BIG IDEA: Abiotic

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SOIL

• BIG IDEA Abiotic biotic factors influence the
  environment

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• SOIL
• organic and inorganic
• formed by weathering, breakdown as a result of
  the physical actions

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• WEATHERING
• freezing and thawing
• dissolving
• attached organisms (lichens)

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• MINERAL CONTENT
• dependent on
• type of rock forming soil
• type of organisms in soil
• amount of precipitation

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• 4 LAYERS OF SOIL
• topsoilorganic and organisms contains humus
• subsoilrock particles and organics
• rock parts weathered
• rock parts
• unweathered

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Soil Horizons

• O horizons or layers Layers dominated by organic
  material consist of undecomposed or partially
  decomposed litter (such as leaves, needles,twigs,
  moss, and lichens)

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• A horizons(topsoil) Mineral horizons which have
  formed at the surface or below an O horizon
  mixture of partially decomposed organic matter
  called humus and some inorganic mineral particles

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• B horizons (subsoil) zone of accumulation
  mineral-rich contain more inorganic than organic
  material mostly broken down rock consisting of
  sand, silt, gravel, clay

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• C horizons (parent material) transition to rock
• R horizons hard bedrock

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As the roots of the grasses die they form a layer
of organic matter called The humus helps hold
water and provides nutrients and food for the
grasses and other organisms to grow.
HUMUS
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• SOIL CLASSIFICATION
• organics
• minerals
• pH
• size of particles

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is the symbol for the degree of acidity or
alkalinity (base) of a substance
pH

• plants require a certain pH to grow properly
• acid rain can burn plants and the animals drink
  it

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1908
1969
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• SOIL CONSERVATION
• strip cropping
• terracing
• contour farming
• windbreaks
• dams
• crop rotation
• fertilizers

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• SOIL CONSERVATION
• strip cropping cover crops are planted between
  strip crops so no exposed soil is left open to
  erosion

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• SOIL CONSERVATION
• terracing flat areas dug in hillside to prevent
  surface water (carrying soils) from running down
  hill

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• SOIL CONSERVATION
• contour farming rows across slopes on uneven
  landscapes mounds formed by plow prevent runoff

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• SOIL CONSERVATION
• windbreaks used to prevent wind erosion, usually
  made of trees

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• SOIL CONSERVATION
• crop rotation growing different crops in
  succeeding years prevents soil depletion
  (reduction of nutrients)

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• SOIL CONSERVATION
• fertilizers replace essential nutrients removed
  by crops include natural (e.g. manure) and
  chemical