An Ohio State University scientist says an abundant byproduct from coal-burning power plants, if spread on farmers’ fields, could help control Lake Erie’s harmful algal blooms.
Warren Dick, a soil biochemist in the university’s College of Food, Agricultural, and Environmental Sciences (CFAES), said applying fluidized gas desulfurization (FGD) gypsum to crop fields can keep soluble phosphorus, the main nutrient feeding the algae, from getting washed from the soil by heavy rains, then running off into streams and rivers and eventually into the lake.
“And FGD gypsum, which is a synthetic form of gypsum, can improve both the soil and the crops,” he said. “Naturally occurring, mined gypsum has a long history as a soil amendment and fertilizer for farming.”
A professor in CFAES’s School of Environment and Natural Resources (SENR), Dick is part of a national program to develop agricultural uses for FGD gypsum, which comes from the air-emission scrubbers at coal-burning power plants. The scrubbers remove sulfur dioxide, which causes acid rain, from the plants’ exhaust emissions. The process creates large amounts of quality gypsum as a byproduct.
FGD gypsum is powdery, resembles flour, and can be applied using conventional farm spreaders. It costs about $35 to $50 per ton spread on the field, with a typical application rate being one or two tons per acre every two or three years. A growing number of farmer co-ops sell it.
Locally, Dick’s research focuses on northwest Ohio’s Maumee River watershed, which is the largest watershed draining into Lake Erie and is the lake’s largest contributor of nonpoint source pollution. Nonpoint source pollution is pollution that comes from many, spread-out sources.
His recently funded project in the Maumee watershed will test FGD gypsum on fields that have high soluble phosphorus levels, will collect soil and water samples from the fields to determine the material’s effects, and will compare crop yields from treated and untreated fields.
The study’s results will contribute to refined recommendations for farmers and should lead to wider and more-effective use of FGD gypsum, he said.
Partners on the project include utility companies, crop consultants and scientists from other universities.
Excess soluble phosphorus is the primary cause of the huge and sometimes toxic algal blooms that have plagued Lake Erie and other water bodies, such as western Ohio’s Grand Lake St. Marys, the past few years, experts say. It comes from fertilizer and manure runoff from farms, sewer overflow from storms, discharge water from wastewater treatment plants, and leaking septic systems. Wide use of gypsum could slash the portion that comes from farms, Dick said.