Soils

1
Soils
2
Importance of Soils

• Plants grow in soils
• Plants convert solar energy into chemical energy
  and produce oxygen.
• Soil provides nutrition to plants.
• Soils serve as a water filter

3
What is soil?

• Soil is a mixture of
• Mineral Matter
• Organic Matter
• Pore Space

4
Can we make more soil?

• Nature is capable of making new soil
• 500-1,000 years to make 1 new inch of topsoil in
  optimal conditions.
• Rate of soil formation is determined by 5 factors.

5
Parent Material

• The mineral matter content of soil originates as
  some form of stone that is eventually broken
  down.
• The original parent material impacts the
  characteristics of the soil.

6
Climate

• Temperature
• Cold
• Hot
• Precipitation

7
Life

• Life forms that exist under the surface of the
  soil help begin the process of soil formation
• Lichens (fungus/algae)
• Mosses
• Eventually conditions become favorable for seeds
  to germinate.
• Eventually animals become a factor as well

8
Topography

• Lay of the land
• Changes in slope and elevation.
• Impacts availability of moisture.
• Presence of moisture increases rate of soil
  formation.

9
Time

• Absolute Age
• Actual years the soils has been developing
• Relative Age
• Stage of maturity of soil

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Parent Material

• Rock that has decomposed in place
• Material that has been deposited
• Glacial Till (glaciers)
• Aeolian (wind)
• Alluvium (streams)
• Colluvium (gravity)
• Lacustrine (lakes)

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Physical Characteristics of Soil

• Particle Size Analysis
• Soil Particles
• Sand
• Silt
• Clay

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Soil Textural Classes

• Based on percentages of Sand, Silt, Clay

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Textural Triangle
Clay
Silt
Sand
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Soil Texture by Particle Analysis

1. 25 sand, 25 silt, 50 clay
2. 75 sand, 15 silt, 10 clay
3. 30 sand, 40 silt, 30 clay
4. 15 sand, 15 silt, 70 clay
5. 40 sand, 40 silt, 20 clay

1. 50 sand, 20 silt, 30 clay
2. 2 sand, 81 silt, 17 clay
3. 47 sand, 47 silt, 6 clay
4. 60 sand, 25 silt, 15 clay
5. 10 sand, 60 silt, 30 clay