Chapter 7 NotesSection 3

Soil Erosion

1 - Soil erosion is important because losing topsoil affects the way _plants_ grow.

2 – Many human activities disturb the natural _balance_ between soil production and soil erosion.

3 - Agricultural Cultivation: increased farming removes plant cover, leaving soils open to wind & water erosion.

Use pages to fill in these notes.

4 – Forest harvesting: removes forest which increases erosion & particularly damages tropical rain forest soil.

5 - Overgrazing results when animals graze until almost all ground cover disappears.

6 - Excess sediment can damage the environment when soil erosion is severe.

We can:(1) manage crops(2) reduce erosion on slopes(3) reduce erosion of exposed soil

How can we prevent soil loss?

What prevention methods are shown in these pictures?

Sand TufaPhotograph by Larry Fellows, Arizona Geological SurveyWith the snow-draped Sierra Nevada as a backdrop, unique erosion formations called sand tufa stand like giant cauliflower stalks in a dry Arizona lake bed. Before this alkaline lake went dry, tufa formed when a freshwater spring percolated from below and formed calcium carbonate deposits. When the lake's level dropped, these fragile formations surfaced, and wind went to work removing the sand beneath the deposits.

FOR MORE INFO, SEE http://www.nationalgeographic.com/topics/erosion/