Study: Spreading gypsum on farms can help keep water clean, not green

Gypsum, which has roots in the past as a farm soil treatment, also may have a bright future, and not just as a booster of crops but also a protector of water.

OARDC scientist Warren Dick is two years into a three-year study of gypsum’s benefits on farms, including to soil quality, crop yields and reducing phosphorus runoff.

So far, he said, farm fields in his study treated with gypsum are seeing an average 55-percent reduction in soluble phosphorus runoff, based on tests of water samples collected from the fields’ drainage tiles.

“There’s no one technology that’s going to solve the issue of phosphorus runoff,” said Dick, professor in the School of Environment and Natural Resources. “But I think gypsum is going to become one of the tools in the toolbox, something farmers will use with other approaches as part of their total management package.”

“There’s no one technology that’s going to solve the issue of phosphorus runoff. But I think gypsum is going to become one of the tools in the toolbox.”—Warren Dick

Big cut in phosphorus runoff may be possible

  • Experts say soluble phosphorus runoff from farms is a cause of the harmful algal blooms plaguing Lake Erie and other lakes.
  • Gypsum, when spread on a farm field, binds with soluble phosphorus. This keeps the phosphorus from running off yet keeps it available to plants.
  • Gypsum also provides calcium and sulfur, nutrients that can improve the soil and crop yields.
  • Dick’s research is taking place on farms in the Maumee River watershed, Lake Erie’s largest tributary, and around Grand Lake St. Marys, which also has suffered from the blooms.
  • To contact the scientist: Warren Dick at dick.5@osu.edu.

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