LOCATION STEVENSGULCH ORTentative Series
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