In article ,
Doug Freyburger wrote:

Billy wrote:

the soil of the prairies was probably produced over
the period of time after the last ice-age. it isn't that
thick. if it could accumulate at a rate of an inch a
year it would be much deeper...

Best guess is 500 years/inch to produce prairie topsoil which was
approximately 10" thick when Europeans showed up..

There are two separate time spans here. One is the 13,000 years of
prarie since the last ice age. One is 5000 years to build 10 inches of
top soil.
I fear that you are using a linear rate of growth instead of a geometric
rate of growth. My reading of the situation is that it maxed out at an
inch every 500 years, but started at a much slower pace.
Either the process eventually maxed out at 10 inches of top soil or
something very dramatic happened 5000 years ago to scour the top soil to
very thin. Let's check back in meteorology - Nope, nothing that
impressive that long ago. Conclusion, once the top soil reached 10
inches it maxed out and no longer grew.
Your inability to to find a causation doesn't exclude a causation.
So the article is about a guy who can grow an inch a year. Excellent.
Let's see how deep it is when it maxes out. Even better let's purchase
the stuff by the truckload and move it elsewhere so it never does max
out.
GUY!!? Google Polyface Farms and/or Joel Salatin.

You want topsoil? Say no more.

Topsoil depth varies from place to place. In the Nile River valley,
built by eons of flooding and deposits of sediment, it is tens of feet
thick.
http://www.kerrcenter.com/HTML/green_excerpt1.html
--
- Billy
"Fascism should more properly be called corporatism because it is the
merger of state and corporate power." - Benito Mussolini.
http://www.democracynow.org/2010/7/2/maude
http://english.aljazeera.net/video/m...515308172.html