Dirt: The Erosion of Civilizations - Kootenay Local Agricultural Society

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Westward Hoe
Since the achievement of our independence, he is
the greatest Patriot, who stops the most gullies.
patrick henry
several years ago, on a breakneck research trip down rough dirt roads
through a recently deforested part of the lower Amazon, I saw how topsoil
loss could cripple a region’s economy and impoverish its people. I was there
to study caves created over a hundred million years as water slowly dissolved
iron-rich rocks that lay beneath soils resembling weathered frying pans.
Walking through an iron cave impressed upon my imagination how long it
must have taken for dripping water to carve them. Just as striking on this
trip were the signs of catastrophic soil loss after forest clearing. Yet what
really amazed me was how this human and ecological catastrophe-in-themaking
did not change people’s behavior, and how the modern story of the
lower Amazon paralleled the colonial history of the United States.
Standing on the edge of the Carajás Plateau, I straddled the skeletal
remains of an ancient landscape and another still being born. Beside me,
high above the surrounding lowlands, I could see landslides chewing away
at the scraps of the ancient plateau. On all sides of this jungle-covered
mesa, erosion was stripping off a hundred million years’ worth of rotted
rock along with the deepest soil I’d ever seen.
Since the time of the dinosaurs, water dripping through the equatorial
jungle and leaching into the ground has created a deep zone of weathered
rock extending hundreds of feet down to the base of the plateau. After
South America split off from Africa, the resulting escarpment swept inland
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