5.1 Intro to Soil

Soil system

a soil profile that has a layered structure (horizons).

Soil renewability

Soil is non-renewable

How is soil made

• Weathering of a rock (transformation)

• Erosion (transfer)

• Decomposition (transformation)

Layers of Soil:

O: Organic Matter

A: Topsoil

B: Subsoil

C: Parent rock

R: Bedrock

Organic Matter

Leaves, grass, organisms, etc

Topsoil

• Has humus (dark, organic material that forms in soil when plant and animal matter decays)

• Is fertile

Subsoil

This layer accumulates iron, clay, aluminum and organic compounds, a process referred to as illuviation.

Parent Rock

Layer of large unbroken rocks. This layer may accumulate the more soluble compounds

Bedrock

Hard, large pieces of rock

Leaching

Water disolves substances and carries them through soil.

Permiability

The amount of space soil has to let water through. Sand allows too much water through, clay allows little water go through since it holds too much water. For primary productivity, loam is the best as it holds water but also allows for some water to leak through. Clay is best for wetland areas since they hold a lot of water.