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CLASSIFYING

RANGELAND

FOR

CONSERVATION

PLANNING

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Agriculture Handbook No. 235

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^ ,j^ U.S. Department of Agriculture

"^ Soil Conservation Service
CONTENTS

Page

Range sites 1

Relation to the environment 1

Determining the climax plant community 2

Permanence of the range site 2

Distinctions between range sites 2

Naming range sites 4

Correlation of range-site names 5

Descriptions of range sites 5

Range sites and standard soil surveys 7

Identifying range sites vifhere standard soil surveys

are available , 7

Identifying range sites where there is no standard

soil survey 7

Cartographic considerations 7

Page

Range condition 8

Determining range-condition classes 8

Evaluating forage on grazed woodland 14

Examples of range sites and range-condition classes.. 14

Trend in range condition 45

Vigor of plants 45

Seedlings and young plants 45

Changes in plant composition 45

Plant residues 4^

Condition of the soil 45

How information on range sites and range condition is

used in conservation planning 47

Use of initial stocking rates by range sites and condition classes 4-7

COLO -1118 0

Coi'er picture: A range landscape showing six range sites. Each range site has distinctive kinds of soil and is capable oj producing a distinctive kind and

amount of native forage plants.

Issued October 1962

Washington, D.C.

For sale by the Superintendent of Uocuments, U.S. Government Printlnp Ollice Washington 25, D.C. - Price 25 cents
Classifying Rangeland for Conservation Planning

by F. G. Renner, former Head Range Conservationist, and B. W. AUred, Head Range Conservationist, Soil Conservation Service

Attempts to appraise the resources of rangeland and to develop

information useful in its management have been underway in the

United States for about 50 years. This problem has been approached in many ways, and the opinions on the kind of information needed have been as varied as the methods proposed for its

collection and evaluation.

Rangeland is land on which the climax, or potential, plant

community consists principally of native grasses, forbs, and

shrubs that are valuable for forage and are in sufficient quantity

to justify its use for grazing. It includes natural grassland,

savannas, and certain kinds of woodland and chaparral useful

for grazing.

Some workers have attempted to evaluate rangeland on the

basis of the digestible nutrients produced. Others have emphasized chemical analysis of individual plant species. Still others

have sought the key to successful management in plant indicators,

in stages of plant succession, in forage types and" forage acres,"

and in the relation of forage production to annual rainfall.

From this experience ir is clear that the successful management

of rangeland has two requirements. The landowner needs to

know the capability of different kinds of rangeland in terms of

the kind and quantity of forage they can be expected to produce,

and he must be able to appraise their present condition in relation

to what can be expected.

This bulletin describes the procedures used in the Soil Conservation Service to collect information on the capability of

rangeland, explains the ecological basis for range sites, and

shows how this information is used in conservation planning.

Range Sites

Simply defined, a range site is a distinctive kind of rangeland

that has a certain potential for producing range plants. Its

inherent productive capacity, like that of other agricultural land,

depends on the combined effect, or interaction, of the soil and

climate peculiar to it. The ultimate expression of its particular

combination of environmental conditions is the characteristic

plant community that occurs on it. Furthermore, the range site

retains its capacity to reproduce this climax plant community so

long as the environment remains unchanged.

Relation to the Environment

A range site is the product of all its environmental factors,

and its distinctive climax community is relatively uniform

throughout the site. Accordingly, a range site is not only an

entity of the environment but is also a specific area of land whose

characteristic features can be recognized and described.
Determining the Climax Plant Community

Because of variations in the microenvironment within a site,

the relative composition of any natural plant community varies.

Consequently, the native plant community that represents the

climax for the site consists of a characteristic grouping of species

and not of precisely defined proportions. Several methods, of

which the following are the most important, are used to determine the nature of the climax plant community.

1. Evaluation of the relict vegetation and the soil on protected or relatively undisturbed areas.

2. Evaluation of grazed areas that have similar soil, topography, and climate where grazing records are available.

3. Evaluation of data from ecological and soil research.

4. Observations on areas currently receiving various degrees

of grazing use and on areas excluded from this use.

5. Historical accounts, including early photographs and

ecological and botanical literature.

Evidence from any single source is not likely to be conclusive.

Furthermore, particular care must be taken to evaluate the facts

to be certain that they are not the result of some abnormal condition such as drought, excessive soil removal or deposition by

wind or water, fire, too many rodents, or too much snow or

water. Some degree of disturbance is normal on all sites, and

the disturbance may or may not be the result of grazing. Generally, however, it may be assumed that the plant community on

areas that have not been subject to pronounced disturbance most

nearly represents the potential community for that site.

Permanence of the Range Site

Range sites are subject to many disturbances that modify or

temporarily destroy the vegetation but do not preclude the reestablishment of the climax plant community. Examples are

drought, grazing, fire, and short-term tillage. Unless particularly severe, the effect of these disturbances usually is corrected

by time or by improved management or other measures, and the

potential of the range site itself is not permanently changed.

But if these disturbances are so severe and so prolonged that

they cause severe erosion, reduce fertility, change the position

of the water table, or otherwise change soil conditions to the

extent that revegetation is seriously affected, the productive

capacity of the site is changed. In such places, a different range

site consistent with the altered potential is recognized.

On some ranges of California characterized by a Mediterranean

climate, the original, or native, plant communities have been

replaced by equally, or more highly, productive annuals. On

these ranges, the goal of management may be improvement of the

present vegetation rather than restoration of the original perennials.

Distinctions Between Range Sites

Different range sites are recognized because of (1) differences

in the kinds or the proportions of plants that make up the

potential plant communities or (2) differences in the total yield

if the vegetation in the potential plant communities is nearly the

same.

To be useful in conservation planning, the difference in the

kind or amount of vegetation must be great enough to require

some change in management, such «s a different rate of stocking.

Different range sites are not recognized because of differences in

soil or in climate unless these factors result in a significant

difference in the potential plant communities.

Individual factors of the environment are useful in distinguishing one range site from another only to the degree that they

regularly occur with differences in the climax vegetation. The

effect of differences in some factors is obvious. In soil, for
example, the presence or absence of a water table in the root zone,

or a high degree of salinity as contrasted to a nonsaline condition,

is dramatically reflected in the kind or amount of vegetation

produced. Differences in soil texture, in soil depth, or in topographic position may also be used to distinguish range sites if

these factors are known to result in significant differences in

plant composition or in yield. Examples are sands as contrasted

to clays, deep soil as contrasted to very shallow soil, and uplands

as contrasted to bottom lands subject to overflow. These different areas are usually in different range sites.

Distinguishing between range sites is more difficult in areas

with similar soil, relatively uniform topography, and gradual

changes in climate—since changes in composition and yield are

gradual. Consequently, the need for site cfifferentiation may not

be apparent until the cumulative effect on the vegetation has

been studied over a broad area. Commonly, these differences are

reflected first in differences in yield and second in changes in

composition.

The effect of any individual factor of the environment varies,

depending on the other factors of the environment. Greater soil

depth, for example, usually means more on a site that receives

moisture from repeated overflow than it does on a sloping upland

site. An additional 2 inches of rainfall annually may be highly

important in an arid area but of minor importance in a humid

area. Similar variations in the degree of importance are true of

most factors of the environment. Consequently, in determining

a range site, the total environment must be considered as well as

the individual factors.

In evaluating the differences in plant composition of rangeland

in "excellent" condition, the relative proportion of individual

species may indicate whether there is one range site or more.

For example, the potential plant community on one range area

may include 60 percent big bluestcm QAndrofogon gerardt) and 10

N. DAK,-700 LA.-62537

Left: A deep sandy loam that has a moderate ujater-holding capacity and

a deep root zone. Right: A deep clay underlain by marl. Thisfine-textured

soil is slowly permeable; it has a high water-holding capacity and a deep root
Lejt: A moderately deep, gravelly sandy loam. Because of the large amount

of gravel, the soil has a low water-holding capacity and is droughty. Right:

A shallow silt loam over weakly consolidated chalk, which limits waterholding capacity and root development.

percent little bluestem (^A. scoparius"), and these proportions may

be reversed in another area. Intensity of grazing and season of

use should be based primarily on the requirements of big bluestem

in the first area and on those of little bluestem in the second area,

and two range sites should be recognized even though the difference in their total yield is minor.

The point at which a difference in composition or in yield

makes it necessary to recognize another range site varies. For

example, a difference in yield of 100 pounds of air-dry herbage

per acre is of minor importance on sites capable of producing

2,000 to 3,000 pounds per acre but is highly important on sites

capable of producing only 200 to 300 pounds per acre.

A single factor of the environment, or a combination of factors,

is not used to differentiate range sites unless the effect of one or

all is clearly reflected in significant differences in composition

or in yield. Nor are factors used that may influence the distribution of grazing but have little, if any, effect on composition

or on yield.

In summary, the criteria for differentiating range sites should

be based on—

1. Significant differences in the kind of vegetation in the

potential plant community.

2. Significant differences in the amount of herbage produced

by the potential plant community.

Naming Range Sites

Range sites are named to help ranchers to recognize and to

remember the important kinds of rangeland in their locality.

Therefore, site names should be brief and should be based on

readily recognized, permanent physical features such as the kind

of soil, climate, topography, or combinations of these features.
Since the vegetation changes or, in some places, disappears, plant

names alone are not adequate for this purpose. Combinations of

a permanent physiographic feature and the kind of potential

vegetation characteristic of the site are more helpful.

Examples of range-site names are Deep sand, Sandy plains. Clay

upland. Saline lowland. Gravelly outwash, Limestone breaks,

Pumice hills. Wet meadow^, and Sandy savanna.

Correlation of Range-Site Names

Because of the limited number of permanent physiographic or

other features that can be used in naming range sites, some duplication of names is inevitable. Deep sands, for example, occur in

areas of widely different climate, and these different areas support

different natural communities. The name ' ' Deep sand" is appropriate for each area and, thus, is used throughout the country to

designate several range sites. Range-site names should not be

duplicated, however, in any one land-resource area or soil

association.

Range areas with similar soil and topography may have

significantly different potential plant communities as the result

of climatic differences. The average annual precipitation of the

sandy plains in the Oklahoma Panhandle, for example, ranges

from 16 to 23 inches. Quantitative evaluation indicates that

there is a significant difference in the amount of vegetation produced in the 16- to 19-inch precipitation zone as contrasted to

that in the 20- to 23-inch zone. In such places, two range sites

are recognized and are distinguished by including the precipitation zone (p.z.) in the site nam.e, e.g., "Sandy plains, 16- to

19-inch p.z." and "Sandy plains, 20- to 23-inch p.z."

An example of range sites that have been named and correlated

with soil surveys follows.

Land-risoum area Range sitt Principal sails

High Plains___ Deep sands (16- to 19-inch p.2.)_ Dalhart loamy fine sand.

Deep sands (20- to 23-inch p.z.)_ Vona loamy fine sand.

Otero loamy fine sand.

Sandy plains Dalhart fine sandy loam.

Manskef fine sandy loam.

Berthoud fine sandy loam.

Rolling Red Alkali flats Port-Solonetz.

Plains. Drummond-Solonctz.

Deep sands Pratt loamy fine sand.

Pratt-Tivoli loamy fine sands.

Enterprise loamy fine sand.

Likes loamy fine sand.

Deep sand savanna Brownfield loamy fine sand.

Nobscott loamy fine sand.

Heavy bottom land Port clay loam.

Spur clay loam.

Sandy plains Pratt fine sandy loam.

Miles fine sandy loam.

Enterprise fine sandy loam.

Dill fine sandy loam.

Dalhart fine sandy loam.

Descriptions of Range Sites

In the Soil Conservation Service, after a range site has been

identified and named, a description of the site is prepared and

placed in the work unit's technical guide. It includes—

1. The site name, including the precipitation zone if it is

needed to identify the site, and the land-resource area.

2. The geographic location of the site (soil conservation

district or work unit).

3- The pertinent features of the climate, including the

amount and distribution of precipitation and the season

when the dominant forage plants make their maximum

growth.

4. The approximate elevation and a brief description of the

topography.
3. The soil types and phases in the range site and a brief 4.

description of their characteristics that directly influence

the growth of range plants. 5

6. A brief description of^the climax plant community for the

site, naming the more important decreasers and increasers.

7. The approximate yield of the site in excellent condition,

expressed in pounds of air-dry herbage per acre, in favorable years and in less favorable years.

8. The location of a typical example of the range site.

An example of a range-site description follows.

1. RANGE-SITE NAME: Sandy land. Rolling Plains landresource area.

2. LOCATION: Hemphill County Soil Conservation District.

3. CLIMATE:

a. Precipitation averages 19 to 25 inches annually. Most of

the rain falls from May through October, with 2 inches

or more in each of those months. The amount fluctuates

from year to year, and there are frequent droughts. 6.

Summer rainfall is characterized by torrential showers

that result in rapid runoff on unprotected soils. Winter

precipitation averages less than 1 inch a month and is in

the form of snow or rain.

b. Wind velocities in this area are high compared with those

in the rest of the United States. High winds in March

and April cause much erosion on unprotected areas.

c. The growing season of the native warm-season plants

extends from the last killing frost in spring, April 10 to

April 21, to October 29, the average date of the first killing

frost in fall, if moisture is available. Winters are characterized by frequent northers (wind) that bring severe cold;

a low of —16° F. has been recorded. The maximum

summer temperature on record is 108° F.; humidity is low

and evaporation, high.

TOPOGRAPHY AND ELEVATION.

Gently to moderately hummocky.

SOILS:

a. The soils in this range site are loamy fine sands, loamy

sands, fine sands, and alluvial sands that are 20 inches or

more deep. The soils are moderately permeable to

rapidly permeable. If unprotected by vegetation, they

are highly susceptible to wind erosion. If protected by

vegetation, the soils have a high moisture-intake rate,

little runoff occurs, and more water is available for plants.'

b. One or more of the following soil types or phases occur in

this range site: Enterprise loamy fine sand, Pratt loamy

fine sand. Likes loamy fine sand. Springer loamy fine sand

Miles loamy fine sand, deep phase, and Miles loamy fine

sand.

c. Complete descriptions of the soils are in the soil survey

descriptive legend.

CLIMAX VEGETATION:

Decreasers

Little bluestem

Sand bluestem

Indiangrass

Switchgrass

Canada wildrye

Needle-and-thread

Texas bluegrass

Sand lovegrass

Climax forbs

Increasers

Big sandreed

Blue grama

Sideoats grama

Silver bluestem

Hairy grama

Threeawns

Sand dropseed

Sand sagebrush

Shinnery oak

Small soapweed

Sand plum

SIcunkbush

Climax forbs

Invaders

Annuals

Red lovegrass

Queensdelight

Western ragweed

Tumble lovegrass

Gummy lovegrass

Decreasers make up 40 percent of the vegetation (35 percent

call grasses, 5 percent mid grasses); increasers the remainder. In some places, 10 percent is woody vegetation.
7. YIELD:

The annual yield of this site in excellent condition, based on

plot clipping, is 4,000 to 6,000 pounds per acre. Basal

herbage covers 5 to 10 percent of the ground.

8. SPECIFIC TYPE LOCATION:

4 miles northeast of Canadian, Texas, along U.S. Highway.

Range Sites and Standard Soil Surveys

It is the policy in the Soil Conservation Service to make one

soil survey that will collect essential soil information to use in

conservation planning, to meet the needs of other users of soil

maps, and to meet the requirements of the National Cooperative

Soil Survey. Soil surveys on rangeland are made in the detail

consistent with the need for soil information for ranch conservation planning. The establishment of mapping legends for

these surveys, therefore, requires an understanding of the soilwater-plant relationships of rangeland and of the need for and

use of soil information in ranch planning.

Soil scientists and range conservationists work as a team in

developing the soil survey work plan, in determining the mapping

units and preparing the legend, in reaching agreement on the

intensity of mapping needed, in grouping the kinds of soil and

miscellaneous land types into range sites, and in conducting field

reviews. The final responsibility for determining the mapping

units, however, is assumed by the soil scientist and that of

grouping the kinds of soil into range sites, by the range conservationist.

Identifying Range Sites Where Standard Soil Surveys Are Available

In areas where a recent standard soil survey and the field

coordination necessary to insure the correct interpretation of

range sites from the soil map have been completed, the boundaries of range sites can be determined directly from the soil map.

These boundaries can be transferred to the conservation-plan map

of an individual ranch unit. They are checked in the field while

the conservation plan is being prepared, and any needed adjustments can be made at that time.

The degree of correlation between the number of soil mapping

units and the number of range sites varies. If the land is mostly

arable, the number of soil mapping units generally exceeds that

needed for ranch planning, since differences in slope and in other

soil characteristics are more important in the management of

cropland than of rangeland. On large areas of nonarable rangeland, the boundaries of soil mapping units and of range sites

commonly arc the same.

Identifying Range Sites Where There Is No Standard Soil Survey

In areas where a recent standard soil survey has not been made

and, thus, where the soils have not been named, described, and

mapped, range sites are described on the basis of the dominant

characteristics of the landscape. For this purpose, a tentative

mapping legend is prepared. The soil scientist and the range

conservationist work together in determining the general soil

characteristics, such as depth, texture, and drainage, that arc

important to range planning in the area. These are described

for the major kinds of landscape and are the basis for making

broad delineations of range sites. These preliminary studies also

contribute to the subsequent soil survey.

Cartographic Considerations

The intensity and detail to be used in mapping range sites are

determined locally. Major consideration is given to delineations

that are significant in the proper use and management of individual pastures or range units.
s.¿< Vh??' fl""!" "u ""'t''"h a minimum size for the range

neeH, i^ t^5 f° ''^ j''°'^° °° ^ "^P" ^he smallest area that wT.h M delineated varies with the productivity of the site,

with the mapping scale, and with the patterns of grazing use!

Range sites capable of producing high yields generally are mtpped

in more detail than range sites of low potential productivity but

mapping in more detail than necessary on a large-scale map

should be avoided. ^

In areas of extensive rangeland, surveys are of low intensity

and the maps usually are at a scale of 2 inches to the mile. In

areas where rangeland and cropland are interspersed, surveys are

of medium intensity and the maps are at a scale of either about

3.2 inches (1:20,000) or 4 inches to the mile.

Range sites are shown on the conservation-plan map as cither a

large area of a single range site or a complex of two or more range

sites so intermingled that their separate delineation is not

practical or meaningful. As much as 20 percent of an area shown

as a single range site may be inclusions of other sites. Where a

single range site is delineated, the name of the range site is shown

on the map. Where a complex of range sites is shown within

one delineation, the name of each range site and the approximate

percentage of each is shown, e.g.. Loamy upland, 65 percentLimestone breaks, 35 percent.

Range Condition

Range condition, as used here, is the present state of the

vegetation compared with that of the climax for that range site.

The purpose in classifying range condition is to provide an

approximate measure of any deterioration that has taken place

in the plant cover and, thereby, provide a basis for predicting the

degree of improvement possible.

Range condition has been called range health. Like health,

condition is relative. If a particular range site is described as

being in "good condition" or in "poor condition," the description is always relative to the kind and amount of native vegetation that range site is capable of producing. In the rangeco.^dltlon classification four classes are used to express the degree

to which the composition' of the present plant community has

departed from that of the climax plant Community. These four

range-condition classes are defined as follows:

Range-condition class:

Excellent

Good

Fair

Poor

Peratitage of fresent vegetation that is

climax ¡or the range site

76 to 100

51 to 75

26 to 50

0 to 25

Determining Range-Condition Classes

To help in determining the range-condition class for a range

site, the plant species in the potential plant community for that

site are classified according to their response to grazing The

categories are decreasers, increasers, and invaders.

Decreasers are species in the potential plant community that

decrease in relative abundance under continued moderately heavy

to heavy grazing use. They generally are perennials that are

Plant composition is determined by an ocular estimate of the relative production by weight, of the species making up the plant community. This estimate is

checked often enough to insure reasonable accuracy by weighing the total amount

of herbage taken from selected plots. On plots 9.6 square feet in size, the weight

of the herbage in grams multiplied by 10 is equivalent to pounds-per-acre
palatable to livestock and, for the most part, are dominant

species in the potential plant community. In determining the

range-condition class, the total of all such species now present is

tallied. ^

Increasers are species in the potential plant community that

normally increase in relative abundance as the decreasers decline.

But increasers do not always react in this simple fashion. Species

that increase at first may decrease later as moderately heavy to

heavy grazing use continues. Increasers commonly are the

shorter, less productive, subdominant species in the potential

plant community. Their forage value ranges from low to high.

Under grazing use, those of low forage value tend to increase

more rapidly than those of high value. The proportion of

increasers in the potential plant community is determined, and

the proportion in the present vegetation up to, but not exceeding,

this maximum is tallied as a part of the potential cover. Ordinarily, by adding this total to that of the decreasers, the rangecondition class can be determined.

Invaders are species that are not members of the potential plant

community for the range site, since they cannot withstand the

competition for moisture, nutrients, and light in the climax

vegetation. They come in and grow along with the increasers

after the climax vegetation has been reduced by grazing. They

arc not restricted to exotics, since they may be members of the

climax plant communities on other range sites in the same general

locality. Some are annual weeds and herbaceous perennials and

some are woody shrubs; many have some grazing value but others

have little. Invaders are not tallied in determining the rangecondition class.

On page 10 is an example of a worksheet used in the Soil

Conservation Service to compare the present vegetation on a

specific range site with the potential vegetation and to determine

the range-condition class of the site.

Special situations.—In some places pronounced irregularities in

the stand may make it necessary to lower the condition-class

rating. Although the potential native-plant community does

not consist of rigid proportions and spacing of plants, it has a

characteristic appearance and usually consists of a characteristic

grouping and spacing of individual species. These characteristics

are modified to different degrees by a decline in range condition.

With a change in condition, the range may look like the potential

plant community or have a radically different appearance. For

example, the amount of ground covered by vegetation may be

sharply reduced or, if bunch grasses are replaced by sod grasses,

it may be increased. The ground surface exposed by the loss of

decrcaser plants is occupied regularly by annuals where rainfall

is plentiful but not on more arid range sites. Significant departures of this kind may make it necessary to lower the condition-class rating. Thus additional, locally suitable guidelines

are developed for range sites where marked irregularities in the

vegetation require the lowering of a condition-class rating that

has been determined by evaluating only plant composition.

Special criteria for the classification of range condition are

used for the annual ranges in a Mediterranean climate where it

is desirable to manage the range for species other than those in

the native, or original, vegetation.

Guides for determining range condition.—In the Soil Conservation Service, guides for determining range condition are

prepared for each range site in a work unit and filed in the workunit technical guide. They may be prepared as a separate guide

for each range site or as a spread sheet showing all the range sites

in the work unit (pp- H and 12). In either case, the significant

decreasers and increasers for each range site should be indicated.

If needed, supplemental lists are prepared that show the increasers,

decreasers, and invaders not included in the guide for determining

range condition but present on the various sites.

844917 o—62-
Site: Deep sand

(16- to 19-liich p. I.)

Ranch unit: Cimarrón

Exanniner: Sam Arid

Location: High Plains, Okla.

Pasture No.: 2

Date: 9/I2/60

Plant species

Maximum

percentage

of climax

Percentage

of present

vegetation

Percentage

used in deternnining range

condition

Decreasers:

Sand blueetem

Sideoats grama

Uttle Uuestem

Svltcbgrass

CTOO .¿^1 /O 10

Increasers:

Blue grama and haliy

grama

Sand drqpseed

Perennial forbs

Sand sagebrush

JO

/O

r

5

b

/o

30

i'

Invaders:

Annuals

Cactus "H.CVLÍ

10 0

Total /OO /OO 70

Condition class r^

Example of a worksheet used in determining range-condition class.
RANGE-CONDITION GUIDE

Range-site name: Moderately deep vplaeAB,

i2- to l$-lx>cli p. z.

Major soils: Asdars silt looa

Beuge (lit loan

Resource area: 6

BitsTllle Soil ConaervKtlon

DUtrlet

Date: 8/27/60

Clinnax decreasers Clinnax increasers Invaders

(Use all in determining (Use no more than percentage (Use none in

range-condition class) shown in determining determining

range-condition class) range-condition

class)

Percent

by weight

Sandberg bluegraas 10 Cbeatgrass

Blusbunch vbeetgrass SqulrreltaU 1 Pacific fescue

Prairie Junegraea Woolgrass U Mustard

Big bluegraas Neadle-and-thread I Xarveed

Oiant vlldrye Balsanroot 1 Thistle

ïarrow 1 China lettuce

Liq>ine 1

Astragalus 1

Daisy 1

Hnikaliearl Phlox 1

Blscultroot 1

Buckvhaat 1

Threetlp sagebrush 1

Rabbltbrush 2

Big sagebrush 2

S<aac 1

Thurber needlegrass 1

Approximate yield of air-dry leaves and

twigs by range-condition class

Excellent Good Fair Poor

Percentage of preaent 100 to 76 75 to 51 50 to 26 25 to 0

vegetation that is

cUnuc for the

Ite.

forage per acre

produced in:

Favorable years 6^0 to liOO 1*50 to 250 300 to 150 100 to 500»

Unfavorable years 450 to 300 350 to 200 250 to 100 75 to 50»-

«Shews extreae variation in cbaatgraas production.

Example 0/ range-condition guide and guide to the approximate yield of air-dry forage

by range-condition classfor a single range site. '
RANGE-CONDITION GUIDE: Bowle »oik unit

Key climax plants and plants that invade range sites if overgrazed. Range sites are

(name, land-resource area, principal soils)--

1. Sandatone hill», Beddlsl» Prairie, »oil» In Darnell «erle».

2. Sandy loam, Beddlsh Prairie, Zanela fine aandy loam.

3. Bottom land. Cross Timbers, Ooven fine sandy loam.

I*. Tlgbt land, Beddlah Prairie, lfii-vi»nj sllty clay.

5. Loa^ prairie. Reddish Prairie, Chlciasha fine sandy loam.

6. Sandy teilend. Cross Timber», Wlndthorst and Stephenyllle fine sandy

7. Deep sand. Cross Timbers, Staphenvllle and ïlarod fine sandy loam».

Key clinnax plants and maximum percentage of increasers

by range site Invaders

1 2 3 It 5 6 7

Little bluestem

Big bluesten

Indlangrasfl

Svltcbgraas

Canada vlldrye

Western vbeatgrass

Sldeoats grama

Blue grama

Hairy grama

Texas vlntergrass

Buffalograss

White trldens

Vlne-mesqulte

Tall dropseed

Purpletop

Sand lovegiaas

Woody plants

20

10

5

nv

10

*

5

10

5

5

5

5

nv

5

10

5

15

10

5

ISV

5

an

JOT

5

10

10

10

15

15

IBT

25

10

my

5

5

07

5

15

JOT

5

5

5

JOT

nv

5

10

10

10

HIT

JOT

IBT

JOT

5

15

10

All annuals

Wlndmnl grasse»

1 Haliy trldens

1 Texas grama

Ttmblegrass

Red grama

Sliver bltiesten

SpUtbeard blueito

VtaiL lovegrasiefi

Low panlctas

Low paspalio»

Saad dropseed

Threeams

Westers ragveed

Hesiiiilte

Opuntia

Maximum percentage of all increasers in

climax generally

does not exceed 30 30 25 to 25 30 20

Blank space indicates that plant is not important on range site; minus sign indicates a

decreaser, all of which are to be counted in deternnining range condition; a figure indicates an increaser and the percentage in climax; INV indicates that plant is an invader

on the site.

Initial safe-stocking rate by range-condition :Iass

Range-condition class and percentage of present vegetation

that is climax for site

Acres per animal unit per year by ran ge site

1 2 3 It 5 6 7

Excellent (lOO to 76)

Good (75 to 51)

Fair (50 to 26)

Poor (25 to 0)

25

35

55

55

13

17

8

10

16

25

16

22

3*

52

10

lU

21

35

13

17

23

38

15

22

.1

Example of range-condition guide and guide to the initial saje-stocking rate by rangecondition classfor all the range sites in a work unit.
FORAGE-CONDITION GUIDE

Resource area: Coastal flatwoods Bite, Lower Coastal Plain

Increasers Invaders

(Plants in climax that (Plants in climax that (Plants that invade

decrease if woodland increase if woodland is the site if woodland

is heavily grazed; heavily grazed; use no is heavily grazed;

use all on the site in more than percentage shown use none in deterdetermining forage in determining forage mining forage

condition.) condition.) condition.)

Percent

by weight

Plnehin bluestem Slender bluestem 10 All fti^Tiiial »

Cutover mihly 5 Broomsedge 1)lue8tem

Svltchgrass Low panlcuB» 10 Snutgraaa

TootbacbesraaB Beaked panlcua 5 Xankeeveed

Svitcbcane Perennleú. threeavna 5

Bastem baccharls

SvBiqi suiiflover Faspalwift ^

DropseedB 5

Carpetgrass ?

Sedgea, rushes 10

Qrassleaf goldaster 3

Initial safe-stocking rate by forage-condition class and timber-canopy class

Forage-condition class

Acres per animal unit per year by

timber-canopy class

Open Sparse Medium Dense

Excellent

Good

Fair

Poor

10

12

15

18

12

15

20

3^

18

2U

36

U8

30

l»2

56

70

Example offorage-condition guide and guide to the initial safe-stocking rate by foragecondition class and timber-canopy classfor a woodland-forage site.
Ev^ljtéttins Forage on Gmze^l W^ootiletnfi

Forage plants form a significant part of the plant community

on some woodland. Examples are the understory grasses, forbs,

and browse plants palatable to livestock in the ponderosa pine

and pinon pine forests of the West and in the longleaf pine and

slash pine forests of the South. The woodland-forage crop may

be secondary in importance to timber to the landowner but still

have economic value. Studies of woodland that is suitable for

grazing and the past grazing history have shown that conservative grazing is compatible with the objectives of woodland

management.

Forage production on a specific woodland site depends on the

inherent capacity of the site, on any changes that have resulted

from past grazing use, and on the density of the crown canopy of

the timber overstory. The potential plant community for a

specific woodland site can be determined in the same way as for

a rangeland site—by evaluating the relict, or near relict, vegetation; by studying the kinds of soil; by observing the vegetation

on both grazed and protected woodland; by studying the grazing

history of grazed woodland; and by evaluating research data.

Cattle are just as selective of the plants they graze on woodland

as on rangeland. Thus, woodland-forage species also can be

classified as decreasers, increasers, and invaders, and the present

condition can be determined in relation to that of the potential

vegetation for a particular site.

The composition of the understory plant cover on woodland

sites and its yield vary with the extent to which the plants are

shaded by the canopy as the timber stand grows. Canopy

classes are determined by estimating the proportion of the ground

shaded by the overstory canopy at midday. They are designated

in the following manner.

Canopy class:

Open

Sparse

Medium

Dense

Ptrcenta^t of ground shaded

0 to 25

26 to 50

51 to 75

76 to 100

On woodland where a part of the ground is covered by nonforage brush to the exclusion of forage plants, the area covered

is estimated and deducted from the total area available for grazing.

Guides for determining woodland-forage sites, forage-condition

classes, and timber-canopy classes are prepared for each woodland-forage site in a work unit (p. 13). In addition to lists of

decreasers, increasers, invaders, and of the percentages of increasers natural to each site, these guides may contain the initial

safe-stocking rate for each forage-condition class and each canopy

class. The initial safe-stocking rate for a site usually is expressed

in acres per animal unit for a specified period and for a specific

condition class and canopy class.

To protect both the timber and forage resources, grazing on

woodland must be carefully controlled.

Examples of Range Sites and Range-Condition Classes

Six range sites in different parts of Western United States are

described and illustrated in the following pages. For each range

site the soils are described and a soil profile is shown, as well

as the changes in the appearance and character of the vegetation

that occur as range condition improves.

14
Sands range site, 10- to 14-inch p.z., Wyoming

The soils are loamy sands that formed in sands reworked by

wind. They are coarse textured, noncalcareous, and well

drained. The surface of the soil generally is hummocky or dunelike. The surface layer, about 5 to 6 inches thick, is moderately

dark colored and is underlain by deep, loose, pale brown sand or

loamy sand. Darker colored, buried A horizons are common and

are former surface layers that have been covered by shifting sands.

Profile of a soil in Sands range site, 10- to 14-inch p.z. Wyoming.

WYO.-715 "^^..y

15
Sa.rtds raage site, 10- to 1'4-iocli p.z., Vf^yomiog

Range-condition class: POOR

I

Production (air-dry herbage):

400 to 750 pounds per acre

Approximate composition:

Sand sagebrush

Annuals

Cactus

Sand dropseed

Blue grama

Needle-and-thread

Percent

35

35

10

10

5

5

100

16
Sands range site, 10- to 14-inch p.z., Wyoming

Range-condition class: FAIR

P» . *>

'^ %«. ^^ •^"""^ "*.

/i''*««Si^'''

iráí.íJí 5^!'.i ,MTb»*'/ íi ,í,y,4'. ., i „.''.'i.'

Production (air-dry herbage):

750 to 1,500 pounds per acre

Approximate composition:

Sand sagebrush

Annuals

Cactus

Blue grama

Sand dropseed

Needle-and-thread

Prairie sandreed

Percent

35

15

10

15

10

10

5

100

644917 O—62 3 17
Sands range site, lO- to 14-inch p.z., "Wyoming

Range-condition class: GOOD

V''^-/-»" • ^ "**^

Production (air-dry herbage):

1,000 to 2,250 pounds per acre

Approximate composition:

Percent

Prairie sandreed 35

Blue grama

Sand sagebrush

Needle-and-thread

15

15

10

Sand dropseed

Annuals

10

10

Sand bluestem 5

100

18
Sands range site, 10- to 14-inch p.z., Wyoming

Range-condition class: EXCELLENT

ti'i-^-^. "

Production (air-dry herbage):

1,500 to 3,000 pounds per acre

Approximate composition:

Percent

Prairie sandreed

Sand bluestern

Needle-and-thread

Blue grama

Sand dropseed

Annuals

35

25

15

10

5

10

100

19
Choppy sandhills range site, 20- to 24-inch p.z-, Nebraska

The soils are deep, loose, fine sands. The upper few inches oí

the surface layer are slightly darkened by organic matter. Rainfall is absorbed quickly, and internal drainage is very rapid.

Consequently, the soils are droughty.

NEBR.-2054

Profile of a soil in Choppy sandhills range site, 20- to 24-inch p.z., Nebraska

20
Choppy sandhills range site, 20- to 24-inch p.z., Nebraska

Range-condition class: POOR

Production (air-dry herbage):

600 to 1,400 pounds per acre

Approximate composition:

Percent

Blue grama and hairy grama 30

Prairie sandreed 15

Annual invaders 15

Needle-and-thread 10

Western ragweed 10

Woody increasers 10

Sandhill muhly 5

Green sagewort 5

100

NEeR.-2045

21
Cfaoppy sandhills range site, 20- to 24-inch p.z., Nebraska

Range-condition class: FAIR

F|» '«i *f "»*'

'^M.i^'y^^^.LC'^

Production (air-dry herbage):

900 to 2,400 pounds per acre

Approximate composition:

Venmt

Prairie sandreed

Blue grama and hairy grama

Needle-and-thread

Forb incrcasers

Annual invaders

Sand bluestem

Prairie junegrass

Western ragweed

Woody increasers

30

20

10

10

10

5

5

5

5

100

NEBR 2044

22
Choppy sandhills range site, 20- to 24-inch p.z., Nebraska

Range-condition class: GOOD

Production (air-dry herbage):

1,600 to 3,000 pounds per acre

Approximate composition:

Percent

Prairie sandreed 30

Sand bluestem 10

Ncedle-and-thread 10

Blue grama and hairy grama 10

Little bluestem 5

Prairie junegrass 5

Sedges 5

Forb incrcasers 5

Woody increasers 5

Annual invaders 5

Sand dropsecd 5

Western ragweed 5

100

23
Choppy sandiiîlls raa^e site, 20- to Z'í-iacli p.z., IVebraska

Range-condition class: EXCELLENT

Production (air-dry herbage):

2,200 to 3,800 pounds per acre

Approximate composition:

Sand bluestem

Prairie sandreed

Little bluestem

Switchgrass

Sand lovegrass

Porcupinegrass

Prairie junegrass

Needle-and-thrcad

Sedges

Forb increasers

Woody increasers

Percent

25

20

15

5

5

5

5

5

5

5

5

100

24
Limestone prairie range site, Texas

The soils are clays in the Austin series. They are shallow, fine

textured, and moderately permeable and have a moderate waterholding capacity. Additional moisture is available to plant

roots in the underlying chalk.

TEX.-4977a

Profile of a soil in Limestone prairie range site, Texas.

25
I-iinestone prairie range site, Texas

Range-condition class: POOR

Production (air-dry herbage):

400 to 900 pounds per acre

Approximate composition:

Threeawns

Annuals

Tridcns

Silver bluestem

Tall dropseed

Perennial forbs

Percent

35

35

15

5

5

5

100

26
Limestone prairie range site, Texas

Range-condition class: FAIR

Production (air-dry herbage):

1,000 to 2,200 pounds per acre

Approximate composition:

Percent

Tall dropseed 20

Silver bluestem 15

Threeawns j 15

Tridens 15

Annuals 15

Sideoats grama 10

Little bluestem 5

Perennial forbs 5

100

TEX.-43967 B

27
Limestone prairie range site, Texas

Range-condition class: GOOD

Production (air-dry herbage):

2,500 to 3,300 pounds per acre

Approximate composition:

Percent

Little bluestem 30

Sideoats grama 25

Tall dropseed 20

BufFalograss \Q

Perennial forbs 10

Threeawns 5

100

TEX.-43966B

28
Limestone prairie range site, Texas

Range-condition class: EXCELLENT

Production (air-dry herbage):

3,500 to 4,000 pounds per acre

Approximate composition:

Percent

Little bluestem 40

Sideoats grama 25

Indiangrass 10

Tall dropseed 10

Perennial forbs 10

Big bluestem 5

100

29
Very shallo^v range site, lO- to 1-i-inch p.2-, Montana

The soils arc Castncr stony loams. They formed in weathered,

fractured sandstone formations and are very shallow, generally

less than 10 inches deep. They have a low water-holding

capacity and low natural fertility; consequently, they are relatively unproductive.

MONT.-20J

Landscape in Very shallow range site, 10- to 14-inch p.z., Montana.

I

30
Very shallow range site, 10- to 14-inch p.z., Montana

Range-condition class: POOR

á*^..

M^

^^ V^'*'-'**r/-

>,>,

Production (air-dry herbage):

Less than 100 pounds per acre

Approximate compositioni:

Percent

Fringed sagewort 20

Annuals 20

Hoods phlox 15

Eriogonum 15

Pussytoes 15

Onespike danthonia 5

Sandberg bluegrass 5

Blue grama 5

100

31
Very shallow range site, lO- to 14-ilich p.z., IVtotitacia

Range-condition class: FAIR

%.T,^^ 'S, -• - "-v ^-- ^ JEW , «t» ;f^ .-Si

Production (air-dry herbage):

100 to 200 pounds per acre

Approximate composition:

Fringed sagewort

Bluebunch wheatgrass

Onespike danthonia

Pussytoes

Sandberg bluegrass

Prairie juncgrass

Hoods phlox

Eriogonum

Annuals

Percent

25

20

15

10

10

5

5

5

5

100
Very shallow range site, 10- to 14-inch p.z., Montana

Range-condition class: GOOD

Production (air-dry herbage):

200 to 350 pounds per acre

Approximate composition:

Percent

Bluebunch wheatgrass

Oncspike danthonia

Annuals

Rough fescue

Idaho fescue

45

10

10

5

5

Prairie junegrass

Hairy goIdaster

Sandberg bluegrass

Pussytoes

Fringed sagewort

5

5

5

5

5

100

33
Very shallow range site, lO- to 14-inch p.z., Montana

Range-condition class: EXCELLENT

Production (air-dry herbage):

350 to_500 pounds per acre

Approximate composition:

Bluebunch wheatgrass

Rough fescue

Idaho fescue

Onespike danthonia

Prairie junegrass

Hairy goldaster

Fringed sagewort

Percent

35

30

15

5

5

5

5

100

34
Gravelly hills range site, Texas

The soils are gravelly and poorly developed. They have a

rapid water-intake rate and a low water-holding capacity.

Consequently, they are droughty and have a limited capacity to

produce forage.

Profile of a soil in Gravelly hills range site, Texas.

35
Gravelly liills raoge site, Texas

Range-condition class: POOR

Production (air-dry herbage):

Less than 400 pounds per acre

Approximate composition:

Percent

Threeawns 30

Hairy grama 15

Blue grama ig

Sand dropseed \Q

Perennial forbs 10

Annuals 20

Woody invaders 5

100

TEX 49783

36
Gravelly hills range site, Texas

Range-condition class: FAIR

^JäSüg^^^-

^

^,.>^^^'

Production (air-dry herbage):

500 to 800 pounds per acre

Approximate composition:

Percent

Hairy grama 20

Threeawns 15

Sand dropseed ' 15

Blue grama 10

Sideoats grama 10

Perennial forbs 10

Annuals 10

New Mexico feathergrass 5

Woody invaders 5

100

37
Cîrav-elly hills ra.ngG site, Texas

Range-condition class: GOOD

Production (air-dry herbage):

900 to 1,300 pounds per acre

Approximate composition:

Percent

Sideoats grama 25

Hairy grama 20

Blue grama 15

New Mexico feathergrass 10

Sand dropseed 10

Little bluestem 5

Threeawns 5

Woody invaders 5

Annuals 5

100

TEX.-49781

38
Gravelly hills range site, Texas

Range-condition class: EXCELLENT

Production (air-dry herbage):

1,200 to 1,500 pounds per acre

Approximate composition:

Percent

Sideoats grama 35

Little bluestem 15

New Mexico feathergrass 15

Blue grama 15

Hairy grama 10

Sand dropseed 5

Perennial forbs 5

100

TFX BTi

39
Stony mountaio range site, Texas

The soils are reddish-brown loams and clay loams that formed

in material derived from basalt. The upper layers contain a

large amount of grit, and stones and rock fragments make up 60

percent or more of the underlying soil mass. The water-intake

rate is rapid, and both water and plant roots readily penetrate

these stony soils.

Profile of a soil in Stony mountain range site, Texas.
Stony mountain range site, Texas

Range-condition class: POOR

Production (air-dry herbage):

400 to 1,000 pounds per acre

Approximate composition:

Fercent

Threeawns

Hairy grama

Crotón

Annuals

Muhly sp.

Sprucetop grama

Cholla

45

15

15

10

5

5

5

100

TEX.—J6019D

41
Sroxiy mountain range site, Texas

Range-condition class: FAIR

Production (air-dry herbage):

1,500 to 2,000 pounds per acre

Approximate composition:

Percent

Hairy grama 35

Sprucetop grama 15

Sideoats grama 5

Threeawns ^5

Crotón 25

Muhly sp. 5

Annuals 5

Yucca 5

100

TEX.-J6019C

42
Stony mountain range site, Texas

Range-condition class: GOOD

Produaion (air-dry herbage):

2,500 to 3,000 pounds per acre

Approximate composition:

Percent

Hairy grama

Sideoats grama

Muhly sp.

Sprucetop grama

Cane bluestem

Little bluestem

Balsamscale

Daleas

Perennial forbs

Threeawns

Crotón

20

20

15

10

5

5

5

5

5

5

5

100

TEX.-46019B

43
Stony mountain range site, Texas

Range-condition class: EXCELLENT

Production (air-dry herbage):

3,000 to 4,000 pounds per acre

Approximate composition:

Percent

Sideoats grama 30

Hairy grama 15

Cane bluestem 10

Little bluestem 10

Muhly sp. 10

Big bluestem 5

Sprucetop grama 5

Balsamscale 5

Daleas 5

Perennial forbs 5

100

44
Trend in Range Condition

Although range-condition classes express the condition of the

present vegetation in relation to that of the potential vegetation

for that site, they do not show whether the range is improving

or deteriorating. Trend is a separate determination, often needed

to plan the adjustments in grazing use and management needed to

maintain or to improve the range resource. The following are

among the more important indicators of trend in range condition.

Vigor of Plants

The size of a plant and its parts in relation to its age and

environment reflect plant vigor. Many plants that form bunches

or tufts if vigorous assume a sod form when vigor is reduced.

The length of rhizomes and stolons also is a good indication of

plant vigor. If the plant is weak, these parts are shorter and

fewer. But care should be used in assuming that an apparent

lack of vigor is caused by heavy grazing, especially in periods of

drought or on sites that have obvious limitations for plant

growth. Increased vigor of plants preferred by livestock indicates improving range condition.

Seedlings and Young Plants

A deteriorated range can improve only if the individual plants

naturally dominant on the site can reproduce themselves. Reproduction on a site is shown by young seedlings and plants of

various ages and by spreading tillers, rhizomes, and stolons.

The extent to which any of these forms of reproduction occurs

varies with the growth habits of individual species and with

current growing conditions. Vigorous reproduction of the species

most attractive co livestock also shows that the range is improving.

Few seedlings, however, arc able to establish themselves on range

in excellent condition.

Changes in Plant Composition

Although the potential plant community, or climax, for a

range site is relatively stable, it is in no sense static. Major

changes in plant composition do not occur, however, unless

they are induced by a pronounced disturbance, such as continued

heavy grazing, severe or prolonged drought, or fire. A decrease in

the perennial species most attractive to livestock and most easily

damaged by grazing is an indication of deterioration caused by

too heavy grazing. An increase in species of low palatibility

generally indicates a trend toward lowered condition also.

When the disturbances that cause deterioration of the range

cease, plant succession operates to reestablish the climax plant

community for the site. Plants that have decreased with the

decline in range condition increase if seed plants or vegetative

parts are present. To varying degrees, plants that have increased as a result of declining range condition then decrease.

Certain woody plants and some other long-lived perennials,

however, are exceptions to this general rule and, once established,

may persist for a long time.

Generally, the invasion of a site by plants not native to it

indicates a decline in range condition. These invaders may

flourish temporarily on locally disturbed areas if the site generally

is in good condition. Some invaders, particularly annuals, may

occupy the site temporarily in favorable years, even if the range

condition is improving. There may also be a material, though

temporary, increase in annuals and short-lived perennials in wet

years, even though the trend in range condition is upward.

Changes in plant composition from either declining or improving range condition generally follow a pattern. Although

all the changes are not predictable, the pattern of succession can

be predicted for a specific kind of soil, climate, and grazing use.

Study of these patterns will provide valuable information on the

trend in range condition.

45
í^itxnf Rssit^Mes

The extent to which plant residues accumulate depends on fl)

the amount of herbage the plant community can produce; (2) the

amount of herbage removed by grazing and haying, by fire, or

by wind or water; and (3) the amount decomposed in place. In

a hot humid climate, decomposition is so rapid that there is little

accumulation of plant residues. Conversely, in a cold climate,

decomposition is slow. If plant residues are used to judge trend

in range condition, the accumulation that can be expected on a

specific site and in a specific climate must be considered. Heavy

grazing, below-normal production of herbage, recent fires, and

abnormal losses because of wind or water erosion may result in

less accumulation of herbage than considered reasonable for that

site. The progressive accumulation of plant residues, however,

generally indicates improving range condition. On the annual

ranges in a Mediterranean climate, plant residues are especially

helpful in judging trend, since they are a measure of range use.

Unless plant residues are adequate, plant composition on these

ranges deteriorates and forage production drops rapidly. But if

these ranges are underused, too much residue accumulates and

less desirable plants replace the more desirable ones.

Condition of the Soil

The condition of the surface layer of the soil affects trend in

range condition and the rate of improvement of a deteriorated

range. The lack of plant residues exposes the soil to splash

erosion and to surface crusting. A surface crust slows down the

intake of water, retards vegetative propagation and the establishment of seedlings, and favors a high surface temperature. These

conditions, in turn, increase runoff and soil loss, reduce the

amount of effective soil moisture, and are generally unfavorable

for the growth of plants. Soil crusting, soil compaction caused

by trampling, soil erosion, plant hummocking, and any increase

N. ME)i.-9457

Soil crusting, severe erosion around dead and dying hunchgrass plants

and land once covered by vegetation now bare show a decline in ranee

condition, *

in the amount of bare ground on a range are all indications of a

declining trend in range condition.

The relative importance of any one of these factors varies with

different soils, with different plant communities, and with

different climates. On a particular range site, the evaluation of

any one factor may indicate whether range condition is improving

or declining. But ordinarily a sounder decision can be reached

if all factors are considered.

46
How Information on Range Sites and Range Condition

Is Used in Conservation Planning

As already discussed, different range sites produce different

kinds of range plants, many of which differ in their seasonal

development, and different amounts of forage. The primary

purpose of recognizing range sites is to help the land owner or

operator to identify those areas of his rangeland that have a

different potential for forage production, regardless of what they

are producing now. This information also points out the areas

that have the greatest capacity for forage production and suggests

to the rancher where he will receive the quickest return for any

expenditure for range improvement. A map showing the

boundaries of his range sites provides a permanent record of their

location and extent and shows their relation to each other and

to the pasture layout. All these factors need to be considered in

making a ranch conservation plan.

By appraising the condition of the range within each site, the

rancher can tell which areas are now producing below their

potential. By determining the cause of the present condition,

he can decide what management changes he needs to make to

improve his range. The classification of range condition also

provides him with the information about the key forage plants

and their relative abundance on which he must base his management to maintain or to improve his range (p. 48).

Knowing what his land can be made to produce in both quality

and quantity of forage, the rancher can then decide if the measures

necessary for improvement are worth what they cost. A record

of range condition within each site has the further advantage of

providing a ' ' benchmark' ' against which to check future improvement or deterioration. The rancher can then determine whether

the planned management is achieving the results desired.

Use of Initial Stocking Rates by Range Sites arid Conätfton Classes'

If the herbage-yield estimates that are made to determine the

production of different range sites in different range-condition

classes are made over a period of years, they will indicate the

approximate yields and the variations in production that can be

expected in favorable years and in unfavorable years. A rough

guide to the relative productivity of different range sites can be

obtained by dividing the forage yield by the presumed forage

requirement per animal but, because of the many variables, a

stocking rate based on this calculation alone is seldom reliable.

The most reliable basis for an initial stocking rate for a specific

range site consists of a combination of use records, a determination

of the degree of use, and an evaluation of the trend in condition.

These records should cover a period that includes seasons in which

forage production is high, low, and near average.

An initial stocking rate for each range site and each rangecondition class can be used as a guide to grazing intensity, but

it is not a " grazing-capacity estimate." Because of seasonal and

annual variations in forage production, it should be emphasized

that periodic adjustments in stocking rates will be needed to

insure proper range use.

In summary, different range sites and a particular range site in

different conditions produce different kinds of plants, which

differ in seasonal development, and different amounts of forage.

The identification of the different range sites on his ranch and the

classification of the present condition of the vegetation on each

site furnish the rancher a basis for making decisions on the stocking rates, the season of use, and the kind of management needed

to improve his range.

47
KEY RANGE PLANTS AND SAFE DEGREE OF USE BY RANGE-CONDITION CLASS (CATTLE)

Rltzvllle, Washloeton

Range-condition

class

Excellent

Good

Fair

Poor

Alkali 'bottom ian/<

9- to 15-inch p. z.

Shallow upland,

12- to 15-lnch p. z.

Key species

Safe

A ! use-"^ I Key species

Safe

Percent!

Olant wUdrye

Olant wlldzye

Giant vlldxye

Saltgrass

50

50

50

50

Percent

Bluehunch vbeatgrass 50

Bluebunsh idieatgraas 50

Bluel>unch vheatgraas 50

Sandberg hluegxass 30

Hodezateljr de«p içland,

12- to 15-inch p. z.

Key species

Safe

us el

Percent

Idaho fesctie ko

Bluehunch vheatgxass 50

Idaho fescue lio

Bluebunch wheatgrass 50

Bluebunch vheatgrass 50

Bluebimch vheatgrass 50

Saadberg blusgrass 30

Proportion of current year's growth, by weight, that can be safely grazed.

Example of a chart showing the key range plants and the safe degree of use by range-condition classfor three range sites.

48

irU.S. GOVERNMENT PRINTING OFFICE: 1962 o—644917
Growth Through AßficultiMal Progress