Natural Resources
Conservation Service

Ecological site R030XC308AZ

Limy Fan 10-13" p.z.

Last updated: 10/21/2024
Accessed: 11/13/2024

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General information

Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.

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Figure 1. Mapped extent

Areas shown in blue indicate the maximum mapped extent of this ecological site. Other ecological sites likely occur within the highlighted areas. It is also possible for this ecological site to occur outside of highlighted areas if detailed soil survey has not been completed or recently updated.

MLRA notes

Major Land Resource Area (MLRA): 030X–Mojave Basin and Range

This unit occurs within the Basin and Range Province and is characterized by broad basins, valleys, and old lakebeds. Widely spaced mountains trending north to south occur throughout the area. Isolated, short mountain ranges are separated by an aggraded desert plain. The mountains are fault blocks that have been tilted up. Long alluvial fans coalesce with dry lakebeds between some of the ranges.

LRU notes

AZ LRU 30-3 – Upper Mohave Desert

Elevations range from 2800 to 4500 feet and precipitation averages 9 to 12 inches per year. Vegetation includes Joshua tree, blackbrush, creosotebush, ratany, bush muhly, big galleta, black grama, desert needlegrass, and Indian ricegrass. The soil temperature regime is thermic and the soil moisture regime is typic aridic.

Ecological site concept

This ecological site is located on gently sloping uplands. Soils are non-skeletal, calcareous, and moderately deep to deep. Textures range from very fine sandy loam to sandy loam.

Associated sites

R030XC305AZ	Coarse Sandy Loam 10-13" p.z.
R030XC311AZ	Limy Upland 10-13" p.z.
R030XC317AZ	Sandy Bottom 10-13" p.z.

R030XC305AZ

Coarse Sandy Loam 10-13" p.z.

R030XC311AZ

Limy Upland 10-13" p.z.

R030XC317AZ

Sandy Bottom 10-13" p.z.

Table 1. Dominant plant species

Tree	Not specified
Shrub	(1) Atriplex canescens
Herbaceous	(1) Pleuraphis rigida (2) Muhlenbergia porteri

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Physiographic features

This ecological site is found in an upland position on fan terraces and toeslopes of steep escarpmets merging onto stream terraces.

Table 2. Representative physiographic features

Landforms	(1) Fan (2) Terrace
Flooding frequency	None
Ponding frequency	None
Elevation	3,000 – 4,200 ft
Slope	1 – 6%
Aspect	Aspect is not a significant factor

Climatic features

The climate is arid and warm. Annual precipitation ranges from 10 to 13 inches. About 65 percent of the rainfall comes from October through May as gentle rain from Pacific storms which may last for a couple of days. The rest of the rainfall comes during the summer monsoon season from July through September as spotty, brief, intense thunderstorms. Snow rarely falls, and only remains on the ground a few hours at most. Annual air temperature ranges from 46 to 76 degrees F. The average frost-free period ranges from 121 to 231 days.

Table 3. Representative climatic features

Frost-free period (average)	231 days
Freeze-free period (average)	269 days
Precipitation total (average)	13 in

Bar

Line

Figure 2. Monthly precipitation range

Bar

Line

Figure 3. Monthly average minimum and maximum temperature

Soil features

The soil of this ecological site is moderately deep to deep. The soil surface textures include very fine sandy loam, sandy lom, very gravelly loam, and gravelly fine sandy loam. Subsoil textures are very fine sandy loam, fine sandy loam, silt loam cobbly very fine sandy loam, extremely very fine sandy loam, sandy clay loam, sandy loam, gravelly sandy loam, and gravelly sandy clay loam. The soil's available water capacity is low to high. Its erosion hazard by water is slight to severe and by wind is moderate to severe. The soil is non-saline, non-sodic with pH 7.4-8.6. The soil moisture regime is typic aridic and temperature regime is thermic.

A typical soil profile is:
0 to 2 inches; very fine sandy loam
2 to 27 inches; very fine sandy loam
27 to 37 inches; silt loam
37 to 53 inches; very fine sandy loam
53 to 60 inches; very gravelly fine sandy loam

Soil taxanomic classifications include Coarse-loamy, mixed thermic Typic Paleorthids and, Coarse-loamy, mixed, thermic Typic Camborthids

This ecological site has been correlated to map unit 627088, Poachie soil, Mohave County, AZ, Central Part SSA.

Table 4. Representative soil features

Surface texture	(1) Cobbly very fine sandy loam (2) Gravelly sandy loam (3) Loam
Family particle size	(1) Loamy
Drainage class	Well drained
Permeability class	Moderately slow to moderately rapid
Soil depth	60 in
Surface fragment cover <=3"	45 – 70%
Surface fragment cover >3"	Not specified
Available water capacity (0-40in)	5.5 – 8 in
Calcium carbonate equivalent (0-40in)	2 – 35%
Electrical conductivity (0-40in)	Not specified
Sodium adsorption ratio (0-40in)	Not specified
Soil reaction (1:1 water) (0-40in)	7.4 – 8.4
Subsurface fragment volume <=3" (Depth not specified)	20%
Subsurface fragment volume >3" (Depth not specified)	Not specified

Ecological dynamics

Limy Fan, 10"-13" p.z., is a grassland ecological site. Shrubs are well-dispersed across the site. Annual forbs and grasses flourish following rainfall. Natural disturbances are rare. After introduction of non-native annuals (forbs and/or grasses), the shift in total productivity is shift increased seasonal herbaceous production following periods of rain. Continuous, yearlong, livestock grazing will remove the perennial grass dominance.

State and transition model

More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective text

State 1
Historic Climax Plant Community

Community 1.1
Historic Climax Plant Community

The dominant aspect of this plant community is grassland with shrubs. Big galleta and sand dropseed are the major grasses. Shrubs include fourwing saltbush, Anderson wolfberry, Nevada Mormon tea and winterfat.

Figure 4. Annual production by plant type (representative values) or group (midpoint values)

Table 5. Annual production by plant type

Plant type	Low (lb/acre)	Representative value (lb/acre)	High (lb/acre)
Grass/Grasslike	169	240	315
Shrub/Vine	113	170	228
Forb	18	40	57
Total	300	450	600

Table 6. Ground cover

Tree foliar cover	0%
Shrub/vine/liana foliar cover	1-3%
Grass/grasslike foliar cover	0-2%
Forb foliar cover	0-2%
Non-vascular plants	0%
Biological crusts	0%
Litter	0%
Surface fragments >0.25" and <=3"	0%
Surface fragments >3"	0%
Bedrock	0%
Water	0%
Bare ground	0%

Table 7. Canopy structure (% cover)

Height Above Ground (ft)	Tree	Shrub/Vine	Grass/ Grasslike	Forb
<0.5	–	–	–	1-3%
>0.5 <= 1	–	–	13-17%	–
>1 <= 2	–	–	–	–
>2 <= 4.5	–	9-11%	–	–
>4.5 <= 13	–	–	–	–
>13 <= 40	–	–	–	–
>40 <= 80	–	–	–	–
>80 <= 120	–	–	–	–
>120	–	–	–	–

Figure 5. Plant community growth curve (percent production by month). AZ3024, 30.3 10-13" p.z. upland sites. Growth begins in the spring and continues through the summer..

Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
J	F	M	A	M	J	J	A	S	O	N	D
0	1	8	18	18	11	14	20	8	2	0	0

State 2
Historic Native Plant Community plus Introduced Annuals

Community 2.1
Non-native Annuals

This plant community resembles the historic native plant community, but exotic annuals have been introduced. Non-native species include wild oat, red brome, Mediterranean grass (Schismus spp.), and filaree. The flourish of non-native annuals that occurs following rainfalls may preclude native annuals.

State 3
Shrubland with Non-Native Annuals

Community 3.1
Shrub Dominated

Years of continuous livestock grazing (same season, yearlong) will remove perennial grasses and reduce desirable shrubs. Non-native annuals flourish in the bare interspaces.

Transition T1A
State 1 to 2

Introduction of non-native annual forb and grass seed.

Transition T1B
State 1 to 3

Yearlong continuous livestock grazing. Introduction of non-native annual forb and grass seed.

Transition T2A
State 2 to 3

Yearlong continuous livestock grazing.

Restoration pathway R3A
State 3 to 2

Prescribed grazing/no grazing. Range seeding may accelerate establishment of perennial grasses and desirable shrubs.

Additional community tables

Table 8. Community 1.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production (lb/acre)	Foliar cover (%)
Grass/Grasslike
1				68–112
	big galleta	PLRI3	Pleuraphis rigida	68–112	–
2				22–45
	sand dropseed	SPCR	Sporobolus cryptandrus	22–45	–
3				22–45
	bush muhly	MUPO2	Muhlenbergia porteri	22–45	–
4				4–22
	black grama	BOER4	Bouteloua eriopoda	4–22	–
5				4–22
	Grass, perennial	2GP	Grass, perennial	4–22	–
6				0–22
	Grass, annual	2GA	Grass, annual	0–22	–
Forb
7				4–22
	desert globemallow	SPAM2	Sphaeralcea ambigua	4–22	–
8				4–14
	Forb, perennial	2FP	Forb, perennial	4–14	–
9				4–9
	Forb, annual	2FA	Forb, annual	4–9	–
Shrub/Vine
10				22–45
	fourwing saltbush	ATCA2	Atriplex canescens	22–45	–
11				4–22
	water jacket	LYAN	Lycium andersonii	4–22	–
12				0–9
	Whipple cholla	CYWH	Cylindropuntia whipplei	0–9	–
13				0–9
	banana yucca	YUBA	Yucca baccata	0–9	–
14				4–22
	Nevada jointfir	EPNE	Ephedra nevadensis	4–22	–
15				0–9
	buckhorn cholla	CYACA2	Cylindropuntia acanthocarpa var. acanthocarpa	0–9	–
16				4–45
	winterfat	KRLA2	Krascheninnikovia lanata	4–45	–
17				0–22
	shadscale saltbush	ATCO	Atriplex confertifolia	0–22	–
18				0–4
	catclaw acacia	ACGR	Acacia greggii	0–4	–
19				0–9
	littleleaf ratany	KRER	Krameria erecta	0–9	–
20				0–22
	creosote bush	LATR2	Larrea tridentata	0–22	–
21				4–22
	Shrub, other	2S	Shrub, other	4–22	–

Rangeland health reference sheet

Interpreting Indicators of Rangeland Health is a qualitative assessment protocol used to determine ecosystem condition based on benchmark characteristics described in the Reference Sheet. A suite of 17 (or more) indicators are typically considered in an assessment. The ecological site(s) representative of an assessment location must be known prior to applying the protocol and must be verified based on soils and climate. Current plant community cannot be used to identify the ecological site.

Author(s)/participant(s)
Contact for lead author
Date	10/21/2024
Approved by	Kendra Moseley
Approval date
Composition (Indicators 10 and 12) based on	Annual Production

Indicators

Number and extent of rills:
Presence of water flow patterns:
Number and height of erosional pedestals or terracettes:
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Number of gullies and erosion associated with gullies:
Extent of wind scoured, blowouts and/or depositional areas:
Amount of litter movement (describe size and distance expected to travel):
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
Functional/Structural Groups (list in order of descending dominance by above-ground annual-production or live foliar cover using symbols: >>, >, = to indicate much greater than, greater than, and equal to):

Dominant:

Sub-dominant:

Other:

Additional:
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Average percent litter cover (%) and depth ( in):
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
Potential invasive (including noxious) species (native and non-native). List species which BOTH characterize degraded states and have the potential to become a dominant or co-dominant species on the ecological site if their future establishment and growth is not actively controlled by management interventions. Species that become dominant for only one to several years (e.g., short-term response to drought or wildfire) are not invasive plants. Note that unlike other indicators, we are describing what is NOT expected in the reference state for the ecological site:
Perennial plant reproductive capability:

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Natural ResourcesConservation Service

Ecological site R030XC308AZ

Limy Fan 10-13" p.z.

Last updated: 10/21/2024 Accessed: 11/13/2024

General information

Figure 1. Mapped extent

MLRA notes

LRU notes

Ecological site concept

Associated sites

Table 1. Dominant plant species

Ecosystem states

State 1 submodel, plant communities

State 2 submodel, plant communities

State 3 submodel, plant communities

Natural Resources
Conservation Service

Last updated: 10/21/2024
Accessed: 11/13/2024