Jan. 21, 2005 Wheat grown under elevated levels of carbon
dioxide over the next half-century will need slightly more
nitrogen to grow, but not as much as previously predicted,
according to a two-year study by Agricultural Research Service
scientists and cooperators. Atmospheric carbon dioxide (CO2)
levels are projected to increase 43 percent by 2050. The
increased CO2 makes plants like wheat grow larger. But a bigger
plant needs more nutrients such as nitrogen, at least in theory,
according to ARS soil scientist Floyd J. Adamsen, who works at
the agency's U.S. Water Conservation Laboratory in Phoenix,
Ariz. So the ARS scientists have been trying to determine
whether higher CO2 levels will increase the amount of nitrogen
that wheat and other crops need to grow. They reported their
findings on the interaction between carbon dioxide and nitrogen
in the January-February 2005 issue of Agronomy Journal. At the
Maricopa Agricultural Center near Phoenix, the team compared
wheat grown under current levels of CO2 to wh