supplemental PPT for educators

1. Chapter 2:
Physical Properties of Soil & Soil Formation

2. There are tens of thousands of soils in the world, and each is a bit
different. Soils have identities: the characteristics are used to
distinguish between different soils.
Soil characteristics are important because they influence:
• water movement into the soil (infiltration)
• water movement within the soil (percolation)
• water storage for plants
• soil erosion
• nutrient status & supply to plants
• heat transfer
• ease of tillage
• root growth
Why Soil Characteristics are Important
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3. Overview of Soil
Image Credit: David Lindbo and Wale Adewunmi, Know Soil Know Life contributors
Physical Properties of Soil
• Color
• Texture
• Structure
• Horizon/Profile
Soil Formation – CLORPT
Soil and Water
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4. Soil Color
• Like M&M’S … soils have color!
• Color is an indicator of certain chemical and physical characteristics.
Image Credit: Adobe Stock; www.lovethispic.com/image/45129/tubes-of-m-ms
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5. Image Credit: Soil! Get the Inside Scoop, 2008, Soil Science Society of America
Soil Color
SPODOSOLS
OXISOLS HISTOSOLS
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6. Since color perception is subjective, soil color
is determined using a standardized chart.
Soil Color
Image Credit: Wale Adewunmi, Know Soil Know Life contributor
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7. • Every soil can be separated into 3 physical sizes based on
the diameter of the particles.
• Sand + Silt + Clay = Soil Texture
Image Credit: SOIL! Get the Inside Scoop, D. Lindbo and others, ©2008 Soil Science Society of America; Adobe Stock
Soil Texture
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8. • Is there an ideal soil?
• Loam ≠ equal parts of sand, silt & clay
Image Credit: Getty images; Everything You Need to Know About Soil, blog.primrose.co.uk
Soil Texture
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9. Image Credit: SOIL! Get the Inside Scoop, D. Lindbo and others, ©2008 Soil Science Societies of America
Soil
Texture Triangle
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10. • Soil structure describes the arrangement of primary particles.
• They are a naturally occurring arrangement.
• A well-structured soil has an abundance of pores for water
and air to move readily into the soil and to root systems.
Soil Structure
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11. Granular
Blocky
Image Credit: Know Soil Know Life, D. Lindbo, D. Kozlowski, and C. Robinson - Editors, © 2012
Soil Structure
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12. Columnar or Prismatic
Platy
Image Credit: Know Soil Know Life, D. Lindbo, D. Kozlowski, and C. Robinson - Editors, © 2012
Soil Structure
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13. Single Grained
Massive
Image Credit: Know Soil Know Life, D. Lindbo, D. Kozlowski, and C. Robinson - Editors, © 2012
Soil Structure
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14. • Water flow through different soil structures
• Which of these soil structures will allow water to move
fastest through the soil?
Image Credit: USDA-NRCS
Effects of Soil Characteristics
Granular Prismatic Subangular
Blocky
Platy
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15. Soil Profile
Image Credit: SOIL! Get the Inside Scoop, D. Lindbo and others, ©2008 Soil Science Societies of America
UTISOLS
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16. • Climate
• Organisms
• Relief
• Parent Material
• Time
Soil Formation . . . or CLORPT!
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17. • Profile thickness
• Horizon development
• Organic Matter and thickness of A Horizon
• Wetness
• Color
• Chemistry (pH, base saturation, salts)
CLORPT Impacts
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18. Major Climatic Forces
• Temperature
• Precipitation
Climatic conditions directly influence
the weathering of materials in the soil.
CLimate
Image Credit: SOIL! Get the Inside Scoop, D. Lindbo and others, ©2008 Soil Science Societies of America
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19. Temperature
• Plant growth
• Biological activity
• Decomposition
• Mineralization
• Evapotranspiration
• Chemical reactions
• A 10oC rise = 2-3x
increase in reaction
• Physical reactions
• Freeze-thaw
Precipitation
• Plant growth
• Biological activity
• Decomposition
• Mineralization
• Dissolves materials
• Translocations (leaching)
• Transformation (chemical
reaction)
• Erosion
Impact of Temperature and Precipitation
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20. Warm - Humid Warm - Dry
Photo Credits: David Lindbo
Climatic Differences
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21. • Plants
• Grasses
• Coniferous
• Deciduous
• Animals
• Burrowing
• Grazing
• Micro- and Meso-organisms
• Bacteria
• Fungi
• Worms, Insects
Photos Credit: Adobe Stock
Organisms
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22. Photo Credit: David Lindbo
Examples of Biological Mixing or Bioturbation
Rabbit Warrens
Crayfish Burrows
Ant Hills
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23. Also known as topography
• Shape – hills/mountains vs
flat/low-lying areas
• Slope – steepness
• Elevation – height above sea level
• Aspect – direction a slope faces
Relief
Image Credit: SOIL! Get the Inside Scoop, D. Lindbo and others, ©2008 Soil Science Societies of America
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24. Slope
Position
Names
Image Credit: SOIL! Get the Inside Scoop, D. Lindbo and others, ©2008 Soil Science Societies of America
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25. • Organic materials
• Bedrock
• Transported materials
Parent Material
Image Credit: SOIL! Get the Inside Scoop, D. Lindbo and others, ©2008 Soil Science Societies of America
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26. Parent Material - Transported Materials
Image Credit: Know Soil Know Life, D. Lindbo, D. Kozlowski, and C. Robinson - Editors, © 2012
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27. How many years
does it take to
form an inch of
soil?
Time
Image Credit: SOIL! Get the Inside Scoop, D. Lindbo and others, ©2008 Soil Science Societies of America
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28. TIME IN SOIL FORMATION IS ALSO RELATIVE
Degree of Development
Hot - Dry Desert SLOW
Cold - Dry Antartica SLOW
Hot - Wet Tropics FAST
Cold - Wet Northern Canada SLOW
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29. YOUNG
few horizons
OLDER
more horizons
Photo Credit: David Lindbo
Time Differences
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30. General
Time
Sequence
Image Credit: Webinar, Soils: Fundamental to Life, ©2018 Soil Science Societies of America
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31. Image Credit: NRCS Kentucky
Soil & Water -
The Water Cycle
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