Lecture 8a Soil Survey: An Inventory of the Soil Resource 3 Main Elements

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Lecture 8aSoil Survey An Inventory of the
Soil Resource 3 Main Elements

• 1) a map showing the geographic relationships of
  each soil
• 2) a text describing the soils
• 3) tables giving physical and chemical data and
  interpretations for various uses.

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Soil Survey

• A soil survey
• describes the characteristics of the soils in a
  given area, usually a county is the unit of
  publication.
• The survey classifies the soils according to a
  standard system of classification,
• plots the boundaries of the soils on a map, the
  map uses an aerial photo as the base
• Makes predictions about the behavior of soils,

House
Tree
soil boundary
Trees
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Soil Survey

• The different uses of the soil and how management
  affects them are considered,
• The information collected in a soil survey helps
  in the development of land-use plans,
• The Survey evaluates and predicts the effects of
  land use on the environment.

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Map Scale
Topographic Map Scale 124,000

• Soil maps differ in their scale
• Map scale refers to how many inches on the map
  represents inches on the ground -
• Scale of 124,000 says 1 inch on map 24,000
  inches on the ground.
• Or 1 inch 2000 ft 0.38 miles.
• Note1 mile 63,360 inches
• 3 in x 24000 /12 6000ft

(----3IN--)
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Making a Soil Map

• 1. Soil maps are not road maps
• - soils boundaries are interpreted and the line
  is placed on the map by the soil scientist
• -the lines on the map represent their
  interpretations of where the soil boundary
  changes.
• - these lines are determined by investigating the
  soil with a hand auger or power auger
• - the use of remotely sensed data ( air photo)
  will also help in determining where these lines
  are placed.

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• 2. Thus the only accurate soil map has a scale of
  11 but that is not possible.
• 3. Soil maps are approximations of the soil
  boundary location - road maps have more precise
  accuracy.
• 4. Soil maps are checked for accuracy by running
  transects (red blue lines) across the mapping
  units.

Transects in red blue
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Soil Mapping Units 2 kinds-Consociation
Complexes

• PwA Port Byron soil on A slope (0-2)
• SdC2 Surrey Dim soils on C slope (6-12 )
• Consociation - 75 named soil 25 inclusions
• Complexes - 2 or 3 named soils 75 25
  inclusions of unnamed soils

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Rectangular Legal Land Description
US Meridans and Base Lines

• Metes and Bounds describe the property by
  noting the location of known objects Can be a
  problem when the object is no longer there. 13
  original states and Spanish land grants
• Rectangular describe the property from the
  intersection of a meridian and base line using
  Townships of 6 square miles. Each section in a
  township is one square mile or 36 sections in a
  township.

T1NR1E
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Legal Land Description

• Every property has a legal land description that
  give the location of the property from smallest
  to largest.
• Largest Town and Range location from
  principal base line and meridian T6NR4E.
• Section 1-36 each a square mile or 6x6
• Location in Section as NW1/4 of the SE1/4

LEGAL LAND DESCRIPTION NE¼, SEC 22, T2
North R3 East of 4th Meridian
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• Largest Town and Range location from
  principal base line and meridian by townships,
  T6NR4E.
• Section 1-36 each a square mile or 6x6
• Location in Section as NW1/4 of the SE1/4

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Orders of Soil Survey

• Order 1 soil survey - very detailed
• Order 2 regular soil survey
• Order 3 US forest survey
• Order 4 general soil map of county
• Order 5 soils of Minnesota Map

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DYAD

• Have you ever used Legal Land Description?
• If so where?
• What about metes and bounds?
• If answer is no to the above two, describe your
  seat in this classroom from the front door of
  Borlaug Hall using Mets and Bounds.

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NRCS Web Based Soil Survey Information System

• WEB SSIS provides the information in the soil
  survey via the internet.
• Thus it is easy to quickly check the capability
  of the soil for a specific use. /
• Counties on Web Soil Survey in Minnesota go to
  http//www.ncgc.nrcs.usda.gov/products/datasets/ss
  urgo/status-maps.html
• Web Soil Survey found at http//websoilsurvey.nrcs
  .usda.gov/app/

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The End