Glickman Says Research May Help Curb Manure Odor
ARS News Service
Agricultural Research Service, USDA
December 14, 1998
Ben Hardin, (309) 681-6597, email@example.com
WASHINGTON, Dec. 14--Unpleasant odor from animal feedlots may be reduced as
U.S. Department of Agriculture scientists learn more about how to "harvest"
manure's ammonia and re-use it as a valuable fertilizer, Agriculture
Secretary Dan Glickman announced today.
"Odors from livestock manure have been a long standing challenge for
scientists," Glickman said. "USDA researchers are working on a solution to
the odor issue that could also turn the smell of waste into valuable
As manure from cattle or swine decays, the released ammonia contributes to
its pungent odor. Researchers are testing chemicals, one of which looks
promising, that keep manure from rapidly decomposing and releasing its
ammonia. An estimated half to three-fourths of the nitrogen in manure from
beef cattle feedlots breaks down to ammonia gas and other compounds before
it ever reaches farm fields.
Glickman's announcement coincides with a listening session on the National
Strategy for Animal Feeding Operations being held today in Denver, Colo.
Today's session is one of 11 held around the country to seek public comment
on the joint USDA-Environmental Protection Agency draft strategy.
The unified national strategy, part of the Clinton Administration's Clean
Water Action Plan, seeks to minimize threats to water quality and public
health caused by animal feeding operations, while ensuring the long-term
sustainability of livestock production in the United States.
According to ARS microbiologist Vincent H. Varel, testing has focused on
NBPT, a chemical that was recently commercialized as a nitrogen preservative
for use in no-till, soil-saving farming. NBPT is one of a number of
compounds known as urease inhibitors.
"Urease is an enzyme that converts the urea in urine into ammonia that
escapes into the air," said Varel, who has been conducting studies on
several urease inhibitors at the Roman L. Hruska U.S. Meat Animal Research
Center at Clay Center, Neb. "In preliminary experiments, NBPT worked even
better in the feedlot than in the laboratory. That is promising."
While urease inhibitors will reduce ammonia emissions, Varel cautioned that
other odor-reducing compounds will be needed to more fully control the
variety of unpleasant-smelling, volatile compounds from manure.
He and his colleagues envision encapsulating mixtures of odor reducers in
starch or other protective materials. Encapsulation would ensure slow
release of active compounds and require fewer applications to cattle
feedlots, manure slurry tanks and covered lagoons used on livestock farms.
Scientific contact: Vincent H. Varel, ARS Roman L. Hruska U.S. Meat Animal
Research Center, Clay Center, Neb., phone (402) 762-4207, fax (402)
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