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> For example, Iowa has lost an estimated 10 inches of topsoil in the last 150 years. Interesting. Reference? When I was in the Midwest farming communities
in Indiana and Ohio, the row crops were
heavily corn, wheat, and soy beans. Then
after harvest, there were
lots of dead corn stalks,
wheat stalks, and soy bean plants on the
ground, and those plants got plowed under. Heavily those plants were carbon, and the
first cut guess where the carbon came from
was CO2 in the atmosphere and not from the
existing soil. So, net, all the plant matter
was heavily from the atmosphere and adding
to the soil. So, typically annual plants,
year by year, add to top soil. Indeed, it
is fair to say that that was mostly the
origin of the top soil. For another example, as a child, we lived
in one house for about 16 years, and I
got to mow the grass twice a month or
so for much of that time. Well, over the
16 years, the top soil rose with respect
to the concrete driveway and walkways,
rose 1-2 inches. So, we added to the
top soil. So, if we are losing a lot of top
soil from, say, Iowa, then where it
is going? Well, it could blow, but
then it stands just to add to
top soil in Illinois, Indiana, and
Ohio, not a net loss. Or, we're carrying the top soil away
via the corn kernels, wheat seeds,
and soy beans themselves? Tough
to believe that the seeds take more
soil than the rest of the plant
adds. Or the top soil could get
washed into rivers which about has to be
the Mississippi River. So, should be
able to see
all that Iowa top soil along the
Mississippi River and, then,
into the Gulf of Mexico. Can the
USGS and Corps of Engineers find
that top soil for us? I can believe that the tree cutting
of the mountains in the East US
by 1930 or so resulted in a lot of
top soil from the mountains
washing into the local
valleys, but Iowa, Illinois, Indiana,
Ohio, etc. are nearly flat as a table,
in part because at one time they
were lake bottoms. I'd want to see a good and careful
argument about loss of top soil
in Iowa. |