If any of you would like my complete notes, just ask. They are too long to
be accepted by this list.
Peggy Murdock
The Pew Oceans Commission is composed of 18 individuals, scientists,
commercial fishermen, and a Kansas farmer who travel the U.S.holding
hearings designed to help them inform congress in order to help design
national policy. There were four of these individuals at the Des Moines
meeting.
Dr. Nancy Rabelias explained hypoxia in the Gulf of Mexico, where her
laboratory is located. It is an area i without oxygen that is created by
runoff from the Mississippi each spring. The size of the hypoxic area
reaches from the Mississippi Delta to and beyond the border of Texas. It
disappears in winter, when the water is mixed and appears again each spring.
Most fish are able to swim out of the area but there are
fishkills. Phytoplankton and sediment cut down on the light, killing
eelgrass and brown algae. Anoxia kills the worms and crabs that fish feed
on, which means that food supplies and cover are lacking even when hypoxia
recedes. Hypoxia interferes with shrimp migration and shrimp harvests are
also affected.
The size of the dead zone is directly related to the amount of water that
comes down the Mississippi and the nitrogen and phosphorus in that water.
Dr. Dennis Keeney reported that there has been a tremendous increase in the
amount of nitrate in streams in the last 30-50 years. There is a direct
correlation between the amount of land planted in rowcrops and nitrate in
streams. High fertilizer use is encouraged. Grain is being produced for
markets that do not exist. Farm and trade policies encourage grain
production and the freedom to farm act has made the situation worse.
In order to lower nitrogen output you have to time nitrogen applications,
match the soil nitrogen and account for crop needs, tighten manure
management rules, create sinks in the landscape such as wetlands, riparian
zones, grasslands.
Solutions will involve landscape scale changes; different cropping
patterns, a 10-20% decline in rowcrops. Universities should be working to
devise different cropping patters rather than on finding out how to grow
more of the same crops.
The third speaker was Donald Goolsby who is retired from USGS. . 80% of the
land in southern Minnesota, Iowa, Illinois, Indiana, and Ohio are devoted
to rowcrops. This land has high water tables and has to be lowered by
tile drainage which takes the poorest water and drains it off into streams
where it runs to the Mississippi River and the Gulf. Without tile drainage
it would take months and years for this water to drain into the Gulf.
Data collected in 1905-7 and 1980-96 studies show that nitrate levels have
increased in small rivers and more than doubled in the large rivers closer
to the Gulf. Before 1970 there was no variability linked to streamflow.
Where agriculture and drainage are most intensive the nitrate is highest.
Nitrate levels are directly related to the application of fertilizer.
Fertilizer and soil are responsible for 50% of the nitrate in our waters,
manure 15%, municipal discharges 11%, atmospheric deposition and
unmeasured inputs 24%. Legumes are not related to nitrate levels in
waters. . A 12% reduction in fertilizer would means a 33% reduction in
output. This is a fairly significant reduction and has little or minimal
effect on crop yields
The fourth speaker was Dr. William Mitsch. Ecosystem wetlands reduce the
load that is eventually passed into the rivers. Well developed forests are
also valuable for taking up nitrates.
There are three things to do: implement better fertilizer management,
develop 5 million acres of wetlands and 19 million acres of riparian
ecosystems. Doing this would result in a 20-40% reduction in the nitrate
going into the Gulf.
A minimum of 4%of the midwest should be soggy and wet. The value of this
to the midwest would be reduced nitrates in drinking water and reduction of
other pollutants, wetland habitat restoration, river restoration and flood
control.
A gain of 10million acres of wetlands should be achieved by the year 2010,
largely through reconverting crop and pastureland and modifying or removing
existing water control structures. 400,000 miles of rivers should be
restored. If three percent of the Mississippi River basin and 12 million
acres of the upper Mississippi were restored to wetlands and backwaters it
would provide flood control. There is already a dialog with the Army Crops
of Engineers about restoration.
His vision is for a restoration on the scale of the Everglades restoration
being done in Florida. This restoration would involve 40% of the lower 48
states. It would require restoration in 23 states at a cost of 27 million
dollars.
Peggy Murdock
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