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In a well-managed farrow-to-finish
pasture system, producers can net more than $10 per pig, according
to Texas Tech University.
Photo by Jerry DeWitt |
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Manure Management
The best type of waste management in
any livestock operation converts manure into a resource rather than
creates a disposal problem. Many hog producers also raise crops, so
manure, treated correctly, offers a valuable soil amendment. Manure
from a 50-sow operation is worth about $4,000 as a fertilizer, although
other benefits such as increasing organic matter, enhancing soil structure
and building more diverse soil organisms make it even more valuable.
In pastured hog operations, the hogs
distribute manure themselves as they move across a field. With proper
rotations and a reasonable stocking rate, manure does not pose a problem.
Manure from hogs raised in deep bedding mixes with the straw or other
material and becomes a solid pack that is relatively easy to handle.
The manure-bedding mix adds another plus. Bedding materials contain
high amounts of complex substances, such as lignin, that do not decompose
rapidly and therefore improve the soil’s organic matter and tilth over
the long term.
Roger Hubmer of Mankato, Minn., analyzes his manure mixed with cornstalk
bedding so he can knowledgeably apply it to his crop fields. Hubmer,
who began finishing hogs in hoop barns when he realized he didn’t
want to spend $100,000 on a new confinement barn, spreads compost
based on the phosphorus rating.
Odor and Pollution
One of the biggest considerations about
raising hogs is odor generated from manure. Stories about bad-smelling
manure lagoons and community opposition to large hog confinement operations
regularly appear in the media. Liquid manure stored in a lagoon sits
in an anaerobic state, and that creates disagreeable odors. The smell
might be unpleasant for people nearby, but some of the gases produced
– methane, hydrogen sulfide, carbon monoxide and ammonia – can be toxic.
If there’s a power outage in a confinement
building, pigs face very real dangers, including death, from heat and
the gases that build up in liquid anaerobic manure systems. Many confinement
hog operators equip their buildings with alarm systems and backup generators.
Such high-tech systems come at considerable cost. The free flow of air
through a hoop structure, however, eliminates the need for such expensive
systems.
“Hog odor is the most divisive issue
ever in agriculture, damaging the fabric of rural society and disenfranchising
pork producers from their communities, even on the roads in front of
their farm,” said R. Douglas Hurt, director of Iowa State’s Center for
Agriculture History and Rural Studies.
Outdoor systems eliminate the problem.
There is virtually no odor at Texas Tech’s pastured pig demonstration
site, said John McGlone, who runs the facility. “I told some colleagues
from NRCS that it wouldn’t smell and they didn’t believe me,” he said.
“I had them out there in the fields a year after we started and they
couldn’t believe it. It doesn’t smell.”
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Marion Storm, a Bosworth,
Mo., hog producer and member of the Patchwork Family Farms Cooperative,
moves his 100 sows and piglets through a series of barns with
access to pasture. By managing his hogs on pasture, Storm alleviates
manure concerns. Photo courtesy of Missouri Rural Crisis Center. |
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Perhaps worse than odor concerns is
the potential of swine lagoons to leak into surface water or groundwater.
In September 1999, Hurricane Floyd wreaked havoc throughout North Carolina.
Particularly hard hit was the state’s huge hog industry. Overall farm
losses were estimated at more than $1 billion, with at least 21,000
hogs drowned or washed away in their pens. Water pollution became a
serious threat partly due to floodwaters carrying away manure from countless
hog lagoons.
“Confinement poses more risks,” Honeyman
said. “If we concentrate these animals, we also concentrate animal waste,
so our risks of environmental degradation increase.”
A solid manure system, on the other
hand, doesn’t leak or spill. The only threat to water quality is possible
leaching from the composting bedding pack if it is stored outside in
heavy rain. As an aerobic process, composting, done correctly, shouldn’t
emit objectionable odors.
“It may sound funny,” said Hubmer,
the Mankato, Minn., farmer, “but the composted manure that comes out
of the hoops is almost sweet-smelling.”
Pastured systems pose even less of
a risk. At Texas Tech, researchers installed a buffer of Old World bluestem
around the site to catch runoff from heavy storms. It works, too, McGlone
said. “You can see the runoff isn’t leaving,” he said. “Our pastures
are dark green, while the buffer is pale green,” indicating that nitrogen
is staying on the pastures.
“If it’s done right, manure and nutrient
runoff is not an issue.”
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