Case Study: Audrain County ELT 1: Loess Summits and Flats

1
Case Study Audrain County ELT 1 Loess Summits
and Flats

• Geo-landform
• broad flat interfluves
• Target soils
• Putnam, Mexico
• Potential Natural Communities
• Hardpan prairie
• Dry-mesic glacial prairie
• Post/Burr oak glacial savannah

2
Comparison ResultsSoils in ELT 1

• 41 Mexico sil, 1-3
• 25 Mexico sicl, 1-3 eroded
• 14 Leonard sicl, 2-4 eroded
• 9 Putnam sil
• 9 Armstrong l, 4-9, eroded
• Green target soil
• Blue adjacent soil
• Red off-target (error)

3
Comparison ResultsELTs in target soils for ELT 1

• Putnam
• 94 ELT1
• 5 ELT 4 (Gentle loess backslopes)
• Mexico (uneroded)
• 88 ELT1
• 6 ELT4
• 5 ELT2 (Loess ridges)
• Mexico (eroded)
• 67 ELT1
• 15 ELT2
• 14 ELT4

4
Putnam soils and ELT 1
ELT 1
ELT Error
34 Putnam
Soil Error
5
Mexico (uneroded) and ELT 1
Minor discrepancies not worth worrying about
Mexico
ELT 1
6
Mexico (eroded) and ELT 1
ELT 1
Leonard-like inclusions?
Mex. eroded
ELT 4
Gorin-like inclusions?
7
Conclusions ELT 1

• A few delineations of Putnam can be trimmed back,
  via ELT 1.
• ELT 1 model can be improved by including all
  areas of (revised) Putnam.
• The Leonard / Mexico Eroded interface can be
  reviewed via the ELT 1 model.
• Most discrepancies are minor fuzzy edges, and
  not worth worrying about.

8
ELT 7 Gentle Till Backslopes

• Target soils Armstrong, Keswick, 5-9
• Soils in ELT 7
• 59 Armstrong 4-9
• 25 Keswick 5-9
• ELTs in Armstrong 4-9
• 53 ELT 7
• 17 ELT1 (summits)
• 10 ELT2 (ridges)
• 7 footslopes/terraces
• 6 floodplains
• 5 upland waterways

9
Armstrong 4-9 and ELT 7
Generally good agreement Minor boundary
discrepancies
10
Conclusions ELT 7 and Armstrong

• Most discrepancies are due to fuzzy boundaries.
• Narrow upland drains are inclusions in Armstrong.
• Small Gorin-like ridges are included in
  Armstrong.
• Minor line adjustments are possible in some areas.

11
ELT 4 Gentle Loess Backslopes

• Target soil Leonard, 2-4
• Head slopes below Mexico interfluves
• Soils in ELT 4
• 60 Leonard 2-4
• 23 Mexico eroded, 1-3
• 13 Mexico 1-3
• ELTs in Leonard, 2-4
• 43 ELT 4
• 43 ELT 1 (summits)

12
Leonard 2-4 and ELT 4
Leonard
Leonard here?
ELT 4
ELT error (seen previously)
13
Callaway CountyWheres the Leonard?

• Leonard soils not mapped in Callaway county.
• Mexico extends down into head slope positions
  where Leonard is usually mapped.
• Can ELT4 be used to estimate Leonard map unit
  locations?

14
ELT4 N. Callaway co.
ELT4 Leonard soil? Mapped Mexico eroded
15
Callaway 18FGoss-Gasconade-RO, 5-35

• ELTs
• 10 Protected Limestone Backslopes
• 11 Exposed Limestone Backslopes
• 12 Protected Shallow to Limestone
• 13 Exposed Shallow to Limestone

16
18F preliminary results of field investigations

• ELTs 12 13 (glades)
• Photointerpret and map at 112,000
• Mostly Gasconade-like, with mod. deep components
  (Bardley, Clinkenbeard)
• Concentrated on exposed aspects
• ELTs 9 10 (forests)
• Different map units, based on soil properties, on
  exposed vs protected
• Exposed less loess, more surface frags,
  shallower
• Possible geologic differences
• Upper watershed positions Mississippian (?)
  cherty surfaces Bardley-like soils
• Lower watershed positions Ordovician (?) less
  chert Gatewood-like or Caneyville-like soils
• Analysis of soil and vegetation data will
  probably result in (potential) new soil map units
  and ELTs.

17
Conclusions to date

• ELTs and soil map units are not exactly
  coincident
• Soil map units may be nested within an ELT
• Putnam, Mexico (uneroded) nest within ELT 1
  (Loess Summits and Flats)
• Gorin, Hatton nest within ELT 2 (Loess/Till
  Ridges)
• Some of these may be used to define ELT phases
• ELTs may nest within soil map units
• Exposed and Protected aspect ELTs within soil
  survey steep backslope units.
• Consider different soil survey map units.
• Fuzzy Boundaries account for much of the
  difference between soil units and ELT units.

18
Conclusions, cont.

• Both soils and ELT model have errors.
• ELT errors due to inconsistency among landforms
  within modeling area, problems with DEM (contour
  line bias), etc.
• Soils inconsistencies for all the reasons that
  we already know about.
• Developing ELTs and evaluating soil surveys
  together can greatly improve both products.
• The use of Fuzzy Logic can create a more
  realistic model for both soils and ELTs.
• We will still need hard lines.
• Soil ELT correlation provides an excellent
  template for future project work.
• More on this tomorrow!