LOCATION STEVENSGULCH       OR
Tentative Series
IRD. RJO/JLW/DAL
10/2008

STEVENSGULCH SERIES


Stevensgulch series consists of very deep, well-drained soils on sideslopes and bench tops of dissected relict valley fill. Stevensgulch soils formed in colluvium and residuum from Tertiary alluvial and lacustrine deposits with minor influence of volcanic ash in surface horizons. Slopes are 0 to 60 percent. Mean annual precipitation is about 21 inches and mean annual temperature about 42 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Vitrandic Haploxeralfs

TYPICAL PEDON: Stevensgulch ashy silt loam - forested, on a 10 percent northfacing slope at 5,040 feet elevation. (Colors are for moist soil unless otherwise noted.)

Oi--0 to 1 inch; slightly decomposed fir needles and twigs. (0.5 to 1.5 inches thick)

A--1 to 4 inches; dark brown (10YR 3/3) ashy silt loam, brown (7.5YR 4/2) dry; weak fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; common fine irregular pores; 5 percent gravel; slightly acid (pH 6.1); clear smooth boundary. (2 to 5 inches thick)

E--4 to 13 inches; dark brown (7.5YR 3/4) gravelly ashy silt loam, brown (7.5YR 5/4) dry; moderate fine and very fine subangular blocky structure; hard, friable, moderately sticky and moderately plastic; common fine and very fine, and few medium roots; few fine irregular pores; 15 percent gravel; neutral (pH 7.0); clear smooth boundary. (7 to 14 inches thick)

Bt1--13 to 21 inches; dark brown (7.5YR 3/4) very gravelly silty clay loam, brown (7.5YR 5/4) dry; moderate fine and very fine subangular blocky structure; very hard, firm, moderately sticky and moderately plastic; common faint clay films on ped faces; common fine and few medium coarse roots; few fine irregular pores; 30 percent gravel, 5 percent cobbles; neutral (pH 7.0); gradual smooth boundary. (7 to 29 inches thick)

Bt2--21 to 61 inches; dark brown (7.5YR 3/4) very gravelly clay loam, brown (7.5YR 5/4) dry; strong medium and fine subangular blocky structure; extremely hard, firm, moderately sticky and moderately plastic; many prominent clay films on ped faces; few fine and medium tubular pores; 35 percent gravel, and 15 percent cobbles; neutral (pH 7.0).

TYPE LOCATION: Baker County, Oregon
Section 5 (NW 1/4, SE 1/4, NW 1/4), T. 14 S., R. 36 E.
Latitude: 44 degrees, 23 minutes, 03 seconds North
Longitude: 118 degrees, 19 minutes, 32 seconds West
UTM coordinates: zone 11; 4,915,181 northing; 394,410 easting NAD27
USGS Quadrangle: Rail Gulch

RANGE IN CHARACTERISTICS:
Soil Temperature: frigid regime
Mean Annual Soil Temperature: 42 to 47 degrees F
Mean Summer Soil Temperature: 50 to 57 degrees F
Mean Winter Soil Temperature: 34 to 38 degrees F
Soil Moisture: xeric regime; dry 60 to 75 consecutive days in summer

Particle-size Control Section: upper 20 inches of argillic horizon
clay content, average: 27 to 34 percent
rock fragment content, average: 45 to 60 percent

Diagnostic Horizons and Features:
vitrandic subgroup properties: upper boundary at the mineral surface; 7 to 18 inches thick
Al+1/2Fe (ammonium oxalate): 0.3 to 0.9 percent
P retention: 20 to 40 percent
glass content in the 0.02-2.0mm fraction: 5 to 15 percent
eluvial layer: 7 to 14 inches thick
argillic horizon: 28 to 48 inches thick

A horizon:
color, moist: 7.5YR 3/2; 10YR 3/2, 3/3
color, dry: 7.5YR 4/2, 5/2, 5/4; 10YR 4/2, 5/3
texture: GR-ASHY-SIL, ASHY-SIL, CB-ASHY-SIL
clay content: 9 to 15 percent
rock fragment content: 5 to 35 percent
gravel: 5 to 15 percent
cobbles: 0 to 10 percent
stones: 0 to 5 percent
reaction: slightly acid to neutral; pH: 6.1 to 7.3

E horizon; may include BE or EB horizons in some pedons:
color, moist: 7.5YR 3/4; 10YR 3/4, 4/3
color, dry: 7.5YR 5/4; 10YR 5/3, 5/4
texture: CB-ASHY-SIL, GR-ASHY-SIL, GR-ASHY-L
clay content: 12 to 25 percent
rock fragment content: 15 to 35 percent
gravel: 15 to 30 percent
cobbles: 0 to 15 percent
stones: 0 to 5 percent
reaction: slightly acid to neutral; pH: 6.1 to 7.3

Bt horizons:
color, moist: 7.5YR 3/4, 4/4; 10YR 4/3, 4/4
color, dry: 7.5YR 5/4, 6/4; 10YR 5/3, 5/4, 6/3
texture: GRV-SICL, GRV-CL, GRX-L, CBV-SIL, CBV-SICL, CBV-CL, STV-SICL, STV-CL
clay content: 18 to 35 percent
rock fragment content: 35 to 75 percent
gravel: 25 to 55 percent
cobbles: 5 to 20 percent
stones: 0 to 10 percent
reaction: slightly acid to neutral; pH: 6.1 to 7.3

BC horizon may occur in some pedons:
clay content: 18 to 27 percent
rock fragment content: 55 to 75 percent

COMPETING SERIES:
Agatha: deep (40 to 60 inches) to a lithic contact; formed in colluvium and residuum from basalt with mixed mantle of loess and volcanic ash; dry 45 to 60 consecutive days in summer
Bennettcreek: moderately deep (20 to 40 inches) to a lithic contact; formed in mixed volcanic ash and colluvium, over colluvium and residuum from basalt; mixed ash mantle has andic soil properties: Al+1/2Fe of 0.6 to 1.2 percent and glass content of 30 to 60 percent; dry 45 to 60 consecutive days in summer
Jummer soils: moderately deep (20 to 40 inches) to a lithic contact; dry 45 to 60 consecutive days in summer
Nebopeak: very deep (greater than 60 inches); formed in a thin, undisturbed mantle of volcanic ash over till from basalt; ash mantle has andic soil properties: Al+1/2Fe of 0.8 to 2.4 percent and glass content of 55 to 85 percent; dry 45 to 60 consecutive days in summer
Outland soils: moderately deep (20 to 40 inches) to a paralithic contact; 45 to 75 percent pararock fragments in lower part of argillic horizon; dry for 90 to 110 consecutive days in summer;
Payraise: very deep (greater than 60 inches); formed in a thin, undisturbed mantle of volcanic ash over colluvium from argillite or other metasedimentary or metavolcanic rocks; ash mantle has andic soil properties: Al+1/2Fe of 0.8 to 2.4 percent and glass content of 55 to 85 percent; dry 45 to 60 consecutive days in summer
Pinuscreek: deep (40 to 60 inches) to a lithic contact; formed in a thin, undisturbed mantle of volcanic ash over colluvium and residuum from basalt or andesite; ash mantle has andic soil properties: Al+1/2Fe of 0.8 to 2.4 percent and glass content of 55 to 85 percent; dry 45 to 60 consecutive days in summer
Ranes: very deep (greater than 60 inches); formed in a thin, volcanic ash mantle over alluvium of basic igneous rocks; ash mantle has andic soil properties: Al+1/2Fe of 0.8 to 2.4 percent and glass content of 55 to 85 percent; particle-size control section is 8 to 17 percent clay
Rasser: very deep (greater than 60 inches); formed in loess mixed with a minor amount of volcanic ash over relict mudflows; dry 45 to 60 consecutive days in summer

GEOGRAPHIC SETTING:
Landform: sideslopes and bench tops of dissected relict valley fill
Slope gradient: 0 to 60 percent
Parent material: colluvium and residuum with a minor amount of volcanic ash
Lithology: Tertiary age alluvial and lacustrine deposits
Elevation: 3,500 to 5,000 feet
Climate: cold, wet winters and warm, dry summers
Mean annual precipitation: 17 to 25 inches
Mean annual air temperature: 40 to 45 degrees F
Frostfree period: 40 to 115 days

GEOGRAPHICALLY ASSOCIATED SOILS:
Barneycreek: on steeper sideslopes of dissected relict terraces; very deep soil with mollic epipedon and argillic horizon, under open-canopy ponderosa pine and western juniper with birchleaf spiraea, curlleaf mountain mahogany, pussytoes, elk sedge and bluebunch wheatgrass
Ranes: on relict alluvial terraces; very deep with a thin undisturbed ash mantle and loamy-skeletal argillic horizon; under ponderosa pine, common snowberry, birchleaf spiraea and elk sedge
Tolo: on gently sloping basalt plateaus with thick ash mantle over a loamy buried argillic horizon; under grand fir and Douglas-fir forest

DRAINAGE AND PERMEABILITY:
Drainage: well drained
Permeability: moderately slow

USE AND VEGETATION:
Use: watershed, wildlife habitat, timber production, livestock grazing and recreation
Native vegetation: Douglas-fir, ponderosa pine, a few grand fir, common snowberry, creeping Oregon grape, snowbrush ceanothus, blueleaf strawberry, white flowered hawkweed, woods strawberry, penstemons, common yarrow, elk sedge, pinegrass and bluegrasses
Plant Association: PSME/SYAL (Douglas-fir/common snowberry).

DISTRIBUTION AND EXTENT:
Distribution: MLRA: 43c; Blue Mountains of northeastern Oregon
Extent: small

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES PROPOSED: Wallowa-Whitman National Forest, Oregon 2008. Name is from a stream near Unity.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
ochric epipedon: 1 to 4 inches; A horizon
eluvial horizon: 4 to 13 inches; E horizon
argillic horizon: 13 to 61 inches; Bt1, Bt2 horizons
vitrandic subgroup properties (ash influenced layer): 4 to 13 inches; A, E horizons
particle-size control section: 13 to 33 inches; Bt1, Bt2 horizons

ADDITIONAL DATA: National Soil Survey Laboratory; pedon ID: 90OR001101


National Cooperative Soil Survey
U.S.A.