The right earthworms can make home septic systems
work better. Photo courtesy of Flagstaffotos.
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Role of Earthworms in Soil Explored
By Don Comis
July 18, 2008 The right earthworms can make home
septic systems work better. The wrong ones could do the opposite.
Thats the finding in a study of worm populations living in the soil
near trenches receiving septic tank flow outside five single family homes in
Arkansas. Carrie L. Hawkins of the University of Arkansas at Fayetteville
performed the study in collaboration with Agricultural Research Service (ARS) soil
scientist
Martin
J. Shipitalo of the
North
Appalachian Experimental Watershed in Coshocton, Ohio.
The scientists found that the worms were favoring the area near the trenches
because they were feeding on the household wastes discharged in the trenches.
They found fives species of earthworms. None of the species were deep-burrowers
like nightcrawlers.
Their burrowing near the surface actually helped the septic wastewater
spread through the soil more evenly, resulting in better cleansing of the
water. Had they been nightcrawlers, the worm burrows might have drained the
trenches so fast that it would bypass the soil filtering.
The results of this study will be published in the journal Applied
Soil Ecology and are currently online.
The earthworm study is part of a longstanding series of worm studies across
the country by Shipitalo, ARS colleagues at Coshocton and elsewhere, and
cooperating university scientists.
This body of earthworm knowledge is one of many aspects of ARS research on
soils that is incorporated into the Smithsonian
Institution's Soil Exhibition, which opens on July 19 and ends December 31,
2010. The exhibition is at the Smithsonian's National Museum of Natural History in
Washington, D.C., and is called "Dig
it! The Secrets of Soils."
Ted
Zobeck and
Michael
Russelle, at ARS labs in Texas and Minnesota, respectively, are state
liaisons for the exhibit. ARS scientists at the
National
Soil Tilth Laboratory in Ames, Iowa, contributed heavily to the exhibition,
as did the late Dennis Linden in Minnesota.
The U.S. Department of Agriculture (USDA)
is a lead sponsor of the exhibition through the
Soil Science Society of America.
ARS is a scientific research agency of the USDA.