SOILS

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SOILS

• Most important result of weathering and Erosion
  is soil
• Soils - soil science PEDOLOGY
• Residual soil - soil made from local bedrock
  (weathered material)
• Transport soil - soil that was moved by wind,
  water, ice, or gravity (weathered and eroded
  material)

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SOIL

• Factors determining soil makeup
• 1. Climate - Rainfall amount and temperature
  (most important)
• 2. Parent Rock - Type and chemical composition
• 3. Vegetation - Roots and Leaves
• 4. Topography - hilliness, etc.
• 5. Time - how long to develop

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MATURE VS. IMMATURE SOIL
Mature soil is soil that is fully developed! Has
a distinguished A,B, and C horizon.Forest soil,
Grassland soil, and Tropical Soil Immature soil
is soil that is not fully developed! Does not
have a distinguished A,B and C horizon. Ex.
Desert soil, Arctic soil
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PEDALFERS VS. PEDOCALS

• Pedalfers - Found in eastern half of U.S. where
  rainfall exceeds 25 inches/year
• a. Ped - soil / Al - aluminum / Fe - ferrum -
  iron al from clay , fe from iron oxide
• 2. Pedocals -

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SOILS PROFILE

• Soil Profile - a cross reaction of soil down to
  the bedrock. Almost all soils show a profile of
  3 distinct layers or zones (A,B,C)
• A. A (horizon) topsoil, gray or black, has
  humus
• B. B (horizon) subsoil, more clay is washed
  down
• C. C (horizon) Rock fragments and slightly
  weathered bedrock
• Note More detailed description in your packet.

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SOIL TYPES AND CLIMATE

• Soil types and climate
• 1.Most important factor affecting soil is the
  climate
• A. Tropical soil - Warm and wet, speed up
  chemical weathering. Thus soil forms more
  quickly. Infertile due to leaching because of
  rain (high temp. and heavy rainfall). Note 3
  meters
• B. Grassland soil - enough rain for grass but
  not trees. Thick A horizon and very fertile.
  Note 1 meter
• C. Forest soil - Humid regions with cool
  season. Well developed horizons. Less than 1
  meter. Not very fertile.
• D. Arctic soils - High elevation and latitude.
  Very few layers, shallow. Permafrost.

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SOIL CONSERVATION
B. SOIL CONSERVATION 1. Soil Erosion - movement
of topsoil by water and wind 4
bill tons (water), 1 bill tons (wind) loss of
topsoil REDUCE IT!!!! 1. Windbreaks (level
plains) 2. Contour farming (plant parallel to
land contours 3. Terraces (flattened slopes) 4.
Strip cropping 5. No till
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RATES OF SOIL FORMATION

• Factors of Rates of Soil Formaiton
• 1. The rocks themselves - Igneous and
  metamorphic most resistant, sedimentary least
  resistant because of pores.
• 2. Surface Area
• 3. Climate - Warm and wet chemical weathering
• Cold and Dry mechanical weathering
• 4. Topography
• 5. Biological Factors