Soil

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Soil

• An important product of
• Weathering.

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Soils

• Weathering produces a layer of rock and mineral
  fragments called Regolith
• Soil The part of regolith that supports plant
  growth.

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Soils

• Soil Composition Soil has 4 major components.
• 1. Mineral Matter - broken rocks
• 2. Organic Matter - Humus
• 3. Water
• 4. Air
• Fill in the percentages using your book on page
  133.

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Soils

• Soil Texture - Refers to the proportions of
  different particle sizes.
• US Department of Agriculture has established
  categories base on the percentages of these in
  Soil
• Clay
• Silt
• Sand

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Texture

• Texture STRONGLY influences soils ability to
  support plants.
• Sandy soils ? dry out to quick
• Clay rich soils ? drain slowly
• Loam soils ? Best for plant growth

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Soils

• Soil Formation The most important factors in
  soil formation are
• parent material,
• time,
• climate,
• organisms and
• slope

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Soils - Soil Formation

• 1. Parent Material The source of the mineral
  matter in soil. (pg. 135)
• 2 Types
• a. Transported gt What is the
• b. Residual gt Difference
• 2. Time The longer a soil has been forming
  Thicker it becomes.
• 3. Climate Climate has the greatest effect on
  soil formation.
• Variation in temperature and precipitation
  influence the rate, depth, and type of weathering.

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• Residual - If soil stays on top of the parent
  rock that it formed from it is called residual
  soil.  Residual soil will be made of the same
  materials as the original rock. 

Residual
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• Transported soil has been moved from another
  location. Most soil on the Earth's surface is
  transported.

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Soil Names? Page 136

• Sometimes soils are named based on the soils
  natural vegetation. What are some of those names?
• What is the main source of organic matter?
• What increases soils fertility?

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Soils - Soil Formation

• 4. Organisms The types of organisms and how
  many there are in a soil have a major impact on
  its physical and chemical properties.

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Soils Soil Formation

• 5. Slope Variations in slope can result in very
  different soil types. Many of the differences are
  related to the amount of erosion and the water
  content of the soil
• What type of slope accelerates erosion? (Pg137)

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Soil Profiles

• Soil varies in composition, texture, structure
  and color at different depths.
• A vertical section through all of the soil
  horizons is called a Soil Profiles.

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Soil Profiles Page 138

• A Horizon - is commonly known as Topsoil. Its
  upper part consists mostly of organic matter?
  HUMUS.
• B Horizon Subsoil Contains fine clay
  particles washed out of the A horizon by water.
• C Horizon Contains partially weathered parent
  material.

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• A Horizon

• B Horizon

• C Horizon

• D Horizon
• (Bedrock)

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Soil Types Page 139

• Three common types of soil are pedalfer, pedocal,
  and laterite.
• Honors ? look up these 3 and put them into a
  graphic organizer NOW!
• Include several places or states where these
  types of soil can be found.

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SoilTypes

• Pedalfer Forms in temperate areas that receive
  more than 30 or 63 cm of rain each year. The
  eastern US falls within this type.
• Acidic in Composition
• Us

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Soil Types

• Pedocal are found in the drier western US in
  areas that have grasses and brush vegetation.
• They also contain abundance of limestone (Calcium
  Carbonate).
• Alkaline in Composition

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Soil Types

• Laterite Laterites form in hot, wet tropical
  areas.
• Chemical weather is intense within these
  regions.
• Usually DEEEEEEP soils.
• Calcite Silica are removed by lots of H2O and
  Iron Oxide and Aluminum are left giving the soil
  a RED Color

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Were any of your soil samples acidic? Some
plants require acid soils to grow and thrive. For
example, pine trees, azaleas, rhododendrons,
cranberries, blueberries, potatoes, and tomatoes
prefer acid soils. However, most plants thrive
only in soils of pH 6 to 7. Were any of your
soil samples basic? Some soils, such as in many
midwestern United States, contain a lot of
limestone and are alkaline. In those locations,
people often add sulfate, such as ammonium
bisulfate to soil to make it less basic.
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Were there any big differences between the plant
and animal life at each location? Some types of
plants and animals are able to live in acid
soils, while others are not. Be aware, however,
that many factors, not just the soil acidity,
determine the types of plants and animals that
occur at a particular site
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Soil Erosion

• Soil Erosion is a natural part of the constant
  recycling of earth materials known as the rock
  Cycle.
• Rates of Erosion In the past, soil eroded more
  slowly than it does today because more land was
  covered by trees, grasses, and other plants.
• Human activity has accelerated this process.
• Farming Logging Construction -- Deforestation

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Soil Erosion

• Sediment Deposition Another problem caused by
  excessive soil erosion is the deposition of
  sediment.
• Rivers that collect sediment, need to be dredged
  to remain open for shipping.

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Soil Erosion

• Controlling erosion Although we cannot
  completely eliminate soil erosion, we can
  significantly slow it by using soil conservation
  measures.
• List some of these METHODS!

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Soil Erosion
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