United States Department of Agriculture

Forest Service

Southwestern Region April

2016

Prescott National Forest

Smith Canyon Grazing Allotment:

Soil Analysis Chino Valley Ranger District, Prescott National Forest Yavapai County, Arizona David Moore, Forest Soil Scientist Francisco Anaya, Forest Ecologist

This page is intentionally left blank.

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File: 2200 Date April 21, 2016

Route: Chris Thiel

Subject: Smith Canyon Livestock Grazing Project – Soil Specialist Report

To: Chino Valley District Ranger

The purpose and need of the proposed action is to continue to authorize livestock grazing on

the Smith Canyon in a manner consistent with the Prescott National Forest’s Land and

Resource Management Plans (2015). This assessment will serve as the soils analysis for the

Smith Canyon Livestock Grazing Allotment and was developed in consideration of the best

available science. The project was also reviewed to determine if it was consistent with the

Prescott National Forest Plan (2015).

The content included in this assessment is based on the direction provided by FSM 2550

Watershed and Air Management – 2552.3 Soil Management Support Service Records (1990b).

1. Purpose. The purpose of the soil analysis is to provide interpretations of soil

characteristics, describe soil conditions, and predict effects to the soil resources.

2. Soils data. The primary data sources used include the Terrestrial Ecosystem Survey of

the Prescott National Forest (2000), Prescott National Forest soil pedon field description

sheets (undated), Ecological Classification of the Prescott National Forest (2005), and

DRAFT Ecological Response Units of the Southwestern United States (2014)

3. Method and intensity of investigation. Represenative Terrestrial Ecological Unit

Inventory (TEUI) map units were analyzed throughout the allotment by pasture. Soil

quality status was identified by assessing soil conditions at key areas within represenative

TEUIs. Soil condition assignments were based on the USFS Southwest Region 3

Technical Guidance for Soil Quality Monitoring (2013) and were conducted inconjunction

with ecological and rangeland management status sampling and identification.

4. Soil map of project area. An allotment map of represenative TEUIs are provided.

5. Characteristics and classification of the soils. The soil characteristics and

classification are identified and based on the Terrestrial Ecosystem Survey of the Prescott

National Forest (2000).

6. Soil interpretations and predictions. Soil interpretations and predictions are identified

identified in the existing condition and effects section.

7. Evaluation of effects and recommendations. Soil effects are disclosed. Soil

management recommendations that are compliant with the Prescott National Forest Plan

(2015) are provided along with Best Management Practices.

DAVID MOORE, Forest Soil Scientist

FRANCISCO ANAYA, Ecologist

Prescott National Forest

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Table of Contents

Page

Methodology ..................................................................................................1

Existing Condition, Objectives, and Recommendations ........................................7

Cottonwood: 425.1 ............................................................................... …7

Smith Canyon: 427.1 ....................................................................................9

Granites: 461.1............................................................................................12

Smith Canyon: 461.2 ....................................................................................15

Spider: 462.2 ..............................................................................................17

Granites: 477.1............................................................................................19

Jones: 486.1 ...............................................................................................21

Moano: 486.2 ..............................................................................................23

Spider: 486.3 ..............................................................................................25

Smith Mesa: 490.1 .......................................................................................28

Direct and Indirect Effects ...............................................................................31

Improvements ...............................................................................................35

Literature Cited ..............................................................................................36

Appendix A: Best Management Practices ...........................................................41

Appendix B: PNF Resource Management Guidelines for Rangeland NEPA ...............46

Appendix C: Proposed New Range Improvement Map ........................................47

Appendix D: EA Proposed Action ......................................................................48

Appendix E: General Soil Effects Analysis ..........................................................52

1

Methodology

This analysis evaluated soil resources using a myriad of different methods. Soil condition

analysis utilized methodologies outlined in the Technical Guidance for Soil Quality Monitoring in

the Southwestern Region, USDA Forest Service (2013). The Terrestrial Ecosystem Survey of

the Prescott National Forest (2000) was used as the basis to evaluate and assess soil and

rangeland condition resources. Forest Plan (2015) elements associated with PNVTs, desired

condition, and standard/guidelines were also used in conjunction with the analysis.

Successional state elements (as described in the DRAFT Ecological Response Units of the

Southwestern United States (2014)) are displayed and described how they relate to the

Prescott National Forests PNVTs and subsequent TEUIs are also evaluated. This data considers

existing successional state, potential successional state, and how this is contributing to soil and

vegetation conditions. Specifics on how PNVT successional states relate to the Forest Plan

direction is described in the Final Environmental Impact Statement for the Prescott National

Forest Land Management Plan, Volume 2 (2015).

Analysis Appendixes include:

Appendix A: Best Management Practices: Soil and water conservation practices

identified to comply with the Clean Water Act

Appendix B: Prescott National Forest Resource Management Guidelines for Rangeland

NEPA. This establishes general prescription guidelines to move toward desired

conditions and resource objectives.

Appendix C: Map of New Range Improvement proposals.

Appendix D: EA Proposed Action

Appendix E: General Soil Effects Analysis

Data collection methodologies included collecting soil and vegetation qualitative and

quantitative data. Qualitative soil quality indicators were collected using the Soil Condition

Rating Guide (2013). Vegetation related collection utilized Daubenmire cover frequency to

describe herbaceous cover and the 1/10th acre plot was used to inventory dominant shrub and

tree species. Soil surface component measurements were taken using the point intercept

method and vegetation gap measurements were taken using the line intercept method. Both

of these methodologies were collected as outlined in the Monitoring Manual for Grassland,

Shrubland and Savanna Ecosystems (2005).

Methodology Process

The Terrestrial Ecosystem Survey (TES) of the Prescott National Forest (2000) was used as the

basis to assess soil and rangeland conditions. The TES Survey consisted of mapping and

interpreting ecosystems through a systematic examination, description, classification and

integration of the primary ecosystem components – soil, vegetation, and climate. TES places

a major emphasis on recognizing the relationships that exist between the primary components,

which in turn define terrestrial ecological map units or terrestrial ecological unit inventory

(TEUI). The TEUI contains detailed information on the biotic and abiotic characteristics of each

of the map units, in addition to interpretations on potential plant communities, surface

components, soil stability, soil condition, and production potential.

The Terrestrial Ecosystem Survey of the Prescott NF identifies a landscape scale soil condition

assignment for all TEUIs across the forest. Project level TEUI’s are selected and soil conditions

are field verified to determine existing site specific conditions. For this analysis, representative

TEUIs were selected, by pasture, to display the effects of livestock grazing. These selected

TEUIs reflect what is happening within a pasture as a result of on-the ground management

actions (USDA 1999).

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Key area sampling sites were identified within each representative TEUI and were chosen

based on their representation of environmental conditions of the selected map unit (USDA

1999). Since key areas were selected based on current managements actions, soil conditions

may differ for the whole map unit versus the key area. For example, a majority of a TEUI’s

soil condition may be deteriorated in thick pinyon-juniper but livestock access is limited in

these areas due to lack of forage, while a small portion of the same TEUI with minimal pinyon-

juniper cover and ample forage production may be selected for a key area because this site

represents current livestock management.

Representative Terrestrial Ecosystem Unit Inventory (TEUI) map units were selected in each

major pasture within the allotment (Figure 1).

There were 7 TEUI map units chosen as key or critical areas to evaluate vegetation ecological

status in 7 pastures. These map units were selected based on their accessibility to livestock,

in other words, they are found on flat to gently sloping areas. Some of the locations are long

term monitoring sites established in the late 1950s and early 1960s.

Figure 1. Smith Canyon key TEUIs.

The TEUI map units can be further grouped together based on the potential natural vegetation

type (PNVT) that occupies a particular TEUI map unit. There are seven PNVTs on the

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allotment. Three PNVTs make up 98 percent of the allotment, Piñon Juniper Evergreen Shrub,

Juniper Grassland, and Interior chaparral. Inventories concentrated on these three areas of the

allotment.

The other PNVTs found on the allotment are Colorado Plateau Grassland, Riparian Gallery

Forest, Ponderosa Pine-Evergreen Oak, and Ponderosa Pine-Gamble Oak. Cattle are known to

prefer grasses over shrubs when they are available, so inventory locations with a low shrub

and tree canopy were selected as key areas to determine grazing influence on herbaceous

vegetation. Shrubs provide a major amount of the available forage on the Smith Canyon

Allotment and areas with a large shrub component were inventoried as well.

Soil, vegetation, and water resource field data was collected by the Prescott National Forest

Rangeland Core Team which consists of the Rangeland Management Specialist, Hydrologist,

and Soil Scientist. The Interdisciplinary Team used this information, along with any other

applicable data, to develop the Proposed Action, Desired Future Conditions, Management

Objectives, and Resource Protection Measures. This information has been integrated and

considered in this analysis

Soil Condition

Soil quality standards were analyzed using the USFS Southwest Region 3 Technical Guidance

for Soil Quality Monitoring (1999). The Prescott National Forest Terrestrial Ecosystem Survey

(TES) was used as the basis for this analysis and is defined as the systematic analysis,

description, classification (soil/vegetation), mapping and interpretation of terrestrial

ecosystems (Robertson 2000). TES was used to determine if the soil resources were

functioning within their ecological capability.

Soil condition is an evaluation of soil quality or the capacity of the soil to function within

ecosystem boundaries to sustain biologic productivity, maintain environmental quality, and

promote plant and animal health (technical). The soil condition rating procedure evaluates soil

quality based on an interpretation of factors that affect three primary soil functions. The

primary soil functions evaluated are soil stability, soil hydrology, and nutrient cycling

(technical). These functions are interrelated.

Soil function is assessed by evaluating soil quality indicators associated with surface soil

properties. Definitions of soil functions are as follows (USDA FS 2013).

Soil Hydrology. The ability of the soil to absorb, store, and transmit water, both

vertically and horizontally. This function is assessed by evaluating or observing

changes in surface structure, surface pore space, consistence, bulk density, and

infiltration or penetration resistance. Increases in bulk density or decreases in porosity

results in reduced water infiltration, permeability and plant available moisture.

Soil Stability. The ability of the soil to resist erosion. Soil erosion is the detachment,

transport, and deposition of soil particle by water, wind or gravity. Vascular plants, soil

biotic crusts, and vegetation ground cover (VGC) are the greatest deterrent to surface

soil erosion. Visual evidence of surface erosion includes sheets, rills, and gullies;

pedestalling, soil deposition, erosion pavement, and loss of the surface "A" horizon.

Erosion models may also be used to predict on-site soil loss.

Nutrient Cycling. The ability of the soil to accept, hold and release nutrients. This

function is assessed by evaluating vegetative community composition, litter, coarse

woody material, root distribution and soil biotic crusts. These indicators are considered

an important source of soil organic matter, which is essential in sustaining long-term

soil productivity. It provides a carbon and energy source for soil microbes, stores and

4

provides nutrients which are needed for the growth of plants and soil organisms and by

providing for cation and anion exchange capacities.

Indicators of each soil function are assessed in order to place the soil into a soil condition

category (technical). There are three soil condition categories which defines how the soil is

functioning. The soil condition categories are satisfactory, impaired, and unsatisfactory. The

definitions for the soil condition rating are as follows (Technical):

Satisfactory. Indicators signify that soil function is being sustained and soil is

functioning properly and normally. The ability of the soil to maintain resource values

and sustain outputs is high.

Impaired. Indicators signify a reduction in soil function. The ability of the soil to

function properly and normally has been reduced and/or there exists an increased

vulnerability to degradation. An impaired category indicates there is a need to

investigate the ecosystem to determine the cause and degree of decline in soil

functions. Changes in land management practices or other preventative measures may

be appropriate.

Unsatisfactory. Indicators signify that a loss of soil function has occurred. Degradation

of vital soil functions result in the inability of the soil to maintain resource values,

sustain outputs or recover from impacts. Unsatisfactory soils are candidates for

improved management practices or restoration designed to recover soil functions.

Some soil quantifiable measurements taken used to assess soil condition include:

Soil Surface Components. Quantifiable soil surface measurements were taken during the soil

condition assessment. One element of the USFS Region 3 Soil Condition Evaluation is to

consider how effective vegetative ground cover (i.e. basal vegetation and litter cover)

contributes to all soil functions. This is done by evaluating how vegetative ground cover (VGC)

is spatially distributed across the landscape both vertically and horizontally (technical, Robbie

2008). VGC measurements were taken in compliance with the Region 3 Soil Quality

Monitoring Methods which defines effective litter as organic materials on the soil surface at

least .5 inch thick (technical). VGC measurements were also taken as comparable values to

Prescott National Terrestrial Ecosystem Survey (TES) potential which defines litter as organic

materials on the soil surface at least 1 inch thick (Robertson 2000). The TES VGC levels are

not used for the soil condition evaluation but provide insight how existing levels compare to

potential levels along with how its spatial distribution contribute to soil condition.

Vegetation Spatial Gap Intercept. The Gap Intercept Measurement provides quantifiable

information on the proportion of the landscape occupied by vegetation and the portion of the

landscape not vegetated (i.e. gap) (Herrick 2005). The gap intercept method does not

measure the vegetation spatial pattern directly, but does proved an insight on vegetation

spatial distribution by indicating the extent plants are aggregated or dispersed across the

landscape (Herrick 2005). Vegetative gaps affect the hydrologic, stability, and nutrient cycling

soil functions (Herrick 2005). Generally as gap sizes increase the organic matter decreases as

you get further away from vegetation. This results in less protective cover, a decrease in

nutrient cycling, poorer soil structure, and a decrease in infiltration. Consequently, soil in the

gaps are more erodible (Herrick 2005). Larger vegetation interspaces are more prone to

vesicular crust development, lower infiltration rates, and greater sediment production

(Blackburn 1975). Erosion is further increased in areas with large gaps because they are more

highly connected due to less vegetation obstruction to water flow (Herrick 2005).

Vegetation gap measurements were conducted, on some TES map units, as outlined in the

Monitoring Manual for Grassland, Shrubland and Savanna Ecosystems (2005). Measurement

5

data is displayed as percent of landscape with non-vegetative “gap” and percent of landscape

occupied by vegetation. Gap measurements have been taken across the forest during soil

condition assessments and these measurements have been compared to other soil quality

indicators and overall soil functions to determine a general correlation between gap percentage

and a qualitative classification. The Gap Intercept Measurement is one soil quality indicator

used with a suite of other soil indicators to determine soil condition.

Bulk Density. Bulk density is defined as the mass of dry soil per unit bulk volume (technical).

This is one of the soil quality indicators used to assess the soil hydrologic function. Bulk

density measurements provide insight on many soil processes such as pore space, infiltration

and subsequent runoff, water storage, soil aeration, and soil resistance. Bulk density

measurements were taken using an AMS 5cm diameter and 10 cm depth impact core sampler

(www.ams.sampler.com). Standard laboratory soil bulk density measurements were utilized

and compared to reference bulk density measurements associated with grazing exclosures.

Bulk density soil quality indicator condition categories were based on the categories identified

in the Soil Condition Rating Guide (2013). These categories are as follows:

Satisfactory: Bulk density not increased.

Impaired: Moderate bulk density increases (5-15%)

Unsatisfactory: Significant increase in bulk density (>15%)

Applicable Forest Plan Desired Condition & Standard and Guideline for Soil Resources

Desired conditions describe how the resources on the Prescott NF should look and function

(cite forest plan). Standard and guidelines provide sideboards and guidance for project and

activity decision-making to help achieve desired conditions and objectives (Table 1).

For each TEUI analyzed applicable forest plan elements refer to specific soil resource conditions

(Table 2). Recommendations are provided to be compliant with Forest Plan desired conditions,

standards and guidelines.

6

Table 1. Land and Resource Management Plan for the Prescott NF 9 DC-Watershed-3

Soil productivity, function, and inherent physical, chemical, and biological processes remain

intact or are enhanced.

Elements necessary to sustain soil productivity and function include:

• Logs and other woody material are distributed across the soil surface to maintain soil

function within the limitations of individual PNVTs.

• Soil loss does not inhibit soil function. Limited soil compaction does not affect ecological

and hydrological functions.

• Vegetative ground cover, including biological soil crusts (i.e., soil consisting of lichens,

mosses, cyanobacteria, and algae organisms), provides stability and fertility for soil

function.

• Vegetative ground cover is distributed across the soil surface in sufficient proportions to

meet or trend toward “natural” conditions listed for each map unit in the terrestrial

ecosystem survey.

• Soils with a condition rating below satisfactory (i.e., impaired or unsatisfactory) do not

further decline in function and trend toward a satisfactory rating where environmental

factors allow.

Table 2. Soil guidelines provide guidance for trending toward or achieving desired conditions

labeled as DC-Watershed-1, DC-Watershed-3, DC-Veg-6 to 7, DC-Veg-9, DC-Veg-13, DC-Veg-

17, DC-Veg-23, and DC-Transportation and Facilities-1 in chapter 2 of this document.

Guideline 1.)

Soils (See also Watersheds Guidelines 1, 5, 7, and 8; Vegetation Guideline 3;

Transportation Guidelines 2 and 6; Wilderness Standard 2; Scenic Guideline 2; All Minerals

Standard 1; Locatable Minerals Standard 3 and Guideline 1; and Heritage

Guide-

Soils-1

Projects should be designed to limit activities that would cause long term impacts

to soils such as loss of ground cover, severely burned soils, detrimental soil

displacement, erosion, puddling, or compaction. Where disturbance cannot be

avoided, project-specific soil and water conservation practices should be

developed.

Guide-

Soils-2

Down logs and coarse woody debris should be retained at the appropriate tonnage

per PNVT as outlined in the “Vegetation” desired condition sections to retain soil

productivity.

Guide-

Soils-3

Operation of heavy equipment, such as dozers, backhoes, or vehicles, on slopes

with a grade of 40 percent or greater should be avoided. If use of equipment in

such areas is required, site-specific design features should be implemented to

minimize disturbance to soil and vegetation.

Guide-

Soils-4

Project-specific design features to avoid soil impacts should be used when projects

occur on slopes with a grade of 40 percent or greater or on soils that are sensitive

to degradation when disturbed.

Guide-

Soils-5

Ground disturbing activity should be avoided when the soil moisture level is such

that activity would cause damage to the soil character or function.

7

Allotment: Smith Canyon

Pasture: Cottonwood

Date: 9/1/2015

TEUI: 425.1

PNVT: Chaparral

Successional State: Potential: open-tree;

Existing: close-shrub

Taxonomy: Lithic Haplustalfs; loamy-

skeletal; shallow; coarse sandy loam

Parent Material: Sedimentary Rock

Landform: Gentle Hills

% Slope: 15

Ground Cover:

Measured Potential

Rock 29 45

Bare soil 54 15

Litter/ 14 30

Basal veg 3 10

Bio crust 0 0

Vegetative Cover:

Measured Reference

Graminoid 16 15

Woody 63-shrub 39-shrub

Diversity:

Measured Reference

Graminoid 6 8

Woody 8 9

Gap:

% Gap % No Gap

Measured 15 85

Reference <25 >75

Bulk Density:

Soil Texture: Sandy Loam; >35%

rock within profile.

Measured: Not measured because

soil structure does not indicate

compaction nor is coarse textured

soils with high levels of internal rock

content on slopes vulnerable to

compaction.

Soil Condition:

Measured: Satisfactory

TEUI Designation: Impaired

Soil Notes: This chaparral PNVT’s

potential vegetative state normally has a

higher tree component but evidence of

historic fire suggests a decrease of tree

cover and a subsequent vegetative state

change to close-shrub.

The close-shrub successional state of this

TEUI has contributed to satisfactory soil

conditions. The litter directly affiliated with

the dense shrub species is producing ample

amounts of litter for soil protection and

nutrient cycling. Litter cover is providing

soil stability and being incorporated into

internal soil organic matter (Mapfumo

2002). Litter associated with the chaparral

is thick and results in the formation of

granular soil structure that promotes

infiltration and water holding capacity (Hart

1993). In addition, in these areas

influenced by shrub species, the soil

aggregate stability is high which suggests

the soils are more resistant to erosion

(Herrick 2001). There is some erosion

pavement formation within the shrub

interspace due to run-off flow patterns.

However, these flow patterns affiliated with

the interspaces are disrupted and non-

continuous due to the random obstruction

of litter associated with shrub species and

basal cover of graminoid species.

PNF LRMP: DC-Watershed-3 (Page 6)

Soil Quality Objective: Maintain existing

condition.

Recommendation: Standard utilization

guidelines for graminoid species within

interspace.

8

Pasture: Cottonwood

Photo:

TEUI: 425.1

TEUI 425 exhibits typical chaparral ecosystem characteristics with closed shrub

canopy cover and litter directly affiliated with shrub species.

Map: TEUI 425

Map of Cottonwood pasture, showing TEUI composition and data collection point.

Highlighted area indicates TEUI 425, as represented by the data collection sample.

In area, Cottonwood is 6,318 acres with TEUI 425 containing 866 acres; therefore,

TEUI 425 makes up approximately 14% of the total area.

9

Allotment: Smith Canyon

Pasture: Smith Canyon

Date: 10/29/2015

TEUI: 427.1

PNVT: Juniper Grass

Successional State: grass-forb

Taxonomy: Vertic Argiustolls; fine; deep

Parent Material: Basalt

Landform: Elevated Plain

% Slope: 6

Ground Cover:

Measured Potential

Rock 12 45

Bare soil 65 40

Litter 20 10

Basal veg 5 15

Bio crust 0 NA

Vegetative Cover:

Measured Reference

Graminoid 5 41

Woody 12 24

Diversity:

Measured Reference

Graminoid 2 7

Woody 4 8

Gap:

% Gap % No Gap

Measured 47 53

Reference <25 >75

Bulk Density:

Soil Texture: silty clay loam; <15%

internal rock

Measured: 0.58-0.77

Reference: 0.85

% Change: none

Soil Condition:

Measured: Unsatisfactory

TEUI Designation: Impaired

Soil Notes: The sampling site was

located between 2 soil types that entailed

an area with a high level of cobble rock

cover and an area that consists of a soil

depositional zone.

Soils are in unsatisfactory condition.

Compaction and soil displacement is

prevalent. However bulk density and

rupture resistance indicates shrink-swell

properties are enabling the compacted soils

to “open up” which enables an increase of

pore space (USDA NRCS 2001). However,

the platy soil structure and formation of

vesicular physical soil crusts disrupts pore

space connectivity and retards infiltration

(Blackburn 1975, Hart 1993). The soils

generally have low surface and internal

biomass and organic matter with high

levels of bare soil. These soils have a very

low aggregate stability which determines

the soils ability to retain it adhesiveness

when wet and causes soil peds to dissolve

and are highly erodible (Herrick 2001).

Nutrient cycling is poor due to the lack of

organic matter. However, areas associated

with dense cobble and boulder cover are

well armored and able to protect graminoid

species. Graminoid diversity is low and can

contribute to soil function (Printz 2014).

PNF LRMP: DC-Watershed-3; Guide-

Soils-5 (Page 6)

Soil Quality Objective: Improve

graminoid diversity and cover, vegetation

spatial distribution and graminoid basal

cover. Utilize these factors to assist in

improving compacted soils (USDA NRCS

2001, Castellano 2007).

Recommendation: Integrate rest through

deferment and control water use to

alleviate concentrated use, compaction and

allow recovery (Van Haveren 1983, Warren

1986). Prescribe incidental use (lower end

of light use) to promote biomass retention

and subsequent litter development (Molinar

2001, Mapfumo 2002).

10

Pasture: Smith Canyon

Photo:

TEUI: 427.1

Soil damage is occurring when wet from hoof impacts causing soil displacement and

compaction.

Soils with higher surface cobble cover is armoring soils and allowing more retention

of graminoid cover.

11

Map: TEUI 427

Map of Smith Canyon pasture, showing TEUI composition and data collection point.

Highlighted area indicates TEUI 427, as represented by the data collection sample.

In area, Smith Canyon is 14,362 acres with TEUI 427 containing 255 acres;

therefore, TEUI 427 makes up approximately 2% of the total area.

12

Allotment: Smith Canyon

Pasture: Granites

Date: 8/28/15

TEUI: 461.1 - medium tree

PNVT: PJ Shrub

Successional State: Potential: close-tree;

Existing: open-tree

Taxonomy: Typic Argiustolls; fine;

moderately deep; clay loam

Parent Material: Basalt

Landform: Elevated Plain

% Slope: 5

Ground Cover:

Measured Potential

Rock 61 60

Bare soil 24 15

Litter 10 20

Basal veg 5 1

Bio crust 0 NA

Vegetative Cover:

Measured Reference

Graminoid 10 16

Woody 44 56

Diversity:

Measured Reference

Graminoid 4 9

Woody 5 9

Gap:

% Gap % No Gap

Measured 39 61

Reference <25 >75

Bulk Density:

Soil Texture: Not measured

Measured: NA

Reference: NA

% Change: NA

Soil Condition:

Measured: Unsatisfactory/Impaired

TEUI Designation: Impaired

Soil Notes: The preponderance of this

TEUI is associated with a close-tree

successional state. However, the sampled

location is an inclusion which is affiliated

with an open-tree successional state and

subsequently produces higher graminoid

forage levels.

Soils associated with the close-tree state

(i.e. dense juniper cover) are in

unsatisfactory condition. The dense juniper

canopy cover has resulted in the loss of a

lower vegetative cover component e.g. lack

of a graminoid component that has resulted

in a lack of protective ground cover and

organic matter (Davenport 1998). This has

resulted in widespread sheet erosion and

gullying in areas; hummocking of trees;

and loss of the A-soil horizon.

Sampled soil conditions, that are associated

with an open-tree successional state, are

impaired. This vegetative patch is

connected hydrologically and ecologically

from open inter-patch areas associated with

closed canopy juniper sites (Ludwig 2005).

Accelerated run-on from these adjacent

unsatisfactory sites has resulted in elevated

overland flow within the graminoid

interspaces. The graminoid cover is well

distributed but the proportion of the

landscape occupied by graminoid cover is

lacking resulting in the lack of surface litter

and lower internal organic matter. This has

resulted in the development of physical soil

vesicular crusts that retard water infiltration

(Blackburn 1975).

TEUI potential woody cover is higher than

sampled conditions and graminoid cover

and diversity is lower than potential. This

suggests that woody competition is not

completely contributing to low graminoid

cover resulting in a decrease to soil

function. However, interconnectivity of

eco-hydrologic processes from adjacent

unsatisfactory soils are negatively

influencing the key area (Ludwig 2005)

13

PNF LRMP: DC-Watershed-3 (Page 6)

Soil Quality Objective: Improve and

maintain graminoid cover, diversity, and

vegetation spatial distribution to maintain

vegetative patchy eco-hydrologic function.

Recommendation: Lower end of

conservative utilization levels (30-40%)

and deferred season of use to allow further

graminoid biomass retention and promote

diversity (Molinar 2001, Valentine 1990,

Trimble 1995). Control water facilities to

improve distribution and alleviated livestock

travel corridor patterns to allow vegetation

and soil recovery.

Photo:

Sampled site location exhibiting impaired soil conditions. Graminoid cover is present but not

well distributed, resulting in elevated run-off and soil loss.

14

Pasture: Granites TEUI: 461.1

Unsatisfactory soil condition associated with TEUI 461. Widespread erosion

pavement, hummocked trees, and loss of the A-horizon are common.

Map: TEUI 461

Map of Granites pasture, showing TEUI composition and data collection point.

Highlighted area indicates TEUI 461, as represented by the data collection sample.

In area, Granites is 4,705 acres with TEUI 461 containing 401 acres; therefore, TEUI

461 makes up approximately 9% of the total area.

15

Allotment: Smith Canyon

Pasture: Smith Canyon

Date: 10/28/2015

TEUI: 461.2

PNVT: PJ Shrub

Successional State: Potential: close-tree;

Existing: grass-forb

Taxonomy: Lithic Argiustolls; clayey-

skeletal; shallow; sandy clay loam

Parent Material: Basalt

Landform: Elevated Plain

% Slope: 5

Ground Cover:

Measured Potential

Rock 36 60

Bare soil 35 15

Litter 6 20

Basal veg 23 10

Bio crust 0 NA

Vegetative Cover:

Measured Reference

Graminoid 41 16

Woody 6 56

Diversity:

Measured Reference

Graminoid 3 9

Woody 9 1

Gap:

% Gap % No Gap

Measured 17 83

Reference <25 >75

Bulk Density:

Soil Texture: sandy clay loam

Measured: 1.05

Reference: <0.85

% Change: +23%

Soil Condition:

Measured: Impaired

TEUI Designation: Impaired

Soil Notes: Soils are in impaired

condition predominantly due to compaction

and low litter levels. Graminoid cover is

high and well distributed across the site

and occupies a large portion of the

landscape. This is providing stability for

the soils (Bird 2007). However, graminoid

diversity is low. Rangeland plant diversity

contributes to the maintenance and

enhancement of above- and belowground

biological and ecological interactions that

keeps soil function intact and maintains soil

resiliency (Printz 2014). Soil compaction is

evident by high bulk density levels, blocky

soil structure, and hard rupture resistance.

Compaction and the lack of pore space has

resulted in low internal and surface organic

matter levels (USDA NRCS 2001). This has

reduced the soils nutrient cycling and

hydrologic function. The decrease of pore

space and low organic matter has resulted

in formation of physical soil crusts that has

decreased infiltration and increased run-off

(Blackburn 1975).

PNF LRMP: DC-Watershed-3; Guide-

Soils-5 (Page 6)

Soil Quality Objective: Increase

vegetative ground cover levels, improve

vegetation diversity, and decrease

compaction.

Recommendation: Standard utilization

levels. Integrate seasonal deferment rest

and improve livestock distribution by

controlling waters and herding. This will

allow an increase of species richness,

improve internal soil biomass and organic

matter, and alleviate compaction (Van

Haveren 1983, Valentine 1990, Warren

1986, Hart 1993).

16

Pasture: Smith Canyon

Photo:

TEUI: 461.2

Soils predominantly have high graminoid levels. However, soil compaction has

elevated overland flow and sheet erosion in places.

Map: TEUI 461

Map of Smith Canyon pasture, showing TEUI composition and data collection point.

Highlighted area indicates TEUI 461, as represented by the data collection sample.

In area, Smith Canyon is 14,362 acres with TEUI 461 containing 1,860 acres;

therefore, TEUI 461 makes up approximately 13% of the total area.

17

Allotment: Smith Canyon

Pasture: Spider

Date: 9/16/2015

TEUI: 462.2

PNVT: PJ Shrub

Successional State: Potential and

Existing: open-tree

Taxonomy: Typic Haplustalfs; clayey-

skeletal; moderately deep

Parent Material: Sedimentary Rock

Landform: Hills

% Slope: 24

Ground Cover:

Measured Potential

Rock 57 70

Bare soil 10 10

Litter 25 20

Basal veg 8 10

Bio crust 0 NA

Vegetative Cover:

Measured Reference

Graminoid 19 17

Woody 77 47

Diversity:

Measured Reference

Graminoid 6 7

Woody 7 8

Gap:

% Gap % No Gap

Measured 28 72

Reference <25 >75

Bulk Density:

Soil Texture: sandy clay

Measured: 0.92

Reference: <1.00

% Change: None

Soil Condition:

Measured: Satisfactory

TEUI Designation: Unsatisfactory

Soil Notes: Site is located on gently

sloping hills with deep sedimentary rock

that supports multiple vegetative structure

classes. These consist of mosaic tree

patches, a dense shrub mid-story

component, and a healthy graminoid

component located within the interspaces.

Soils are in satisfactory condition. The

chaparral component is the predominant

catalyst contributing to soil function by

producing high levels of litter for favorable

soil structure, nutrient cycling, and soil

stability. Graminoid cover is well

distributed within the interspaces and the

proportion of the landscape occupied by

vegetation is high. This decreases overland

flow, promotes water infiltration, and

provides soil stability (Herrick 2005, Bird

2007).

PNF LRMP: DC-Watershed-3 (Page 6)

Soil Quality Objective: Maintain existing

condition.

Recommendation: Standard rangeland

management practices.

18

Pasture: Spider

Photo:

TEUI: 462.2

Typical view of TEUI 462. Map unit has a strong chaparral component with a mosaic

of juniper and pinyon trees.

Map: 462

Map of Spider pasture, showing TEUI composition and data collection point.

Highlighted area indicates TEUI 462, as represented by the data collection sample.

In area, Spider is 7,123 acres with TEUI 462 containing 988 acres; therefore, TEUI

462 makes up approximately 14% of the total area.

19

Allotment: Smith Canyon

Pasture: Granites

Date: 09/16/2015

TEUI: 477.1

PNVT: PJ Shrub

Successional State: Potential & Existing:

open-tree

Taxonomy: Lithic Haplustalfs; loamy-

skeletal; shallow; loamy coarse sand

Parent Material: Granite

Landform: Hills

% Slope: 20

Ground Cover:

Measured Potential

Rock 47 65

Bare soil 7 5

Litter 43 30

Basal veg 2 10

Bio crust 1 NA

Vegetative Cover:

Measured Reference

Graminoid 8 13

Woody 53 51

Diversity:

Measured Reference

Graminoid 5 7

Woody 9 13

Gap:

% Gap % No Gap

Measured 21 79

Reference <25 >75

Bulk Density:

Soil Texture: Loamy Sand; internal

rock 6%.

Measured: 1.08

Reference: <1.00

% Change: Soil structure indicates

favorable condition.

Soil Condition:

Measured: Satisfactory

TEUI Designation: Satisfactory

Soil Notes: Soils are stable and in

satisfactory condition. Shrub density is

high and producing ample litter levels for

nutrient cycling and favorable soil

structure. The interspaces are bouldery

and well armored which is stabilizing the

soils.

PNF LRMP: DC-Watershed-3

Soil Quality Objective: Maintain existing

condition.

Recommendation: Standard rangeland

management practices.

20

Pasture: Granites

Photo:

TEUI: 477.0

Site is well armored and stable due to high levels of boulders and shrub cover.

Map: TEUI 477

Map of Granites pasture, showing TEUI composition and data collection point.

Highlighted area indicates TEUI 477, as represented by the data collection sample.

In area, Granites is 4,705 acres with TEUI 477 containing 2,104 acres; therefore,

TEUI 477 makes up approximately 45% of the total area.

21

Allotment: Smith Canyon

Pasture: Jones

Date: 08/26/2015

TEUI: 486.1

PNVT: PJ Shrub

Successional State: Potential & Existing:

open-tree

Taxonomy: Typic Haplustalfs; fine-

loamy; moderately deep; coarse sandy loam

Parent Material: Granite

Landform: Elevated & Lowland Plain

% Slope: 5

Ground Cover:

Measured Potential

Rock Ocular

similar

Potential

35

Bare soil 15

Litter 45

Basal veg 10

Bio crust NA

Vegetative Cover:

Measured Reference

Graminoid Ocular

similar

Potential

21

Woody 57

Diversity:

Measured Reference

Graminoid 6 8

Woody 9 14

Gap:

% Gap % No Gap

Measured Not

measured

Not

measured

Reference NA NA

Soil Condition:

Measured: Satisfactory

TEUI Designation: Unsatisfactory

Soil Notes: Site is meeting TEUI

vegetation potential and is in satisfactory

soil condition. Sampling location is highly

productive and able to maintain multiple

vegetative structural states of large tree

species and a strong chaparral component.

The coarse textured granitic soils inherently

have a high infiltration rate with minimal

run-off (Brady 1990). Soils are stable due

to boulder conditions, high vegetative

cover, and thick litter levels.

PNF LRMP: DC-Watershed-3

Soil Quality Objective: Maintain existing

condition.

Recommendation: Standard rangeland

management practices.

22

Pasture: Jones

Photo:

TEUI: 486.1

Sampled location supports multiple vegetation structure of monarch trees and a strong

chaparral component.

Map: TEUI 486

Map of Jones pasture, showing TEUI composition and data collection point. Highlighted area

indicates TEUI 486, as represented by the data collection sample. In area, Jones is 1,735

acres with TEUI 486 containing 588 acres; therefore, TEUI 486 makes up approximately 34%

of the total area.

23

Allotment: Smith Canyon

Pasture: Moano

Date: 08/26/2015

TEUI: 486.2

PNVT: PJ Shrub

Successional State: Potential: open-tree;

Existing: grass-forb

Taxonomy: Typic Argiustolls; fine-loamy;

deep

Parent Material: Sedimentary Rock

Landform: Elevated & Lowland Plain

% Slope: 5

Ground Cover:

Measured Potential

Rock 67 30

Bare soil 24 25

Litter/ 6 35

Basal veg 3 10

Bio crust 1 NA

Vegetative Cover:

Measured Reference

Graminoid 55 21

Woody 3 47

Diversity:

Measured Reference

Graminoid 5 8

Woody 4 14

Gap:

% Gap % No Gap

Measured 10 90

Reference <25 >75

Bulk Density:

Soil Texture: Loamy Sand; 35%

internal rock

Measured: 0.94

Reference: <1.00

% Change: None

Soil Condition:

Measured: Satisfactory

TEUI Designation: Unsatisfactory

Soil Notes: Soil conditions are

satisfactory. These soils are formed from

sedimentary deposits with granite lithology

which makes them inherently erosive.

These depositional soils and their landscape

position makes these soils more amenable

to support a strong grassland component

(Jacobs 2008). TES describes this map

unit’s potential state as open-tree but the

sampled state is grass-forb. Hence, due to

the lower level of woody cover and lack of

competition, graminoid production is

expected to be higher than described by

TEUI.

Soil conditions are satisfactory. Graminoid

cover is well distributed across the

landscape and enabling ample protective

cover to stabilize soils from splash erosion,

overland flow and promote favorable

infiltration rates. The soils hydrologic

processes and nutrient cycling is functional.

This is indicated by lower bulk density

measurements, favorable soil structure,

high levels of pore space, favorable root

distribution, and high levels of internal soil

organic matter. Graminoid diversity is

below potential slightly and vegetative

ground cover is low. Rangeland plant

diversity contributes to the maintenance

and enhancement of above- and below

ground organic matter that keeps soil

function intact and maintains soil resiliency

(Printz, 2014).

PNF LRMP: DC-Ecosystem Resilience-1;

DC-Watershed-3

Soil Quality Objective: Manage and move

graminoid diversity and vegetative ground

cover in an upward trend.

Recommendation: Integrate seasonal

deferment to improve/ maintain graminoid

diversity and vegetative ground cover

(Vallentine 1990). Standard utilization

guidelines.

24

Pasture: Moano

Photo:

TEUI: 486.2

Sedimentary depositional site provides favorable niche for a grassland ecological

state.

Map: 486

Map of Moano pasture, showing TEUI composition and data collection point.

Highlighted area indicates TEUI 486, as represented by the data collection sample.

In area, Moano is 2,070 acres with TEUI 486 containing 370 acres; therefore, TEUI

486 makes up approximately 18% of the total area.

25

Allotment: Smith Canyon

Pasture: Spider

Date: 9/26/15

TEUI: 486.3

PNVT: PJ Shrub

Successional State: Potential: open-tree;

Existing: open-shrub

Taxonomy: Typic Haplustalfs;loamy;

shallow

Parent Material: Granite

Landform: Elevated Plain

% Slope: 5

Ground Cover:

Measured Potential

Rock 40 40

Bare soil 17 20

Litter 36 35

Basal veg 3 1

Bio crust 4 NA

Vegetative Cover:

Measured Reference

Graminoid 7 16

Woody 35 32

Diversity:

Measured Reference

Graminoid 2 5

Woody 9 12

Gap:

% Gap % No Gap

Measured 35 65

Reference <25 >75

Soil Condition:

Measured: Satisfactory/

Unsatisfactory

TEUI Designation: Unsatisfactory

Soil Notes: Site is in an open shrub

successional state. This consists of a

mosaic pattern of dense chaparral and

openings that support forbs and

graminoids.

Areas associated with dense chaparral are

in satisfactory soil condition. The litter

directly affiliated with the dense shrub

species is producing ample amounts of litter

for soil protection and nutrient cycling.

Litter cover is providing soil stability and

being incorporated as internal soil organic

matter (Mapfuma 2002). Litter associated

with the chaparral is thick and results in the

formation of granular soil structure that

promotes infiltration and water holding

capacity (Hart 1993). In addition, in these

areas, the soil aggregate stability is high

which suggests the soils are more resistant

to erosion (Herrick 2001). Shrub species

are randomly and well distributed across

the landscape which disrupts overland

water patterns and promotes infiltration

(USDA NRCS 2001).

The large mosaic openings located within

the open shrub component are exhibiting

unsatisfactory soil conditions. Soil

structure shows signs of compaction and

minimal pore space which retards

infiltration, increases run-off, and elevates

soil loss (Brady 1990, USDA NRCS 2001).

Continuous sheet erosion is prevalent with

the formation of erosion pavement in

places. Organic matter is sparse and not

being incorporated into the soil resulting in

a loss to the nutrient cycling function.

PNF LRMP: DC-Watershed-3

Soil Quality Objective: Improve

graminoid cover, vegetation spatial

distribution, and vegetative ground cover

within the mosaic openings.

Recommendation: Alleviate regular use

through assignment of non-capacity that

will result in incidental use (i.e. lower end

of light use). This will allow graminoid

establishment and retention of additional

biomass for litter development and internal

soil organic matter (Molinar 2001, Warren

1986).

26

Pasture: Spider

Photo:

TEUI: 486.3

The dense chaparral component is in satisfactory soil condition.

Mosaic openings are exhibiting unsatisfactory soil conditions as indicated by high

levels of bare soil and lack of surface organic matter.

27

Map: TEUI 486

Map of Spider pasture, showing TEUI composition and data collection point.

Highlighted area indicates TEUI 486, as represented by the data collection sample.

In area, Spider is 7,123 acres with TEUI 486 containing 988 acres; therefore, TEUI

486 makes up approximately 36% of the total area.

28

Allotment: Smith Canyon

Pasture: Smith Mesa

Date: 09/02/15

TEUI: 490.1

PNVT: Juniper Grass

Successional State: Potential, Parker

Sample Site, & Exclosure: open-tree;

Sample outside exclosure: grass-forb

Taxonomy: Vertic Paleustolls, fine, deep

Parent Material: Basalt

Landform: Elevated Plain

% Slope: 5

Ground Cover:

Parker TEUI

Potential

Rock 16 45

Bare soil 77 25

Litter 0 15

Basal veg 7 15

Bio crust 0 NA

Outside

Exclosure

Inside

Exclosure

Rock 26 21

Bare soil 34 30

Litter 36 0

Basal veg 3 0

Bio crust 0 NA

Vegetative Cover:

Parker TEUI

Potential

Graminoid 24 23

Woody 15 Tree 10 Tree

Outside

Exclosure

Inside

Exclosure

Graminoid 11 59

Woody <5 tree 28 tree

Diversity: (Not calculated inside and

outside of exclosure)

Parker TEUI

Potential

Graminoid 8 5

Woody 1 1

Gap:

% Gap % No Gap

Parker 44 56

Reference <25 >75

Inside

Exclosure

22 78

Outside

Exclosure

33 77

Bulk Density:

Soil Texture: Clay

Parker: 0.94

Outside Exclosure: 0.86

Inside Exclosure: 0.77

% Change: +15%

Soil Condition:

Measured: Impaired/ Unsatisfactory

TEUI Designation: Unsatisfactory

Soil Notes: All sampling sites are within

component .1 of TEUI 490. Soil sampling

occurred, within Smith Mesa pasture, on a

number of sites within close proximity.

Sampling areas include: 1. Inside a grazing

exclosure which has maintained its natural

juniper cover of 28%, is in an open-tree

successional state, and represents

reference conditions; 2. immediately

outside the exclosure that is regularly

grazed. This site has been previously

treated for juniper species and has less

than 5% cover from juniper cover, resulting

in a grass-forb successional state; 3. A

Parker 3-step monitoring location that was

established to determine long-term trend

and rangeland conditions. This site has

lower juniper cover than the exclosure

sampling site but has the same

successional state of open-tree.

Soil conditions are impaired/ unsatisfactory.

Unsatisfactory soil conditions are generally

affiliated with juniper treated areas in a

grass-forb successional state. Impaired

29

soils are generally affiliated with areas

associated with an open-tree successional

state.

Soils are compacted as indicated by bulk

density measurements and massive to platy

soil structure. Soil displacement due to

hoof impact when the soils are wet is

prevalent in areas associated with the

grass-forb successional state. The soil

displacement has damaged the soil

structure ability to retain aggregation and

connectivity of pore space.

Spatial vegetation is poor as indicated by

the spatial gap data which indicates a large

proportion of the area is not protected from

vegetative cover. Bare soil levels are high

and susceptible to splash and sheet erosion

(USDA NRCS 2001). Aggregate stability is

minimal due to the lack of surface and

internal soil organic matter. This impacts

the soils ability to retain its ped structure,

has a low aggregate stability, and are

erodible (Herrick 2001). Nutrient cycling is

poor due to the lack of organic matter.

However, areas associated with open

juniper sites have a graminoid presence

and are providing additional soil stability by

retarding overland flow and soil movement.

PNF LRMP: DC-Watershed-3; Guide-

Soils-5 (Page 6)

Soil Quality Objective: Improve

compacted soils and vegetation spatial gap

distribution. Maintain or improve graminoid

cover and vegetative ground cover levels

that are similar to exclosure reference

conditions and TEUI potential.

Recommendation: Promote management

practices that result in incidental use (i.e.

lower end of light use) and integration of

rest. Management practices, such as

controlling water and supplement location

that focusses livestock use in northern

portion of pasture and discourages regular

use in TEUI 490. This will promote biomass

retention, litter development, and alleviate

compaction (Van Haveran 1983, Warren

1986, Molinar 2001, Mapfumo 2002).

30

Pasture: Smith Mesa TEUI: 490.1 Photo:

TEUI 490. Exclosure on left is in an open-tree successional state and has satisfactory soil

conditions. The grazed area on the right is in a grass-forb successional state and has

unsatisfactory soil conditions.

Map: TEUI 490

Map of Smith Mesa pasture, showing TEUI composition and data collection point. Highlighted

area indicates TEUI 490, as represented by the data collection sample. In area, Smith Mesa is

8,838 acres with TEUI 490 containing 4,730 acres; therefore, TEUI 490 makes up

approximately 54% of the total area.

31

Direct and Indirect Effects

Appendix E: General Soil Effects Analysis provides a detailed assessment of soil processes and

how livestock grazing can impact those processes and soil function. The following Direct and

Indirect Effects is based on research findings and rationale provided in Appendix E. Table 3 is

a synthesis of predicted projection of soil conditions by Alternative.

Table 3. Current soil condition with direct and indirect effects of grazing versus no grazing. Pasture TEUI Acres Existing Soil Condition Alternative 1: Grazing Alternative 2:

No Grazing

Cottonwood 425 6,318 Satisfactory Satisfactory Satisfactory

Smith Canyon 427 14,362 Unsatisfactory Impaired Impaired/Satisfactory

Granites 461 4,705 Unsatisfactory/Impaired Unsatisfactory/Impaired Unsatisfactory/Impaired

Smith Canyon 461 14,362 Impaired Satisfactory Satisfactory

Spider 462 7,123 Satisfactory Satisfactory Satisfactory

Granites 477 4,705 Satisfactory Satisfactory Satisfactory

Jones 486 1,735 Satisfactory Satisfactory Satisfactory

Moano 486 2,070 Satisfactory Satisfactory Satisfactory

Spider 486 7,123 Satisfactory/Unsatisfactory Satisfactory/Impaired Satisfactory/Impaired

Smith Mesa 490 4,730 Impaired/Unsatisfactory Impaired Satisfactory

Alternative 1: Grazing

Cottonwood-425, Spider-462, Granite-477 and Jones 486 are all within the Pinyon-Juniper

Shrub and Chaparral PNVT which support high levels of shrub cover. All of these soils

satisfactory conditions would be maintained. The dense shrub cover would continue to provide

high litter levels for soil stability protection, favorable soil structure and infiltration, and

nutrient cycling. Some interspaces are experiencing some elevated runoff and erosion within

the interspace but soils are in functional status. In addition, Jones-486 and Granite-477

interspaces are extremely boulder and well armored which is stabilizing the soils. Utilization

guidelines would continue to maintain residual graminoid cover within the shrub interspaces

for additional soil protection. Livestock use may have negligible impacts to the soils.

However, the high shrub cover and litter production would maintain functional soil status and

the effects would be immeasurable. Soil conditions would remain in satisfactory condition.

Smith Canyon-427 is in unsatisfactory condition and affiliated with the Juniper Grassland

PNVT. The management objective is to improve graminoid cover and the spatial distribution of

vegetation to improve soil organic matter, soil stability, and to assist in improving compacted

soils. Project design features include integrating rest to improve soil compaction and

controlling water access to improve pasture distribution. Prescribe incidental use levels (0-

30%) to promote biomass retention and subsequent litter development. Design features

include integrating seasonal deferment or rest and improving livestock distribution by

controlling access to waters and herding. These practices would alleviate compaction by

discouraging concentrated use, allow additional recovery periods and retain additional biomass

and mulch for soil function. This would allow soils to improve to impaired condition. However,

non-incidental use that regularly uses this site at 30% could limit the soils ability to improve

and the soils could remain in unsatisfactory status but show some improvement. Regular use

would continue to have some soil impacts from hoof impacts and partial-removal of biomass

and organic matter retention. Because of the soils non-functional status, the soils resiliency

and resistance would retard the soils ability to recover because of continued regular stress

(Seybold 1999).

32

Granites-461 is located in the Pinyon Shrub PNVT and exhibits unsatisfactory/impaired soil

condition. Unsatisfactory conditions are affiliated with dense juniper cover which is limiting

herbaceous recruitment resulting in accelerated runoff and erosion in the form of extensive

erosion pavement. Impaired soil conditions are affiliated within the interspaces which support

herbaceous cover that is below TEUI potential by half. The management objective for TEUI 461

is to improve litter and graminoid cover and vegetation spatial distribution. Design features

include deferred season of use to allow further graminoid biomass retention and control access

to water facilities to improve distribution. An additional water source is proposed that would

distribute cattle away from the area needing improvement. This would decrease the frequency

and duration of use and utilization level would decrease slightly. EA proposed levels of 35-45

would subsequently result in less hoof impact; some increase in biomass retention; and

surface and subsurface organic matter may potentially improve slightly. Accelerated run-off,

soil instability, subsequent loss of organic matter, and further reduction to nutrient cycling

could have a higher probability of stabilizing. Overall, impaired/unsatisfactory soil conditions

would likely remain the same. Erosion pavement from adjacent unsatisfactory sites could

expand resulting in continued impacts to soil conditions.

Smith Canyon-461 is located within a Pinyon Juniper Shrub PNVT and is in impaired condition.

Soils have VGC and graminoid levels that are greater than potential and its spatial distribution

is favorable. However, compaction is prevalent and accelerating runoff which is creating

elevated erosion levels. Soil objectives are to alleviate compaction by integrating seasonal

deferment or rest and improve livestock distribution by controlling access to waters and

herding. Soil conditions are expected to improve to satisfactory status because soil

compaction would improve.

Spider-486 is within the Pinyon-Juniper Shrub PNVT and exhibits a combination of

satisfactory/unsatisfactory conditions. Soils exhibiting satisfactory conditions are affiliated

with dense shrub cover areas that provide high litter levels for soil stability protection,

favorable soil structure and infiltration, and nutrient cycling. However, the interspaces are

experiencing some elevated runoff and erosion. Livestock use may have negligible impacts to

these areas but, the high shrub cover and litter production would maintain functional soil

status and the effects would be immeasurable.

Mosaic openings in Spider-486 are highly compacted, have minimal graminoid cover, and have

high levels of bare soil. The management objective for TEUI 486 is to improve grass and litter

cover and vegetation spatial distribution within these mosaic openings. Project design features

have assigned these areas no capacity and incidental use may occur (0-30%). These practices

would alleviate concentrated use by discouraging concentrated use, allow additional recovery

periods for compaction and retain additional biomass and mulch for soil function. This would

allow soils to improve to impaired condition. However, non-incidental use that regularly uses

this site at 30% could limit the soils ability to improve and the soils could remain in

unsatisfactory status but show some improvement. Regular use would continue to have some

soil impacts from hoof impacts and partial-removal of biomass and organic matter retention.

Because of the soils non-functional status, the soils resiliency and resistance would retard the

soils ability to recover because of continued regular stress (Seybold 1999).

Moano-486 is in the Pinyon-Juniper Shrub PNVT but the sampled area is representative of a

grassland. Soil conditions are satisfactory. Adaptive management measures and Best

Management Practices would continue to be practiced. Standard grazing intensity levels would

be employed and be commensurate with soil conditions. This will allow sufficient residual

biomass for vegetation ground cover retention and protection of the soil resources as

described in Alternative 2.

33

Smith Mesa-490 is in impaired/unsatisfactory condition and affiliated with the Pinyon-Juniper

Grass PNVT. Impaired conditions are affiliated with areas supporting juniper cover.

Unsatisfactory soil conditions are associated with grasslands and the juniper species have been

previously treated. The management objective is to improve compacted soils and vegetation

spatial gap distribution and maintain or improve graminoid cover and vegetative ground cover

levels that are similar to exclosure reference conditions and TEUI potential. Project design

features include the integration of rest to alleviate soil compaction and the use of management

practices such as controlling water access and supplement locations to discourage

concentrated use in TEUI 490 with incidental use levels prescribed as 0-30% until conditions

improve. If these management options are not successful in improving soil condition, then a

fencing option is proposed that would split the pasture and allow for more control of livestock

access to areas needing improvement. These practices would alleviate compaction by

discouraging concentrated use, allow additional recovery periods and retain additional biomass

and mulch for soil function. This would allow soils to improve to impaired condition. However,

non-incidental use that regularly uses this site at 30% could limit the soils ability to improve

and the soils could remain in unsatisfactory status but show some improvement. Regular use

would continue to have some soil impacts from hoof impacts and partial-removal of biomass

and organic matter retention. Because of the soils non-functional status, the soils resiliency

and resistance would retard the soils ability to recover because of continued regular stress

(Seybold 1999).

Alternative 2: No Grazing

Cottonwood-425, Spider-462, Granite-477 and Jones 486 soil conditions would be similar as

described in Alternative 1 and remain in satisfactory soil condition. The dense shrub cover

biomass and litter production would continue to provide soil stability protection, favorable soil

structure and infiltration, and nutrient cycling. No grazing would show a negligible to no

difference as described in Alternative 1. However, Graminoid cover and litter within the

interspace may show improvement and provide additional soil protection, because no grazing

would occur. Jones-486 and Granite-477 interspaces would show no difference because of the

armoring of the interspaces associated with extremely boulder conditions.

Smith Canyon-427 unsatisfactory soil conditions are expected to improve because no grazing

impacts would occur. Graminoid cover and soil and surface organic matter would increase and

be retained on site. This, in addition to a lack of load bearing stress associated with livestock

grazing would improve soil compaction and soil structure. Nutrient cycling and infiltration

rates would improve resulting in a decrease in run-off and soil stability. Soil conditions are

expected to move toward satisfactory condition but maybe limited due to climatic restrictions

as represented by the presence of desert shrub species. Soil conditions are expected to

achieve satisfactory/impaired condition.

Granites-461 soil conditions would improve but soil condition status would remain in

unsatisfactory/impaired condition. No grazing would allow graminoid and organic matter

production to improve and subsequently retard accelerated erosion to an extent, within the

interspaces. Improvement is expected to occur predominantly within the interspaces and

would assist in stabilizing impaired soil conditions. However, the high density of juniper cover

would continue to limit the soils ability to recruit an herbaceous component and would have

large portions that would remain in unsatisfactory condition. Unsatisfactory soils would

continue to influence adjacent impaired soils with accelerated run-on and soil deposition.

34

Smith Canyon-461 would improve as depicted in Alternative 1 but to a greater extent.

Graminoid cover, VGC, and its spatial distribution are expected to remain the same but may

show some improvement because the lack of grazing. Soil compaction associated with hoof

impact would not occur. This would result in soil conditions improving to satisfactory status.

Moano-486 would remain in satisfactory soil condition because no livestock grazing would

occur. Existing elevated vegetation ground cover would be retained on site for nutrient

cycling, favorable soil structure and infiltration, and soil stability.

Spider-486 soil conditions, affiliated with dense shrubs, would be similar as described in

Alternative 1 and remain in satisfactory soil condition. Measurable differences of soil

conditions associated with Alternative 1 and Alternative 2 would be difficult to discern. The

dense shrub cover biomass and litter production would continue to provide soil stability

protection, favorable soil structure and infiltration, and nutrient cycling. No grazing would

show a negligible to no difference as described in Alternative 1. However, Graminoid cover and

litter within the interspace may show improvement and provide additional soil protection,

because no grazing would occur.

Spider-486 unsatisfactory soil conditions, affiliated with mosaic openings, are expected to

improve to a greater extent than Alternative 1 because no grazing impacts would occur.

Graminoid cover and soil and surface organic matter would increase and be retained on site.

This, in addition to a lack of load bearing stress associated with livestock grazing, would

improve soil compaction and soil structure. Nutrient cycling and infiltration rates would

improve resulting in a decrease in run-off and soil stability. However, soil conditions would only

improve to impaired status. The severely compacted soils would not recuperate in a timely

manner because of its low shrink-swell priorities associated with granitic coarse textured soils.

In addition, the droughty characteristics of these coarse textured soils would limit its ability to

recruit an herbaceous component.

Smith Mesa-490 unsatisfactory soil conditions are expected to improve to satisfactory

condition because no grazing impacts would occur. Graminoid cover and soil and surface

organic matter would increase and be retained on site. This, in addition to a lack of load

bearing stress associated with livestock grazing would improve soil compaction and soil

structure. Nutrient cycling and infiltration rates would improve resulting in a decrease in run-

off and soil stability. Soil conditions are expected to move toward representative conditions

exhibited within the Smith Mesa exclosure (see Existing Condition section).

35

Improvements

Range Improvements

Adaptive management provides the flexibility to employ a myriad of rangeland management

strategies to achieve desired conditions and effects. This includes constructing, re-

constructing, re-locating, and maintaining range improvements. All existing and proposed

range improvements are listed and described in the Vegetation Specialist Report. The indirect

effects of range improvement impacts to the soil resources have been considered in the Soil

Condition Direct/Indirect Effects section because it was based on adaptive management being

employed.

The direct effects of the physical impact associated with range improvement installation and

maintenance has the potential to decrease and damage protective vegetative ground cover,

cause soil displacement, and compaction. This has the potential to decrease infiltration,

increase runoff, accelerate soil loss, disrupt nutrient cycling, and ultimately negatively impact

productivity. Soil disturbance and excavation can also expose unfavorable subsurface soil

properties that may reduce soil productivity. For example, subsurface soils with high levels of

clay may negatively impact infiltration, soil aeration, and plant propagation. Also, disturbance

to calcareous soils may expose lime to the soil surface resulting in the increase of pH levels

which can negatively impact the cation exchange capacity and ultimately soil fertility. These

potentially negative impacts would be largely mitigated by implementing range improvement

soil and water conservation practices identified in the BMPs.

Range Improvement Effects

Alternative 1: Grazing.

The installation and maintenance of range improvements has the potential to damage the soil

resources but these adverse effects would be largely mitigated by implementing Best

Management Practices. Range improvement soil and water conservation practices, identified

in the BMPs, provide guidance on site evaluation, site preparation, and erosion control

measures as a means to minimize soil damage to productivity.

Alternative 1: No Grazing.

There would be no impacts to the soil resources from range improvement installation and

maintenance because livestock grazing would not occur. However, the removal of range

improvements has the potential to negatively impact the soil resources but these impacts

would be largely mitigated by implementing Best Management Practices. Range improvement

soil and water conservation practices, identified in the BMPs, provide guidance on site

evaluation, site preparation, and erosion control measures as a means to minimize soil

damage to productivity.

36

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41

Appendix A: Best Management Practices

Best Management Practices

Soil and water conservation measures are means to comply with the Non-Point Source Section

of the Clean Water Act and the Intergovernmental Agreement (IGA) signed by the Forest

Service (R3) and the Arizona Department of Environmental Quality (ADEQ) (Jolly 1990). As

per the IGA, the most practical and effective means of controlling potential non-point source

pollution is through the development of Best Management Practices (BMPs). The general BMP

categories were largely derived from the Soil and Water Conservation Handbook, but were

supplemented and modified to meet project needs (USDA FS 1990a). The number affiliated

with each BMP references Southwestern Region FSH 2509.22 (1990a).

The following BMPs will be employed. Practice numbers and titles are followed by a brief

explanation of site-specific application plans.

22.0 Range Management

Soil and water resources were considered in the development of the proposed action to ensure

desired conditions are maintained or achieved. Part of the adaptive management strategy

employs the use of soil and water conservation practices to achieve soil and water desired

results. Adaptive management is dynamic and utilizes a number of rangeland management

practices based on site specific characteristics and conditions. Some adaptive management

strategies that may be considered are: assigning and adjusting stocking levels, adjusting

livestock distribution, establishing deferred or rest rotation schedules, setting utilization and/or

stubble height standards, adjusting season and duration of use, fencing, exclosures, range

improvements, supplementing, etc.

22.1 Range Analysis, Allotment Management Plan, Grazing Permit System, and

Permittee Operating Plan.

Objective. To manage rangelands through integrated resource management and ensure they

are meeting Forest Land Management Plan objectives (USDA FS 1990a).

An interdisciplinary approach was used to ensure objectives of the Forest Land Management

Plan are or will be met. This entails reviewing the forest plan and other policy, procedural, and

environmental law guidance. Affected environment and current conditions are analyzed for

applicable resources and used to determine what is needed to achieve desired conditions.

Land managers evaluate current rangeland strategies and integrate adaptive rangeland

prescriptions as a proposal to achieve desired conditions. The analysis is incorporated into the

10-year term permit in the form of an Allotment Management Plan (AMP). Annual operating

instructions are created every season to implement the AMP and the terms of the permit.

22.11 Controlling Livestock Numbers and Season of Use.

Objective. Safeguard water and soil resources under sustained forage production. Managed

forage utilization by livestock to maintain healthy ecosystems for all resource objectives (USDA

FS 1990a).

For specifics review soil recommendations by TEUI and the Effects Analysis. Appendix B

provides the Rangeland Utilization Guidelines developed by the Prescott National Forest

Rangeland NEPA Core Team.

22.14 Determining Grazing Capability of Lands.

Objective. To maintain or improve soil stability, soil productivity and water quality by grazing

the land within its capability (USDA FS 1990a).

42

This practice is an administrative and preventative control (USDA FS 1990a). Grazing capacity

was determined by evaluating historical use records and reviewing historical production and

utilization studies. Projections of livestock capacity were performed based on distance to

water, available forage production, and topography. Resource conditions and concerns were

evaluated through an interdisciplinary team setting and desired conditions and site specific

management objectives were developed. Adaptive management strategies will integrate the

resources capabilities to ensure resource desired conditions and objectives are met.

22.12 Controlling Livestock Distribution.

Objective. To manage sustained forage production and forage utilization by livestock while

protecting soil and water resources. Maintaining healthy ecosystems for wildlife and other

resources (USDA FS 1990a).

Pasture fencing and natural barriers are used to control the distribution of grazing on all

allotments. Distribution within each pasture occurs by controlling access to water, by herding,

changing season of use, and supplement placement. Distribution needs and techniques will be

implemented through Adaptive management.

22.15 Revegetation and Reseeding

Objective. Establish vegetative cover on sites to prevent accelerated erosion and

sedimentation (USDA FS 1990a).

Reseeding/revegetation, mycorrhizae inoculation, and/or fertilization may occur to

improve/maintain rangeland, vegetation, soil, riparian, watershed, and ecosystem health.

Revegetation/reseeding preparation may include scarifying and /or ripping soils.

22.16 Erosion Control

Objective. Maintain soil productivity and safeguard water quality (USDA FS 1990a).

Erosion control practices and/or maintenance may be employed to improve/maintain

rangeland, vegetation, soil, riparian, watershed, and ecosystem health. Some vegetation, soil,

and water conservation practices may include:

Mulching, wattle construction, water bars, soil imprinting.

Constructing channel stabilization structures such as weirs/check dams and bank

revetments.

Re-contouring landscapes associated with gullies and constructing erosion control

structures and revetments.

Placing barricades and/or signage to discourage public access to sensitive areas.

25.12 Protection of Wetlands and Riparian Areas.

Objective. To avoid adverse impacts, including impacts to water quality, associated with

disturbance of modification of wetlands (USDA FS 1990a).

43

The following provides general utilization levels based on riparian/ wetland ecosystem

conditions. Site specific conditions and characteristics may require site specific prescriptions.

Riparian

Condition –

including springs,

seeps, and

wetlands

Woody Herbaceous

Fully Functional 20% Use

5” minimum stubble

height on key riparian

species.

Partially

Functional 20% Use

8” minimum stubble

height on key riparian

species.

Non-Functional Incidental

use Incidental use

Riparian/wetland areas are properly functioning when adequate vegetation, physical channel

features and debris is present to 1) develop root masses that stabilize streambanks against

cutting action, 2) dissipate energies associated with stream flow, 3) filter sediment, capture

bedload, and aid floodplain development; and 4) improve flood-water retention and ground

water discharge.

In riparian areas utilization guidelines – for both woody and herbaceous species -- are

appropriate only if there is adequate cover or density of riparian vegetation. Generally

speaking, riparian areas with perennial surface or subsurface water should support riparian

vegetation. Grazing should be deferred on key areas with very low cover or density of riparian

vegetation until livestock grazing impacts can be minimized though the application of

utilization guidelines.

Trailing cattle through riparian areas, especially in narrow valley bottoms where cattle must

walk in the channel, greenline and near floodplain, should be avoided.

Proper allowable use within riparian areas will not exceed 20 percent on woody species.

The goal of the herbaceous species guidelines is primarily to provide residual vegetation for

stream channel protection, and secondarily to protect plant vigor. In areas where livestock

grazing is occurring stubble height is commonly used as an indicator of sufficient use and as a

threshold for removal of livestock from the specific riparian area. It is used where herbaceous

vegetation is dominant along the stream edge and controls streambank stability. Stubble

height has also been evaluated in terms of plant physiology and the needs to maintain healthy

plants. Stubble height, itself, is not a riparian management objective but an indicator of

livestock use and potential impacts. It is appropriate where herbaceous vegetation is

dominant along the stream edge and controls streambank stability (University of Idaho Stubble

Height Study Team 2004). It helps to determine if there is enough herbaceous vegetation to

move toward meeting management objectives of streambank stability and bank building.

31.0 Fire and Other Post Vegetation Treatment Recovery

Soil and vegetation resources will be evaluated after post treatment activities to determine

livestock adaptive management strategies to ensure the maintenance of site productivity. An

evaluation of sites exposed to treatments is required at the end of the second growing season

44

to determine if adequate resource recovery has occurred and identify if any additional adaptive

management strategies are needed.

22.13 Rangeland Improvements.

Objective. To improve, maintain or restore range resources, including soil and water through

the use of rangeland improvements (USDA FS 1990a).

Resource protection in the form of rangeland improvements can be constructed as a means to

protect soil, water, and vegetation resources and the ecological services they provide.

The following BMP’s provide general guidelines for newly constructed or reconstruction of

range improvements. Range improvements may be constructed as an adaptive management

technique.

Existing range improvements will be reconstructed and maintained as needed. Adaptive

management strategies may lead to constructing new facilities in order to achieve the

desirable attainable effects.

24.22 Special Erosion Prevention Measures on Disturbed Land

All sites subjected to surface disturbance will be inspected to determine appropriate

erosion control measures. Areas will be evaluated to determine the need for prepatory

erosion control measures, such as re-smoothing or sloping areas to its natural contours,

ripping or scarifying the soil surface, etc.

24.16 Streamside Management Zone

A designated zone that consists of the stream and an adjacent area of varying width

where management practices that might affect water quality, fish, or other aquatic

resources are modified. The SMZ is not a zone of exclusion, but a zone of closely

managed activity. It is a zone which acts as an effective filter and absorptive zone for

sediment; maintains shade; protects aquatic and terrestrial riparian habitats; protects

channel and streambanks; and promotes floodplain stability. The SMZ may be wider

that the riparian area. Evaluations are done to determine if there is a need for special

soil and water conservation prescriptions and, if so, to develop them. Normally areas

up to 150 feet from the channel are evaluated; however, wide floodplains may require a

greater area of evaluation and evaluation may determine that a narrower area is all

that is required for specific prescriptions.

25.16 Soil Moisture Limitations

All operations will be conducted during periods when the probabilities for precipitation,

wet soils, and runoff are low.

25.18 Revegetation of Surface Disturbed Areas

All areas that have been disturbed will be evaluated to determine if reseeding is

necessary or if natural recruitment is adequate. TES will be used to determine the

appropriate grass seed specification.

24.3 Slash Treatment in Sensitive Areas

When conditions are warranted, all disturbed sites will be mulched with vegetation

slash, certified weed free hay, or any other material deemed appropriate. Other

erosion control practices may be implemented in lieu of mulch on a case-by-case basis

(e.g., water bars, etc.).

45

24.14 Protection of Extremely Unstable Lands

Range improvement installation locations will avoid unstable lands. Unstable lands that

are unavoidable will require special erosion control measures.

41 Access and Transportation Systems

To protect soil and water resources cross country travel will not occur during wet

conditions or on slopes 40% gradient or greater.

41.25 Maintenance of Roads

Road maintenance will concentrate on improving drainage. Road drainage measures

will not channel run-off directly into stream channels. This includes out-sloping the

road and maintaining leadoff ditches. Roadwork will not occur during wet or storm

conditions.

46

Appendix B

Prescott National Forest Resource Management Guidelines for Rangeland NEPA

Prepared by the Range NEPA Core Team

Soils Conditions:

Soil Condition: Satisfactory Impaired Unsatisfactory

Rx: Conservative

Intensity (30-40%

Use).

Light Intensity (0-

30% Use).

Incidental use

regardless of season.

Upland Vegetation Conditions:

Trend

Rangeland

Management Status

Towards Static Away From

Satisfactory Conservative Intensity (30-40% Use) --

Unsatisfactory -- Light Intensity (0-

30% Use)

Incidental Use

regardless of season.

*Incidental Use: Discourage regular use while recognizing that use within the lower end of the

light use category may occur. However, adaptive management methods and practices to

achieve this will be based on site specific allotment management scenarios.

Riparian (all riparian vegetation including springs and seeps) Conditions:

Fully Functional Partially Functional Non-Functional

Rx: Woody 20% Use (Forest Plan

S+G’s)

20% Use (Forest Plan

S+G’s)

Discourage Use

Herbaceous 4-8” minimum stubble

height* on key

riparian herbaceous

species.

8-12” minimum

stubble height on key

riparian herbaceous

species.

*Higher end of stubble height is more applicable to facultative species (e.g., deergrass).

47

Appendix C

Smith Canyon proposed new range improvement map.

48

Appendix D: EA Proposed Action

Introduction

The Chino Valley District Ranger is proposing to continue the authorization of livestock grazing

on the Smith Canyon and Williamson Valley Allotments under an adaptive management

system. These two allotments are managed separately, and this analysis will result in two

separate decisions being issued. An analysis of the environmental effects of this proposal is

hereby being initiated and will result in documentation which will display the effects of the

proposed action and a no grazing alternative. Based on this analysis, the responsible official

will make a decision on which alternative to select for each allotment.

The Smith Canyon Allotment represents an area of approximately 48,000 acres. The allotment

is located in the southwest portion of the district, approximately 17 miles west of Chino Valley,

Arizona. Elevation ranges from 3,195 feet at the junction of Smith Canyon and Cottonwood

Creek to ~6,200 feet on Sheridan Mountain. The topography is rough and broken on much of

the allotment. There are a few areas providing flat to gentle slopes on mesa tops such as

Smith Mesa in the northern portion and in the vicinity of Dillon Field. Over 80% of the

allotment is in the Santa Maria River watershed and the remaining area is in the Big Chino

Watershed. Major drainages include Smith Canyon and Cottonwood Canyon which are

tributaries of the Bill Williams and Colorado Rivers. Riparian vegetation occurs along these

stretches and is dominated by woody species such as cottonwood, velvet ash, and willows,

with some areas of grass and grass-like vegetation where sediment has built up to form

stream banks.

Precipitation patterns for these areas are bi-modal with monsoon events occurring during the

summer and a second period of precipitation occurring within the winter season. Precipitation

at the Chino Valley station recorded 13.7” for 2015, and likely ranges from 12-16 inches in the

project area. The average minimum temperature typically occurs in December, and is around

20 degrees, and the average maximum temperature occurs in July at just over 90 degrees.

Purpose and Need

The purpose of and need for this action is to continue to authorize livestock grazing on the

Smith Canyon Allotment in a manner consistent with the Forest Plan while meeting resource

management needs, and to apply adaptive management principles to management of these

allotments. There is a need to provide for management flexibility in order to address changing

ecosystem conditions, site specific concerns, and desired resource conditions. There is also a

need to utilize range improvements to improve livestock distribution, facilitate herd

management, and address resource concerns.

Grazing Proposal

Smith Canyon Allotment: Authorize a range of livestock numbers from 200-275 head of

cattle yearlong. The upper limit is equivalent to 3,300 Animal Unit Months (AUMs) of available

forage use. The annual authorization will vary based on forage production, water availability,

and resource conditions. Annual stocking could fall below the low end of the proposed stocking

range. There are five large main pastures and two smaller pastures used in a rotational

grazing system. Pasture rest and deferment will be scheduled to provide for achieving desired

resource conditions.

The term grazing permits for this will be issued for up to ten years. The permit will authorize

livestock use within parameters identified in this proposal, and subsequent permits may be

49

issued as long as resources continue to move further toward desired conditions or are being

maintained in satisfactory condition, as appropriate.

Adaptive Management

The proposal includes the application of adaptive management principles. Adaptive

management is designed to provide sufficient flexibility to allow management to address

changes in climatic conditions, seasonal fluctuations in forage production and other dynamic

influences on the ecosystem in order to effectively make progress toward or maintain desired

conditions of the rangeland and other resources. Adaptive management will also include the

implementation of resource protection measures.

Under the adaptive management approach, regular/annual monitoring may suggest the need

for administrative changes in livestock management. The need for adaptation would be based

on the magnitude or repeated re-occurrence of deviations from guidelines provided, or due to

indications of a lack of progress toward desired resource conditions. The timing of such man-

agement changes would reflect the urgency of the need for adaptation. Annual Operating

Instructions and the Allotment Management Plan may be modified as appropriate to adapt

management within the parameters of this proposal.

If monitoring indicates that progress toward desired conditions is not being achieved on the

allotment, management will be modified. Modifications may include adjustments in timing,

intensity and duration of grazing. Timing is the time of year the livestock are present in a

pasture. Intensity is the degree to which forage is removed through grazing and trampling by

livestock. Duration is the length of time livestock are present in a given pasture.

These modifications would be made through administrative decisions such as: the specific

number of head stocked on the allotment; the class of animals stocked (cow/calf pairs vs.

yearlings, steers or heifers, etc.); specific dates of grazing; livestock herd movement; and/or

periods of rest, deferment or non-use of portions or all of the allotments for an appropriate

period of time, as conditions warrant. Such changes will not result in exceeding the AUMs

authorized for livestock use that are developed through the analysis.

Resource Protection Measures

Resource protection measures will be incorporated into the project as design features to

protect forest resources and to maintain or make progress toward desired conditions. Best

Management Practices will be implemented to comply with the Clean Water Act.

Allotment-wide Measures: On those portions of the allotment where no specific resource

concerns were identified by the Interdisciplinary (ID) Team, livestock will be managed with the

objective of maintaining or improving the condition of rangeland resources through the use of

grazing intensity guidelines. Grazing intensity is measured by determining the level of

utilization on forage plants. Utilization is the proportion or degree of current year’s forage

production that is consumed or destroyed by animals. Allowable utilization levels are guidelines

to be achieved as an average over the long term to maintain or improve rangeland vegetation

and long-term soil productivity. Relative utilization may be measured during the growing

season and can be utilized as a tool to manage livestock so that expectations of end of growing

season utilization measurements can be achieved. Grazing intensity and forage use guidelines

for areas of the allotment that are generally described to be in satisfactory condition include:

1. A management guideline of 35-45% utilization of key forage plants in upland key areas

as measured at the end of the growing season;

2. Up to 50-60% leaders browsed on key upland woody species;

3. Minimum stubble height on key riparian herbaceous species: four to six inches where

sedges and rushes are key and eight inches where deergrass is key;

50

4. Up to 20% use by weight on key woody species within riparian areas; or less than 50%

of terminal leaders browsed on woody species less than 6 feet tall.

Site-specific Resource Protection Measures: Through the allotment analysis process

undertaken by the interdisciplinary team, some areas have been identified where management

adjustments and site specific design features were developed in order to attain desired

resource conditions.

Smith Canyon:

There are 7 main pastures on the allotment that were evaluated for soil and vegetation

condition by the interdisciplinary team. The desired condition for vegetation is the maintenance

of vegetation with mid- to high similarity to the site potential of the soil map unit, providing for

ecological functionality and resiliency following disturbance while sustaining long-term

productivity of the land. The desired soil condition is to be in satisfactory functioning condition

or trending towards that state, providing for nutrient cycling, soil stability, and hydrologic

functions. Desired conditions for vegetation and soil are being met in the Cottonwood, Jones,

Moano, and portions of the Granites and Spider pastures. The following is a list of areas that

are not meeting desired conditions:

• Smith Canyon Pasture: Key soil map unit Terrestrial Ecosystem Unit Inventory (TEUI)

427, there is a low-similarity between existing perennial grass cover and composition as

compared to what the soil and climate is capable of supporting. The management objective is

to improve the canopy cover and diversity of perennial grasses. The soil condition is rated as

unsatisfactory. The management objective is to improve graminoid cover and the spatial

distribution of vegetation to improve soil organic matter, soil stability, and to assist in

improving compacted soils. Project design features include integrating rest to improve soil

compaction and controlling water access to improve pasture distribution. Prescribe incidental

use levels (0-30%) to promote biomass retention and subsequent litter development. Also in

this pasture, key soil map unit TEUI 461 is in impaired soil condition. The management

objective for soils is to increase litter cover levels and decrease soil compaction. Design

features include integrating seasonal deferment or rest and improving livestock distribution by

controlling access to waters and herding.

• Granites Pasture: Key soil map unit TEUI 461 is not meeting desired condition for soils

and has a mixture of unsatisfactory and impaired soil condition. The other inventoried soil map

unit, TEUI 477, was meeting desired condition for vegetation and soil. The management

objective for TEUI 461 is to improve litter and graminoid cover and vegetation spatial

distribution. Design features include deferred season of use to allow further graminoid biomass

retention and control access to water facilities to improve distribution. An additional water

source is proposed that would distribute cattle away from the area needing improvement.

• Spider Pasture: Key soil map unit TEUI 486 is not meeting desired condition for soils

and displays a mixture of satisfactory and unsatisfactory soil condition. The other inventoried

soil map unit, TEUI 462, was meeting desired condition for vegetation and soil. The

management objective for TEUI 486 is to improve grass and litter cover and vegetation spatial

distribution within the mosaic openings in this soil type. There are areas within this soil type

that are not producing enough forage to be considered in forage capacity calculations. Project

design feature is to implement incidental use (0-30%) in the no capacity areas of TEUI 486.

• Smith Mesa Pasture: Key soil map unit TEUI 490 is not meeting desired condition for

soils that display a mixture of impaired and unsatisfactory soil condition. The management

objective is to improve compacted soils and vegetation spatial gap distribution and maintain or

improve graminoid cover and vegetative ground cover levels that are similar to exclosure

reference conditions and TEUI potential. Project design features include the integration of rest

to alleviate soil compaction and the use of management practices such as controlling water

access and supplement locations to discourage concentrated use in TEUI 490 with incidental

use levels prescribed as 0-30% until conditions improve. If these management options are not

51

successful in improving soil condition, then a fencing option is proposed that would split the

pasture and allow for more control of livestock access to areas needing improvement.

Once desired conditions for vegetation or soil are being met in areas needing improvement,

then the allotment-wide utilization standards could be applied.

Structural Range Improvements

Construction of New Range Improvements: This proposal includes construction of the

following new structural improvements that have been developed to address resource concerns

or improve grazing management. Upland water developments will provide livestock water

away from riparian areas and allow for achievement or maintenance of desired conditions for

riparian areas. Monitoring may indicate that some of these improvements are not necessary;

however, if some or all of these improvements are not implemented, the upper limit of

permitted livestock numbers may not be achievable on a sustained basis, or pasture use

periods may be shortened.

Smith Canyon:

Because of limited road access for large vehicles like well-drilling rigs, the proposed water

developments on the Smith Canyon Allotment would likely be trick tanks (catchment apron

that directs rainfall into a storage tank and pipeline system with troughs), or earthen stock

tanks (dug out areas that collect rainfall directed from shallow ditches) (Appendix C).

• Construct 3 reliable water developments in Smith Canyon Pasture: one north of

Sheridan Lake in the north half of section 21; one on the south benches in NE quarter of

section 35; one in north half of section 6. Two of these (section 21 and 35) are to replace

existing earthen stock tanks that are non-functional and replace with trick tanks.

• Five additional water developments in the following locations: Cottonwood Pasture SW

quarter of section 31; Granites Pasture north half section 4; Moano Pasture west half of section

22 (replace non-functional earthen stock tank); Spider Pasture NE quarter of section 32; Jones

Pasture NW quarter of section 33.

• Construct drift fences to better control livestock distribution: one in Smith Canyon

Pasture near Sycamore Spring; one in Smith Mesa Pasture along the trail west of Horseshoe

Tank; and one in the Granites Pasture along the trail north of Saddle Tank.

• Construct fences (water lots) around Alkaline Tank and Dyke Pond in the Smith Canyon

Pasture to better control livestock use patterns in the pasture.

• Construct an east-west fence to split Smith Mesa Pasture into Mesa and Rincon

Pastures if controlling access to water does not sufficiently improve distribution and result in

achieving desired resource conditions.

• Expand the existing fencing at Alkaline Spring to include protection for the spring area.

52

Appendix E: General Soil Effects Analysis

Livestock grazing influences soil resources and ecological processes through defoliation,

trampling, and nutrient redistribution (Pieper 1988, Heitschmidt 1990). This influences soil

productivity mainly through the modification of soil hydrologic properties which consequently

influences soil stability and nutrient cycling (Hart 1993). Differing livestock use can reduce the

health and vitality of rangeland vegetation that impacts the amount of ground cover provided

by the vegetation. Potential impacts include (EPA 1994):

• Trampling cause’s soil compaction, thus decreasing water infiltration, causing increased

runoff, and decreased water availability to plants.

• Herbage is removed, which allows soil temperatures to rise and increases evaporation

to the soil surface.

• Physical damage to the vegetation occurs by rubbing, trampling, and browsing.

Intense continued defoliation causes plants to lose their photosynthetic capacity which may

reduce plant vigor as measured by such factors as level of carbohydrate reserves, root growth,

and reproductive capacity (Pieper 1988). As grazing intensities increase protective surface

cover, herbage and root biomass, organic matter content, and aggregate stability have been

repeatedly shown to decline (Hart 1993). In addition, trampling has been shown to result in

mechanical injury or loss of vegetation standing crop (Abdel-Magid 1987). Although, intense

herbivore use has been shown to enhance above-ground net primary production in mesic

indigenous grasslands but there is little research that supports this phenomenon occurring in

arid and semiarid rangelands (Heitschmidt 1990). Selective intense use of individual plants

can alter their competitive ability which leads to a shift in plant composition at the community

levels (Pieper 1988). This can also negatively impact the total cover and spatial distribution of

herbaceous cover. The shift of vegetation composition usually favors the establishment and

regeneration of less preferred plants and decline of plant diversity (Pieper 1988). Lower

vegetative diversity can have a negative impact to soil function (Printz 2014). Cole (1988)

found that monolithic vegetative communities were less resistant to trampling impacts versus

mixed vegetative communities. However, adaptive management measures which manage for

defoliation frequency, intensity levels, and season of use can assist in the maintenance and

promotion of plant health and cover. Using intensity guidelines have shown that rangeland

conditions, trend, and standing crop biomass can be maintained or improved (Holechek 2000;

2004).

Vegetative ground cover includes surface organic matter and living plant biomass but for

quantifiable measuring purposes includes surface organic matter, .5 inch or greater in size,

and basal vegetation (Mapfumo 2002, USDA FS 2013). Vegetative cover protects the soil

surface from raindrop impact, slows runoff, and enhances infiltration (Hart 1993). Litter

reduces soil erosion by reducing runoff and improves soil structure and fertility through

addition of organic matter (Mapfumo 2002). Soil organic matter includes plant, animal, and

microbial residue in various stages of decomposition (USDA NRCS 2001). Soil organic matter

contributes to favorable soil function by enhancing aggregate stability, water holding capacity,

fertility, cation adsorbtion and productivity, improves porosity, infiltration, and root

penetration; and reduces physical soil crusting, runoff, and erosion (USDA NRCS 2001).

Grazing can change plant composition and distribution and increase or decrease the amount of

organic matter in the soil through trampling and defoliation (USDA NRCS 2001, Heitschmidt

1990, Pieper 1988). Total, live and dead standing crop retention is inversely related to grazing

intensity (Cassels 1995). Trampling can incorporate plant material into the soil but can also

expose organic matter to decomposition and loss through erosion (USDA NRCS 2001). Cole

(1988) found that organic matter decreased linearly as trampling increases. Mapfumo (2002)

also has shown that standing and fallen litter mass decreases as grazing intensity increases.

Bare soils are more susceptible to raindrop impact and aggregate break down which can lead

53

to surface sealing and increased erosion (Mapfumo 2002). Hoffman (1991) found vegetative

and ground cover decreased; and bare soil, runoff, and erosion rates increased as grazing

intensity increased. Organic matter losses increase as erosion increases through soil loss,

decomposition, and oxidation (USDA NRCS 2001). Soil fertility (i.e. Carbon and Nitrogen

pools) associated with litter and root mass decreases as grazing intensities increases (Hart

1993, Mapfumo 2002). Herbage removal and redistribution by domestic livestock grazing has

been described as a principal means by which nutrients are lost from grasslands (Hart 1993).

Establishing intensity levels can assist in increasing and maintaining vegetative ground cover

levels and organic matter. The retention of vegetation biomass promotes plant health and

reproduction for the recruitment of favorable plant distribution across the landscape for

organic matter accumulation, enhances root production, promotes favorable soil structure,

decreases bare soil, stabilizes soils, and enhances nutrient cycling and soil fertility (USDA

NRCS 2001).

Soil aggregates are groups of soil particles that are bound to each other more strongly than to

adjacent particles and influence soil structure (USDA NRCS 2001). Aggregate stability is

closely related to a number of ecosystem properties, processes and functions including the

quantity and composition of soil organic matter, soil biotic activity, infiltration capacity,

resistance to erosion, and water availability (Herrick 2001, USDA NRCS 2001) Aggregate

stability is largely associated with soil organic matter (Herrick 2001). Soil organic matter and

aggregate stability is sensitive to management (Herrick 2001). Research has shown that as

grazing intensities increase aggregate stability decreases through the reduction of vegetation

cover and trampling (Heitschmidt 1990, Hart 1993, Mapfumo 2002). Grazing can also

incorporate litter above the ground and standing dead vegetation into the soil, increasing the

content of organic matter (USDA NRCS 2001). Heavy grazing that reduces plant production

and its spatial distribution reduces aggregate stability by increasing the sizes of bare soil

patches and reducing the inputs of organic matter (USDA NRCS 2001). Range management

practices can maintain and increase aggregate stability by retaining vegetation biomass, litter,

and promote soil organic matter while reducing the size and number of bare soil areas (USDA

NRCS 2001).

Soil compaction is the packing together of soil particles by forces at the soil surface, resulting

in an increase in soil density through a decrease in pore space (Hart 1993). Soil compaction

has important hydrologic implications in terms of reduced infiltration rates, impacts on plant

growth, and increases in runoff and erosion (Van Haveren 1983). Compaction reduces soil

water holding capacities and water movement through the soil which can limit available water

for plant growth and nutrient cycling (USDA NRCS 2001). Negative alterations of soil aeration,

soil temperature, nutrient cycling, and physically restricting root growth are also products of

soil compaction (USDA NRCS 2001).

As load bearing stress is applied, soil colloids align themselves and the volume of pore space

decreases (Brady 1990). Coarse textured soils have a greater proportion of larger pores (i.e.

macropores) while finer textured soils have a greater proportion of smaller pores (i.e.

micropores). Coarse textured soils have a greater resistance to be compacted because their

soil colloids have less surface area and pore space to enable realignment of soil colloids. Finer

textured soils have a lower soil strength, or lower resistance to be deformed from load

stresses, than coarse textured soils because the soil colloids have a higher surface area and

lower bulk density due to more pore space (Brady 1990). Hence, finer-textured soils are more

susceptible to compaction than coarse textured soils. Rock fragments within a soil profile and

on the soil surface also tend to minimize soil compaction by dissipating load bearing stress and

minimizing the amount of pore space within a soil profile.

54

Soil water content is one of the most influential factors in determining soil displacement and

compaction (Hart 1993). More force is needed to compact a dry soil than to compact the same

soil when wet (Van Haveren 1983). Soil moisture lubricates individual soil particles and

enables them to rearrange and displace the air in the pore space when compactive force is

applied, resulting in an increase of bulk density (Hart 1993). As discussed previously, soil

moisture content tends to be more influential on finer textured soils because of their inherently

low bulk densities and ability to hold more water (Hart 1993). However, dry and sandy soils

can easily be gouged and displaced, either burying or uprooting plants (Cole 1988).

Livestock grazing can compact soil and significantly reduce water infiltration rates (Castellano

2007). Vegetation removal and trampling associated with increasing levels of grazing

intensities show a corresponding increase of bulk density and compaction (Van Haveren 1983,

Hart 1993). Soil penetration associated only with trampling impacts increased as trampling

intensity increased (Cole 1988). Castellano (2007) found that sites that had been grazed

versus ungrazed with similar vegetation cover still experienced higher levels of compaction and

lower infiltration rates.

Livestock management can limit compaction and physical crust formation through a myriad of

practices. Minimizing livestock trampling when the soils are wet and discouraging livestock

concentration on sensitive soils minimizes the continued load bearing stress and realignment

of soil particles and loss of pore space. Soil compaction recovery is likely associated with wet-

dry and freeze-thaw cycles as well as biotic activity (Castellano 2007). Maintaining or

increasing the content of organic matter, root biomass, and activity of soil organisms by

improving plant cover and plant production assists in maintaining or improving soil structure

(USDA NRCS 2001). Organic matter and living biomass associated with vegetative ground

cover allows soils to be resistant to compaction by improving soil strength and helps cushion

forces applied to the soil.

The process of water entering the soil is infiltration and the infiltration rate is how fast water

enters the soil (USDA NRCS 2001). Soil water storage is replenished through infiltration which

is needed for plant production, soil ecological function, and watershed processes. Poor

management can reduce infiltration rates resulting in an increase of run-off or water ponding

(USDA NRCS 2001). As infiltration decreases there is less water stored in the soil for plant

growth, and plant production decreases, resulting in less organic matter for the soil and

weakened soil structure that can further increase runoff (USDA NRCS 2001). Accelerated

runoff can cause accelerated erosion and the loss of organic matter and nutrients.

Inherent soil properties that influence infiltration include soil texture, dense and/or restrictive

sub-soil layers, and soil depth (USDA NRCS 2001). Coarse textured soils have larger pores

than finer textured soils and provide higher infiltration rates. Soil depth and a restrictive

dense subsurface soil layer restrict the amount of water a soil can hold and can cease

infiltration when the soils become saturated.

Management and vegetation attributes that can influence infiltration include vegetative ground

cover that decreases overland flow, vegetation biomass and organic matter that contribute to

favorable soil structure and aggregate stability, and physical crust formation and compaction

that seals and decreases pore space (USDA NRCS 2001). Livestock grazing can influence

infiltration rates through defoliation and trampling. Innumerable studies have shown that

infiltration rates decrease as a result of livestock trampling (EPA 1994). These impacts

increase as the intensity of grazing increases (Warren 1986, EPA 1994). Vegetative cover

protects the soil surface from raindrop impact, slows runoff, and enhances infiltration rate

(Hart 1993). Vegetative ground cover generally decreases and bare soil increases as grazing

intensities increase (Cassels 1995, Mapfumo 2002). Typical models suggest that increases in

55

grass cover concurrently increase water infiltration where reductions in grass cover

concurrently reduce water infiltration (Castellano 2007). However, soils with similar ground

cover that have been compacted from livestock grazing versus not compacted have shown a

decrease in infiltration (Castellano 2007). The combination of trampling and defoliation

increases the decline of herbaceous cover (Pieper 1988). The decline of soil compaction and

increase of grass abundance has also been shown to increase infiltration (Castellano 2007).

Livestock management measures that promote and maintain favorable infiltration rates

include: Improving or maintaining plant production and vegetative ground cover to minimize

continuous waterflow patterns and decrease overland flow while promoting water residence

time and infiltration. Vegetation biomass and organic matter also promotes favorable soil

structure and aggregate stability and alleviates physical crust formation which enhances

infiltration. Practices that alleviate soil compaction and promote soil compaction recovery will

consequently help maintain or improve infiltration.

Soil surface crusts are important soil quality indicators that influence the soils hydrologic,

stability and nutrient cycling function. Physical crusts form when organic matter is depleted,

soil aggregates become weak, and raindrops disperse the soil into individual particles that clog

soil pores, seal the surface, and form a physical soil layer with reduced porosity (USDA NRCS

2001). They seal the soil surface, reduce infiltration rates, impede seeding emergence, and

increase runoff. Physical crusts generally help to control wind erosion but contribute to

accelerated water erosion. Although trampling degrades physical crusts, the benefits are short

lived because the soil remains disaggregated and subject to re-sealing during the next rainfall

(Hart 1993). Livestock influences and management implications for physical crusts are

commensurate and directly linked to plant biomass, organic matter and aggregate stability

(Belnap 2001).

A biological soil crust is a living community of lichen, cyanobacteria, algae, and moss growing

on the soil surface and binding it together (USDA NRCS 2001). Biological crusts enhance

aggregate stability, soil structure, organic matter, and stabilize soils (Belnap 2001). Biological

crusts influence to static infiltration is variable but they increase surface roughness, reduce

runoff, and increase infiltration (Belnap 2001, USDA NRCS 2001). Some biological crusts can

increase the amount of nitrogen and other nutrients in the soil (USDA NRCS 2001). Research

has shown that biological crusts do not compete with vascular plants or that vascular plant

vigor and cover is enhanced by the presence of biological crust (Belnap 2001). The vertical

and horizontal vascular plant structure of many arid and semi-arid vegetation communities

optimizes growth of biological soil crusts (Belnap 2001). Biological soil crusts are highly

susceptible to degradation from intensive trampling and severe ground disturbance (Belnap

2001, USDA NRCS 2001). Non-severe disturbances such as, non-concentrated trampling,

tends to only compress the surface and not have a negative impact upon biological soil crusts

(Belnap 2001).

Livestock management strategies for biological soil crust health are similar to management

strategies for other vegetation ground cover components. Biological crusts on coarse textured

soils are less susceptible to disturbance when the soils are wet or moist, and the ones on fine

textured soils are less susceptible when soils are dry (Belnap 2001). Biological crusts are also

less susceptible to disturbance when soils are frozen and/or snow covered (Belnap 2001).

Establishing intensity guidelines will consequently regulate trampling impacts and not

negatively impact biological soil crusts.

Water erosion is the detachment and removal of soil material by water (USDA NRCS 2001).

Less vegetation and residue provide less cover, which increases erosion (Gifford 1982).

Vegetative cover was also found to have a pronounced effect on runoff and sediment yields

56

(Baker 1991). Hoffman (1991) found as grazing intensity increased the vegetative and ground

cover decreased; and bare soil, runoff, and erosion rates increased. Vegetation is known to

have several desirable effects including reduction of raindrop impact, thereby limiting soil

detachment and splash (baker. Both vegetative cover and organic material improve the water

storage capacity of the soil surface, thereby delaying and reducing runoff. Plant cover itself

also obstructs overland flow, reducing flow velocity and sediment transport capacity. Soil

crusting is also less likely to occur under vegetation. Accelerated erosion is erosion levels that

are above natural conditions and has the potential, in some cases, to exceed natural soil

formation rates and negatively impact soil productivity. Accelerated erosion occurs when plant

cover is depleted, the spaces between plants increase, and soil structure is degraded by

excessive disturbance or reduced inputs of organic matter (USDA NRCS 2001). This results in

a decrease in infiltration and a corresponding increase of runoff and erosion. Erosion breaks

down soil structure, exposing organic matter within soil aggregates to decomposition and loss,

diminishes nutrient cycling and fertility, and reduces water holding capacity and infiltration

(Gifford 1982, USDA NRCS 2001). Degradation of soil structure increases soil erodibility,

surface sealing, and crusting (Gifford 1982). Surface sealing and crusting reduce seedling

emergence and infiltration that provides less opportunity for soil water storage (Gifford 1982).

Livestock grazing impacts and management strategies that influence vegetation production,

organic matter, aggregate stability, compaction, and infiltration indirectly influence erosion

(EPA 1994).

Allowable use levels are designed to be commensurate with soil conditions to ensure

maintenance and improvement of soil function. The intensity of grazing governs the severity

of defoliation and trampling which impacts the soils hydrologic, stability, and nutrient cycling

function (Heitschmidt 1990, Hart 1993, Trimble 1995). Total live and dead standing crop

retention and vegetative ground cover decreases as grazing intensity increases (Rauzi 1963,

Cassels 1995, Mapfumo 2002). Favorable distribution of vegetative ground cover and soil

aggregate stability also decrease as grazing disturbance increases (Hart 1993, de Soyza 1997,

Bird 2007). The corresponding decrease of vegetation ground cover and redistribution of

organic matter related to grazing intensities results in a decrease of nutrient cycling (Hart

1993, Mapfumo 2002). Due to vegetation removal and trampling, areas that are subjected to

increasing levels of grazing intensities show a corresponding increase of bulk density and

compaction (Rauzi 1966, Van Haveren 1983, Hart 1993, Trimble 1995, Daniel 2002). This also

negatively impacts infiltration rates as they generally decrease in areas that are grazed versus

those that are ungrazed and as grazing intensities increase on predominantly non-coarse-

textured soils (Rauzi 1960;1963;1966, Johnston 1962, Lusby 1970, Pieper 1988, Daniel 2002).

In addition, innumerable studies have shown that infiltration rates decrease as a result of

trampling. The impacts increase as the intensity of grazing increases (EPA 1994). Castellano

(2007) found that sites that had been grazed versus ungrazed with similar vegetation cover

still experienced higher levels of compaction and lower infiltration rates. Increased erosion

rates and sedimentation have been associated with increased grazing intensities and differ

between grazed and ungrazed areas because of defoliation and trampling impacts (Lusby

1970, Pieper 1988, Hoffman 1991, Hart 1993). High levels of sediment production have also

been associated with gullies being grazed versus not grazed (Lusby 1970).

Allowable use levels are designed to be commensurate with soil conditions to ensure

maintenance and improvement of soil function. The intensity of grazing governs the severity

of defoliation and trampling which impacts the soils hydrologic, stability, and nutrient cycling

function (Heitschmidt 1990, Hart 1993, Trimble 1995). Utilization levels identified for livestock

forage capacity do not account for vegetative inputs needed for sustainability to soil resources.

Numerous studies have shown that above ground biomass, litter, below ground biomass, bulk

density, infiltration, run-off, and erosion become perturbed and their ability to function

57

declines as grazing intensity increases (Hoffman 1991, Van Haveren 1983, Jones 2000, Molinar

2001, Mapfumo 2002, Castellano 2007). In general, the adverse effects associated with

grazing increase as the intensity of grazing increases (EPA 1994). Regardless of a soils

functional status all soil disturbances influence soils resiliency (soils ability to recover from a

perturbation) and soil resistance (soil susceptibility to change during a perturbation) (Seybold

1999). The degree of a disturbance and the soils conditional status will dictate the

sustainability of soil quality. The nature of a soil in less than satisfactory condition indicates

that a disturbance has negatively impacted a soils ability to function. The reduction of soil

functions (i.e. hydrologic, stability, and nutrient cycling) has a cascading effect and are

interrelated and impact its ability to maintain its resistance and resiliency. Over time, the

capacity to resist or recover soil functions after a disturbance can be degraded or lost as a

result of improper and poor soil management, resulting in concomitant reduction in soil quality

(Seybold 1999). To offset and retain the soils resiliency and resistance and allot for

satisfactory soil conditions, grazing intensity levels can be adjusted to offset a decline to soil

function (hydrologic, stability, and nutrient cycling. Generally, moderate use levels retain

existing production levels and conditions (Holecheck 1999). However, to maintain satisfactory

soil condition utilization levels that enables extra vegetation production inputs for soil

protection and maintenance is needed to retain soil function. Additional vegetation production

inputs are needed to retard a reduction of soil function and allot for an improvement to soil

function. Conservative to light use has been shown to improve forage production (Holecheck

1999; 2003). However, the range of intensity of levels within conservative use has a range of

variability of production levels but not to the extent of light use (Holecheck 1999; 2003, Galt

2000). In relationship to soil resources, conservative to light use also differ. Lowering of

intensity levels is of utmost importance because the soils ability to produce vegetation biomass

and mulch has been reduced but greater vegetative inputs are needed to offset a reduction of

loss of soil function. Light use has been shown to have the greatest results of improving forage

production and ecological conditions (Holecheck 1999; 2003). A harvest coefficient of 25% has

been recommended in some ecosystems as a means to improve ecological condition and

forage production (Galt 2000, Holecheck 2003). However, light use does continue to impact

soils resistance and resiliency and differs between non-use (Jones 2000).