SOIL HORIZONS
Your
Objective:
Describe
a mature soil
profile.
© Copyright 2004 - 2005.! M. J. Krech. All rights reserved.
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SOIL HORIZONS
This is a typical
mature soil profile.
Notice the Horizons
that are present in
this profile: O, A, B, C!
What Horizons are
missing from this picture?
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O HORIZON
The O Horizon contains layers of Organic material, such as leaves, pine needles and twigs and decaying animal tissues.
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A HORIZON
The dark color of the A Horizon is from the mixing of Humus
(Organic Matter)
with weathered minerals.
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E Horizon
E Horizon: E stands for
“eluviation,” which is the movement of dissolved or suspended materials out of the A Horizon. It is lighter in color than the layers above or below it.
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B HORIZON
B Horizon: Commonly called
Subsoil. The
illuviated zone, where containing soil materials leached from above. Color: yellow or red.
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C HORIZON
C Horizon: Partially weathered parent material and mineral particles are in this horizon.
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R HORIZON
R Horizon: Unaltered bedrock within a few feet of the surface. Common in Missouri. (Dolomite, dolostone, or limestone.) Typically requires blasting to dig through.
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In the Real World:
Soil Profiles are as different as People are different! Every state has dozens of Soil Profiles. Cole County has seven main soil profiles alone! Everyone one of them is different.
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Can you identify the Horizons?
A.
B.
C.
D.
E.
F.
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Can you identify the Horizons?
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The End
What is a typical
mature soil profile?
Write your answer
on a scrap of paper
and turn into your
teacher.
© Copyright 2004 - 2005.! M. J. Krech. All rights reserved.
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