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News and analysis on the global poultry
and animal feed industries.
on June 23, 2009

Conflicts over farm atmospheric emissions

Attempts have been made by farm-State legislators to remove manure from an EPA list of pollutants defined in Superfund law.

In December 2007 during the Congressional recess, the U.S. Environmental Protection Agency (EPA) published a proposal in the Federal Register to rescind the rule mandating that large agricultural enterprises must report levels of atmospheric discharge of gases with potential deleterious health or environmental effects. This requirement, introduced in the mid-1980’s has been opposed by agribusiness associations including the National Chicken Council, U.S. Poultry and Egg Association and the National Turkey Federation. Industry groups claimed that compulsory reporting was “inappropriate---and does not reflect the nature of poultry management practices nor improve environmental or public health outcomes” as quoted in the February 26th edition of the Washington Post. A small proportion (0.6%) of local emergency responders who indicated that they were not using the data supported the EPA action. In contrast, local air pollution entities affiliated to the National Association of Clean Air Agencies were opposed to the exemption from reporting emissions from farms.

The issue has become embroiled in the current political cauldron heated by the quadrennial election cycle. Attempts have been made by farm-State legislators to remove manure from an EPA list of pollutants defined in Superfund law.  This is opposed by the chairpersons of two powerful house committees.

Irrespective of the disposition of the EPA mandate, the U. S. Poultry Industry must face the reality of atmospheric pollution and apply scientific principles to reduce the release of ammonia and other nitrogenous compounds. These arise during production of eggs and poultry meat, during storage and handling of excreta and ultimately at the time of disposal, usually by land application. Numerous studies have quantified ammonia and nitrogen release to the atmosphere. Up to 40% of ammonia is derived from animal wastes with contributions from swine, dairy and feedlot operations in addition to egg, broiler and turkey production. Nitrogen compounds as nitrous oxide, alone and in combination with ammonia contribute to acidification of the atmosphere.

Quantifying nitrogenous releases from different housing and management systems is critical to developing cost-effective solutions. A model developed at the prestigious Center for Applied Poultry Research, Spelderholt in Holland in conjunction with scientists at North Carolina State University during 1988, demonstrated profound differences in ammonia release by egg-producing flocks according to house design. High-rise houses produce ten times the level of ammonia (on a per hen basis) compared to units equipped with on-belt manure drying. Hen waste piped to lagoons generates nine times more ammonia than product from houses with belt drying. More than twice the level of ammonia is released by applying slurry to land as compared to dry manure.  Feeding diets with unbalanced amino acid content or excess crude protein is non-productive, expensive and contributes to excessive excretion of nitrogen.

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