Soil Horizons

Question 1

List the horizons from top to bottom

Answer 1

O
A
E
B
C
R

Question 2

O

Answer 2

Humus or organic topmost layer.

Question 3

A

Answer 3

TOPSOIL

Looks darker because of organic matter. Most fertile part of soil profile. “plow layer”

Question 4

Which layer is the most fertile?

Answer 4

A

Question 5

E

Answer 5

ELUVIATED horizon

only REALLY weather soils. Material starts moving out and leaching into bottom layer. Lighter color. Sandy texture.

Question 6

B

Answer 6

SUBSOIL
layer of accumulation (usually clay)
Different texture (sand, silt, clay)

Question 7

C

Answer 7

PARENT MATERIAL

rock actively weathering

Question 8

R

Answer 8

Bedrock bottom most layer.

Question 9

subordinate: t

Answer 9

TOUGH
zone of clay illuviation
used with B master horizon (Bt)

Question 10

subordinate: w

Answer 10

WEAK
Non-illuvial development
Color or structure change caused by weathering in place. Used with B master horizon (Bw)

Question 11

subordinate: g

Answer 11

GLAY OR GRAY
lack of oxygen has reduces iron from red to gray.
Often find (Btg)

Question 12

subordinate: h

Answer 12

HUMIC
illuvial organic matter, washed out by acidic condition
Usually below an E horizon
Used with B master horizon (Bh)