MAPPING AND
REPRESENTING SOIL
INFORMATION AND DATA
SOIL AND SCALE
 Scales and complexities range
 Use/application determines appropriate scale
COUNT Y SOIL SURVEYS
 Inventories, descriptions, evaluations, maps of soils in a county
 Program established 1899 in USDA
 Farmers suitable crops and management practices
 Now includes evaluation for other uses: construction, septic,
farm planning, tax assessment, forest management, ecological
research
 Originally hard copy, paperback books
 Useful in the field
 Now available as pdf files
COUNT Y SOIL SURVEYS:
 Paper copy available from County NRCS of fice
 For counties that have been surveyed
 Free to public
 PDF file available on NRCS MN web
http://www.mn.nrcs.usda.gov
 Surveys include:
-general information about the county
-descriptions of all the soil types in the county
-tables of information on:
suitabiity, limitations, management for specific uses
HOW ARE SURVEYS MADE?
(Goal: map county soils)
 By digging a lot of holes! to observe profiles
 Observing slopes, water tables, landscape, parent material,
vegetation, crops, climate
 Create a conceptual model of how soils were formed
 Use these models during mapping to PREDICT what kind of soil will
be present in a particular landscape
 Sample some soils to determine laboratory and engineering
characteristics
GENERAL SOIL MAP UNITS
(also called ASSOCIATIONS)
 Broad areas with soils, relief and drainage
 Each unit represents a particular natural landscape
 Useful for general land uses; not good for a farm or field or
road or building
 General map units are shown as:
 Soil- landscape block diagrams
 Written descriptions
 Color map in soil survey
AITKIN COUNT Y EXAMPLE
 Aitkin County, Volume One
 (look at general description of county, climate tables, general map
unit descriptions and block diagrams)
 (look at General Soil Map)
DETAILED SOIL MAP UNITS
 “Map unit”
 Soils blend into one another; do not follow strict boundaries,
therefore a challenge to map
 Areas of one particular soil can hardly ever be mapped without including
other soils
 Map unit solves this issue by including similar soils
 Named by the dominant soil in the unit
 Each map unit has a dominant soil and inclusions (other similar soils)
 Example: p. 43 of Aitkin survey:
 #292 Alstad Loam (Map Unit)
 85% Alstad
 15% inclusions
SERIES DESCRIPTIONS
 Unit of taxonomy
 All major horizons in a series are similar
 But they can differ in some characteristics, like stoniness, texture,
wetness, etc.
 These allowable differences are listed as Range of Characteristics
after each series description
 Each series gives its taxonomic class :
 “Fine-loamy mixed Glossaquic Eutroboralf”
 We can find a detailed description of the Alstad Series
 Series descriptions are listed alphabetically
 Example: Alstad series, Aitkin County
 (look for series description, range in characteristics, taxonomic class)
Hierarchical categories
“ F in e - lo amy mixe d G lo ssaquic E ut r o bor alf ”
Order
Suborder
Great group
Subgroup
Family
Series
Alfisol
Boralfs
Eutroboralfs
Glossaquic Eutroboralf
 “Fine-loamy mixed Glossaquic
Eutroboralf”
Alstad
TAXONOMIC CLASS
 Alstad Series:“Fine-loamy mixed Glossaquic Eutroboralf”
Fine-loamy
mixed
superactive
Particle size
frigid
mean annual
temp <8°C;
>6°C range
Mixture of clay minerals
High CEC
 Note : Series are listed alphabetically, but map unit numbers
are not in order, therefore need to consult Soil Legend to look
up numbers from maps
 “The objective of mapping is not to delineate pure taxonomic
classes but rather to separate the landscape into segments
that have similar use and management requirements…if
intensive use of small areas is planned, onsite investigations
is needed to define and locate the soils…”
 Soil survey maps do not preclude field checking!!!
OTHER USEFUL LINKS ON MN NRCS
 Soil series descriptions
www.soils.usda.gov/technical/classification/osd
 Soils Data Mart
www.soildatamart.nrcs.usda.gov
PUBLICATIONS
www.soils.usda.gov
Soil Taxonomy
Keys to Soil Taxonomy
Glossary
GIS SOIL DATA
 Spatially referenced
 GIS-compatible format
 Geographic Information Systems
Data sets identify soils with similar characteristics and tables
describe attributes (characteristics) of each delineated soil
type
 STATSGO
 SSURGO
STATSGO
 State Soil Geographic database
 More generalized than SSURGO
 1;250,000
 For land use planning over large areas
 Need GIS or Web Soil Survey
SSURGO
 Soil Survey Geographic database
 “SSURGO-certified”
 National cartographic standards
 More detail than STATSGO
 1:12,000 to 1:63,360
 Landowners and county -level planning
 Need GIS or Web Soil Survey
 Current state of mapping in MN
DATA USES AND SCALE
 Site-Level Management:
 Detailed applications:
 Precision agriculture, UMD farm recommendations, septic mound location
 On-site investigation by soils person to augment info in county survey (if one is available)
 Up to 1: 5000
 Local Planning:
 Residential and commercial development, transportation, recreation,
open space and natural areas
 County soil surveys: 1:20,000
 Generalized characterization of Landscape:
 Broad management and ecological research
 Statewide data sets
WEB SOIL SURVEY
 Interface for users who do not have/use/know GIS; can
access SSURGO data.
 Web Soil Survey
SAMPLE PROJECT USING SSURGO
DATA:
 Include past hydrology in the MN/Model.
Mn/Model 2002
 Archaeological predictive
model used by Mn DOT to
avoid destroying or
disturbing archaeological
sites during road
construction projects.
 GIS statistical model of
High, Medium, Low
likelihood
 Impor tant input to model
is landscape
 Lacked past hydrology
Soil Criteria
Mn/DOT formatted soil dataset
Map Unit Components
Taxonomy
Great Groups (18)
Histosols, Aquic Suborders, Udifluvents
Blue Earth example, Hennepin example
Hydric Rating
Drainage Classes
existing lakes, streams, and wetlands
county SSURGO soils data
30m elevation data / geomorphology
General Land Office survey
maps
Existing GIS data used to derive historic water features
Landform Sediment
Assemblages
Identify riverine
features
Input GIS dataset
Tool output dataset
Final model output dataset
Conceptual Model to
Create Historic Water
Features layer for
Mn/Model Phase 4.
GLO lakes
Tool in ModelBuilder
2. GLO lakes
and wetlands
Correspondence
GLO wetlands
1. select great groups and
eliminate_less_3acres
Potential Historic
Lake / Wetland
areas derived
from soil polygons
Potential historic
lake / wetland
areas with source
field populated
Use if GLO delineations
are not available
Mn/DOT soils
Derived from
SSURGO
Select
great groups
for riverine features
Potential historic
riverine
features
3. Identify historic riverine features
Identify riverine
features
Identify fluvial
features
Identify perennial
features
MN DNR
Geomorphology
MN DNR
Streams
NWI wetlands
4. NWI natural
feature selection
plus RDWI
RDWI wetlands
only if available
Selected natural
palustrine,
Lacustrine features
And areas derived
from RDWI
5. Combine all
potential
historic water
features
All historic water
features
Identification of Historic Lake and Wetland Features
Select Great Groups meeting hydric criteria
Filter Hydric = “P” and not Drainage = “VP” or “P”
Aggregate neighboring polygons
Delete areas < 3 acres
Dissolve soil polygons of same Landform together
Example of Tool 1 output in Hennepin Counties with GLO surveyed features
Example of Tool 1 output in Hennepin County with HCD Wetland Inventory
Figure 6. Historic features illustrating Great Group selection in Blue Earth County
Figure 7. Historic features illustrating Great Group selection in Hennepin County
Figure 8. Example of Tool 1 output in Hennepin Counties with GLO surveyed features
Figure 9. Example of Tool 1 output in Hennepin Counties with HCD Wetland Inventory
Identify historic riverine features tool in ArcGIS ModelBuilder
Select Hydric Great Groups
Subset Great Groups that intersect Fluvial Geomorphology (set 1)
Select Riverine Features from NWI (set 2)
Combine Set 1, Set 2, and Set 3 for Historic Riverine Features
Historic riverine features and associated data in Blue Earth County
Natural Features Selection Plus RDWI Tool in ArcGIS ModelBuilder
Eliminate artificial wetlands from NWI
(Wreg = K, artificial; Spec_mod1 = b [beaver], h [impounded], or x [excavated])
Select NWI that corresponds with RDWI, populate RDWI field = ‘y’
Combine RDWI and NWI features
Combine all potential historic water features
Compare to General Land Office data?
Other studies in other counties (Hennepin)
Demonstration of SSURGO for use in GIS
http://soildatamart.nrcs.usda.gov/
http://www.lmic.state.mn.us/chouse/soil.html
Downloading data
Importing ssurgo into template
Shapefiles
Tables
Linking and Joining Tables