Dirt: The Erosion of Civilizations - Kootenay Local Agricultural Society

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replaced through weathering of fresh rock, the soil, the landscape, and
whole plant communities evolve together because of their mutual interdependence
on the balance between soil erosion and soil production.
Such interactions are apparent even in the form of the land itself. Bare
angular hillslopes characterize arid regions where the ability of summer
thunderstorms to remove soil chronically exceeds soil production. In wetter
regions where rates of soil production can keep up with soil erosion, the
form of rounded hills reflects soil properties instead of the character of
underlying rocks. So arid landscapes where soil forms slowly tend to have
angular hillslopes, whereas humid and tropical lands typically have gentle,
rolling hills.
skin of the earth
Erosion
Weathering
Figure 1. The thickness of hillslope soils represents the balance
between their erosion and the weathering of rocks that produces
soil.