LOCATION GRUBCREEK ORTentative Series
TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Vitrandic Haploxerolls
TYPICAL PEDON: Grubcreek gravelly ashy loam - forested, on a 12 percent southwestfacing slope at an elevation of 6,160 feet. (Colors are for moist soil unless otherwise noted. Textures are apparent field textures.)
Oi--0 to 1 inches; slightly decomposed needles and twigs
Oe--1 to 3 inches; moderately decomposed needles
A--3 to 7 inches; dark brown (7.5YR 3/2) gravelly ashy loam, brown (7.5YR 4/2) dry; weak fine granular and weak fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and few fine roots throughout; common very fine irregular pores; 25 percent gravel; slightly acid (pH 6.2); clear wavy boundary. (4 to 7 inches thick)
AB--7 to 15 inches; very dark grayish brown (10YR 3/2) very gravelly ashy loam, brown (7.5YR 4/2) dry; weak medium subangular blocky structure parting to weak fine subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; common very fine, and few fine and medium roots throughout; common very fine irregular and tubular pores; 30 percent gravel and 6 percent cobbles; neutral (pH 6.8); abrupt wavy boundary. (6 to 11 inches thick)
Bw--15 to 26 inches; dark brown (7.5YR 3/4) very gravelly sandy clay loam, brown (7.5YR 5/4) dry; weak fine and weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots throughout; few very fine tubular and irregular pores; 40 percent gravel and 15 percent cobbles; neutral (pH 6.8); abrupt irregular boundary. (10 to 28 inches thick)
R--26 inches; andesitic basalt.
TYPE LOCATION: Grant County, Oregon
Section 15 (SW1/4, SE1/4, SE1/4), T. 11 S., R. 33 E.
Latitude: 44 degrees, 36 minutes, 23 seconds N.
Longitude: 118 degrees, 43 minutes, 06 seconds W.
UTM coordinates: zone 11; north 4,940,430 meters, east 363,650 meters; NAD27
USGS Quadrangle: Dixie Meadow
RANGE IN CHARACTERISTICS:
Soil Temperature: frigid regime
Mean Annual Soil Temperature: 40 to 46 degrees F
Mean Summer Soil Temperature: 49 to 54 degrees F
Mean Winter Soil Temperature: 30 to 35 degrees F
Soil Moisture: xeric regime; dry 60 to 75 consecutive days in summer
Particle-size Control Section: 10 inches to the lithic contact
clay content, average: 18 to 33 percent
rock fragment content, average: 35 to 55 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
mollic epipedon: 10 to 18 inches thick
cambic horizon: 10 to 28 inches thick
ultic subgroup feature: base saturation less than 75 percent in AB horizon
lithic contact, depth from mineral soil surface: 20 to 40 inches
A horizon:
color, moist: 7.5YR 2/1, 2.5/1, 2.5/2, 3/2
color, dry: 7.5YR 3/1, 4/2, 5/2
texture: GR-ASHY-L, ASHY-SL
clay content: 8 to 22 percent
rock fragment content: 2 to 35 percent
gravel: 2 to 35 percent
cobbles: 0 to 2 percent
stones: 0 to 2 percent
reaction: slightly acid; pH: 6.1 to 6.5
base saturation (sum of cations): 40 to 70 percent
AB horizon:
color, moist: 7.5YR 2.5/2, 3/2; 10YR 3/3
color, dry: 7.5YR 4/2, 5/2, 5/3; 10YR 5/3
texture: GRV-ASHY-SCL, GRV-ASHY-L, GR-ASHY-SCL, GR-ASHY-SL
clay content: 16 to 30 percent
rock fragment content: 15 to 45 percent
gravel: 15 to 45 percent
cobbles: 0 to 10 percent
stones: 0 to 2 percent
reaction: slightly acid to neutral; pH: 6.1 to 7.3
base saturation (sum of cations): 55 to 75 percent
Bw horizon; BC horizon in some pedons:
color, moist: 7.5YR 3/4, 4/2, 4/3; 10YR 3/4
color, dry: 7.5YR 4/2, 4/3, 5/3, 5/4; 10YR 5/4
texture: GRV-SCL, GRV-CL
clay content: 20 to 32 percent
rock fragment content: 35 to 60 percent
gravel: 25 to 45 percent
cobbles: 6 to 15 percent
stones: 0 to 10 percent
reaction: slightly acid to neutral; pH: 6.1 to 7.3
base saturation (sum of cations): 70 to 90 percent
COMPETING SERIES:
Bearspring: very deep (>60 inches) in granitic colluvium; mollic epipedon is 10 to 15 inches thick; particle-size control section averages 7 to 15 percent clay
Bigelk: very deep (60 inches) in mixed till; mixed ash mantle, 7 to 14 inches thick (35 to 50 percent glass content) with discontinuity between mantle and buried cambic horizon; particle-size control section averages 7 to 17 percent clay; dry 45 to 60 consecutive days in summer
Cassal: deep (40 to 60 inches) to densic contact (till); discontinuity between volcanic ash influenced layer and till substratum; distinct redoximorphic features at 30 to 45 inches
Cherrycreek: deep (40 to 60 inches) to a lithic contact (basalt); does not have an organic (O) horizon above surface of mineral soil (not forested); mixed mantle of volcanic ash and loess (glass content 15 to 30 percent), 35 to 50 inches thick; mollic epipedon is 20 to 35 inches thick; particle-size control section averages 12 to 18 percent clay
Deck: moderately deep (20 to 40 inches) to a lithic contact (metavolcanic rock); mixed volcanic ash mantle (glass content 30 to 55 percent) with discontinuity between mantle and buried cambic horizon
Eastpine: moderately deep (20 to 40 inches) to a lithic contact (metasedimentary rock); dry 45 to 60 consecutive days in summer
Egyptcreek: moderately deep (20 to 40 inches) to a lithic contact (welded tuff); mollic epipedon is 7 to 14 inches thick; dry 75 to 90 consecutive days in summer
Fredonyer: moderately deep (20 to 40 inches) to lithic contact (andesite or basalt); does not have organic horizon above surface of mineral soil (not forested); mollic epipedon is 20 to 40 inches thick; dry more than 90 consecutive days in summer
Golfer: moderately deep (20 to 40 inches) to a paralithic contact (weathered granite); particle-size control section averages 2 to 10 percent clay; dry 60 to 75 consecutive days in summer
Kettlecreek: deep (40 to 60 inches) to a lithic contact (argillite)
Longs: deep (40 to 60 inches) to a lithic contact (basalt); mollic epipedon is 20 to 45 inches thick; subsoil has faint clay films on ped faces; dry 45 to 75 consecutive days in summer
Midpeak: moderately deep (20 to 40 inches) to a lithic contact (breccia); discontinuity between mixed volcanic ash mantle and buried cambic horizon; particle-size control section averages 5 to 15 percent clay
Mineral: moderately deep (20 to 40 inches) to a lithic contact (granitic rocks)
Peahke: moderately deep (20 to 40 inches) to a paralithic contact; volcanic ash mantle (glass content 20 to 30 percent), 7 to 14 inches thick; particle-size control section has 60 to 70 percent channers; dry 45 to 60 consecutive days in summer
Piersonte: very deep (>60 inches) in colluvium from shale; mollic epipedon is 20 to 35 inches thick; particle-size control section are mostly shale channers; dry 60 to 90 consecutive days in summer
Porch: moderately deep (20 to 40 inches) to lithic contact (argillite); particle-size control section averages 10 to 17 percent clay
Scoap: very deep (>60 inches) in till or outwash materials of mixed lithology; mollic epipedon is 20 to 30 inches thick; particle-size control section averages 8 to 12 percent clay
Shalrock: moderately deep (20 to 40 inches) to a lithic contact (sandstone); discontinuity between mixed volcanic ash mantle and substratum; particle-size control section averages 5 to 12 percent clay, and has 25 to 50 percent medium and coarse sand
Shilling: very deep (greater than 60 inches) in colluvium from basalt; dry 45 to 75 consecutive days in summer
Umatilla: very deep (> 60 inches) in colluvium from basalt; mollic epipedon is 20 to 30 inches thick (mollic colors throughout); discontinuity between ashy layer and subsoil horizons
Webbgulch: moderately deep (20 to 40 inches) to a lithic contact (andesitic basalt or basalt); particle-size control section averages 11 to 17 percent clay
Yellcreek: very deep (>60 inches) in mixed colluvium; discontinuity between minor volcanic ash influence zone and substratum; mollic epipedon is 7 to 15 inches thick; particle-size control section averages 5 to 15 percent clay and 50 to 80 percent rock fragments
GEOGRAPHIC SETTING:
Landform: convex to planar, mid to upper, erosional summits and benches, of water dissected hard pyroclastic flows
Slope gradient: 10 to 60 percent
Parent material: volcanic ash mixed with loess and colluvium
Lithology: andesite, andesitic basalt or basalt
Elevation: 4,000 to 6,200 feet
Climate: cold, wet winters; warm, dry summers
Mean annual precipitation: 20 to 37 inches
Mean annual air temperature: 36 to 43 degrees F
Frost-free period: 25 to 80 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Anatone: on plateaus, ridge tops and south or west facing slopes; shallow soil without an argillic horizon; skeletal particle-size control section; minor ash influence under sagebrush, Idaho fescue or bluebunch wheatgrass
Bocker: on shoulders and plateau summits; very shallow soil without an argillic horizon; minor ash influence under sagebrush, Idaho fescue or bluebunch wheatgrass
Bolletto: on convex to planer, mid to upper erosional backslopes; moderately deep with minor influence of volcanic ash and an argillic horizon with less than 35 percent rock fragments, under Douglas-fir, ponderosa pine, common snowberry, elk sedge and Idaho fescue
Cougarrock: on backslopes; moderately deep to lithic contact (andesitic tuff breccia); mixed volcanic ash and colluvium over buried clayey-skeletal argillic horizon; under grand fir, lodgepole pine, western larch, big huckleberry, birchleaf spiraea and pinegrass
Fivebit: on plateaus and backslopes, shallow to bedrock with a minor influence of volcanic ash in loamy-skeletal colluvium under scattered ponderosa pine, Douglas-fir or western juniper with sagebrush and Idaho fescue
Hafmau: on rolling mountain sideslopes and benches; shallow to bedrock with an argillic horizon, under Douglas-fir, ponderosa pine, elk sedge and heartleaf arnica
Humarel: on eroding backslopes of andesitic tuff breccia mudflow deposits; moderately deep to bedrock with an influence of volcanic ash, mollic epipedon and argillic horizon, under ponderosa pine, Douglas-fir, common snowberry and elk sedge
Meaufun: on mountain backslopes with a mollic epipedon of ash mixed with colluvium and an argillic horizon, under Douglas-fir and ponderosa pine forest
Sharpridge: on lower backslopes, footslopes and toeslopes; deep to hard tuff, with volcanic ash mantle 14 to 18 inches thick and an argillic horizon; under grand fir, Douglas-fir, western larch, big huckleberry, darkwoods violet and western fescue
DRAINAGE AND PERMEABILITY:
Drainage: well drained
Permeability: moderately slow
USE AND VEGETATION:
Use: timber production, livestock grazing, recreation, wildlife habitat, watershed
Native vegetation: grand fir, Douglas-fir, ponderosa pine, western juniper, common snowberry, common yarrow, western strawberry, sedum, heartleaf arnica, elk sedge, mountain brome and pinegrass.
Plant Association: PSME/CARU (Douglas-fir/pinegrass), PSME/SYAL (Douglas-fir/common snowberry), PSME/CAGE (Douglas-fir/elk sedge) or PIPO/CARU (ponderosa pine/pinegrass)
DISTRIBUTION AND EXTENT:
Distribution: MLRA 43c; South Central Blue Mountains, Oregon
Extent: Moderate
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Malheur National Forest, Oregon 2008. The name is from a stream.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
mollic epipedon: 3 to 15 inches; A, AB horizons
cambic horizon: 15 to 26 inches; Bw horizon
vitrandic subgroup properties: 3 to 15 inches; A, AB horizons
particle-size control section: 13 to 26 inches; AB, Bw horizons