This is not a problem restricted to Africa or peasant agriculture. The
following is courtesy of Bill Totten on A-list.
It's Disappearing
by Tom Paulson
The Seattle Post-Intelligencer (January 22 2008)
The planet is getting skinned.
While many worry about the potential consequences of atmospheric
warming, a few experts are trying to call attention to another global
crisis quietly taking place under our feet.
Call it the thin brown line. Dirt. On average, the planet is covered
with little more than three feet of topsoil - the shallow skin of
nutrient-rich matter that sustains most of our food and appears to play
a critical role in supporting life on Earth.
"We're losing more and more of it every day", said David Montgomery, a
geologist at the University of Washington. "The estimate is that we are
now losing about one percent of our topsoil every year to erosion, most
of this caused by agriculture".
"It's just crazy", fumed John Aeschliman, a fifth-generation farmer who
grows wheat and other grains on the Palouse near the tiny town of
Almota, just west of Pullman.
"We're tearing up the soil and watching tons of it wash away every
year", Aeschliman said. He's one of a growing number of farmers trying
to persuade others to adopt "no-till" methods, which involve not tilling
the land between plantings, leaving crop stubble to reduce erosion and
planting new seeds between the stubble rows.
Montgomery has written a popular book, Dirt: The Erosion of
Civilizations (University of California Press, 2007), to call public
attention to what he believes is a neglected environmental catastrophe.
A geomorphologist who studies how landscapes form, Montgomery describes
modern agricultural practices as "soil mining" to emphasize that we are
rapidly outstripping the Earth's natural rate of restoring topsoil.
"Globally, it's clear we are eroding soils at a rate much faster than
they can form", said John Reganold, a soils scientist at Washington
State University. "It's hard to get people to pay much attention to this
because, frankly, most of us take soil for granted".
The National Academy of Sciences has determined that cropland in the US
is being eroded at least ten times faster than the time it takes for
lost soil to be replaced.
The United Nations has warned of worldwide soil degradation - especially
in sub-Saharan Africa, where soil loss has contributed to the rapidly
increasing number of malnourished people.
Healthy topsoil is a biological matrix, a housing complex for an
incredibly diverse community of organisms - billions of beneficial
microbes per handful, nitrogen-fixing fungi, nutrients and earthworms
whose digestive tracts transform the fine grains of sterile rock and
plant detritus into the fertile excrement that gave rise to the word
itself ("drit", in Old Norse).
As such, true living topsoil cannot be made overnight, Montgomery
emphasized. Topsoil grows back at a rate of an inch or two over hundreds
of years. Very slowly.
"Globally, it's pretty clear we're running out of dirt", Montgomery said.
<snip>
Perelman, Michael wrote:
Not really. The peasants like the barren hillsides, which are much more
interesting than the fertile plains.
Jim wrote:
I agree, but even fragile soils can be helped with old-fashioned
techniques (though perhaps not healed). Part of the problem, of
course, is that in many places the best lands were grabbed by the
Europeans during colonization.
