Gypsum for Phosphorus Runoff Reduction

Sand County Foundation’s work to find ways to limit agriculture’s impact on water quality involves an unlikely product: gypsum.

We evaluated gypsum extracted from the exhaust of electric power plants and applied it to cropland as a way to reduce phosphorus draining into waterways after intense rainstorms.

Flue Gas Desulfurization (FGD) is a technology that was integrated into the coal fire power generation process to reduce sulfur dioxide emissions, a chemical contributor to acid rain. The chemical reaction used in FGD technology can remove sulfur dioxide by mixing it with limestone, resulting in a synthetically made gypsum product, nearly identical to naturally mined gypsum.

The goal is to keep phosphorus (beneficial for growing corn, soybeans and alfalfa) on farmland and out of the water where it can lead to harmful algae growth.

To evalute the agronomic and environmental benefits of applying synthetic gypsum onto farm fields, Sand County Foundation collaborated with the following partners: Electric Power Research Institute, Milwaukee Metropolitan Sewerage District, We Energies, University of Wisconsin's College of Agricultural and Life Sciences' Department of Soil Science, Gypsoil and Water Resources Monitoring Group, LLC.

To learn more, view our Conservation Brief on this topic.

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