
Glickman Says Research May Help Curb Manure
OdorBy Ben Hardin December 14, 1998WASHINGTON, Dec. 14Unpleasant odor from animal feedlots may be
reduced as U.S. Department of Agriculturescientists learn more about how to harvest manures ammonia
and re-use it as a valuable fertilizer, Agriculture Secretary
Dan Glickmanannounced 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 nitrogen fertilizer. 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. Glickmans announcement coincides with a listening session on
the National Strategy for Animal Feeding
Operations being held today in Denver, Colo. Todays 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 Administrations
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)
762-4209, [email protected] U.S. Department of Agriculture | |