Dirt: The Erosion of Civilizations by David R. Montgomery

Author:David R. Montgomery
Language: eng
Format: mobi, epub, pdf
Tags: Technology & Engineering, Ecology, Geology, Science, Nature, General, Environmental Conservation & Protection, Civilization, Soil Science, World, Agronomy, Agriculture, Earth Sciences, History
ISBN: 9780520258068
Publisher: University of California Press
Published: 2008-10-02T06:40:40+00:00

Figure 15. Map of the Piedmont region of the southeastern United States showing the net depth of topsoil eroded from colonial times to i98o (modified from Meade i98z, 241, fig. 4).

Evidence for colonial-era soil erosion is apparent all along the eastern seaboard. Estimates of the average depth of soil erosion in the Piedmont range from three inches to more than a foot since colonial forest clearing. Truncated upland soils missing the top of their A horizon indicate four to eight inches of topsoil loss since colonial farmers began migrating inland. Soils of the southern Piedmont from Virginia to Alabama lost an average of seven inches. Upland soils across two-thirds of the Georgia Piedmont lost between three and eight inches. A century and a half of agriculture in the Carolina Piedmont stripped off six inches to a foot of topsoil. Accelerated erosion was particularly bad under colonial land use, and the problem remains significant today. Sediment yields from forested and agricultural lands in the eastern United States show that agricultural lands still lose soil four times faster than forested land.

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