Recommending the Use of Gypsum—What to Consider.

Gypsum use in agriculture in the United States was recorded more than 200 years ago.  However, widespread use of gypsum (calcium sulfate dihydrate) has been limited.  This may be due to gypsum mines marketing to higher margin markets such as wall board, etc.  It may also be that gypsum has been difficult to spread in the dry form with the spreading equipment that has been used in the fertilizer industry.  Retail dealers have thus not promoted the product due to its handling characteristics and low margins.

Probably the most important reason, however, that gypsum has not been widely used is because it is misunderstood and most crop advisors do not know how to recommend the product or what its benefits are.  In many areas the agricultural producer has driven the interest in gypsum by going directly to the supplier and applying the product themselves.  However, knowing what rates to apply is usually the question.  In this presentation, some of the factors that need to be considered when recommending gypsum as a soil amendment to producers will be discussed.  The use of soil test parameters and knowledge of soil types and crops is important for making precise recommendations of other soil amendments.  It is no different when recommendations are made for gypsum applications.  This presentation will conclude with suggested areas of research needed to optimize the use of gypsum to enhance crop production.