On a 33-foot tower in Doug Wulf's cornfield near
Morris, Minn., ARS scientists mounted sensors to monitor the flow of carbon
dioxide and water in and out of the soil.
Wente; not available at 300 dpi)
Prairie Towers Watch Carbon and Water Losses from
By Don Comis
April 29, 2005
A pair of 33-foot towers flanking a
road that divides two of Doug Wulf's cornfields puzzles drivers south of Morris
in western Minnesota. The towers hold instruments that monitor wind, carbon
dioxide and water vapor year-round, 24 hours a day. The instruments have to be
moved upwards as the corn grows each season, so they always stay about six feet
above the corn tassels.
Reicosky and research technician
Wente from the Agricultural Research Service's (ARS)
Central Soil Conservation Research Laboratory at Morris work on the
Baker and colleagues from the ARS
and Water Management Research Unit at St. Paul. The experiment is
monitoring Wulf's attempt to boost his corn yields to 400 bushels of corn per
acre mainly by applying higher amounts of manure and fertilizer. Wulf is also
using deeper plowing and denser stands of corn.
Wulf and the scientists want to check for manure and fertilizer losses and
their effects on the environment, as well as effects of deep tilling, and the
corn's increased use of soil water.
Manure and tillage can release carbon dioxide, methane and nitrous
oxide--all greenhouse gases associated with potential global warming--and can
also increase nutrient losses in rain runoff. This spring the scientists will
begin testing water from field drainage pipes for nitrogen and phosphorus.
Eventually, they'll measure emissions of carbon dioxide, methane and nitrous
oxide with ground-based chambers as well as their meteorological instruments.
The research is timely as large dairy confinement operations expand in the
area as well as nationwide. If this manure can be converted into nutrients that
grow more corn, without harm to the environment, then it would be a double
benefit to farmers. Dairy farmers usually have no other way to get rid of the
manure than to apply it on nearby fields to fertilize corn or other crops.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.