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The dirt on CO2
| Just a quick
comment on your article "Carbon dioxide shakes off its
pursuers" (SN: 7/24/99, p. 54). While it certainly seems
unlikely that North America would have a monopoly on carbon sinks,
the time frame of the original Princeton study, 1988 through 1992,
did grab my attention.
At that
time, conservation-compliance regulations in the United States and
relatively warm and dry weather conditions in the northern corn
belt led to sharp decreases in tillage and corresponding increases
in surface residue on farm fields. Also, farmers were making
significant cuts in nitrogen-fertilizer use, which might have
slowed the breakdown and release of carbon from crop residues. And
acres had not yet begun to be released from the Conservation
Reserve Program to be burned off, tilled, and brought back into
crop production.
Fred Wirtz Jr.
West Bend, Iowa |
| I am
disappointed by the implications of your article. First, despite
political rhetoric to the contrary, there is no logic in the
notion that identifying the missing sink in the global carbon
cycle would justify the United States’ failing to decrease
emissions (as suggested by the quote from Richard Houghton).
Regardless of where the unaccounted-for carbon is going, the level
of atmospheric carbon dioxide continues to rise, the United States
is a huge contributor to that rise, and reducing emissions cannot
help but counter future increases.
Second, the
statement that modern agricultural practices have stored extra
carbon in soil, reinforced by the photograph accompanying the
article, is simply not true. Research has shown that conversion of
land to agriculture typically produces a 20 to 30 percent drop in
the organic content of the soil and that continued agricultural
use of the land does not restore the lost organic matter.
Practices such as tilling and the addition of large quantities of
nitrogen fertilizers promote decomposition of soil organic matter.
In addition, continued loss of huge volumes of topsoil through
erosion further reduces the organic matter contained on our
agricultural lands.
Contrary to
your reporting, modern industrialized agriculture is a net cause
of the carbon dioxide problem, not a cure.
Steve Trudell
Seattle, Wash. |
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