Virginia Tech Soil Judging Team

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Virginia TechSoil Judging Team

• Describing the Properties and Behavior of
  Different Soils

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What is Soil Judging?

• Soil Judging is the act of
• describing soil and site features and comparing
  answers
• with local expert soil scientists.
• identifying geology, hydrology, and the
  potential use
• of the site for agriculture and development.
• classifying the soil so that we can relate it
  to other
• soils that we see in other places.

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Why is Soil Judging Important?

• Soil Judging teaches students to go to unfamiliar
  places, study the resources, investigate the
  soil, hydrology, and land use, and then describe
  the soil resources. This information is vital to
  provide useful information to land users and
  planners so they may enact proper stewardship of
  the land, water, and environmental resources. The
  ability to assess the properties and behavior of
  the soils enables our students to properly advise
  decision makers to allow them to protect the
  nations resources for future generations.
  Students must perform as individuals but must
  communicate and compete as a team as well,
  fostering their ability to work together and
  cooperate under stressful and time-constrained
  conditions.

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What is a Soil Profile?
A set of different horizons in a vertical sequence
C
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Why are Soils Different?

• Whenever there is a change in
• the geologic material that a soil forms in, or
• the topography of the site, or
• the regional or soil climate, or
• the organisms that live in or on the soil, or
• the amount of time that a soil has been in
  place
• a different kind of soil will form as a
  result.

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Horizon Boundaries and Names and Depths
Depths
Names
Boundaries
0 inches
A
2
E
Bh
15
18
34
BC
44
C1
C2
50
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Mineral Soil Classes
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Texture Triangle
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Texturing
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Colors
What do we Describe?
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Matching Colors
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Structure Amount and Shape
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Consistence
How difficult is it to break the soil structure
apart? What does that tell us? If the soil is
dense and root-limiting
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Water Table Indicators
Gray or light gray with and red/orange/yellow
color spots
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What Do Those Properties Tell Us?
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Infiltration and Percolation
High sands and high organic matter Medium all
others Low - clays
Rapid sands Moderate all others Slow dense
layers, clays with no structure, some bedrock
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Depth of Soil and Water Table
Shallowest depth of gray color spots or dark
topsoil with red rusty spots tells us an average
depth of where the water table comes each year.
Depth to bedrock or to a dense soil layer limits
air and water movement and growth of fine roots.
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Water-Holding Capacity
Texture tells us how much it can potentially
hold, but we reduce that amount if there are
rocks or there is a root-limiting layer.
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How Limited is the Soil for Certain Purposes?

• We use
• flooding
• slope
• percolation
• depth to water table
• depth to rock
• to tell us how suitable a soil and site are
  for specific uses
• Septic Tank Absorption Fields
• Buildings With Basements
• Roads and Streets

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What is the Landform Position and Slope?
Floodplain, terrace, upland, summit, shoulder,
sideslope, footslope, closed depression,
drainageway
Slope A 0 2 B 2 6 C 6 12
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Example Interpretation Table
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What is the Runoff Potential?
Based on slope and infiltration rate. Actual
runoff is also dependent on vegetation cover
present
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What is the Erosion Potential?
Based on runoff potential and surface texture.
Actual erosion is also dependent on the
vegetation cover present and current landuse
Guide to Evaluating Erosion Potential
Surface Horizon Texture Surface Horizon Texture Surface Horizon Texture Surface Horizon Texture
Surface runoff s, ls scl, sc sl, cl, c, sic l, si, sil, sicl
Ponded Very low Very low Very low Very low
Very slow Very low Very low Low Medium
Slow Very low Low Medium Medium
Medium Very low Low Medium High
Rapid Low Medium High Very high
Very rapid Medium High Very high Very high
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What is the Classification?
Classification is an international system that
allows us to identify the class of soil so that
when we learn something about that soil, we can
give it a name and share that information through
research and soil maps.
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The Contest
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The Students
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The Experience
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Learning
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Winning
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Gotta Love Those Hokies