Natural Resources
Conservation Service
Ecological site R007XY010OR
Sandy Bottom
8-10 PZ
Last updated: 2/06/2025
Accessed: 06/27/2026
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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
R007XY011OR Sands 8-10 PZ
R007XY012OR Sandy 8-10 PZ
R007XY013OR Sandy Loam 8-10 PZ
R007XY014OR Loamy 8-10 PZ
R007XY015OR Shallow Loam 8-10 PZ
R007XY020OR South 8-10 PZ
Similar sites
R007XY012OR Sandy 8-10 PZ
R007XY011 has a coarser texture. R007XY012 is droughtier and has no water table.
R007XY011OR Sands 8-10 PZ
R007XY011 has a coarser texture. R007XY012 is droughtier and has no water table.
Table 1. Dominant plant species
Tree Not specified
Shrub Not specified
Herbaceous Not specified
Physiographic features
The site occurs on moderately level to gently sloping floodplains and stream terraces. Slopes commonly range from 0-3%. Elevations range from 400 to 1,100 feet.
Table 2. Representative physiographic features
Landforms (1) Flood plain
(2) Stream terrace
Flooding duration Extremely brief (0.1 to 4 hours) to very brief (4 to 48 hours) Flooding frequency None to rare Ponding duration Very brief (4 to 48 hours) Ponding frequency None to rare Elevation 400 – 1100 ft Slope 0 – 3 % Ponding depth 0 – 2 in Water table depth 60 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 during the months of November through April. The average annual air temperature is 53 degrees F, with extremes ranging from 115 degrees F to -10 degrees F. The frost-free period ranges from 100 to 180 days and the optimum period of plant growth is from mid-March to mid-June.
Table 3 Representative climatic features
Frost-free period (average) 180 days Freeze-free period (average) Precipitation total (average) 10 in ">Influencing water features
Soil features
The soils of this site are deep, well drained fine sandy loam. Soil reaction is neutral to mildly alkaline on the surface and moderately to strongly alkaline in the subsoil. Permeability is moderately rapid and the available water capacity is 5 to 10 inches for the profile. In addition to rainfall moisture is supplied to this site through lateral subsurface flows. Runoff is low. The erosion hazard is slight for water and moderate for wind.
Table 4. Representative soil features
Surface texture (1) Fine sandy loam
Family particle size (1) Loamy
Drainage class Well drained Permeability class Moderately rapid Soil depth 60 in Available water capacity
(0-40in)5 – 10 in Ecological dynamics
Basin wildrye and other perennial grasses decrease in the stand with deterioration of the site. Basin big sagebrush strongly increases in the absence of fire. Rabbitbrush increases with fire. Annuals such as cheatgrass, russian thistle, and china lettuce will invade degraded sites. Scurfpea will increase and diffuse; russian knapweed (noxious weed) can invade the site.
Loss of deep rooted perennial grasses constitutes an ecological threshold; only shallow rooted grasses remain. Loss of sandberg bluegrass and other shallow rooted grasses results in another threshold dominated by big sagebrush and annuals (particularly cheatgrass).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
Basin Wildrye, Needle and Thread, and Basin Big SagebrushBasin wildrye - needle and thread community. The HCPC is the interpretative plant community for this site. Production of basin wildrye will vary considerably depending on the extent of subsurface moisture. Needle and thread will increase with coarseness of the soil texture and as subsurface moisture becomes less of an influence. Bluebunch wheatgrass will occur as the amount of silt in the subsurface layer increases.
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 2100 2550 3000 Forb 60 105 150 Shrub/Vine 60 105 150 Total 2220 2760 3300 Figure 3. Plant community growth curve (percent production by month). OR2251 , B7 SANDY BOTTOM GC . Growth curve for RPC B7 SANDY BOTTOM 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 10 20 25 15 10 5 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 1800–2250 basin wildrye LECI4 Leymus cinereus 1800–2250 – 2 Sub-dominant deep rooted perennial 210–600 needle and thread HECO26 Hesperostipa comata 150–450 – beardless wildrye LETR5 Leymus triticoides 60–150 – 5 Other perennial grasses 90–150 Indian ricegrass ACHY Achnatherum hymenoides 0–90 – squirreltail ELEL5 Elymus elymoides 0–90 – tufted wheatgrass ELMA7 Elymus macrourus 0–90 – Sandberg bluegrass POSE Poa secunda 0–90 – bluebunch wheatgrass PSSP6 Pseudoroegneria spicata 0–90 – Forb9 Other forbs 60–150 common yarrow ACMI2 Achillea millefolium 0–60 – milkvetch ASTRA Astragalus 0–60 – buckwheat ERIOG Eriogonum 0–60 – desertparsley LOMAT Lomatium 0–60 – lupine LUPIN Lupinus 0–60 – phlox PHLOX Phlox 0–60 – scurfpea PSORA2 Psoralidium 0–60 – Shrub/Vine11 Dominant evergreen 60–150 basin big sagebrush ARTRT Artemisia tridentata ssp. tridentata 60–150 – 15 Other shrubs 60–120 rubber rabbitbrush ERNA10 Ericameria nauseosa 0–60 – green rabbitbrush ERTE18 Ericameria teretifolia 0–60 – broom snakeweed GUSA2 Gutierrezia sarothrae 0–60 – Interpretations
Animal community
Native Wildlife Associated with the Climax Community:
Mule deer and pronghorn antelope will use this site for food and cover during the fall, winter, and early spring. Various birds, rodents, rabbits, and their associated predators commonly occupy the site.
Livestock Grazing:
This site is well suited to livestock grazing in all seasons but is ideally suited to winter use. Special care must be exercised during the growing season to protect the very sensitive basin wildrye.Hydrological functions
Watershed:
TThe soils of this site have rapid intake rates and low runoff potential. The hydrologic soil group is B.Other information
The site has medium potential for range seeding. Special care must be exercised in seeding because the soils are droughty, subject to wind erosion, and often occur next to intermittent drainages subject to high runoff.
Supporting information
Contributors
Alan Bahn
E Ersch (OSU)
J P ReppApproval
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 07/25/2012 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:
None -
Number and height of erosional pedestals or terracettes:
None -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
5-12% -
Number of gullies and erosion associated with gullies:
None to few -
Extent of wind scoured, blowouts and/or depositional areas:
None to few, moderate wind erosion hazard -
Amount of litter movement (describe size and distance expected to travel):
Fine - limited movement -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Moderately resistant to erosion; aggregate stability = 2-3 -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Deep fine sandy loam and loam surface textures, mollisols, low OM (1-2%) -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Relatively high ground cover (50-70%) and low (0-3%) slopes should reduce rainfall impact and overland flow -
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:
Basin wildrye > Needle and thread> creeping wildrye > other perennial grasses > basin big sage >= perennial forbs > 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):
Cover of mostly herbaceous and limited woody litter scattered throughout the site -
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
Favorable: 5000, Normal: 3000, Unfavorable: 2000 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, broom snakeweed and sage brush may increase and reduce cover of herbaceous plants. Cheatgrass and Medusahead 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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