[permaculture] Poplar trees may be new draw for pig farms
saor at ycbtal.net
Tue Dec 16 13:44:20 EST 2003
Poplar trees may be new draw for pig farms
Tuesday, December 16, 2003
By Estes Thompson, Associated Press
WHITAKERS, N.C. — After years of struggling with the dirty disposal
problem of sludge from hog waste lagoons, researchers have come up with
a possible green solution: poplar trees that suck up the waste like soda
If the procedure works well enough to be approved by state water quality
officials, it could more than cut in half the cost of closing a waste
lagoon, currently done with bulldozers and dump trunks.
"It is a simple method," said Frank Humenik, coordinator of the animal
waste management program at North Carolina State University.
Humenik has been working with Oregon researchers who have been
experimenting the past few years with technology that relies on groves
of fast-growing hybrid poplars to suck up waste.
Studies have found the trees can absorb nearly 3,000 gallons of effluent
per acre per day, ridding the ground ammonia and nitrogen by safely
metabolizing the compounds in their woody tissue.
Oregon State University water quality researcher Ron Minor said it could
take 10 years before the trees clean the land well enough that it can be
"Over time, the trees take up the nutrients and it is natural
purification," Humenik said. "With the trees, you have a harvestable
The current method approved by the state of North Carolina to clean up
hog lagoons is complex. First, the liquid is drained from the top of the
lagoon onto existing sprayfields of grass at the farm. Then the farmer
pays to have the sludge scooped out and trucked away to be spread thinly
on acres of fields.
"We don't like to haul that stuff around," Humenik said.
Humenik said the sludge usually isn't welcomed by neighbors of the
fields. The cost and politics of cleanup may be the reason only 20
lagoons were closed last year in the state, he said.
There are 1,700 inactive lagoons in North Carolina waiting cleanup and
4,500 more lagoons in use. North Carolina ranks second in hog production
at 9.6 million animals, behind Iowa at 15 million head.
National Pork Board figures show one animal produces between 8,000
pounds and 64,000 pounds of waste a year, depending on its development.
Cleaning out a typical lagoon could cost as much as $40,000 an acre, not
counting the cost of land on which to spread the sludge. The sludge
can't fertilize crops for human consumption. Humenik said the typical
lagoon cleanup using the poplars would cost between $15,000 and $20,000
for a lagoon that is two to three acres.
Source: Associated Press
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