Gypsum (calcium sulfate)

GypsoilGypsum is a soft mineral that often appears in nature in crystalized formations and masses called selenite.  Alabaster is a very fine white grain or tinted gypsum used in ornamental works.  Natural gypsum is mined throughout the world.


Ben Franklin's fertilizer

The benefits of applying gypsum to agricultural soils were established more than 200 years ago. Ben Franklin is often cited for having recognized the beneficial effects of gypsum or “land plaster” to his crops.  Thomas Jefferson also reportedly used gypsum on his farm fields.  But because gypsum was expensive to mine and transport the practice was lost, except in certain specialty crops, such as peanuts and potatoes.

Now GYPSOIL is a better and much more economical source of gypsum.

GYPSOIL brand gypsum is a synthetic form of gypsum that has the exact same chemical composition as mined gypsum -- calcium sulfate dihydrate (CaSO4 2H2O).  Although it is less expensive, it is typically more pure than mined gypsum.

GYPSOIL is a co-product of the process that cleans the air from coal-fired plants and is sometimes called FGD gypsum.  GYPSOIL is also made as a co-product of certain processing plants for food-grade products.

Co-product gypsum

GypsoilThe Clean Air Act Amendments of 1990 gave rise to new scrubbing systems used by many coal-fired utilities to remove sulfur dioxide (SO2) from their emissions.  These scrubbers produce high-quality and very pure FGD gypsum.

The scrubbers create gypsum via a wet process that first forms calcium sulfite (CaSO₃•0.5H₂O) which is then oxidized into gypsum (CaSO - 2H₂O) and dried.  The resulting material is ideal for land application because it is consistent and free of debris or impurities.  

Annual production of FGD gypsum is predicted to double in the next ten years to nearly 40 million tons/annually.  That means gypsum supplies will be even more readily available to crop growers in the coming decades. Read more

Gypsum is unlike other bulk-applied materials and so it requires the operator to understand a few basic things about handling it.  It isn’t difficult to apply once you learn these basics and how to set up your spreader.

FGD gypsum is a fine white powder that’s damp to the touch, similar to moistened flour or biscuit baking mix.

FGD Gypsum

Gypsum from manufacturing is white to grey with somewhat larger crystalline particles.

Gypsum from manufacturing

OSU GuideSoil scientists at Ohio State University have completed a comprehensive field guide on the use and benefits of gypsum. To learn more click here.

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