Soil%20Horizons

1
Soil Horizons
2
(No Transcript)
3
(No Transcript)
4
Soil Profile

• sequence of horizons from the surface down
  through the horizons to the parent material

5
Soil Horizon

• layer approximately parallel to the soil surface,
  with characteristics produced by soil forming
  processes. If you dig very deeply into the soil,
  you will see that soil lies in distinct layers.
  These layers are called soil horizons.

6
3 Major Horizons

• A dark colored zone of organic matter
  accumulation lying on the surface of the soil
  profile. It is generally darker than the lower
  layers. The A horizon is where life in the form
  of plant roots, bacteria, fungi and insects are
  most abundant. It is often called top soil.
• B This horizon lies just below the A horizon
  and is often called the sub-soil. It is often
  finer in texture than the A horizon. It is
  usually higher in clay and has more pronounced
  structure than the A horizon.
• C This horizon is located below the true
  soil. This horizon is often called parent
  material. It has not been weathered enough to be
  called soil. This zone may show an accumulation
  of calcium and magnesium salts causing it to be
  light in color.

7
AC Horizon designation means What??

• ??

8
O Horizon

• Organic horizon of decomposed and undecomposed
  organic matter. Present in forested soils.
  Absent in grassland, cultivated and many other
  soils.

9
E Horizon

• Mineral horizon that is usually light in color
  due to the leaching out of iron, aluminum, clay
  and organic matter. Typically present in
  forested soils.

10
R Horizon

• Underlying consolidated bedrock such as granite
  or shale. Absent under many soils

11
Ap What??

• ??

12
Lets Put it all in order
O
A
E
B
C
R
13
Soil Profile Changes

• Additions Materials such a fallen leaves,
  wind-blown dust, or chemicals from air pollution
  that may be added to the soil.
• Losses Materials may be lost from the oil as a
  result of deep leaching or erosion from the
  surface.

14
Soil Profile Changes cont.

• Translocations Materials may be moved within the
  soil. This can occur with deeper leaching into
  the soil or upward movement caused by evaporating
  water.
• Transformations Materials may be altered in the
  soil. Examples include organic matter decay,
  weathering of minerals to smaller particles or
  chemical reactions.