Natural Resources
Conservation Service
Ecological site R007XY015OR
Shallow Loam
8-10 PZ
Last updated: 2/06/2025
Accessed: 08/07/2026
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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.
Associated sites
R007XY010OR Sandy Bottom 8-10 PZ
Sandy Bottom 8-10" PZ
R007XY011OR Sands 8-10 PZ
Sands 8-10" PZ
R007XY012OR Sandy 8-10 PZ
Sandy 8-10" PZ
R007XY013OR Sandy Loam 8-10 PZ
Sandy Loam 8-10" PZ
R007XY014OR Loamy 8-10 PZ
Loamy 8-10" PZ
R007XY020OR South 8-10 PZ
South 8-10" PZ
Similar sites
R007XY020OR South 8-10 PZ
South 8-10" PZ (deeper soil)
R007XY014OR Loamy 8-10 PZ
Loamy 8-10" PZ (deeper soil)
Table 1. Dominant plant species
Tree Not specified
Shrub Not specified
Herbaceous Not specified
Physiographic features
This site occurs on the tops, shoulders, and side slopes of dissected basalt flows.
Table 2. Representative physiographic features
Landforms (1) Hill
(2) Plateau
(3) Ridge
Flooding frequency None Elevation 500 – 1700 ft Slope 2 – 20 % Water table depth 72 in Aspect Aspect is not a significant factor Climatic features
The annual precipitation ranges from 8 to 10 inches, most of which occurs as rain between the months of November and April. The mean annual air temperature is 48 degrees F. Extremes range from 115 degrees F to -30 degrees F. The period of optimum plant growth is from mid-April to mid-June.
Table 3 Representative climatic features
Frost-free period (average) Freeze-free period (average) Precipitation total (average) 10 in ">Influencing water features
Soil features
The soils of this site are shallow over basalt or strongly cemented or indurated duripans. Surface textures are loams, gravelly loams, or very fine sandy loams. Permeability is moderate and the available water capacity is 2 to 4 inches for the profile. Water and wind erosion hazards are slight.
Table 4. Representative soil features
Surface texture (1) Loam
(2) Gravelly loam
(3) Very fine sandy loam
Family particle size (1) Loamy
Permeability class Moderate Soil depth 10 – 20 in Available water capacity
(0-40in)2 – 4 in Ecological dynamics
If heavy grazing causes site deterioration, bluebunch wheatgrass is significantly reduced; sandberg bluegrass increases and annuals invade as well. Periodic fire with proper grazing use will reduce the amount of wyoming big sagebrush and encourage perennial grass growth. Frequent burning will favor rabbitbrush.
Variability in this site is related to soil depth or textural changes. A decrease in soil depth will reduce plant density and increase Sandberg bluegrass percentage, while changes in texture toward sandy loam will increase the amount of needleandthrerad in the stand. Gravelly loam soils will give rise to an increase presence of Thurber needlegrass.State and transition model
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Click on state and transition labels to scroll to the respective textEcosystem states
State 1 submodel, plant communities
State 1
ReferenceCommunity 1.1
Bluebunch Wheatgrass, Sandberg Bluegrass, and Wyoming Big SagebrushVariability in this site is related to soil depth or textural changes. A decrease in soil depth will reduce plant density and increase sandberg bluegrass percentage, while changes in texture toward sandy loam will increase the amount of needle and thread in the stand. Gravelly loam soilswill give rise to an increase in thurber needlegrass.
Figure 2. 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 237 310 375 Forb 18 33 45 Shrub/Vine 12 20 27 Total 267 363 447 Figure 3. Plant community growth curve (percent production by month). OR2271 , B7 LOAMY, GOOD CONDITION. RPC growth curve B7 LOAMY, GOOD CONDITION.
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 15 25 20 15 10 0 0 5 10 0 0 Additional community tables
Table 6. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Dominant deep rooted perennial grasses 180–240 bluebunch wheatgrass PSSP6 Pseudoroegneria spicata 180–240 – 2 Sub-dominant deep rooted perennial grasses 21–60 needle and thread HECO26 Hesperostipa comata 15–45 – Thurber's needlegrass ACTH7 Achnatherum thurberianum 6–15 – 3 Dominant shallow rooted perennial grasses 30–60 Sandberg bluegrass POSE Poa secunda 30–60 – 5 Other perennial grasses 6–15 Indian ricegrass ACHY Achnatherum hymenoides 0–6 – squirreltail ELEL5 Elymus elymoides 0–6 – Forb7 Dominant perennial forbs 6–18 common yarrow ACMI2 Achillea millefolium 3–9 – phlox PHLOX Phlox 3–9 – 8 Sub-dominant perennial forbs 9–18 pussytoes ANTEN Antennaria 3–6 – milkvetch ASTRA Astragalus 3–6 – desertparsley LOMAT Lomatium 3–6 – 9 Other perennial forbs 3–9 onion ALLIU Allium 0–3 – balsamroot BALSA Balsamorhiza 0–3 – naked mariposa lily CANU2 Calochortus nudus 0–3 – fleabane ERIGE2 Erigeron 0–3 – lupine LUPIN Lupinus 0–3 – Shrub/Vine11 Dominant evergreen shrubs 6–15 Wyoming big sagebrush ARTRW8 Artemisia tridentata ssp. wyomingensis 6–15 – 12 Sub-dominant evergreen shrubs 3–6 rubber rabbitbrush ERNA10 Ericameria nauseosa 3–6 – 15 Other shrubs 3–6 basin big sagebrush ARTRT Artemisia tridentata ssp. tridentata 0–3 – green rabbitbrush ERTE18 Ericameria teretifolia 0–3 – broom snakeweed GUSA2 Gutierrezia sarothrae 0–3 – Interpretations
Animal community
The site provides limited food and cover for songbirds, small mammals and their associated predators. It provides part of the yearly diet for mule deer and pronghorn antelope.
The scarcity of water is the limiting factor in the use of this site by wildlife. When located near dependable water sources, the site may support ring-necked pheasants, chukar and gray partridge.
Livestock Grazing:
This site is suited to livestock grazing during all seasons of the year under a system of grazing that allows for full growth and seed production of the desirable species in two out of thre years. This site is especially well-suited to winter grazing.Hydrological functions
The soils of this site have moderate intake rates and low runoff potential except for short reaches under saturated soil conditions. The hydrologic soil group is D.
Other information
This site has low potential for range seeding because it is droughty, shallow and usually very stony or rocky.
Supporting information
Contributors
Alan Bahn
E Ersch (OSU)
JPRApproval
Kirt Walstad, 2/06/2025
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) Jeff Repp Contact for lead author Oregon NRCS State Rangeland Management Specialist Date 07/26/2012 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
None, slight sheet & rill erosion hazard -
Presence of water flow patterns:
Few, in interspaces -
Number and height of erosional pedestals or terracettes:
None to few -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
2-10% -
Number of gullies and erosion associated with gullies:
None -
Extent of wind scoured, blowouts and/or depositional areas:
None, slight wind erosion hazard -
Amount of litter movement (describe size and distance expected to travel):
Fine - limited to moderate movement -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Moderatley to strongly resistant to erosion; aggregate stability = 5-6 -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Shallow loams, gravelly loams, or very fine sandy loams, low OM (1%) -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Moderately limited ground cover (25-50%) and slopes (0-20%) should slightly limit rainfall impact and overland flow; slightly increased flow possible on steeper slopes (up to 20%) -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
None -
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:
Bluebunch wheatgrass > sandberg bluegrass > Needle and thread > Thurber needlegrass = Wyoming big sagebrush > dominant forbs > other forbs = Gray rabbitbrush = other shrubsSub-dominant:
Other:
Additional:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Normal decadence and mortality expected -
Average percent litter cover (%) and depth ( in):
In areas with adequate plant cover -
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
Favorable: 500, Normal: 300, Unfavorable: 200 lbs/acre/year at high RSI (HCPC) -
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:
Rabbitbrush, sage brush and broom snakeweed may increase and reduce cover of herbaceous plants. Cheatgrass and annual forbs invade sites that have lost shallow rooted perennial grass functional groups -
Perennial plant reproductive capability:
All species should be capable of reproducing annually
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