MAPPING AND REPRESENTING SOIL
INFORMATION AND DATA
Scales and complexities range Use/application determines appropriate scale
SOIL AND SCALE
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
COUNTY SOIL SURVEYS
Paper copy available from County NRCS office 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
COUNTY SOIL SURVEYS:
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
HOW ARE SURVEYS MADE?(Goal: map county soils)
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
GENERAL SOIL MAP UNITS(also called ASSOCIATIONS)
Aitkin County, Volume One (look at general description of county, climate tables, general map
unit descriptions and block diagrams) (look at General Soil Map)
AITKIN COUNTY EXAMPLE
“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
DETAILED SOIL MAP UNITS
Unit of taxonomyAll 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)
SERIES DESCRIPTIONS
Hierarchical categories“Fine-loamy mixed Glossaquic Eutroboralf”
OrderSuborderGreat groupSubgroupFamily
Series
AlfisolBoralfsEutroboralfsGlossaquic Eutroboralf“Fine-loamy mixed
Glossaquic Eutroboralf”
Alstad
Alstad Series:“Fine-loamy mixed Glossaquic Eutroboralf”
Fine-loamy
TAXONOMIC CLASS
Particle size
mixed
Mixture of clay minerals
superactive
High CEC
frigid
mean annualtemp <8°C;>6°C range
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!!!
Soil series descriptionswww.soils.usda.gov/technical/classification/osd
Soils Data Mart www.soildatamart.nrcs.usda.gov
OTHER USEFUL LINKS ON MN NRCS
www.soils.usda.gov
Soil TaxonomyKeys to Soil TaxonomyGlossary
PUBLICATIONS
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
GIS SOIL DATA
State Soil Geographic database
More generalized than SSURGO 1;250,000
For land use planning over large areas
Need GIS or Web Soil Survey
STATSGO
Soil Survey Geographic database “SSURGO-certified”
National cartographic standards
More detail than STATSGO 1:12,000 to 1:63,360
Landowners and county-level planningNeed GIS or Web Soil Survey
Current state of mapping in MN
SSURGO
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
DATA USES AND SCALE
Interface for users who do not have/use/know GIS; can access SSURGO data.
Web Soil Survey
WEB SOIL SURVEY
Include past hydrology in the MN/Model.
SAMPLE PROJECT USING SSURGO DATA:
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
Important input to model is landscape
Lacked past hydrology
Soil CriteriaMn/DOT formatted soil datasetMap Unit ComponentsTaxonomyGreat Groups (18)Histosols, Aquic Suborders, UdifluventsBlue Earth example, Hennepin exampleHydric RatingDrainage 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
Conceptual Model to Create Historic
Water Features layer for Mn/Model
Phase 4.
GLO wetlands
Selected natural palustrine,
Lacustrine featuresAnd areas derived
from RDWI
NWI wetlands
4. NWI natural feature
selection plus RDWI
GLO lakes
Potential HistoricLake / Wetlandareas derived
from soil polygons
RDWI wetlands
MN DNRGeomorphology
Potential historicriverinefeatures
Mn/DOT soilsDerived from
SSURGO
MN DNRStreams
Identify fluvialfeatures
Identify perennialfeatures
Landform Sediment Assemblages
All historic water features
Identify riverinefeatures
5. Combine all potential
historic water
features
2. GLO lakes and wetlandsCorresponden
ce
1. select great groups and
eliminate_less_3acres
Identify riverinefeatures
3. Identify historic riverine features
Select great groupsfor riverine
features
Potential historiclake / wetland
areas with source field populated
Use if GLO delineations are not available
only if available
Input GIS dataset
Tool output dataset
Final model output dataset
Tool in ModelBuilder
Identification of Historic Lake and Wetland Features
Select Great Groups meeting hydric criteriaFilter Hydric = “P” and not Drainage = “VP” or “P”Aggregate neighboring polygonsDelete areas < 3 acresDissolve soil polygons of same Landform togetherExample 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 GroupsSubset 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 ModelBuilderEliminate 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 dataImporting ssurgo into templateShapefilesTablesLinking and Joining Tables
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