System Offers New Option for Managing
Manure By Laura
McGinnis November 13, 2007
A typical 1,000-head beef feedlot produces up to 280 tons of manure in
just one week. That's a lot of manureand for hundreds of U.S. cattle
feedlots, disposal is an important management issue.
Fortunately, Agricultural Research Service (ARS) scientists in the
Management Research Unit at the U.S. Meat Animal Research Center (USMARC)
at Clay Center, Neb., have developed and tested a new method of runoff control.
In the United States, feedlot runoff is often stored in a large pond
or basin. From there, it is either distributed as nutrient-rich irrigation
water or processed for safe disposal. This method is approved by
U.S. Environmental Protection Agency, but is
far from perfect. Over time, nutrients can percolate through the soil into
groundwater. Also, pond maintenance is expensive and difficult.
Nienaber worked with agricultural engineers
Woodbury to design an alternative system, in which runoff containing manure
solids enters temporary storage basins at the base of the sloped feedlot.
The basin is large enough to hold runoff for several hours to allow
the solid waste to settle to the bottom. The remaining liquid is then drained
through distribution tubes that provide even dispersal over a grassy field or
"vegetative treatment area" (VTA).
The VTA system, conditionally approved by EPA, has many benefits. It
requires minimal management, significantly reduces waste storage time,
eliminates the need for costly runoff pumping, and removes standing water.
This manure-disposal technology could also be applied to other
livestock. The system should be less expensive to construct and maintain than
the traditional system, though the cost and suitability would vary with
topography, climate and animal type.
about the research in the November/December 2007 issue of Agricultural