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

• bfenviro@ptd.net

• 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

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PDH – please send an email to

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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.

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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

• bfenviro@ptd.net

• 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

bfenviro@ptd.net 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.