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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