Dirt: The Erosion of Civilizations - Kootenay Local Agricultural Society

more than three thousand years and then increased four- to fivefold when
land clearance reached the crest of the range around 1880.
Slavery wasn’t the only reason that erosion was a bigger problem in the
South than in the North. Bare fields were particularly vulnerable to erosion
in the South because rainfall intensities could reach up to one and a half
inches per hour and the frozen ground and snow cover in the North
allowed for little erosion during winter storms. In addition, the South’s
topography is carved into rougher slopes than the gentle contours of
glacier-sculpted New England.
Erosion continued to degrade the South after the Civil War. After surveying
regional erosion problems in the southern Appalachians from 1904
to 1907 for the U.S. Geological Survey, Leonidas Chalmers Glenn described
farming practices little changed from colonial days.
When first cleared, the land is usually planted in corn for about two
or three years, is then for two or three years put in small grain ...and
then back into corn for several years. Unless it is well cared for the land
has by this time become poor, for it has lost its original humus. The
soil has become less porous and less able to absorb the rainfall and erosion
begins. Means are rarely taken to prevent or check this erosion,
so it increases rapidly and the field is soon abandoned and a new one
cleared. ...Many fields are worn out and abandoned before the trees
girdled in its clearing have all fallen. Then new grounds are usually
cleared beside the abandoned field and the same destructive process
is repeated.
It took a few hundred years, but agricultural clearing was finally reaching
into the remotest uplands of the region in a process much like what happened
in Greece, Italy, and France. “In some places it was found that the
entire surface wore away slowly, each heavy rain removing a thin layer or
sheet of material, so that the fertile soil layer gradually wore thin and poor
and the field was at last abandoned as worn out. ...Sheet-wash erosion is
so slow and gradual that some farmers fail to recognize it and believe that
their soils have deteriorated through exhaustion of the fertility, whereas
they have slowly and almost imperceptibly worn away to the subsoil.” 29
By the early 1900s more than five million acres of formerly cultivated
land in the South lay idle because of the detrimental effects of soil erosion.
When the government began to support aggressive soil conservation
efforts in the 1930s, the new U.S. Soil Conservation Service did not offer
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