HomeMy WebLinkAboutCustom Soil Resource ReportUSDA United States
- ff3:iil:J,"
NRCS
A product of the National
Cooperative Soil Survey,
a joint effort of the United
States Department of
Agriculture and other
Federal agencies, State
agencies including the
Agricultural Experiment
Stations, and local
participants
Natural
Resources
Conservation
Service
Custom Soil Resource
Report for
Rifle Area, Colorado,
Parts of Garfield and
Mesa Gounties
Porter OWTS
June 18,2O21
Preface
Soil surveys contain information that affects land use planning in survey areas.
They highlight soil limitations that affect various land uses and provide information
about the properties of the soils in the survey areas. Soil surveys are designed for
many different users, including farmers, ranchers, foresters, agronomists, urban
planners, community officials, engineers, developers, builders, and home buyers.
Also, conservationists, teachers, students, and specialists in recreation, waste
disposal, and pollution control can use the surveys to help them understand,
protect, or enhance the environment.
Various land use regulations of Federal, State, and local governments may impose
special restrictions on land use or land treatment. Soil surveys identify soil
properties that are used in making various land use or land treatment decisions.
The information is intended to help the land users identify and reduce the effects of
soil limitations on various land uses. The landowner or user is responsible for
identifoing and complying with existing laws and regulations.
Although soil survey information can be used for general farm, local, and wider area
planning, onsite investigation is needed to supplement this information in some
cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/
portal/nrcslmai nlsoils/health/) and certain conservation and engi neeri ng
applications. For more detailed information, contact your local USDA Service Center
(https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil
Scientist (http//www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/?
cid=nrcs1 42p2_053951 ).
Great differences in soil properties can occur within short distances. Some soils are
seasonally wet or subject to flooding. Some are too unstable to be used as a
foundation for buildings or roads. Clayey or wet soils are poorly suited to use as
septic tank absorption fields. A high water table makes a soil poorly suited to
basements or underground installations.
The National Cooperative Soil Survey is a joint effort of the United States
Department of Agriculture and other Federal agencies, State agencies including the
Agricultural Experiment Stations, and local agencies. The Natural Resources
Conservation Service (NRCS) has leadership for the Federal part of the National
Cooperative Soil Survey.
lnformation about soils is updated periodically. Updated information is available
through the NRCS Web Soil Survey, the site for official soil survey information.
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its
programs and activities on the basis of race, colo¡ national origin, age, disability,
and where applicable, sex, marital status, familial status, parental status, religion,
sexual orientation, genetic information, political beliefs, reprisal, or because all or a
part of an individual's income is derived from any public assistance program. (Not
all prohibited bases apply to all programs.) Persons with disabilities who require
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alternative means for communication of program information (Braille, large print,
audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice
and TDD). To file a complaint of discrimination, write to USDA, Director, Office of
Civil Rights, 1400 lndependence Avenue, S.W., Washington, D.C.20250-9410 or
call (800) 795-3272 (voice) or (202)720-6382 (TDD). USDA is an equalopportunity
provider and employer.
3
Contents
Preface
SoilMap
Soil Map (Porter OWTS)
Legend
Map Unit Legend (Porter OWTS).
Map Unit Descriptions (Porter OWTS)........
Rifle Area, Colorado, Parts of Garfield and Mesa Counties
S5-Potts loam, 3 to 6 percent slopes.
Soil lnformation for All Uses.
Soil Reports.
Soil Physical Properties
Engineering Properties (Porter CIWTS)..
Physical Soil Properties (Porter OWTS).
References
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Soil Map
The soil map section includes the soil map for the defined area of interest, a list of
soil map units on the map and extent of each map unit, and cartographic symbols
displayed on the map. Also presented are various metadata about data used to
produce the map, and a description of each soil map unit.
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Gustom Soil Resource ReportMAP LEGENDMAP INFORMATIONThe soil surveys that comprise your AOI were mapped at1:24,O0O"Please rely on the bar scale on each map sheet for mapmeasurements.Source of Map: Natural Resources Conservation ServiceWeb Soil Survey URL:Coordinate System: Web Mercator (EPSG:3857)Maps from the Web Soil Survey are based on the Web Mercatorprojection, which preserves direction and shape but distortsdistance and area. A projection that preserves area, such as theAlbers equal-area conic projection, should be used if moreaccurate calculations of distance or area are required.This product is generated from the USDA-NRCS certified data asof the version date(s) listed belowSoil Survey Area: Rifle Area, Colorado, Parts of Garfield andMesa CountiesSurvey Area Data: Version 13, Jun 5, 2020Soil map units are labeled (as space allows) for map scales1:50,000 or larger.Date(s) aerial images were photographed: Dec 31, 2009--Oct12,2017The orthophoto or other base map on which the soil lines werecompiled and digitized probably differs from the backgroundArea of lnterest (AOl).'-*: Area of lnterest (AOl)Soils,J So¡l Map Unit Polygons¡r/ Soil Map Unit L¡nesE Soil Map Un¡t PointsBlowoutBonow PitClay SpotClosed DepressionGravel PitGrevêlly SpotLandfillLava FlowMarsh or swempMine or QuarryMiscellaneous WãterPerennial WaterRock OutcropSaline SpotSandy SpotSeverely Eroded SpotS¡nkholeSl¡de or SlipSodic Spotä Spoil Area* StonySpotffi VeryStonySpotS wet Spotå Other.- Spec¡âl Line FeaturesWater Featurcs. Streems and CenalsTransportât¡on¡-r-+ Rails.r/t lnterstate Highwaysi*e's US Routes- MajorRoadsLocel RoadsBackgroundI Aerial Photooraohv(9tHH*,¡È|rf"s,t&#Ð&+;*Ft97Waming: Soil Map may not be valid at this scale.Enlargement of maps beyond the scale of mapping can causemisunderstanding of the detail of mapping and accurary of soilline placement. The maps do not show the small areas ofcontrasting soils that could have been shown at a more detailedscale.
Custom Soil Resource ReportMAP LEGENDMAP INFORMATIONimagery displayed on these maps. As a result, some minorofunit boundariesbe evident.I
Custom Soil Resource Report
Map Unit Legend (Porter OWTS)
Map Unit Descriptions (Porter OWTS)
The map units delineated on the detailed soil maps in a soil survey represent the
soils or miscellaneous areas in the survey area. The map unit descriptions, along
with the maps, can be used to determine the composition and properties of a unit.
A map unit delineation on a soil map represents an area dominated by one or more
major kinds of soil or miscellaneous areas. A map unit is identified and named
according to the taxonomic classification of the dominant soils. Within a taxonomic
class there are precisely defined limits for the properties of the soils. On the
landscape, however, the soils are natural phenomena, and they have the
characteristic variability of all natural phenomena. Thus, the range of some
observed properties may extend beyond the limits defined for a taxonomic class.
Areas of soils of a single taxonomic class rarely, if ever, can be mapped without
including areas of other taxonomic classes. Consequently, every map unit is made
up of the soils or miscellaneous areas for which it is named and some minor
components that belong to taxonomic classes other than those of the major soils.
Most minor soils have properties similar to those of the dominant soil or soib in the
map unit, and thus they do not affect use and management. These are called
noncontrasting, or similar, components. They may or may not be mentioned in a
particular map unit description. Other minor components, however, have properties
and behavioral characteristics divergent enough to affect use or to require different
management. These are called contrasting, or dissimilar, components. They
generally are in small areas and could not be mapped separately because of the
scale used. Some small areas of strongly contrasting soils or miscellaneous areas
are identified by a special symbol on the maps. lf included in the database for a
given area, the contrasting minor components are identified in the map unit
descriptions along with some characteristics of each. A few areas of minor
components may not have been observed, and consequently they are not
mentioned in the descriptions, especially where the pattern was so complex that it
was impractical to make enough observations to identify all the soils and
miscellaneous areas on the landscape.
The presence of minor components in a map unit in no way diminishes the
usefulness or accuracy of the data. The objective of mapping is not to delineate
pure taxonomic classes but rather to separate the landscape into landforms or
landform segments that have similar use and management requirements. The
delineation of such segments on the map provides sufficient information for the
development of resource plans. lf intensive use of small areas is planned, howeve¡
onsite investigation is needed to define and locate the soils and miscellaneous
areas.
I
Map Unit Symbol Map Unit Name Acres in AOI Percent ofAOl
55 Potts loam, 3 to 6 percent
slopes
2.9 '100.0%
Totals for Area of lnterest 2.9 10O.Oo/o
Custom Soil Resource Report
An identifying symbol precedes the map unit name in the map unit descriptions.
Each description includes general facts about the unit and gives important soil
properties and qualities.
Soils that have profiles that are almost alike make up a soi/ senes. Except for
differences in texture of the surface layer, all the soils of a series have major
horizons that are similar in composition, thickness, and arrangement.
Soils of one series can differ in texture of the surface layer, slope, stoniness,
salinity, degree of erosion, and other characteristics that affect their use. On the
basis of such differences, a soil series is divided into soi/ phases. Most of the areas
shown on the detailed soil maps are phases of soil series. The name of a soil phase
commonly indicates a feature that affects use or management. For example, Alpha
silt loam, 0 to 2 percent slopes, is a phase of the Alpha series.
Some map units are made up of two or more major soils or miscellaneous areas.
These map units are complexes, associations, or undifferentiated groups.
A complex consists of two or more soils or miscellaneous areas in such an intricate
pattern or in such small areas that they cannot be shown separately on the maps.
The pattern and proportion of the soils or miscellaneous areas are somewhat similar
in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example.
An assocrafion is made up of two or more geographically associated soils or
miscellaneous areas that are shown as one unit on the maps. Because of present
or anticipated uses of the map units in the survey area, it was not considered
practical or necessary to map the soils or miscellaneous areas separately. The
pattern and relative proportion of the soils or miscellaneous areas are somewhat
similar. Alpha-Beta association, 0 to 2 percent slopes, is an example.
An undifferentiated group is made up of two or more soils or miscellaneous areas
that could be mapped individually but are mapped as one unit because similar
interpretations can be made for use and management. The pattern and proportion
of the soils or miscellaneous areas in a mapped area are not uniform. An area can
be made up of only one of the major soils or miscellaneous areas, or it can be made
up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example.
Some surveys include miscellaneous areas. Such areas have little or no soil
material and support little or no vegetation. Rock outcrop is an example.
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Custom Soil Resource Report
Rifle Area, Colorado, Parts of Garfield and Mesa Counties
S5-Potts loam, 3 to 6 percent slopes
Map Unit Setting
National map unit symbol: inyr
Elevation: 5,000 to 7,000 feet
Farmland classification' Prime farmland if irrigated
Map Unit Composition
Potts and similar soils:85 percent
Esfimafes are based on obseruations, descriptions, and transects of the mapunit.
Description of Potts
Setting
Landform: Valley sides, benches, mesas
Down-slope shape: Convex, linear
,4cross-s/ope shape : Convex, linear
Parent material: Alluvium derived from basalt and/or alluvium derived from
sandstone and shale
Typical profile
H1 -Oto4inches: loam
H2 - 4 to 28 inches: clay loam
H3 - 28 to 6O inches.' loam
Properties and qualities
S/ope;3to6percent
Depth to restrictive feature: More than 80 inches
Drainage c/ass.' Well drained
Runoff class: High
Capacity of the most limiting layer to transmit water (Ksat); Moderately high (0.20
to 0.60 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum content: I5 percent
Maximum salinity: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm)
Available water capacity: High (about 10.3 inches)
lnterpretive groups
Land capability classification (irrigated): 3e
Land capabi lity cl assification (non i nig ated) : 3c
Hydrologic Soil Group: C
Ecologicalsife: R048AY298CO - Rolling Loam
Hydric soil rating: No
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Soil lnformation for All Uses
Soil Reports
The Soil Reports section includes various formatted tabular and narrative reports
(tables) containing data for each selected soil map unit and each component of
each unit. No aggregation of data has occurred as is done in reports in the Soil
Properties and Qualities and Suitabilities and Limitations sections.
The reports contain soil interpretive information as well as basic soil properties and
qualities. A description of each report (table) is included.
Soil Physical Properties
This folder contains a collection of tabular reports that present soil physical
properties. The reports (tables) include all selected map units and components for
each map unit. Soil physical properties are measured or inferred from direct
observations in the field or laboratory. Examples of soil physical properties include
percent clay, organic matte¡ saturated hydraulic conductivity, available water
capacity, and bulk density,
Engineering Properties (Porter OWTS)
This table gives the engineering classifications and the range of engineering
properties for the layers of each soil in the survey area.
Hydrologic soil group is a group of soils having similar runoff potential under similar
storm and cover conditions. The criteria for determining Hydrologic soil group is
found in the National Engineering Handbook, Chapter 7 issued May 2007(http//
directives.sc.egov.usda.gov/OpenNonWebContent.aspx?content=17757 .wba).
Listing HSGs by soll map unit component and not by soil series is a new concept for
the engineers. Past engineering references contained lists of HSGs by soil series.
Soil series are continually being defined and redefined, and the list of soil series
names changes so frequently as to make the task of maintaining a single national
list virtually impossible. Therefore, the criteria is now used to calculate the HSG
using the component soil properties and no such national series lists will be
maintained. Allsuch references are obsolete and their use should be discontinued.
Soil properties that influence runoff potential are those that influence the minimum
rate of infiltration for a bare soil after prolonged wetting and when not frozen. These
properties are depth to a seasonal high water table, saturated hydraulic conductivity
after prolonged wetting, and depth to a layer with a very slow water transmission
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Custom Soil Resource Report
rate. Changes in soil properties caused by land management or climate changes
also cause the hydrologic soil group to change. The influence of ground cover is
treated independently. There are four hydrologic soil groups, A, B, C, and D, and
three dual groups, A/D, B/D, and C/D. ln the dual groups, the first letter is for
drained areas and the second letter is for undrained areas.
The four hydrologic soil groups are described in the following paragraphs:
Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly
wet. These consist mainly of deep, well drained to excessively drained sands or
gravelly sands. These soils have a high rate of water transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well drained
soils that have moderately fine texture to moderately coarse texture. These soils
have a moderate rate of water transmission.
Group C. Soils having a slow infíltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of water
transmíssion.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay layer at
or near the surface, and soils that are shallow over nearly impervious material.
These soils have a very slow rate of water transmission.
Depth to the upper and lower boundaries of each layer is indicated.
Texture is given in the standard terms used by the U.S. Department of Agriculture.
These terms are defined according to percentages of sand, silt, and clay in the
fraction of the soil that is less than 2 millimeters in diameter. "Loam," for example, is
soil that is7 to 27 percent clay,28 to 50 percent silt, and less than 52 percent sand.
lf the content of particles coarser than sand is 15 percent or more, an appropriate
modifier is added, for example, "gravelly."
Classification of the soils is determined according to the Unified soil classification
system (ASTM, 2005) and the system adopted by the American Association of
State Highway and Transportation Officials (AASHTO, 2OO4}
The Unified system classifies soils according to properties that affect their use as
construction material. Soils are classified according to particle-size distribution of
the fraction less than 3 inches in diameter and according to plasticity index, liquid
limit, and organic matter content. Sandy and gravelly soils are identified as GW, GP,
cM, GC, SW SR SM, and SC;silty and clayey soils as ML, CL, OL, MH, CH, and
OH; and highly organic soils as PT. Soils exhibiting engineering properties of two
groups can have a dual classification, for example, CL-ML.
The AASHTO system classifies soils according to those properties that affect
roadway construction and maintenance. ln this system, the fraction of a mineral soil
that is less than 3 inches in diameter is classified in one of seven groups from A-l
through A-7 on the basis of particle-size distribution, liquid limit, and plasticity index.
Soils in group A-1 are coarse grained and low in content of fines (silt and clay). At
the other extreme, soils in group A-7 are fine grained. Highly organic soils are
classified in group A-8 on the basis of visual inspection.
lf laboratory data are available, the A-1 , A-2, and A-7 groups are further classified
as A-1-a, A-1-b, A-2-4, A-2-5, A-2-6, A-2-7, A-7-5, or A-7-ô. As an additional
refinement, the suitability of a soil as subgrade material can be indicated by a group
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Custom Soil Resource Report
index number. Group index numbers range from 0 for the best subgrade material to
20 or higher for the poorest.
Percentage of rock fragments larger than '10 inches in diameter and 3 to '10 inches
in diameter are indicated as a percentage of the total soil on a dry-weight basis. The
percentages are estimates determined mainly by converting volume percentage in
the field to weight percentage. Three values are provided to identify the expected
Low (L), Representative Value (R), and High (H).
Percentage (of soil pañicles,) passrng designated sieyes is the percentage of the soil
fraction less than 3 inches in diameter based on an ovendry weight. The sieves,
numbers 4, 10, 40, and 200 (USA Standard Series), have openings of 4.76, 2.00,
0.420, and 0.074 millimeters, respectively. Estimates are based on laboratory tests
of soils sampled in the survey area and in nearby areas and on estimates made in
the field. Three values are provided to identify the expected Low (L), Representative
Value (R), and High (H).
Liquid limit and plasticity rndex (Atterberg limits) indicate the plasticity
characteristics of a soil. The estimates are based on test data from the survey area
or from nearby areas and on field examination. Three values are provided to identify
the expected Low (L), Representative Value (R), and High (H).
References:
American Association of State Highway and Transportation Officials (AASHTO).
2004. Standard specifications for transportation materials and methods of sampling
and testing. 24th edition.
American Society for Testing and Materials (ASTM). 2005. Standard classification of
soils for engineering purposes. ASTM Standard D2487-00.
14
Custom Soil Resource ReportAbsence of an entry indicates that the data were not estimated. The asterisk'*' denotes the representative texture; otherpossible textures follow the dash. The criteria for determining the hydrologic soil group for individual soil components isfound in the National Engineering Handbook, Chapter 7 issued May 2007(http://directives.sc.egov.usda.gov/OpenNonWebContent.aspx?content=17757.wba). Three values are provided to identify the expected Low (L),Representative Value (R), and High (H).Engineering Properties-Rifle Area, Colorado, Parts of Garfield and Mosa CountiesPlasticity indexL-R-H5-8 -'1010-15-205-8 -l 0LiquidlimitL-R-H25-28-3030-35-4025-28-30Percentage passing sievE number-200L.R-H60-68-7570-75-8060-68-75/tOL.R.H85-90-9590-95-10085-90-95t0L-R.HI 00-1 00-1001 00-1 00-100100-r00-1004L-R-H100-100-100100-100-100't00-100-1 00Pct Fragments3-10inchesL-R-H0-0-00-0-00-0-0>10inchesL.R-H0-0-00-0-00-0-0GlassificationAASHTOA4A-6A-4UnifiedcL, cL-MLCLCL, CL.MLUSDA texturcLoamClay loamLoamDepthIn0-44-2828-60HydrologicgroupcPc't. ofmapunit85Map unit symbol andsoil nameS5-Potts loam, 3 to 6percent slopesPotts15
Custom Soil Resource Report
Physical Soil Properties (Porter OWTS)
This table shows estimates of some physical characteristics and features that affect
soil behavior. These estimates are given for the layers of each soil in the survey
area. The estimates are based on field observations and on test data for these and
similar soils.
Depth lo the upper and lower boundaries of each layer is indicated.
Particle size is the effective diameter of a soil particle as measured by
sedimentation, sieving, or micrometric methods. Particle sizes are expressed as
classes with specific effective diameter class limits. The broad classes are sand,
silt, and clay, ranging from the larger to the smaller.
Sand as a soil separate consists of mineral soil particles that are 0.05 millimeter to 2
millimeters in diameter. ln this table, the estimated sand content of each soil layer is
given as a percentage, by weight, of the soil material that is less than 2 millimeters
in diameter.
S/f as a soil separate consists of mineral soil particles that are 0.002 to 0.05
millimeter in diameter. ln this table, the estimated silt content of each soil layer is
given as a percentage, by weight, of the soil material that is less than 2 millimeters
in diameter.
Clay as a soll separate conslsts of mlneral soil particles that are less than 0.002
millimeter in diameter. ln this table, the estimated clay content of each soil layer is
given as a percentage, by weight, of the soil material that is less than 2 millimeters
in diameter.
The content of sand, silt, and clay affects the physical behavior of a soil. Particle
size is important for engineering and agronomic interpretations, for determination of
soil hydrologic qualities, and for soil classification.
The amount and kind of clay affect the fertility and physical condition of the soil and
the ability of the soil to adsorb cations and to retain moisture. They influence shrink-
swell potential, saturated hydraulic conductivity (Ksat), plasticity, the ease of soil
dispersion, and other soil properties. The amount and kind of clay in a soil also
affect tillage and earthmoving operations.
Moist bulk density is the weight of soil (ovendry) per unit volume. Volume is
measured when the soil is at field moisture capacity, that is, the moisture content at
1/3- or 1110-bar (33kPa or 1OkPa) moisture tension. Weight is determined after the
soil is dried at 105 degrees C. ln the table, the estimated moist bulk density of each
soil horizon is expressed in grams per cubic centimeter of soil material that is less
than 2 millimeters in diameter. Bulk density data are used to compute linear
extensibility, shrink-swell potential, available water capacity, total pore space, and
other soil properties. The moist bulk density of a soil indicates the pore space
available for water and roots. Depending on soil texture, a bulk density of more than
1.4 can restrict water storage and root penetration. Moist bulk density is influenced
by texture, kind of clay, content of organic mafter, and soil structure.
Saturated hydraulic conductivity (Ksaf) refers to the ease with which pores in a
saturated soil transmit water. The estimates in the table are expressed in terms of
micrometers per second. They are based on soil characteristics observed in the
field, particularly structure, porosity, and texture. Saturated hydraulic conductivity
(Ksat) is considered in the design of soil drainage systems and septic tank
absorption fields.
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Custom Soil Resource Report
Available water capacity refers to the quantity of water that the soil is capable of
storing for use by plants. The capacity for water storage is given in inches of water
per inch of soil for each soil layer. The capacity varies, depending on soil properties
that affect retention of water. The most important properties are the content of
organic matter, soil texture, bulk density, and soil structure. Available water capacity
is an important factor in the choice of plants or crops to be grown and in the design
and management of irrigation systems. Available water capacity is not an estimate
of the quantity of water actually available to plants at any given time.
Linear extensibility refers to the change in length of an unconfined clod as moisture
content is decreased from a moist to a dry state. lt is an expression of the volume
change between the water content of the clod al113- or 1i1O-bar tension (33kPa or
1OkPa tension) and oven dryness. The volume change is reported in the table as
percent change for the whole soil. The amount and type of clay minerals in the soil
influence volume change.
Linear extensibility is used to determine the shrink-swell potential of soils. The
shrink-swell potential is low if the soil has a linear extensibility of less than 3
percent; moderate if 3 to ô percent; high if 6 to 9 percent; and very high if more than
9 percent. lf the linearextensibility is more than 3, shrinking and swelling can cause
damage to buildings, roads, and other structures and to plant roots. Special design
commonly is needed.
Organic matter is the plant and animal residue in the soil at various stages of
decomposition. ln this table, the estimated content of organic matter is expressed
as a percentage, by weight, of the soil material that is less than 2 millimeters in
diameter. The content of organic matter in a soil can be maintained by returning
crop residue to the soil.
Organic matter has a positive effect on available water capacity, water infiltration,
soil organism activity, and tilth. lt is a source of nitrogen and other nutrients for
crops and soil organisms.
Erosion factors are shown in the table as the K factor (Kw and Kf) and the T factor.
Erosion factor K indicates the susceptibility of a soil to sheet and rill erosion by
water. Factor K is one of six factors used in the Universal Soil Loss Equation
(USLE) and the Revised Universal Soil Loss Equation (RUSLE) to predict the
average annual rate of soil loss by sheet and rill erosion in tons per acre per year.
The estimates are based primarily on percentage of silt, sand, and organic matter
and on soil structure and Ksat. Values of K range from 0.02 to 0.69. Other factors
being equal, the higher the value, the more susceptible the soil is to sheet and rill
erosion by water.
Erosion factor Kw indicates the erodibility of the whole soil. The estimates are
modified by the presence of rock fragments.
Erosion factor Kf indicates the erodibility of the fine-earth fraction, or the material
less than 2 millimeters in size.
Erosion factor T is an estimate of the maximum average annual rate of soil erosion
by wind and/or water that can occur without affecting crop productivity over a
sustained period. The rate is in tons per acre per year.
Wnd erodibility groups are made up of soils that have similar properties affecting
their susceptibility to wind erosion in cultivated areas. The soils assigned to group I
are the most susceptible to wind erosion, and those assigned to group I are the
least susceptible. The groups are described in the "National Soil Survey Handbook."
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Custom Soil Flesource Report
Wind erodibility indexis a numerical value indicating the susceptibility of soil to wind
è¡oslon, or the tons pêr âcrê per yêar thät can be expected to be lost to wind
erosion. There is a close correlation between wind erosion and the texture of the
surface laye¡ the size and durability of surface clods, rock fragments, organic
matter, and a calcareous reaction. Soil moisture and frozen soil layers also
influence wind erosion
Reference:
United States Department of Agriculture, Natural Resources Conseruation Service.
National soil survey handbook, title 430-Vl. (http://soils. usda. gov)
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Custom Soil Resource ReportThree values are provided to identify the expected Low (L), Representative Value (R), and High (H).Physical Soil Properties-Rífle Area, Colorado, Parts of Garfield and Mesa GountiesWinderodibilityindex56Winderodibilitygfoup5ErosionfactorcT5Kf.37.32.37Kw.37.32.37Organ¡cmatterPct1.0- 1.5-2.O0.5- 0.8-1.00.0- 0.3-0.5LinêarextensibilityPct0.0- 1_5- 2-93.0- 4.5- 5,90.0- 1.5- 2.9Ava¡lablewatercapac¡ty0.14-0"16-0.170.17-0.19-O.200.14-0.16-0.17Satu¡atedhydraulicconduc'tivitymicro m/sec4.23-23.2842.341.41-2.824,234.23-23.2842.34Moistbulkdensityg/cc1"25-1"33-1.401.25-1.33-1.401.25-'t.33-1.40ClayPctl0-15- 2027-31- 3415-20-25s¡ltPct41--36--38-SandPct44--33-42-Depthln044-2A28-60Map symboland soil names5-Potts loam,3 to 6 percentslopesPotts19
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