ROCKS FOR JOCKS AND SOIL FOR GUYRLS

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ROCKS FOR JOCKS AND SOIL FOR GUYRLS
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ROCK CYCLE
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IGNEOUS ROCK

• Formed when
• magma cools underground
• EX granite
• Or above ground
• EX lava rock/pumice

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SEDIMENTARY ROCK

• Repeated settling of eroded soil.
• Compressed layer by layer until it turns into
  rock.
• Ex shale, limestone

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METAMORPHIC ROCK

• Sedimentary or igneous rock that has morphed into
  another type of rock
• Due to intense pressure or heat
• EX schist, gneiss

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SOIL
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What is soil?

• The loose covering of broken rock particles and
  decaying organic matter (humus) covering bedrock.

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Why is soil important?

• Grow food
• Wood for building
• Plants provide oxygen
• Filter pollutants

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How is soil created?

• Rock is chemically and physically weathered.
• Bacteria, fungi, lichens, insects live in
  weathered rock.
• These organisms die and add nutrients to
  weathered rock.
• As soil builds, larger organisms can move in and
  colonize.
• Takes 100s of years to create a few cm of soil.

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What is a soil profile?

• Vertical sequence of soil layers (horizons).
• O Horizon- vegetation/ leaf litter on top of soil
• A Horizon- dark-colored thin layer rich in
  organic matter humus
• B Horizon- thick layer of subsoil may be red or
  brown clay based soil
• C Horizon- contains weathered parent rock larger
  particles of rock no organic matter
• R Horizon- unaltered parent bedrock

O horizon
R horizon
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TYPES OF SOIL

• Polar soil
• Form at high elevations high altitudes
• No distinct horizons- soil too thin
• Under top few inches of soil, ground is
  permanently frozen- PERMAFROST.

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• Temperate soils
• Vary depending on rainfall type of vegetation
• Tropical Grasslands- very thick, rich, humus
• Forests- thinner, less fertile clay soil
• Prairies- less rain, so soil not as thick, but
  still fertile.

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• Desert soils
• Very thin A horizon
• Very little organic matter
• High in minerals
• Soil is usually light colored and coarse
  textured.

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• Tropical soils
• Intensely weathered due to high precipitation and
  temp.
• Very little humus very few nutrients
• High concentrations of iron- when oxidizes causes
  characteristic red color.

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SOIL TEXTURES

• Size of particles determines
• Water holding capacity
• How compacted soil is
• Ability to support plant
• Sand- larger particles
• Silt- smaller particles
• Clay- smallest particles
• Loam- equal mix of sand, silt, and clay

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SOIL FERTILITY

• Measure of how well soil can support plant life.
• Factors that affect fertility of soil
• Level of minerals nutrients
• Level of bacteria
• Amount of precipitation
• Topography
• Acidity of soil

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• Farmers may adjust level of fertility by
• Adding commercial fertilizers

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• Crop rotation- alternating corn crop with legume
  (peas, beans, clover) to add nutrients back to
  soil

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• Limestone- reduces acidity of soil

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• Organic fertilizers- compost, mulch, peat moss

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SOIL CONSERVATION

• Soil is easily eroded.
• Methods to prevent erosion include

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Contour Farming- plowing along slope instead of
up and down it. Furrows btwn rows of crops
collect water.
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• Terracing- series of platforms are built into
  slopes. Effective with steep slopes, slows water
  flow.

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• Shelter Belts- rows of trees planted along outer
  edges of s creating a windbreak to prevent wind
  erosion.

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• Strip-Cropping- Farmers plow so that plowed
  strips are separated by planted strips. Roots of
  planted strips hold soil in place.

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• Reduce Grazing Permits
• Put up fencing
• Animals cannot compact and destroy plants