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  • From: "Tradingpost" <tradingpost@gilanet.com>
  • To: livingontheland@lists.ibiblio.org
  • Subject: [Livingontheland] Worldwide Loss of Soil and a Possible Solution
  • Date: Wed, 08 Dec 2004 07:24:25 -0700


Worldwide Loss of Soil and a Possible Solution
http://www.growbiointensive.org/biointensive/soil.html

Reports during the 1970's indicated that large-scale agricultural techniques
in the United States were depleting the soil about 8 times faster than they
were being created naturally. Recently, in 1994, the United States Department
of Agriculture reported that approximately 12,000 pounds of soil were being
lost per acre per year from wind and water erosion of U.S. land farmed with
large-scale techniques.1 According to soil conservation specialists in Iowa,
approximately 16,000 pounds of soil per acre per year were being lost earlier
due to wind and water erosion at the time when soil conservation practices
were instituted in the 1970's. 2

Since the average person consumes approximately 2,000 pounds of food
annually, the above data can be developed to show that approximately 8 pounds
of soil were previously lost due to wind and water erosion for each pound of
food eaten. Currently, approximately 6 pounds of soil are being lost due to
wind and water erosion per pound of food eaten annually.

In addition, in the late 1970's, the California government issued statistics
indicating that in California it was taking as much as 2,000 years for nature
to build up 1 inch of soil, and that California large-scale agriculture was
depleting as much as 1 inch of topsoil every 25 years. As a result,
California agriculture was depleting the soil as much as 80 times faster than
it was being created in nature.3

Normally it takes an average of 500 years for nature to build up 1 inch of
topsoil. To grow good crops agriculturally, 6 inches of topsoil are required.
Therefore, approximately 3,000 years are needed to build up a reasonable
agricultural soil. In contrast, the 12,000 pounds per acre of soil being lost
in the U.S. on the average annually is 0.0356 inch (approximately 1/28th of
an inch) of soil over 1 acre. Since only 1/500th of an inch of topsoil is
being built up naturally on the average annually in the U.S., soil is being
depleted on the average each year approximately 18 times faster than it is
being built up in nature.

In contrast, a Master's thesis4 at the University of California, Berkeley in
1983 indicated that GROW BIOINTENSIVE practices, over an eight-year period,
(as performed by Ecology Action on Syntex Corporation land at the Stanford
University Industrial Park) built up the humified carbon level in the upper 1
to 1.5 inches of the soil, which began as only 'C'-horizon subsoil, to a
level that would have taken nature alone 500 years to accomplish. Therefore,
this thesis indicated that GROW BIOINTENSIVE techniques have the potential to
build soil up to 60 times faster than it can be developed by nature alone.

In addition, preliminary indications from research performed at the
Environmental Research Laboratory at the University of Arizona by Dr. Ed
Glenn are that high yields and reduced resource consumption may be possible
with GROW BIOINTENSIVE agriculture on a sustainable basis. Additional testing
will be needed for a final evaluation, but in comparison with other
agricultural practices generally being used, GROW BIOINTENSIVE techniques
offer hope for the depleted world soil situation.

1 Exact figure is 11,572 pounds per acre, from: Summary Report 1992 National
Resources Inventory (Soil Conservation Service, U.S. Department of
Agriculture, Washington, D.C., 1994).

2 Worldwide soil erosion rates are highest in Asia, Africa, and South
America, averaging approximately 13 metric tons (exact figure: 26,768 pounds)
to 17.5 metric tons (exact figure: 35,637 pounds) per acre per year. From:
C.J. Barrow, Land Degradation (Cambridge University Press, Cambridge, 1991).

3 Based on statistics given in Footnote 2, in developing nations, soil
appears to be being depleted up to approximately 36 times faster than it is
being built up in nature; and, in China, 54 times faster that it is being
built up in nature.

4 Douglas Edward Maher, Changes in Carbon Content in a Soil under Intense
Cultivation with Organic Amendments (University of California, Berkeley,
1983).





  • [Livingontheland] Worldwide Loss of Soil and a Possible Solution, Tradingpost, 12/08/2004

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