John Fisher
Senior Regional Soil Scientist
775 857-8500 ext 127
john.fisher@nv.usda.gov
What is soil
Soil is a natural body comprised of solids (minerals and organic matter), liquid,
and gases that occurs on the land surface, occupies space, and is characterized
by one or both of the following: horizons, or layers, that are distinguishable
from the initial material as a result of additions, losses, transfers, and
transformations of energy and matter or the ability to support rooted plants in
a natural environment.
The upper limit of soil is the boundary between soil and air, shallow water, live
plants, or plant materials that have not begun to decompose. Areas are not
considered to have soil if the surface is permanently covered by water too deep
(typically more than 2.5 meters) for the growth of rooted plants.
The lower boundary that separates soil from the nonsoil underneath is most
difficult to define. Soil consists of horizons near the earth's surface that, in
contrast to the underlying parent material, have been altered by the
interactions of climate, relief, and living organisms over time. Commonly, soil
grades at its lower boundary to hard rock or to earthy materials virtually devoid
of animals, roots, or other marks of biological activity. For purposes of
classification, the lower boundary of soil is arbitrarily set at 200 cm.
A History of Soil Survey in Nevada
A compilation of short stories commemorating the 100th
Anniversary of the Soil Survey Program
Compiled by Paul W. Blackburn MLRA Leader in Elko,
NV
July 2000
Publication available under soils at
http://www.nv.nrcs.usda.gov/
Present Status
Official soil surveys on Web Soil Survey at
http://websoilsurvey.nrcs.usda.gov/app/HomePage.htm
or at Soil Data Mart
http://soildatamart.nrcs.usda.gov/
Published copies are outdated but still can be useful
Foreseeable Priorities for Nevada
Soils
1. Complete the mapping of Federal Lands.
2. Updates of soil data and soil lines by MLRAs
3. Soil data in the National Soil Information System (NASIS) will
be “harmonized”. (3 year projects)
4. Official series descriptions OSDs will be edited to be metric and
to be located by longitude and latitude in NAD 83 (field
verified).
5. Benchmark soils will be emphasized.
6. Continue collecting and add sites for soil temperature data.
7. Sample temperature sites for lab data.
8. Soils support for state and transition modeling and ecological
site development.
Scan Site Porter Canyon
Benchmark Soils
A Benchmark soil is one that is selected to represent a
number of other soils.
Criteria used:
Large extent
Key taxonomic Class
Existing data (laboratory information)
Other considerations
Major parent material
Major landform
Ecological importance
Significant land uses
GIS Tools for Nevada Soils
Map Unit Description Report developed by Lucas Wisely
which verifies: landforms, component percents,
slopes, precipitation, temperature and elevations.
ArcSIE (Soils Inference Engine) will be used to model
probable locations for components and possible
ecological site locations - used for premapping and to
compare predicted component locations with mapped
component locations.
Mapping Concepts
“Soil mapping is possible only because men can examine
a profile at one point and successfully predict its
occurrence at another point where surface indications
are similar.” - Author unknown.
0r
“Soil mapping is possible because of observable
discontinuities between landscape units and a strong
relation between landscape units and soils. These
relationships make it possible to accurately delineate
bodies of soil with limited observations. “ Hudson.
Procedure for Mapping Soils
Prediction - mapping concept
Validation - check prediction
Compromise – same use and management -same
interpretations
Documentation and Consistency – extremely important
for updates
Prediction
Concepts for Soil Prediction
Five soil forming factors
Use of the soil-landscape model
Conceptualize soil individuals and natural bodies of soils
on the landscape.
Use of vegetation to predict soil properties
Repeatable patterns
Implicit or Tacit knowledge - experience
Five Soil Forming Factors
 Parent Material (geology, depositional history)
 Climate (rainfall, temperature)
 Relief or Topology (slope, aspect, geomorphology)
 Biological Factors (plants, animals, microbes and Us)
 Time (geomorphology, stability)
Natural Bodies of Soils on the
Landscape.
A map unit is a collection of areas defined and named
the same in terms of their soil components or
miscellaneous areas or both. Each map unit differs in
some respect from all others in a survey area and is
uniquely identified on a soil map. Each individual area
on the map is a delineation.
Landscape is used to describe the map unit general
appearance for example, mountains, hills, piedmont
slopes, fan piedmonts, basin floors, bolson floors, and
semi-bolson flooors
Conceptualize soil individuals
Soil Series-the lowest category of the national soil
classification system.
Nationally there are about 22,000 series recognized and
about 2,000 originated in Nevada.
Soil Series are defined by Official Soil Series Descriptions
contain soil properties that define the soil series,
distinguish it from other soil series, serve as the basis for
the placement of that soil series in the soil family, and
provide a record of soil properties needed to prepare soil
interpretations.
Soil series or phase is a component of the map unit and is
located by a landform.
Pyropatti Series
Consociations
Delineated areas are dominated by a single soil taxon
usually a soil series or miscellaneous area and similar
soils with no more than 15 percent contrasting
components (inclusions).
Name includes surface texture and usually slope
Used mostly in order II soil mapping.
Complexes and Associations
Complexes and associations consist of two or more
dissimilar components (usually soil series) occurring
in a regularly repeating pattern with no more than 15
percent contrasting components (inclusions).
Complex-major components cannot be mapped
separately at a scale of about 1:24,000 .
Association- major components can be separated at a
scale of about 1:24,000
Used mostly in order III soil mapping.
Use of the soil-landscape model
Landforms of the Basin and Range Province By Fredrick
F Peterson January 1981
Publication available under soils at
http://www.nv.nrcs.usda.gov/
A landform is a three-dimensional part of the general
land surface which is distinctive and recognizable
because it has some significance to people and repeats
across the landscape in a fairly consistent position with
respect to surrounding landforms.
Fan remnants and inset fans on fan
piedmonts with hills in background
Plants Used to Predict Some of the
Soil Properties in the Great Basin
 Soil depth: type of sagebrush, height of sagebrush, amount of
mature trees, amount of large young trees.
 Soil color: type of sagebrush, height of sagebrush, Antelope
bitterbrush, amount of bluebunch wheatgrass, amount of
mature trees
 Organic matter: type of sagebrush, height of sagebrush,
Antelope bitterbrush, amount of bluebunch wheatgrass, amount
of mature trees.
 Depth to water table: black greasewood, saltgrass, rushes and
sedge, cattails, cottonwood, willows (types), salt cedar, silver
sage.
 Soil texture: types of sagebrush, winterfat, Indian ricgrass, galleta,
fourwing saltbush, Nevada dalea, four-part horsebrush
 Carbonates: black sagebrush, littleleaf mahogany, winterfat.
 Soil temperature-creosote bush, Idaho fescue, Idaho fescue, antelope
bitterbush, mountain big sagebrush, white bur sage.
 Horizon boundary: type of sagebrush.
 Soil pores: shadscale, Bailey greasewood, spiny mendora, sagebrush
 Effective soil moisture: shadscale, sagebrush, singleleaf pinyon,
antelope bitterbrush, Bailey’s greasewood, snowberry, bluebunch
wheatgrass
Tacit Knowledge
Tacit knowledge is gained by experience.
Soil-landscape concept is extremely dependant on tacit
knowledge.
Difficult to pass this tacit knowledge to newer soil
scientists.
Potential and Actual Retirement of
Tacit Knowledge
Verification
Soil Contacts
Reno State Office/MO-03 Office (775) 857-8500
Levi Steptoe, State Soil Scientist/MO-03 Leader ext. 120
Tom Champa, Soil Data Quality Specialist ext. 122
Lucas Wiseley, GIS Specialist ext. 126
Erin Hourihan, Range Management Specialist ext. 130
levi.steptoe@nv.usda.gov
tom.champa@nv.usda.gov
lucas.wisely@nv.usda.gov
erin.hourihan@nv.usda.gov
Elko MLRA Office: (775) 738-8431
Paul Blackburn, MLRA leader ext. 122
Nathan Lurie, Soil Scientist ext. 129
paul.blackburn@nv.usda.gov
nathan.lurie@nv.usda.gov
Ely MLRA Office: (775) 289-4065
Curt Leet, Soil Scientist ext. 108
Brien Park, Soil Scientist ext.111
curt.leet@nv.usda.gov
brien.park@nv.usda.gov
Minden MLRA office: (775) 782-3661
Ed Blake, MLRA leader ext. 110
Matt Cole, Soil Scientist ext. 103
Steve Herriman, Resource Soil Scientist ext. 109
Las Vegas Office (702) 262-9047
Doug Merkler, Resource Soil Scientist ext 106
ed.blake@nv.usda.gov
matt.cole@nv.usda.gov
steve.herriman@nv.usda.gov
doug.merkler@nv.usda.gov
It is all sand,
silt & clay
But it Feels
Like . . .
Textural Triangle
Trust me – it is all sand,
silt or clay
But it looks like ….