Coal Plant Byproduct, If Spread on Farms, Could Fight Lake Erie Algae
Ohio State scientist Warren Dick, right, says a byproduct of coal-burning power plants called FGD gypsum, shown here in the foreground, can be used to improve farm soils, crop yields and Lake Erie. (K.D. Chamberlain image.)
Ohio -- 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
Dick, a soil biochemist in the
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.
that, but 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.”
Video (1:17): Warren Dick discusses gypsum and its benefits to plant nutrition and soil structure.
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 would cause acid rain, from the plants’ exhaust emissions. The process creates large
amounts of quality gypsum as a byproduct.
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.
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.
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.
Photo: Warren Dick holds a double handful of FGD gypsum, which is powdery and resembles flour. (K.D. Chamberlain image.)
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.
the project include utility companies, crop consultants and scientists from
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.
“Based on various
studies, gypsum can cut the amount of soluble phosphorus running off soils by
40 to 70 percent,” he said.
When spread on a field, gypsum binds in the soil with phosphorus to make calcium phosphate, which is a much less soluble form of phosphorus. This means it’s less able to run off in water.
Video (1:15): Warren Dick explains how gypsum keeps soluble phosphorus from running off soils and getting into water.
is also an excellent source of sulfur nutrition for plants for improving crop
yields,” Dick said. “It interacts with nitrogen to make it more efficient. And
it interacts with the soil itself.
aggregates the soil, which improves its structure, and improves aeration and
water infiltration, which reduces runoff. It allows water to move into the soil
but doesn’t keep the soil waterlogged so that air can move into the soil and
allow the crops to grow well.”
previous studies, Dick has documented a nearly 7-percent increase in corn
yields from using gypsum and an 18-percent jump in alfalfa tonnage.
are getting more and more deficient in sulfur,” he said, one reason being that the
coal-plant scrubbers are working. Over the past 30 years, Ohio has seen nearly
a 40-percent drop in how much sulfur rains down on the ground, according to the
National Atmospheric Deposition Program.
continue to harvest huge amounts of alfalfa off a field, if you harvest corn
grain or soybean grain, you’re removing a lot of sulfur every year. If you
never put anything back, eventually you start to run deficits,” Dick said.
Photo: A harmful algal bloom, fueled mainly by soluble phosphorus, covers much of Lake Erie's Western Basin in this October 2011 NASA image.
crops, such as soybeans and alfalfa, have an especially high sulfur
requirement, he said.
gypsum is a readily available, less-expensive source of sulfur,” Dick said. “And
there’s a lot of research now across the U.S. showing that crops are becoming
more responsive to sulfur as a nutrient fertilizer input.
calcium, too, which can stimulate plant root growth and help crops reach more
water and nutrients.”
also can allow farmers to use conservation tillage practices, such as
no-tillage, on the Maumee watershed’s heavy clay soils, which often don’t lend
themselves well to the methods, he said. This would cut soil erosion into Lake
Erie, boost carbon sequestration by the farms’ soils, and let farmers spend
less money on tillage equipment and fuel.
on corn, for instance, could increase yields by about five bushels an acre, and
at a conservative price of $5 per bushel “would almost pay for itself the first
year,” Dick said.
contributes to the Ohio State-based National Research and Demonstration Network of FGD Products in
Agriculture. The program has projects in Ohio
and six other states, including at the Mill Creek MetroParks Farm near
project is supported in part by a Conservation Innovation Grant from the U.S.
Department of Agriculture’s Natural Resources Conservation Service.
joint appointments with the Ohio Agricultural Research and Development Center and Ohio State University Extension, which are the research and outreach arms, respectively, of
CFAES. SENR, too, is part of the college.
Extension bulletin that Dick co-authored, called “Gypsum as an Agricultural
Amendment,” can be purchased through OSU Extension’s eStore at http://go.osu.edu/Qzu or downloaded free at http://go.osu.edu/gypsumforfarms (pdf).