Regulating Ammonia Emissions From
Hog Farms Would Raise Costs
Nigel
Key
Tim McCabe, USDA/NRCS
Nitrogen from livestock waste can
degrade both surface water (via runoff from cropland)
and air quality (via emissions of ammonia from manure
storage facilities and cropland). Nitrogen runoff
is regulated, in part, by requiring large livestock
operations to follow a nutrient management plan.
Except in California, there are no regulations on
ammonia emissions from animal feeding operations,
even though livestock operations are the Nation’s
largest source of ammonia. A recent ERS study considers
the economic and environmental implications of a
hypothetical ammonia restriction for the U.S. hog
industry. The study finds that the effects of the
policy on costs and emissions would vary by region
and by the type of manure storage system used.
Hog operations usually store manure
in lagoons or pits. Their choice of storage facility
has major consequences for the level of ammonia
emissions. Lagoons are designed to reduce manure’s
nitrogen content through ammonia volatilization,
which allows farmers to apply more manure on less
land without exceeding crop nutrient requirements,
thereby lowering manure transportation costs by
eliminating the need to transport manure to more
distant cropland. Lagoons tend to be more cost effective
in relatively cropland-scarce regions, such as the
South and Southeast. In contrast, pit manure facilities,
which conserve manure nutrients for use on cropland,
emit less ammonia and are more cost effective in
cropland-abundant regions such as the Midwest.
In the current environment with
no ammonia emission restrictions in place, ERS estimates
that large operations using lagoons have ammonia
emissions of twice as much per animal and almost
three times as much in total compared with large
operations using pit systems.
Lagoon
operations are more responsive to a
hypothetical ammonia restriction than pit
operations |
|
Ammonia nitrogen
emissions with no
restriction
|
Ammonia nitrogen
emissions with
hypothetical restriction
|
Per
hundredweight
hog produced
|
Total |
Per
hundredweight
hog produced |
Total |
|
|
|
|
Large
lagoon operations |
Manure storage facility |
7.9 |
281.1 |
4.1 |
144.2 |
Field |
0.5 |
16.3 |
1.3 |
44.9 |
Total |
8.4 |
297.4 |
5.3 |
189.0 |
Large
pit operations |
Manure storage facility |
3.3 |
79.9 |
3.3 |
79.9 |
Field |
0.9 |
20.9 |
0.6 |
13.7 |
Total |
4.2 |
100.9 |
3.9 |
93.7 |
Note: Large hog operations (at least 1,000
animal units) with lagoon operations are
shown to emit substantially more ammonia
per unit and in aggregate than large pit
operations as measured by estimated levels
of ammonia per unit (pounds of ammonia nitrogen
per hundredweight of hog produced) and the
total ammonia produced nationally (1,000
tons of ammonia nitrogen).
Source: Economic Research Service calculations
calibrated with data from the 1998 USDA-ARMS
Hogs Production Practices and Returns Report.
|
In a scenario requiring lower ammonia
emissions using currently available ammonia-abatement
technologies—lagoon covers and manure slurry
injection—ERS finds that all large hog farms
would face higher costs, but the restrictions would
cause a greater decline in profits for lagoon operations
than for pit operations (12 percent versus 2 percent).
Lagoon operations, however, would see a 36-percent
drop in ammonia emissions, compared with a 7-percent
drop for pit operations. The geographic distribution
of large lagoon and pit operations implies that
farms in the South and Southeast would face greater
declines in profits but would generate larger reductions
in air pollution than farms in the Midwest.
Managing Manure
To Improve Air and Water Quality, by Marcel
Aillery, Noel Gollehon, Robert Johansson, Jonathan
Kaplan, Nigel Key, and Marc Ribaudo, ERR-9, USDA,
Economic Research Service, September 2005.
|