Soil defined
 Soil classification and identi...
 Category I - orders
 Category V - families
 Practical classifications...
 Class V land
 Soil identification
 Soil areas

Title: Soil classification, identification, and survey
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00078698/00001
 Material Information
Title: Soil classification, identification, and survey
Physical Description: Book
Creator: Brown, R. B.
Publisher: Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida
Subject: University of Florida.   ( lcsh )
Spatial Coverage: North America -- United States of America -- Florida
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Bibliographic ID: UF00078698
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida

Table of Contents
    Soil defined
        Page 1 (MULTIPLE)
    Soil classification and identification
        Page 2 (MULTIPLE)
    Category I - orders
        Page 3 (MULTIPLE)
    Category V - families
        Page 4
    Practical classifications of land
        Page 5 (MULTIPLE)
    Class V land
        Page 6 (MULTIPLE)
    Soil identification
        Page 7 (MULTIPLE)
    Soil areas
        Page 8
        Page 9
        Page 10
Full Text


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source

site maintained by the Florida
Cooperative Extension Service.

Copyright 2005, Board of Trustees, University
of Florida

Soil Classification, Identification, and Survey1

R. B. Brown2


Soil is a natural body composed of minerals,
organic matter, water, and air which covers the earth's
surface and is capable of supporting plant growth. A
typical mineral soil contains approximately 45%
mineral materials, 5% organic matter, 25% soil water,
and 25% soil air (by volume). Other soils, of course,
may vary widely from these proportions depending on
their nature and mode of formation. The organic
matter content of Florida soils, for example, ranges
from practically zero in some of our sand dunes to
almost 100% of the solid portion of some soils in the
Florida Everglades, with 1 to 5% being more
commonly found in the surface layers of most soils.

There are many different kinds of soil. Each and
every soil has a profile which consists of a succession
of layers extending down to bedrock. The nature of
the soil profile has considerable influence on the
growth of plants. It influences root growth, moisture
storage, and the supply of plant nutrients. The
scientific study of the profile is fundamental to the
understanding of a soil's nature and development, for
it carries within itself a record of its history for those
who would desire to read it.


A soil profile is a vertical section of the soil
extending from the surface down through all of its
horizons -"A," or surface soil; "E" and "B," or subsoil;
and "C," or unconsolidated materials; above the solid
bedrock, "R." For detailed information on horizon
designations and soil profile descriptions, see Soil
Science Fact Sheet SL-41, new Soil Profile and
Horizon Designations (1984) by M.E. Collins and V.
W. Carlisle.


"Soil Texture" is a term commonly used to
designate the proportionate distribution of the
different sized mineral particles in a soil. It does not
include organic matter. These mineral particles vary
in size from those easily seen with the unaided eye to
those below the range of a high-powered microscope.
According to their size, these mineral particles are
grouped into "separates." A soil separate, then, is a
term used to designate a grouping of these mineral
particles, such grouping to be based on definite
diameter limits usually expressed in millimeters (mm).
The classification of mineral soil particles by the
U.S.D.A. is as shown in Table 1.

1. This document was published December 1992 as RF-AA001, Florida Cooperative Extension Service. For more information, contact your
county Cooperative Extension Service office.
2. Extension Soil Scientist, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville.

The Institute of Food and Agricultural Sciences is an Equal Opportunity/Affirmative Action Employer authorized to provide research, educational
information and other services only to individuals and institutions that function without regard to race, color, sex, or national origin.
Florida Cooperative Extension Service / Institute of Food and Agricultural Sciences / University of Florida / John T. Woeste, Dean

Soil Classification, Identification, and Survey

Table 1. Particle Size Distribution of Two Florida Soils

Very coarse sand 2.00 1.00 2 1 0 1
Coarse sand 1.00 0.50 11 7 12 11
Medium sand 0.50 0.25 18 12 40 33
Fine sand 0.25 0.10 31 21 37 38
Very fine sand 0.10 0.05 20 14 7 7
Silt 0.05 -0.002 11 7 4 6
Clay less than 0.002 7 38 0 4
100% 100% 100% 100%

Since these various sized particles have quite
different physical characteristics, the nature of
mineral soils is determined to a remarkable degree by
the particular groups that are present in larger
amounts. Thus, a soil possessing large amounts of clay
has quite different physical properties from one made
up mostly of sands and silts. The analytical procedure
by which the percentages of the various soil separates
are obtained is called a "mechanical analysis" or a
"particle size determination". It should now be
obvious that any and all mineral soils are made up of
a mixture of soil separates, and it is on the basis of
the proportion of these various separates that the
textural class names of soils are recognized. There
are twelve major classes of soils. Their composition is
shown by a diagram called the "soil textural triangle"
(See "Soil Texture"--Soil Science Fact Sheet SL-29.)


These two terms, "classification" and
"identification," are often confused as being
synonymous. Such confusion is perhaps caused by
their close relationship.

Soil Classification is the logical grouping of
individual soils into certain taxonomic groups or
categories according to their similarities to one
another. Such a grouping will include many
individual soils that have been recognized as well as
those that have not.

Soil Identification is the recognition of an
individual soil according to its location and profile
characteristics and its subsequent placement into an

already predetermined scheme of classification. For
example, an agricultural worker can identify a soil if
sufficient information is known about that particular

Both "classification" and "identification" of soils
are important. Of the two, however, soil identification
is more important to the farmer and to the
agricultural worker than is classification. These
people are primarily interested in being able to
identify a particular soil; by doing so they will know
many of that soil's characteristics by referring to
research data that have been collected on that same
kind of soil in other localities. Such identification will
also greatly aid other agricultural scientists in
assessing the productivity of that soil and enabling
them to make good recommendations as to its best
use and management.


Soils have been classified in some manner or
another for hundreds of years. They have been
grouped according to their (1) agronomic use good
wheat soil, poor corn soil, etc.; (2) color black soil,
red soil, etc,; (3) organic matter content mineral
soil, muck soil, peat soil, etc.; (4) texture sand, sandy
loam, loam, etc.; (5) moisture condition wet soil, dry
soil, etc,; and many other soil characteristics. Each of
these groupings serves a particular purpose; however,
they are not very scientific or up-to-date according to
our present knowledge of soil genesis, morphology,
and classification. In fact, a new system of soil
classification was adopted for use in the United States
on January 1, 1965. The development of this
classification began in 1951 and underwent a series of

Page 2

Soil Classification, Identification, and Survey

seven major revisions or approximations. Gradually,
a workable system evolved which can be used to
classify soils anywhere in the world, and it is hoped
that other countries will also adopt and use it.
Basically, this new system treats soils as individual
three-dimensional entities which can be grouped
together according to their similar physical, chemical,
and mineralogical properties. Categories of this
system of classification and properties of soil used to
subdivide different groups of soils within each
category are discussed in the following paragraphs.
Since this is a new system of soil classification, it is
being tested continuously and slight modifications
may be anticipated.

Category I -- Orders

These divisions are based on broad dil ffr nI~ s in
measurable and visible characteristics of certain kinds
of soil horizons. The presence or absence of these
definite kinds of layers indicates either the dominant
active soil-forming process which has caused that soil
to develop as it has, or the lack of such development.
There are ten soil orders, many of which fall into
definite geographic ranges which are indicative of the
importance of climate. Nine of these orders are used
to classify the mineral soils, and one order includes all
of the organic soils. The soil orders are: Entisols,
Mollisols, Vertisols, Inceptisols, Aridisols, Spodosols,
Alfisols, Ultisols, Oxisols, and Histosols. These
orders and their origins are shown in Table 2.

Category II -- Suborders

Each of the orders is divided into several
suborders, each of which in turn consists of soils
grouped together which have somewhat similar
developmental characteristics. The characteristics used
to group soils within the same suborder include such
properties as accumulation of soluble materials within
the profile, degree of mottling as reflected by
moisture conditions, presence or absence of B
horizons, and broad diff ri .nc in mineralogy and
chemistry. Of course, the same criteria are not always
used to classify soils into suborders within each and
every order.

Page 3

Table 2. Origins of Soil Orders
Order Word Origin
Entisol Ent from "recent", a nonsense
Vertisol L. verto, meaning "turn" or
Inceptisol L. inceptum, meaning "beginning"
Aridisol L. aridus, meaning "arid" or "dry"
Mollisol L. mollis, meaning "soft"
Spodosol Gk. spodos, meaning "wood ash"
Alfisol Alfi from "pedalfer", a nonsense
Ultisol L. ultimus, meaning "last" or
Oxisol F. oxide, meaning "oxide"
Histosol Gk. histos, meaning "tissue"

Category III -- Great Groups

The suborders are further subdivided into great
groups each of which consists of soils grouped
together based largely on the presence or absence of
certain kinds of important horizons that have not
already been used in the broader categories above.
The relative thickness of these soil layers is also
important. Other soil properties which are often used
include color, degree of base saturation, tonguing of
one soil horizon into another, irreversible hardening,
and the presence or absence of self-mulching clays.

Category IV -- Subgroups

Each of the great groups is further subdivided
into several subgroups, with the typical or central
concept of a great group making up one of the
subgroups. This subgroup has the same name as the
great group, prefixed with the word typicc." Other
subgroups have soil characteristics that are somewhat
similar to both those of the central concept and to
those of another classification unit. They are said then
to be "intergrades" and carry the names of both
classification units, the last term indicating the
dominating properties of that particular soil.

Soil Classification, Identification, and Survey

Category V -- Families

Each subgroup is divided again into several
families, each of which consists of soils grouped
together according to their textural classes,
mineralogy, reaction (acid or nonacid), and soil
temperature. Such characteristics generally are
indicative of plant response, so that soils grouped
together in the same family are thought to react in a
similar manner to the same crops grown under the
same system of management.

Category VI -- Series

The definition of soil series has not been changed.
It still consists of a group of soils similar to each
other in all their profile characteristics except for
texture of the surface soil. Several closely similar soil
series, of course, are usually grouped together in the
same family.

Soil Types and Phases

Soil types and soil phases are also terms used in
classifying soils but are no longer recognized as
categories within the system. A soil type consists of
a group of soils similar to one another in all their
profile characteristics including the surface texture. A
soil phase is usually used to explain some minor
variation within a soil series or soil type that is not
significant to the classification of the soil in its natural
landscape but may be important to the use and
management of the soil. Example: Lakeland fine sand,
sloping phase is a soil belonging to the Lakeland fine
sand; and it occurs on sloping topography rather than
on level, gently sloping, or steep slopes.

The names of the suborders, great groups, and
suborders automatically identify the order to which
they blN1'nL,, because each term includes a portion of
the soil order name. For example, soils of the
suborder Aquods are the wetter soils (L. aqua for
"water") of the Spodosol order and include the letters
"od" in both order and suborder names. Likewise, the
name of the great group identifies the suborder and
order of which it is a part. Haplaquods are aquods
with a certain kind (Gr. haplous, meaning "simple") of
horizon within the profile. If the soil is considered to
be near the middle concept of all Haploquods, the
subgroup designation is obtained by placing the term
typicc" in front of the great group name. This can be
illustrated in Table 3.

Page 4

Table 3. Sample Classification Terms
Order Spodosol
Suborder Aquod
Great Group Haplaquod
Subgroup Typic Haplaquod

Thus, it can be seen that, if only the subgroup of
any soil is known, a person familiar with this
classification system would also know the great group,
suborder, and order to which that soil belonged. If a
soil is not considered to be typical of the central
concept of the great group, one or more other terms
are prefixed to the great group name to explain in
what manner the soil varies from the modal concept.
This can be illustrated in a diagram which also shows
certain family criteria and selected soil series (See
"Soils of Florida" section of latest Florida Soil
Identification Handbook for such a diagram).


The terms "land" and "soil" are often used
interchangeably; however, the term "land" has a much
broader meaning. The term "land" usually connotes
"use"; for example, forest land, crop land, waste land,
etc. As such, these lands are made up of many
different kinds of soils. There are, of course, many
different ways in which we can classify our lands into
types or classes. The kind of soils is one of the
determining factors in any land type or class. In a
land classification system, soils are grouped according
to their suitability for certain uses. It is based on
land-surface features and soil properties that can be
evaluated. Such an appraisal includes certain basic
factors relating to both the topsoil and subsoil soil
type, slope, degree of erosion, etc.

While several systems are used in classifying land,
some are rather simple, while others are more
technical and scientific.

Simple Classification of Land

Simple classifications are often useful to people
who are buying or selling land; however, they are not
as scientific as the present-day practical systems which
are discussed below.

Soil Classification, Identification, and Survey

An example of a simple classification of land is
illustrated by the way a citrus farmer might classify his
citrus land: (1) good citrus land, (2) fair citrus land,
(3) poor citrus land, (4) land unfit for citrus. Another
grower, might classify his land as: (1) good corn land,
(2) fair corn land, and (3) poor corn land; or as (1)
good pasture land, (2) fair pasture land, and (3) poor
pasture land. A similar classification is sometimes
made for timberland as well as for land used in other

Banks and other lending agencies often place a
monetary classification on land, such as: (1) $1,000 per
acre land, (2) $500 per acre land, (3) $200 per acre
land, and (4) $50 per acre land.

Practical Classifications of Land

Several practical land classification systems are
presently in use. For example, the agronomist may
classify land on the ability of soils to grow the
common field crops. Such a classification might be as
shown in Table 4.

Table 4. Practical Land Classification
Class I Excellent land
Class II Good Land
Class III Fair land
Class IV Poor land
Class V Land unfit for field crops

The forester may classify land in still another way
- according to the rate of tree growth; using good,
fair, poor, etc., as land classes.

One of the most widely used systems of land
classification is one that was developed by the Soil
Conservation Service as a basis for its work
throughout the nation. This system divides all lands
into eight capability classes, each being based on the
capability of the land to produce and withstand
cultivation without appreciable erosion or fertility
losses (Table 5). Each class in this system, as well as
other systems, represents a combination of soil
conditions such as soil type, slope of land, degree of
erosion, etc. The land capability classes are as

Page 5

Class I Land

Composed of soils having few, if any, limitations
that restrict their use. Such land is nearly level and
does not erode readily. The topsoil is deep and easy
to work. It holds water well, but some areas may
need water management. It is fairly well-supplied
with plant nutrients. Anyone who is fortunate
enough to have some of this land can use it safely in
almost any way that he chooses. Naturally, he would
want to use it for his highest income crops and, of
course, it should be well-managed in order to
maintain both a good supply of plant nutrients and
good physical conditions.

Class II Land

Composed of soils having some limitations that
restrict the choice of crops or require moderate
conservation practices. Such land can be cultivated
safely, but has certain physical conditions that make
it not quite as good as Class I land. The slope may be
just steep enough to make water run off at a speed
that will carry away some soil. Some Class II land is
naturally wet and requires some drainage. Since class
II land has some moderate use limitations, some
special treatment is required which may include the
use of conservation practices such as contouring,
protective cover crops, simple water management,
crop rotations, or the use of more fertilizers.

Class III Land

Composed of soils having severe limitations that
reduce the choice of crops or require special
conservation practices or both. Such land can be
cultivated safely if such intensive treatments as
terracing and strip cropping are followed. Usually,
Class III land on flat areas needs some kind of water
management. The limitations of Class III land may
be the same in general as those of Class II land, but
are present to a greater degree.

Class IV Land

Composed of soils that can still be used for
cultivation, though very severe limitations on the
choice of crops and very careful management may be
required. Ordinarily, row crops cannot be grown
safely and close-growing crops are used extensively.
Choice of crops may be limited by erosion hazards or
excess moisture. One or more of the following

Soil Classification, Identification, and Survey

constitute the most limiting factors of these soils:
steep slopes, severe erosion, shallow soil, poor
drainage, low water-holding capacity, or severe alkali
and/or salinity.

Class V Land

Composed of soils generally not suited to
cultivation and limited in their safe use by factors
other than erosion hazards. Examples of such
limitations are as follows: soils subject to frequent
stream overflow, too-short growing season for plants,
stony or rocky soils, and ponded areas not feasible to

Class VI Land

Composed of soils having several limitations that
restrict their use largely to pasture, range, woodland,
or wildlife. The limitations are similar to, but more
severe than, those for Class IV land.

Table 5. Land classes and safe uses.

Prime and Unique Farmlands

Another approach to land designation that has
taken on increased importance in recent years is the
identification of "prime and unique farmlands" by the
U.S. Soil Conservation Service.

Page 6

Class VII Land

Composed of soil having very severe limitations
which restrict their use to grazing, woodland, or
wildlife. The limitations are the same as for Class VI
land except more severe. Even pasture improvement
is impractical.

Class VIII Land

Composed of soils that should not be used for any
kind of commercial cropping. The limitations are so
difficult to overcome that the use of these soils should
be restricted to "recreation, wildlife, water supply, or
aesthetic purposes". Examples of Class VIII land
include sandy beaches, rock outcrops, and river


Each land capability class (with the exception of
Class I) is further subdivided into subclasses based
upon the dominant limitations for agricultural use.
These are as follows: erosion (e), wetness (w), root
zone limitations (s), and climatic limitations (c).

Prime farmland is land that has the best
combination of physical and chemical characteristics
for producing food, feed, forage, fiber, and oilseed
crops, and is also available for these uses (that is, it is
not wetland or built-up urban land). It has the soil
quality, growing season, and moisture supply needed
to produce sustained high crop yields under treatment
and management. Most of Florida's prime farmland


Recreation & Wildlife X X X X X X X X
Forestry X X X X X X X
Limited Grazing X X X X X X
Intensive Grazing X X X X X
Limited Cultivation X X X X
Moderate Cultivation X X X
Cultivation X X (No Cultivation Below Class IV)
Very Intensive Cultivation X

Soil Classification, Identification, and Survey

is located in the northern and western parts of the

Unique farmland is land other than prime
farmland that is used for production of specific
high-value food and fiber crops. It has the special
combination of soil quality, location, growing season,
and moisture supply needed to produce sustained
high quality and/or high yields of a specific crop when
treated and managed appropriately. Among the
high-value food crops that, when combined with other
favorable factors, qualify lands as unique farmlands
are: citrus, avocado, mangos, papayas, strawberries,
vegetables, and sugarcane. Most of Florida's unique
farmland is located in the central and southern parts
ofthe state.

Prime and unique farmlands have been identified,
county-by-county, across Florida. For information on
where these lands are located, contact the Soil
Conservation Service.

For additional information on farmlands in
Florida and the U.S., and on trends in the use of
these lands, see:

-Notes in Soil Science, No. 5, The National
Agricultural Lands Study (April 6, 1981).

-Notes in Soil Science, No. 7, Agricultural
Lands in Florida--Summary of the Legislative
Staff Report to the House Committee on
Agriculture and General Legislation (May 14,

-Florida Agricultural Land Use--What Do We
Know? pp. 28-45 In Proceedings of First
Agricultural Policy Forum on Public or
Private Property Rights. Available from R.
Clouser, Food and Resource Economics

Soil Science Fact Sheet S1-36, Land Use
Planning and Farmland Retention (May,

-Farmland Notes. Newsletter of NASDA
Research Foundation Farmland Project, 1616
H St. NW, Washington, D.C. 20006.

Page 7

Notes in Soil Science, No. 8, Identification of
Important Farmland in Florida (September
20, 1982).

Symposium: The Future of Agriculture Land
in Florida. Soil and Crop Science Society of
Florida Proceedings, Vol. 41, 1982. Reprints
available from IFAS Soil Science Dept.

Soil identification

In soil identification, soils are recognized as
belonging to a certain soil series by their similarities
in most, if not all, of the following criteria:

1) Number of horizons
2) Arrangement of horizons
3) Thickness of horizons
4) Color of horizons
5) Texture of horizons
6) Structure of horizons
7) Chemical composition of horizons
8) Geology of parent material

If two soils are similar to one another in all of these
characteristics, they must be placed into the same
series and be given only one series name. If two soils
differ from one another in two or more of these
characteristics, they cannot belong to the same series
and, therefore, are two different kinds of soils.

When attempting to identify a particular kind of
soil, one needs to know as much as possible about
that particular soil, its profile characteristics, its
general location within the state, and the properties
of other somewhat similar soils in the same general

Soil regions

A soil region is a physiographic division based on
origin of the soil material. All of Florida is a portion
of a broad province known as "coastal plain soils", and
consists largely of sands and clays overlying limestone
at variable depths. In places, this limestone outcrops
at the surface; in others, it is several hundreds of feet

Soil Classification, Identification, and Survey

Soil areas

A soil area is a smaller geographic division than
a soil region. The state of Florida has several such
divisions based on location, topography, native
vegetation, and the physical and chemical nature of
the soils (See Section 1-2, Soil Conservation). Each
soil area is unique in that it contains a certain kind or
group of somewhat related soils. As an example, soils
of the northern portion of west Florida tend to be
fine-textured, with clay contents that are considerably
higher than those most of other areas. Also, soils of
the central ridge section are composed mostly of thick
deposits of sands which are well to excessively drained
and are quite acid in reaction. Soils of the Florida
Everglades have large amounts of organic materials
and are classified as peats and mucks.


Modern soil surveys are underway at a rapid pace
in Florida. Status of mapping and publication is
shown in Table 6.

Table 6. Status of modern soil surveys as of September, 1

For copies of Soil Survey Reports or for related
information on soil classification and survey in a
county, contact the Soil Conservation Service.

Additional information on types of soil surveys
and uses that can be made of them is available in Soil
Science Fact Sheet Sl-11, The Nature and Use of a
Soil Survey (1977) by R. E. Caldwell, and in "Guide
to the Practical Use of Soil Surveys," published
cooperatively in 1984 by the SCS and IFAS.

See also the 1982 generalized Soil Map of
Florida, by Caldwell and Johnson, available from the
SCS or from the Soil Science Dept., and the 1981
Atlas of Florida, edited by E.A. Fernald, Fla. State
Univ. Foundation, Inc., Tallahassee.

Alachua --- --- X
Baker --- X ---




Page 8

Soil Classification, Identification, and Survey Page 9


Franklin --- X ---
Gadsden --- --- X
Gilchrist --- X ---
Glades --- X
Gulf --- X
Hamilton --- X ---
Hardee --- --- X
Hendry --- --- X
Hernando --- --- X
Highlands --- --- X
Hillsborough --- --- X
Holmes --- --- X
Indian River --- --- X
Jackson --- --- X
Jefferson --- --- X
Lafayette X -
Lake --- --- X
Lee --- --- X
Leon --- --- X
Levy --- X
Liberty X -
Madison --- --- X
Manatee --- --- X
Marion --- --- X
Martin --- --- X
Monroe --- X ---
Nassau --- --- X
Okaloosa --- X ---
Okeechobee --- --- X
Orange --- --- X
Osceola --- --- X
Palm Beach --- --- X
Pasco --- --- X
Pinellas --- --- X
Polk --- --- X
Putnam --- --- X
St. Johns --- --- X
St. Lucie --- --- X
Santa Rosa --- --- X

Soil Classification, Identification, and Survey Page 10


Sarasota --- --- X
Seminole --- --- X
Sumter --- --- X
Suwannee --- --- X
Taylor X -
Union --- --- X
Volusia --- --- X
Wakulla --- --- X
Walton --- --- X
Washington --- --- X

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