Conservation Practice Standard: Amending Soil Properties with Gypsiferous Products.

Beginning in January, 2014, the ASA By-product Gypsum Uses in Agriculture Community led the development of a USDA-Natural Resources Conservation Service (NRCS) Conservation Practice Standard for “Amending soil properties with gypsiferous products.” A completed draft of this national standard will be submitted to NRCS for consideration of adoption during the 2014 annual meetings of the tri-societies. Over 70 scientists from land grant universities, the USDA Agricultural Research Service, NRCS and the broader international scientific community contributed to the development of this standard. The standard covers the use of natural or industrial gypsiferous products to change physical and/or chemical properties of soil. Specific chemical criteria that define product purity were established, and it is the responsibility of the amendment provider to furnish the results of product analyses to the producer. Defined purposes for amending soils with gypsiferous products are to 1) improve infiltration and reduce soil erosion, 2) reduce dissolved phosphorus concentrations in surface runoff and subsurface drainage, 3) mitigate subsoil acidity, and 4) reduce the potential for pathogen transport from areas of manure and biosolids application. Specific rates and methods of application are provided for each purpose. The use of gypsiferous products to remediate sodic soils or address nutrient management concerns are excluded as these purposes are covered under NRCS standards 610 and 490 respectively. The standard cautions against raising the soil pH to levels detrimental to plant growth, creating calcium or other nutrient imbalances, and raising trace element concentrations to detrimental levels. Operation and maintenance guidelines restrict livestock access to stacked gypsum and gypsum amended vegetation that could be ingested. Plans and specifications shall include required soil analyses that demonstrate the need for the amendment.