or call 402-649-5919.