Section 3
Ms. Musich
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Think of an area of land that has a wide are of
dirt like a construction site or a vacant lot…
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What do you think happens to an area like this
when it rains?
What is the water like that runs off the area?
Is there anything that could be done to prevent
this erosion of soil?
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You would have seen lots of prairies on your
settler’s journey. (Think Oregon Trail)
Prairie soil is very fertile
and is rich with humus.
Sod –the thick mass of
tough roots at the surface
of the soil keeps it in
place and holds onto
moisture.
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Soil is one of Earth’s most valuable resources
because everything that lives on land
depends directly or indirectly on soil.
Plants depend on soil to live and grow.
Animals depend on plants (or animals that eat
plants) for food.
Soil formation can take hundreds of years for
just a few centimeters of soil to form.
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Fertile soil is very valuable because less than
one-eighth of the land on Earth has soil that is
well suited for farming.
What does it mean for soil to be fertile?
 What substance must be in soil for it to be fertile?
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Soil is so important, but can be damaged or
lost.
Soil can lose its fertility.
This happened in the South in the late 1800s
when cotton was the only crop grown on
farms.
In the early 1900s, George Washington Carver
developed new crops and farming methods to
make the soil fertile again.
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As settlers began settling among the Great
Plains, they began plowing the earth.
Why do you think
these settlers
plowed the earth?
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Plowing removed the grass from the Great
Plains and exposed the soil. In times of
drought, the topsoil quickly dried out, turned
to dust, and blew away.
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After the Dust Bowl, people began to realize
how important soil is and developed new
farming techniques.
Soil conservation is the management of soil to
prevent its destruction.
Two ways that soil can be conserved include
contour plowing and conservation plowing.
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Contour plowing is the practice of plowing
fields along the curves of a slope.
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This helps slow the runoff of excess rainfall and
prevents it from washing the soil away.
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Conservation plowing disturbs the soil and its
plant cover as little as possible.
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Dead weeds and stalks of the previous year’s crop
are left in the ground to help return soil nutrients,
retain moisture, and hold soil in place.