Lecture 15 Soil Morphology and Classification

7/21/2019 Lecture 15 Soil Morphology and Classification

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Soil Morphology and ClassificationSoil Mor

phology and Classification


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The Language of Soils

Loamy, siliceous, hyperthermic grossarenic paleudult

Purpose


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Color

Texture

Structure

Density/Porosity

Water Movement

eactivity of mineral and organic colloidsSoil acidity and p!

Morphology and Classification of Soils

"ased on physical and chemical properties


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Color Dar#/grayish$%lac# color

&range vs' (ray colors

Texture Sandy vs' Clayey

Structure (ood vs' Poor Structure

Density Porosity, organic matter, compaction

Water Pore si)es, porosity, *ater movement, saturation

eactivity Cation exchange capacity

+cidity Plant tolerances, %uffering, %ase saturation

+ll are used to classify soils


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Soil ormation


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actors +ffecting Soil ormation

Climate

&rganisms/-egetationParent material

Topography

Time

The . soil forming factors


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Climate

Temperature and Precipitation

ates of chemical, physical, %iological processes

Cold dry climates *ea# to modest profile development

Warm, humid climates strong, deep profile development


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&rganisms/-egetation

&'M' accumulation

Profile mixing

0utrient cyclingSoil structure

Soil solution 12 "'S'3


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Parent Material

+ffects texture, vegetation, nutrientsclay mineralogy, C4C

Colluvial 1gravity3

+lluvial 1streams3

Marine 1oceans3

Lacustrine 1la#es3(lacial 1ice3

4olian 1*ind3 silt and clay

Deposition


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Topography

Configuration of land surface elevation, slope, depressions

!astens or delays climatic forces'

5mpacts depth of profile development'

Water

4rosion

-egetationSlope

+spect


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Time

Duration of *eathering and all other factors

+dditionslosses

translocations

transformations


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Shands

Limestone

Hawthorne Formation (geologic Clay)

McCarty Hall

4

Sta%le, older sediments

6ounger sediments


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Soil !ori)ons7 first step in classification


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Master !ori)onsMaster !ori)ons

& organic

+ topsoil, &'M', cycling

4 elluvial

" developed/accumulation

C parent material

%edroc#

+ hori)on

" hori)on

C hori)on

& hori)on

Soil Horizon designationsSoil Horizon designations

4 hori)on

&rganic matter

Sandy

Clays/iron

Parent


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4 hori)on

+ hori)on

" hori)on15lluvial3

14lluvial3

C hori)on

R horizon

& hori)on

Master HorizonsMaster Horizons

" hori)on

4nough information8


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Su%ordinate Distinctions


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% %uried hori)onc concretions

d root restrictive

g gleying

h illuial organic matter

# car%onatesm cementation

o ! o"ic

p plowing#distur$ance

9 secondary silica

r soft %edroc# 1saprolite3

s illuvial ses9uioxides and &'M't clay accumulation

v plinthite

w deelopment of color#structure

x $ fragipan

Su%ordinate Distinctions


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Su$ordinate %istinctionsSu$ordinate %istinctions

g gleying

h illuvial organic matter

p plo*ing/distur%ance

t clay accumulation* development of color/structure

o oxic


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(g & gleying)(g & gleying)

:'"ygen depried or reduced state due to water saturation:Reduction of iron (Fe to Fe ):low chroma:'ften used with * master horizon (*g horizon)+ also , and C horizon

gleyed

material

oxidi)ed

material

oxidi)ed

e; ?*ea#@

Commonly used *ith the

" master hori)on 1e'g' "*3"*

Su%ordinate Distinction


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o > oxic hori)on

Lo* activity clays

e* *eathera%le materialsLittle roc# structure

e and +l oxides



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Su$ordinate %istinctionsSu$ordinate %istinctions

g gleying

h illuvial organic matter

p plo*ing/distur%ance

t clay accumulation* development of color/structure

o oxic


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Su%ordinate Distinctions and &rganic Matter


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a, e, i

Denotes the degree of organic matter decomposition

in the & hori)on'

&a highly decomposed 1sapric3&e moderately decomposed 1hemic3

&i slightly decomposed 1fi%ric3

Sapric most decomposed, lo* plant fi%er, lo* *ater content

!emic intermediate decompostion

i%ric least decomposed, recogni)a%le fi%ers



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SummarySummary

Master7 &, +, 4, ", C,

Su%ordinate sym%ols7 g, h, p, t, * and a,e,i

4xamples7 &a, &e, &i"t

"g

"tg

"*

+p


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&ther Designations


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-ertical Su$diisions-ertical Su$diisionsCharacteri)ed %y similar master and/or su%ordinate

properties separated %y ?degree@'

"tB

"t=

"t;

Bt horizons


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.ransitional Horizons.ransitional Horizons

Transitional layers %et*een master hori)ons'

+44"

"4

Dominant

character

Su%ordinate

Character


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Soil Classification#.a"onomySoil Classification#.a"onomy

"ased on soil profile characteristics and

the concept of soils as a natural %ody'

&%serva%le properties7 color, texture, structure,

p!, &'M

Soil Profile!ierarchical

(enesis

B; -'-' Du#achaev7 climate, vegetation, soil

BE=F C'' Mar%ut 1ASD+3 applied to A'S' 1BEG.3


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Soil Classification/TaxonomySoil Classification/Taxonomy

:+damsville7 !yperthermic, uncoated +9uic Huart)ipsamment

ASD+ classification system

Soil Survey Staff BEG.

Soil Taxonomypu%lished BEF.


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&rder

Su%order

(reat group

Su% group

amily

Series

B=

BE,III

Soil .a"onomy HierarchySoil .a"onomy Hierarchy

G;

=.I

BJII

III

KingdomPhylum

Class

&rder

amily

(enus

Species


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/nits for Soil Classification/nits for Soil Classification

Pedon smallest three$dimensional unit that displays the full range of properties characteristic of

a given soil' 1B$BI m=of area3

$ the fundamental unit of soil classification

Polypedon group of closely associated pedons in the field

Soil Series class of soils *orld$*ide *hich share a common

suite of soil profile properties


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Soil Sampling /nitsSoil Sampling /nits

Mala$ar Series


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%iagnostic Horizons for Classification%iagnostic Horizons for Classification

Surface

Su%surface


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%iagnostic Surface Horizons%iagnostic Surface Horizons

4pipedons MollicAm%ric

&chric

!istic

Melanic

Plaggen

+nthropic


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Mollic ,pipedonMollic ,pipedon

Thic#ness B$=. cm

Color value ;'. moist

chroma ;'. moist

&rganic Car%on I'G 2

"ase Saturation .I 2Structure stronglydeveloped

&rganic car%on > organic matter x I'.F


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/m$ric ,pipedon/m$ric ,pipedon

Meets all criteria of the Mollic epipedon,

except %ase saturation .I2

Chemically different than Mollic


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'chric ,pipedon'chric ,pipedon

Too7 thin

light

lo* in &'M

Mollic

Am%ric

&chric > pale

4xtremely common


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Histic ,pipedonHistic ,pipedon

&rganic hori)on

ormed in *et areas

"lac# to dar# %ro*n

Lo* %ul# density

=I$;I cm thic#

&rganic > =I2 $ ;.2 &'M'

1*ater saturation, clay content3


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Melanic 4pipedonMelanic 4pipedon

Similar in properties to Mollic

ormed in volcanic ash

Light*eight, luffy


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+nthropic !ori)on+nthropic !ori)on

:esem%les mollic

1color, o'm'3:Ase %y humans:Shells and %ones:Water from humans


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Plaggen 4pipedonPlaggen 4pipedon

Produced %y long$term 1BIIs yrs'3 manuring

&ld, human$made surface hori)on

+%sent in A'S'

.I cm thic#


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%iagnostic Surface Horizons%iagnostic Surface Horizons

4pipedons

Mollic

Am%ric&chric

!istic

Melanic

Plaggen+nthropic

-ery common

!uman$derived

?speciali)ed@


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-egetation

esta%lished

&'M' accumulation

time

&rganic Matter +ccumulation&rganic Matter +ccumulation

!istic

Mollic, Am%ric

ochric

Parentmaterial

tmax> ;III yrs


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Diagnostic Su%$surface !ori)ons


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&rganic Matter Clays &xides

smectites

Su$surface HorizonsSu$surface Horizons

Kaolinite

+lso7 salts, car%onates, sulfides

Dar# colors

Metals 1e, +l35ron

+luminum

ormation

Translocation

Transformation

Di ti S % f


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Diagnostic Su%surfaceDiagnostic Su%surface

!ori)ons!ori)ons

+l%ic

+rgillic

Spodic&xic

Kandic

Cam%ic

Som%ricsulfuric

0atric

+gric

Calcic(ypsic

Salic

Duripan

ragipanPlacic

Su%$!ori)on Designations


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%iagnostic Su$surface Horizons%iagnostic Su$surface Horizons

+l%ic 1*hite3 !ori)on

Light$colored 1-alue G moist 3

4lluvial 14 master hori)onN3

Lo* in clay, e and +l oxides

(enerally sandy textured

Lo* chemical reactivity 1lo* C4C3

Typically overlies "h or "t hori)ons

al%ic

Nnot all 4 hori)ons are al%ic hori)ons


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+rgillic !ori)on5lluvial accumulation of silicate clays

5lluvial %ased on overlying hori)on

Clay %ridges

Clay coatings



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+rgillic !ori)on Kandic !ori)on

+ctivity of Clays!igh Lo*

5lluviation of clay0ecessary 0ot 0ecessary


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Spodic !ori)on

Spodic

:5lluvial accumulation of organic matter

and aluminum 1


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4lluviation 14 hori)on and + hori)ons3

&rganic matter Clays

Spodic hori)on

"h hori)on "t hori)on

+rgillic hori)on

,lluiation and lluiation,lluiation and lluiation

+

4

"h

+

"t

4

%i ti S $ f%i

ti S $ f


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%iagnostic Su$surface%iagnostic Su$surface

HorizonsHorizons

&xic hori)on:!ighly *eathered 1high temperatures, high rainfall3

$ !igh in e, +l oxides

$ !igh in lo*$activity clays 1#aolinite smectite vermiculite3activity


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+l%ic

Kandic

+rgillic

Spodic

&xic

%iagnostic Horizons%iagnostic Horizons

Mollic

Am%ric&chric

!istic

Melanic

Plaggen

+nthropic

4pipedons Su%surface


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Soil .a"onomySoil .a"onomyDiagnostic 4pipedons

Diagnostic Su%surface hori)ons

Moisture egimesTemperature egimes

Documents

Lecture 15 Soil Morphology and Classification