Dirt: The Erosion of Civilizations - Kootenay Local Agricultural Society

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Figure 17. Eroded land on tenant farm, Walker County, Alabama, February 1937
(Library of Congress, LC-USF346–025121-D).
up radical new ideas. “Most of the erosion-control practices in use at the
present time, such as the use of legumes and grasses, deep plowing, contour
plowing and hillside ditching, the prototype of modern terracing,
were either developed by the Virginia farmers or became known to them
during the first half of the nineteenth century.” 30 Actually, most of these
techniques, or similar practices, had been used in Europe for centuries and
were known in Roman times. If these ideas were so good and had been
around for so long why did they take so long to become widely adopted?
While Thomas Jefferson and George Washington might disagree on both
the reason and the cure, the lessons of the Old World and colonial America
remain on the sidelines as a similar story unfolds in the Amazon basin,
where the Brazilian government has a long history of encouraging peasants
to clear rainforest in order to pacify demands for land reform.
Ironically, the Amazon itself holds clues to a solution. Archaeologists
recently discovered areas with incredibly fertile black soil not far from the
Carajás Plateau. This rich dirt, called terra preta, may cover as much as a
tenth of Amazonia. Not only did this distinctly untropical soil sustain large
w estward hoe