Natural Resources
Conservation Service
Ecological site R030XB221AZ
Sandy Upland
6-9" p.z.
Last updated: 10/21/2024
Accessed: 08/11/2026
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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 30-2 – Middle Mohave Desert
Elevations range from 1500 to 3200 feet and precipitation averages 6 to 9 inches per year. Vegetation includes creosotebush, white bursage, yucca, prickly pear and cholla species, Mormon tea, flattop buckwheat, ratany, winterfat, bush muhly, threeawns, and big galleta. 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 sand throughout.
Associated sites
R030XB205AZ Sandy Loam Upland 6-10" p.z. Limy Subsurface, Gravelly
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Ambrosia dumosa
(2) Larrea tridentataHerbaceous (1) Sporobolus cryptandrus
(2) Pleuraphis rigidaPhysiographic features
This ecological site occurs in an upland position on fan terraces and valley floors in areas where wind blown coarse textured sand has collected over the dominant soil to a depth of several inches or more.
Table 2. Representative physiographic features
Landforms (1) Terrace
(2) Fan
(3) Valley floor
Flooding frequency None Ponding frequency None Elevation 1500 – 2500 ft Slope 2 – 8 % Aspect Aspect is not a significant factor Climatic features
The climate is arid and warm. Annual precipitation ranges from 6 to 9 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 59 to 70 degrees F. The average frost-free period ranges from 156 to 259 days.
Table 3 Representative climatic features
Frost-free period (average) 260 days Freeze-free period (average) 290 days Precipitation total (average) 10 in BarLineFigure 2. Monthly precipitation range
BarLineFigure 3. Monthly average minimum and maximum temperature
">Influencing water features
Soil features
The soil of this ecological site is deep. Its available water capacity is very low to low. The soil erosion hazard is low for water, but high for wind. Runoff is very slow. The soil is
non-saline, non-sodic with pH of 7.9-8.4 (moderately alkaline). The soil moisture regime is typic aridic and temperature regime is thermic. The soil surface is generally non-calcareous.
A typical soil profile is:
A-0 to 1 inch; sand, non to slightly calcareous
C1-1 to 3 inches; sand; noneffervescent
C2-3 to 30 inches; sand noneffervescent
C3-30 to 60 inches; sand; slightly effervescent
The soil taxonomic classification is Mixed, thermic Typic Torripsamments.
This ecological site has been correlated to map units 701010, Bluepoint soil, and 701147, Typic Torriorthents, Grand Canyon Area, AZ, Parts of Coconino and Mohave Counties SSA and an inclusion in map unit 623001, Shivwits Area, AZ, SSA.Table 4. Representative soil features
Parent material (1) Eolian deposits – sandstone
Surface texture (1) Gravelly fine sand
(2) Fine sand
Family particle size (1) Sandy
Drainage class Somewhat excessively drained Permeability class Rapid Soil depth 60 – 0 in Surface fragment cover <=3" 0 – 10 % Surface fragment cover >3" Not specified Available water capacity
(0-40in)3 – 5 in Calcium carbonate equivalent
(0-40in)0 – 5 % Electrical conductivity
(0-40in)0 – 2 mmhos/cm Sodium adsorption ratio
(0-40in)0 – 13 Soil reaction (1:1 water)
(0-40in)7.9 – 8.4 Subsurface fragment volume <=3"
(Depth not specified)Not specified Subsurface fragment volume >3"
(Depth not specified)Not specified Ecological dynamics
Sandy Upland, 6"-9" p.z., is a dispersed desert shrub-grassland. Perennial grasses are well-distributed across the site. Annual forbs and grasses flourish following rainfall. Natural disturbances are rare. Yearlong livestock grazing will diminish perennial grass basal cover and shift site to shrubland aspect. After introduction of non-native annuals (forbs and/or grasses), the shift in total productivity with shift slightly toward seasonal herbaceous production following periods of rain. Dominant shrubs are creosote and white bursage. Assorted half-shrubs are widely scattered.
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 textEcosystem states
State 1 submodel, plant communities
State 2 submodel, plant communities
State 3 submodel, plant communities
State 1
Historic Climax Plant CommunityCommunity 1.1
Historic Climax Plant CommunityThe dominant aspect of this plant community is desert shrub-grassland. The major grasses are sand and Mesa dropseed, big galleta and Indian ricegrass. The dominant shrubs are white bursage and creosotebush.
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)Shrub/Vine 151 220 323 Grass/Grasslike 90 160 231 Forb 3 10 23 Tree 6 10 23 Total 250 400 600 Table 6. Ground cover
Tree foliar cover 0% Shrub/vine/liana foliar cover 0-0% Grass/grasslike foliar cover 0% Forb foliar cover 0% 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/
GrasslikeForb <0.5 – – – – >0.5 <= 1 – – 0-2% – >1 <= 2 – – – – >2 <= 4.5 – 8-12% – – >4.5 <= 13 – – – – >13 <= 40 0-2% – – – >40 <= 80 – – – – >80 <= 120 – – – – >120 – – – – Figure 5. Plant community growth curve (percent production by month). AZ3022 , 30.2 6-9" p.z. upland sites. Growth begins in the late winter, most growth occurs in the spring..
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 2 19 33 18 7 7 11 3 0 0 0 Figure 6. Plant community growth curve (percent production by month). AZ3070 , 30.23 6-9" p.z. big galleta. Growth begins in the spring, most growth occurs during the summer rainy season..
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 0 10 15 5 0 10 45 15 0 0 0 Figure 7. Plant community growth curve (percent production by month). AZ3072 , 30.23 6-10" p.z. white bursage. Most growth occurs from March through May..
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 0 15 60 20 5 0 0 0 0 0 0 State 2
Historic Native Plant Community plus Introduced AnnualsCommunity 2.1
Non-native AnnualsThis plant community resembles the historic native plant community, but exotic annuals have been introduced. Non-native species include Asian mustard (Brassica tournefortii), red brome, Mediterranean grass (Schismus spp.), and filaree. The flourish of non-native annuals that occurs following rainfalls may preclude native annuals.
State 3
ShrublandCommunity 3.1
Shrub DominatedThis plant community is dominated by creosote with mixed shrubs throughout. The understory is dominated by annual forbs and grasses. Remnant perennial grasses may occasionally be found within the protection of shrub bases. Non-native annuals flourish.
Transition T1A
State 1 to 2Introduction of non-native annual forb and grass seed.
Transition T1B
State 1 to 3Yearlong livestock grazing. Introduction of non-native annual forb and grass seed.
Transition T2A
State 2 to 3Yearlong livestock grazing.
Restoration pathway R3A
State 3 to 2Prescribed grazing/no grazing.
Additional community tables
Table 8. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 80–100 sand dropseed SPCR Sporobolus cryptandrus 80–100 – mesa dropseed SPFL2 Sporobolus flexuosus 80–100 – spike dropseed SPCO4 Sporobolus contractus 40–50 – 2 20–40 big galleta PLRI3 Pleuraphis rigida 20–40 – 3 8–20 Indian ricegrass ACHY Achnatherum hymenoides 8–20 – 4 0–8 Grass, perennial 2GP Grass, perennial 0–8 – threeawn ARIST Aristida 0–8 – low woollygrass DAPU7 Dasyochloa pulchella 0–8 – 5 0–8 Grass, annual 2GA Grass, annual 0–8 – Forb6 0–8 desert trumpet ERIN4 Eriogonum inflatum 0–8 – 7 0–4 Forb, perennial 2FP Forb, perennial 0–4 – cassia CASSI Cassia 0–4 – desert globemallow SPAM2 Sphaeralcea ambigua 0–4 – Forb, perennial 2FP Forb, perennial 0–4 – cassia CASSI Cassia 0–4 – desert globemallow SPAM2 Sphaeralcea ambigua 0–4 – 8 0–4 Forb, annual 2FA Forb, annual 0–4 – buckwheat ERIOG Eriogonum 0–4 – Shrub/Vine9 100–160 burrobush AMDU2 Ambrosia dumosa 100–160 – 10 20–60 creosote bush LATR2 Larrea tridentata 20–60 – 11 8–24 Nevada jointfir EPNE Ephedra nevadensis 8–24 – 12 8–20 white ratany KRGR Krameria grayi 8–20 – 13 8–12 turpentinebroom THMO Thamnosma montana 8–12 – 14 8–20 pricklypear OPUNT Opuntia 8–20 – 15 8–12 rayless goldenhead ACSP Acamptopappus sphaerocephalus 8–12 – 16 4–28 Shrub, other 2S Shrub, other 0–15 – broom snakeweed GUSA2 Gutierrezia sarothrae 0–15 – winterfat KRLA2 Krascheninnikovia lanata 0–15 – Utah mortonia MOUT Mortonia utahensis 0–15 – whitestem paperflower PSCO2 Psilostrophe cooperi 0–15 – Tree17 8–200 Joshua tree YUBR Yucca brevifolia 8–20 – Table 9. Community 2.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 10. Community 3.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Supporting information
Contributors
Larry D. Ellicott
Stephen CassadyApproval
Kendra Moseley, 10/21/2024
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 08/11/2026 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
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Presence of water flow patterns:
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Number and height of erosional pedestals or terracettes:
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Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
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Number of gullies and erosion associated with gullies:
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Extent of wind scoured, blowouts and/or depositional areas:
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Amount of litter movement (describe size and distance expected to travel):
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Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
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Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
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Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
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Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
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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:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
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Average percent litter cover (%) and depth ( in):
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Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
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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:
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Perennial plant reproductive capability:
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