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Soil Classification and Profile
Descriptions – POT Approach
Presented by:
Mr. Brian Oram, PG, PASEO,
Soil Scientist
B.F. Environmental Consultant Inc.
15 Hillcrest Drive
Dallas, PA 18612
http://www.bfenvironmental.com
Document
• © 2014 by B.F. Environmental Consultants Inc. All rights reserved. No part of this document may be reproduced or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission of B.F. Environmental Consultants Inc.
• For permission – Contact Mr. Brian Oram, PG
• 570- 335-1947
http://www.water-research.net http://www.bfenvironmental.com
Continuing Education Credits
for Licensed Professional
• This presentation is part of a 2 hour education
training session.
• If you would like to obtain 2 hours of
continuing education credits or 2 hours of
PDH – please send an email to
[email protected] with your name, address,
license number, state, and contact
information.
• The fee for the credits will be $ 30.00(US)
B.F. Environmental
Consultants Inc.
• Professional Consulting Services in the areas of
water quality, soils, stormwater, geology, aquifer
analysis, and land-development.
• Baseline – Chain-of-Custody
• Expert Testimony
• Faciliate Distance Learning and Custom Training
Programs
• http://www.bfenvironmental.com
Water-Research Center
Education and Outreach Program funded by
B.F. Environmental Consultants Inc.
Outreach Programs
• Environmental and Professional Education and Training for Citizens and Local Municipalities
• Water Quality Help Guides – Information Library
• Community and Business Outreach Programs
• Low Cost – Informational Water Testing Program with National Laboratory
• Citizen Monitoring Programs
Website: http://www.water-research.net
Training For PA SEOs and Other
Professionals
• Through Wilkes University we are an
approved service provider for “Soil Based”
Training Courses.
• We will be scheduling a 1-day “Hands-On
Soils Refresher Course in Luzerne County,
PA (2014)”
• We will also be scheduling custom “Hand-
on Training Courses Regionally”.
My Approach is Called
The POT Method
• Lets Get a Donut, Cookie, and a Drink
• Site Back and Relax
• Try to Stay Wake !
Role of Background Information
Landform Perspective / Parent Materials
Soil Formation and Horizonation
Soil Terminology
Soil Morphology - Horizonation, Structure, and
Water Movement.
Todays Focus
Soils Defined
• Natural Body that Occurs on the Land
Surface that are Characterized by One or
More of the Following:
– Consists of Distinct Horizons or Layers
– The Ability to Support Rooted Plants in a Natural
Environment
– Upper Limit is Air or Shallow Water
– Lower Limit is Bedrock or Limit of Biological Activity
– Classification based on a typical depth of 2 m or
approximately 6.0 feet
Another Definition of Soils
• A Natural 3 - Dimensional Body at the
Earth Surface
• Capable of Supporting Plants
• Properties are the Result of Parent Material,
Climate, Living Matter, Landscape Position
and Time.
• Soil Composed of 4 Components (mineral
matter, organic matter, air, and water)
Major Components of Soil
Pore Space (50%)
• This may contain air and/or
water
Soil Space (50%)
• Organic Matter
• Mineral Matter
Our Job Lots of Questions
Where is
the LZ?
Water Table ?
Redox Features?
Slope ? Isolation Distances
HQ or EV?
Open Voids ? Wells ?
Gets Overwhelming
Problem
• These questions deal with the interpretation
of the site conditions – Not the
Documentation of the Site Conditions.
• After confirming, isolation distances, and
general site physical suitability , Put on
Your “Soil Description and Classification
Hat”
• Focus on What the Soil is Telling You!
The “POT” Process
Horizonation?
Diagnostic Horizons
Landscape Position?
Organic or Mineral?
Observable Properties?
Observe
Translate
Research - Mapping Prepare
Where is
the LZ (s)?
“POT” =
Happiness
The Research
• Websoils – Online Mapping Tool
• http://websoilsurvey.sc.egov.usda.gov/
• Past Work and Your Experience in the Area
• Site Mapping
• Database of Soil Series
• https://soilseries.sc.egov.usda.gov/
• Reviewing Wetland Maps or Hydric Soils
Directories http://www.fws.gov/wetlands/Data/Mapper.html
Five Soil Formation
Factors
• Organisms
• Climate
• Time
• Topography and
Landscape Setting
• Parent Material
R
0
Name are the 5 Soil Forming Factors ?
Organisms Climate and Climate
Change
Landscape Position Parent Material
Geologic
Time
Landscape and Relief
(Drainage)
Image Source: NJ NRCS, 2002
Water Movement
Soil Drainage
Landscape
Configuration
(Convex, Concave)
Elevation
Water Movement
Landscape Position (Hydrology)?
Discharge Zone Recharge Zone
Unsuitable Alternative Conventional Alternative
Parent Material
• Geological Materials
– Minerals and Rocks
– Glacial Materials
– Loess (wind blown)
– Alluvial Deposits
– Marine Deposits
– Organic Deposits
• Influences
– Minerals Present
– Colors
– Chemical Reactions
– Water Movement
– Soil Development
Glacial Material
Bedrock
Five Soil Formation
Factors • Organisms
• Climate
• Time
• Topography and
Landscape Setting
• Parent Material
R
How is Parent
Material Transformed ?
Additions
Losses
Transformations
Translocations
Examples
Additions – Adding Example: Accumulation of Organic
Material
Loss – Leaching or Erosion
Translocation – Upward, Downward, or Lateral Movement of
material, salts, etc – Salt Accumulation
Transformation – change that takes place in the soil – such as
Formation of redoximorphic features
Types of Parent Material
Form Either Organic or Mineral Soils
Organic Soils Mineral Soils
Mineral Soil
• Is never saturated with water for more than a few days and contains less than 20 % (by weight) organic carbon
• If saturated with water for longer periods or artificially drained and excluding live roots, has an organic-carbon content of: – Less than 18 % if the mineral fraction contains 60% or more
clay;
– Less than 12 %, if the mineral fraction contains no clays; or
– Less than 12 + (clay percentage multiplied by 0.1) %, if the mineral fraction contains less than 60%.
Soil material containing more than the above organic carbon is an organic soil.
Difference Between Organic and
Mineral Soils
Mineral
Soil
Organic
Soil
Potentially Suitable
Organic and Mucky Mineral (Unsuitable)
The Regolith – What ?
• The Regolith is the Unconsolidated
material overlying Rock.
The Overburden !
• This material may be rather thin to
hundreds of feet thick and can
include material dislodged or
weathered from local rock,
transported to the area by wind,
water, ice, or gravity.
Image Source: http:///soils.ag.uidaho.edu
The Soil or Solum
• The Soil or Solum is the portion of the Regolith that has been influenced by the 5 Soil Formation Factors.
• The processes are controlled by Time, Climate, Topography (Landform and Position), Organisms, and Parent Material.
• Formation Process are in 4 Broad Categories (additions, losses, translocation, and transformations)- Genetic Soil Forming Processes.
Rock – R Horizon
SOIL
Regolith
Soil Horizons
• Layer of Soil Parallel
to Surface
• Properties a function
of climate, landscape
setting, parent
material, biological
activity, and other soil
forming processes.
• Horizons (A, E, B, C,
R, etc)
Image Source: University of Texas, 2002
Polypedons and Pedons
• This is the smallest unit used for soil mapping (1 to 10 m2)
• This is a 3 Dimensional Structure that extends to the limits of the genetic soil horizons
• Unit is large enough to describe the vertical and lateral variation in the soil
• Polygonal Surface
• Described as Unit of Sampling
• A combination of pedons is a polypedon.
Polypedon represents a single
soil series or soil individual
Pedon
Polypedon
Pedon
Master Soil Horizons
(Some) • O Horizon- leaf litter / humus
• A Horizon- organic accumulation in mineral soil
• E Horizon- leached horizon (elluviation) (out)
• B Horizon- zone of illuviation (in)
• C Horizon – unconsolidated parent material
• R Horizon – lithic material (Rock)
R
Not All the Master Horizons Will Be Present in All Profiles
Soil Horizons
O- Organic Horizons • Organic Layers of
Decaying Plant and Animal Tissue
• Aids Soil Structural Development
• Helps to Retain Moisture
• Enriches Soil with Nutrients
• Organic Matter Critical in Maintaining Water Stable Peds
• Oi – Fibric - Peat Oe – Hemic- Mucky Peat Oa – Sapric - Muck
O Horizon
Dark in Color Because of
Humus Material - 1,000,000
bacteria per cm3
Soil Horizons
A Horizons: “ Topsoil” • Mineral Horizon Near
Surface
• Eluviation Process Removes Humic and Minerals from O Horizon into A horizon
Subordinates
• Ap - Plowed A Horizon
• Ab - Buried Horizon
• Soil dark in color, coarser in texture, and high porosity
A Horizon
Soil Horizons: E Horizons
Albic Horizon (Latin - White)
• Mineral Horizon Near
Surface
• Deposition of Silicate Clay,
Iron, and Aluminum from the A
Horizon through illuviation
• Horizon does not mean a water
table is present, but the horizon
can be associated with high
water table , use Symbol Eg
(gleyed modifier)
• Underlain by a B (illuvial)
horizon
E Horizon
Soil Horizons: B Horizons
Zone of Maximum Accumulation • Mineral Horizon
• Illuviation is Occurring - Movement into the Horizon
• B Horizon Receives or Accumulates Organic and Inorganic Materials from Upper Horizons.
• Color Influence by Organic, Iron, Aluminum, and Carbonates
Subordinantes
• Bw - Weakly Colored or Structured
• Bhs- Accumulation of illuvial organic material and sesquioxides
• Bs- Accumulation of sesquioxides
• Bt- Translocation of silicate clay
• Bx- Fragipan Horizon, brittle
Bhs Horizon
Bs Horizon
Bw Horizon
Soil Horizons: Bx and Bt Horizons
Bx: B horizon with fragipan, a compact,
slowly permeable subsurface horizon
that is brittle when moist and hard
when dry. Prismatic soil structure,
mineral coatings and high bulk density
Horizons Indicate Reduced Infiltration
Capacity and Permeability
Bt: Clay accumulation is indicated
by finer soil textures and by clay
coating peds and lining pores
Area of Highest
Permeability
along Prism
Contact
C- Horizons Distinguished by Color,
Structure, and Deposition
• Mineral Horizon or Layer, excluding Rock
• Little or No Soil-Forming
• May be Similar to Overlying Formation
• May be Called Parent Material
• Layer can be Gleyed (Redoximorphic Feature)
• Developed in Place or Deposited
• May be Weathered Parent Material
R- Horizons
• Hard, Consolidated
Bedrock
(Lithic Material)
• Typically Underlies a
C Horizon, but could
be directly below an A
or B Horizon.
• CR – Saprolite – not a
soil – “Rock that lost
cement”.
R Horizon
CR
Diagnostic Horizons
• Master horizons describe a soil profile, while diagnostic horizons are used to classify soils.
• Master horizons are based on appearance, diagnostic horizons are based on soil formation processes.
• These two classification schemes are not complementary. Diagnostic horizons can contain all or part of more than one master horizon.
Diagnostic Horizon at Surface
The Epipedon
• An epipedon is the surface, or uppermost
soil horizon.
• It may be thinner than a given horizon,
include all of the horizon, or include the E
or part or all of the B horizon.
The common epipedons in NEPA
• Histic epipedon – wetland soils
• Umbric epipedon – similar to mollic, but
low base saturation ( < 50%)- mollic
epipedon associated with prairie or
grassland soils (grass lands)
• Orchirc epipedon- does meet criteria of
other epipedons
Ochric Epipedon
• This epipedon does not meet the definitions of any other surface horizon. It does not have the thickness, percent organic carbon, or color to be a mollic or umbric epipedon. The ochric epipedon extends to the first illuvial (B) horizon.
Diagnostic Horizon at Depth
Subsurface
• Subsurface horizons develop due to translocation,
transformations and losses. The are zones of
accumulations or changes in the parent material
where color or structure develop.
• Diagnostic subsurface horizons can be categorized
as weakly developed horizons, as horizons
featuring an accumulation of clay, organic matter,
or inorganic salts, as cemented horizons, or as
strongly acidic horizons.
The common diagnostic subsurface
horizons in NEPA
• Cambic
• Fragipan
• Albic
• Argillic
• Spodic
Cambic (Bw)
• Changed or altered by physical movement or by chemical reacions
• Generally -A non-illuvial horizon
• Symbol- Bw or Bg
• Cambic horizons may form as a result of fluctuating groundwater table or in a well-drained position
• Typically associated with structural and/or color change.
Bw
Fragipan (Bx)
• A loamy subsurface horizon, often (but not required to be) underlying a cambic, spodic, argillic, or albic horizon.
• It has a very low organic matter content, high bulk density relative to horizons above it, and hard to very hard consistence.
• It is brittle and appears to be cemented when dry. When moist, it has moderate or weak brittleness, and peds tend to rupture suddenly with pressure. It is usually mottled and has a slow to very slow permeability.
Albic and Spodic
• Albic - Clay, humus, and other coatings have been leached from this eluvial horizon, leaving light-colored sand and silt particles (E)
• Spodic -The spodic horizon is the result of an illuvial accumulation of amorphous materials composed of organic matter and aluminum with or without iron (Bhs/ Bs).
Argillic (Bt)
• This illuvial horizon of mostly high-charged layer silicate clay has clay films on the faces of peds or some indication of clay movement.
• In general, this is a B horizon which has an increase in clay content of at least 1.2 times that of the eluvial horizon above and is, in general, parallel to the surface of the polypedon.
• < 15 % exchangeable sodium.
Soil Horizons: Bx and Bt Horizons
Bx: B horizon with fragipan, a compact,
slowly permeable subsurface horizon
that is brittle when moist and hard
when dry. Prismatic soil structure,
mineral coatings and high bulk density
Horizons Indicate Reduced Infiltration
Capacity and Permeability
Bt: Clay accumulation is indicated
by finer soil textures and by clay
coating peds and lining pores
Area of Highest
Permeability
along Prism
Contact
Describe Horizons
any change in Properties
(at less 2 inches thick)
• Color
• Structure
• Texture
• Redoximorphic Features – “presence of
features is a new horizon”
Describing Soil Color
• Munsell Charts are used to provide
standard descriptions and names of
color. Munsell Chart displays 322
standard color chips.
• The Munsell description is divided
into three parts:
– Hue
– Value
– Chroma
Soil Color Munsell Notations
• Soil Color based on or designated by 3
components:
– Hue – name of the color.
– Value – darkness or lightness of the color.
– Chroma – intensity or strength of the color
• For Example – 10YR4/3
• Hue (10YR), Value (4), Chroma (3)
Special Cases for Describing Color
• For Colors that are pure gray, white, and black. There are no chroma and no hue- these are “pure” colors. The letter N (neutral) takes the place of a hue designation, such as N 2.5/ (black).
• When coloring soil – use a moist soil sample.
• Describe the soil color in the field. Evaluate the color with the sun at your back. No sunglasses !
• Describe a fresh face and do not crush the sample. Describe the matrix and any “mottled” patterns.
• The matrix color is the dominant soil color – 50% or more of the sample.
Ribbon > 2.5 inches Ribbon 1 to
2.5 inches
Ribbon < 1 inch NO Ribbon
Texture
• Use a moist sample.
• Remove Coarse Fragments and Rock
Modifiers
• Describe the relative abundance of sand
(gritty), silt (floury), and clay (sticky) – by
Feel
• Use Rock Modifier
• Full description
• Rock Modifier then Soil Texture, such as:
very gravelly sandy loam
Steps
1. Remove rock modifiers
2. Moisten
3. Knead
4. Can you form a ball?
No - Sand
5. Can you make a ribbon?
No- Loamy sand
6. Ribbon Length
< 1 inch
1 to 2.5 inch
> 2.5 inch
< 1 inch > 2.5 inch
Soil Structure Controls
Water Movement (Rate and Path)
Describing Soil Structure
• Grade – how well the structure is
expressed in place.
• Size – relative size of the structure
• Type – shape of the structure
When described in a soil profile the full description of the
structure is describe in the following order – grade, size,
shape.
Such as: weak medium subangular blocky
Soil Structural Types
• Granular
• Blocky – Angular Blocky
– Subangular Blocky
• Platy
• Wedge
• Prismatic
• Columnar
• Massive
• Single Grain
Structure and Sub-Structure
Structure is Prismatic Within this Structure it is
also Platy
Stable Soil Structural Boundaries
•Redoximorphic features can
form along stable structural
boundaries
•Stable boundaries are part of
macroporosity
Redoximorphic feature along
Platy Boundary
Redoximorphic Feature along Prismatic Boundary
Mottled / Redoximorphic
What Was the Difference?
Associated with alternating periods
of unsaturated and saturation
conditions with alternating aerobic
and anaerobic conditions.
Associated with alternating
periods of unsaturated and
saturation conditions, variation
in moisture, textural variation,
but under aerobic conditions.
Example Description • -2 to 0 leaf litter
• 0 to 3 inches black, silt loam, sl sticky, sulfur
odor, decomposing roots
• 3 to 10 inches 10YR7/2, light brown, gravelly silt
loam, faint fine granular, v. friable
• 10 to 18 inches 2.5RY2/1, grayish brown, gravelly
sandy silty clay loam, moderate strong prismatic
tight
• Approved – Spray Irrigation – LZ 10 inches
• Problems? Yes – the Top of the mineral
horizon is not zero – others?
Goals
• Evaluate all 4 sides of test pits.
• Write Good Full Descriptions.
• Interpret Your Descriptions – What is the
soil telling you?
• Describe an area – Not just a single profile.
• Perhaps add the Master Horizons and
diagnostic horizon short-hand.
• Tell the Story First – Then get your answer!
Prepare Observe Translate
Hope YOU Enjoyed !
The POT Approach !
Prepare Observe Translate
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Document
• © 2014 by B.F. Environmental Consultants Inc. All rights reserved. No part of this document may be reproduced or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission of B.F. Environmental Consultants Inc.
• For permission – Contact Mr. Brian Oram, PG
• 570- 335-1947
http://www.water-research.net http://www.bfenvironmental.com
Continuing Education Credits
for Licensed Professional
• This presentation is part of a 2 hour education
training session.
• If you would like to obtain 2 hours of
continuing education credits or 2 hours of
PDH – please send an email to
[email protected] with your name, address,
license number, state, and contact
information.
• The fee for the credits will be $ 30.00(US)
Soil Classification and Profile
Descriptions
Presented by:
Mr. Brian Oram, PG, PASEO,
Soil Scientist
B.F. Environmental Consultant Inc.
15 Hillcrest Drive
Dallas, PA 18612
http://www.bfenvironmental.com
Histric Epipedon • This organic horizon is water saturated long
enough for reduced conditions to occur unless artificially drained. It is 20 to 60 cm thick and has a low bulk density often less than 1 g cm3.
• The actual organic matter content is dependent on the percent clay. If the soil has not been plowed, it must contain between 12 percent or more organic carbon with no clay and 18 percent or more organic carbon with 60 percent or more clay. When the soil has been plowed, the organic carbon content is from 8 percent with no clay to 16 percent with 60 percent or more clay.
• Hydric Soil – Associated with wetland complex
Umbric Epipedon • Its organic carbon content is 0.6
percent or more resulting in a color value of 3 or less moist, 5 or less dry. Its base saturation is 50 percent or more. It measures a minimum of 18 cm thick if not directly above a petrocalcic horizon, duripan, or a lithic or paralithic contact, and contains less than 250 ppm P2O5.
• It differs from the mollic epipedon by having a base saturation of less than 50%, which requires supporting laboratory data. If the soil is always moist, the restriction of not becoming hard or massive when dry, as in the case for a mollic epipedon, does not apply.