LOCATION COOKCREEK               OR

Established Series
Rev. JLW/RJO/DAL
10/2012

COOKCREEK SERIES

The Cookcreek series consists of moderately deep, well-drained soils on backslopes of canyons and dissected plateaus. Cookcreek soils formed in volcanic ash and loess mixed with colluvium from metavolcanic or metasedimentary rock. Slopes are 30 to 90 percent. Mean annual precipitation is about 13 inches and mean annual temperature about 48 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Vitrandic Haploxerolls

TYPICAL PEDON: Cookcreek very gravelly ashy silt loam shrub steppe, on a 90 percent planar northeast-facing slope at an elevation of 2,170 feet. (Colors are for moist soil unless otherwise noted.)

A--0 to 13 inches; black (10YR 2/1) very gravelly ashy silt loam, dark grayish brown (10YR 4/2) dry; weak medium and fine granular structure; soft, friable, slightly sticky and slightly plastic; many fine roots; few medium and common fine irregular pores; neutral (pH 7.0); 30 percent gravel and 5 percent cobbles and 2 percent stones; gradual smooth boundary. (4 to 13 inches thick)

AB--13 to 24 inches; dark brown (10YR 3/3) very gravelly loam, yellowish brown (10YR 5/4) dry; weak fine subangular blocky structure; soft, friable, slightly sticky and slightly plastic; common fine roots; few fine tubular and common fine irregular pores; 35 percent gravel and 5 percent cobbles; moderately alkaline (pH 8.0); gradual smooth boundary. (8 to 11 inches thick)

BC--24 to 35 inches; brown (10YR 4/3) very gravelly loam, yellowish brown (10YR 5/4) dry; massive; soft, very friable, slightly sticky and slightly plastic; few fine tubular pores; 45 percent gravel and 5 percent cobbles; strongly effervescent; moderately alkaline (pH 8.0); clear wavy boundary.

R--35 inches; fractured, indurated metavolcanic rock.

TYPE LOCATION: Wallowa County, Oregon
Section 24 (SE 1/4, NE 1/4, NE 1/4), T. 05 N., R. 47 E.
Latitude 45 degrees, 54 minutes, 8.3 seconds N
Longitude 116 degrees, 52 minutes, 29.1 seconds W
UTM coordinates: zone 11, north 5082982.8 meters, east 509715.7 meters; NAD27
USGS Quadrangle: Wapshilla Creek

RANGE IN CHARACTERISTICS:
Soil Temperature: mesic regime
Mean Annual Soil Temperature: 48 to 51 degrees F
Mean Summer Soil Temperature: 60 to 64 degrees F
Mean Winter Soil Temperature: 31 to 34 degrees F
Soil Moisture: xeric regime; dry 60 to 90 consecutive days in summer

Particle-size Control Section: from 10 inches below mineral soil surface to bedrock
clay content, average : 12 to 18 percent
rock fragment content, average: 40 to 70 percent

Diagnostic Horizons and Features:
vitrandic subgroup properties: from the mineral soil surface 7 to 13 inches thick
Al+1/2Fe (ammonium oxalate): 0.3 to 0.9 percent
glass content in the 0.02-2.0 mm fraction: 5 to 15 percent
mollic epipedon: 20 to 25 inches thick
lithic contact, depth below mineral soil surface: 20 to 40 inches

A horizon:
color, moist: 10YR 2/1, 3/1, 3/2; 2.5Y 3/2
color, dry: 10YR 3/2, 4/2, 4/3, 5/3; 2.5Y 5/2
texture: GRV-ASHY-SIL, GRV-ASHY-L, CBV-ASHY-SIL
clay content: 10 to 14 percent
rock fragment content: 35 to 45 percent total
gravel: 15 to 35 percent
cobbles: 5 to 15 percent
stones: 0 to 5 percent
reaction: neutral; pH: 6.6 to 7.3

AB horizon; Bw in some pedons:
color, moist: 10YR 3/2, 3/3; 2.5Y 3/2
color, dry: 10YR 4/4, 5/2, 5/4; 2.5Y 5/2
texture: GRV-L, CBV-L
clay content: 12 to 17 percent
rock fragment content: 40 to 55 percent total
gravel: 15 to 40 percent
cobbles: 5 to 25 percent
stones: 0 to 5 percent
reaction: neutral to moderately alkaline; pH: 6.6 to 8.4

BC horizon; includes C horizon in some pedons:
color, moist: 10YR 4/3, 5/3; 2.5Y 4/2
color, dry: 10YR 5/4, 6/4; 2.5Y 6/2
texture: GRV-L, CBV-L, GRX-L, CVX-SL
clay content: 10 to 19 percent
rock fragment content: 50 to 85 percent total
gravel: 20 to 65 percent
cobbles: 5 to 55 percent
stones: 0 to 5 percent
non-effervescent to strongly effervescent
reaction: neutral to moderately alkaline; pH: 6.6 to 8.4

COMPETING SERIES:
Brickmill soils - very deep (lacks a lithic contact within 60 inches); formed in relict alluvium; mollic epipedon 10 to 20 inches thick; redox features at 30 to 40 inches (oxyaquic)
Eaglespring soils - deep (40 to 60 inches) to a lithic contact (sedimentary lithology)
Foggydew soils deep (40 to 60 inches) to a lithic contact (andesite); dry 90 to 105 consecutive days in summer
Garrison soils - very deep (lacks a lithic contact within 60 inches); formed in glacial outwash; mollic epipedon 12 to 20 inches thick; secondary carbonates at 44 inches or more
Metmill soils very deep (lacks a lithic contact within 60 inches) formed in alluvium; mollic epipedon 30 to 60 inches thick; redox features at 20 to 30 inches (oxyaquic); dry 60 to 75 consecutive days in summer
Neviot soils - very deep (lacks a lithic contact within 60 inches); formed in colluvium from basalt; secondary carbonates at 44 inches or more; dry 100 to 120 consecutive days in summer
Northstar soils - moderately deep (20 to 40 inches) to a lithic contact (rhyodacite); O horizons, 2 inches thick; mollic epipedon 8 to 15 inches thick; base saturation (sum of cations) less than 75 percent in one or more horizons between 10 and 30 inches (ultic); dry 75 to 90 consecutive days in summer
Opportunity soils - very deep (lacks a lithic contact within 60 inches); formed in glacial outwash; mollic epipedon 10 to 20 inches thick; secondary carbonates at 44 inches or more; sandy-skeletal material at 36 to 60 inches
Peka soils deep (40 to 60 inches) to densic contact (dense till from granite); O horizon 1 inch thick; mollic epipedon 10 to 18 inches thick; dry 75 to 90 consecutive days in summer
Thuso soils very deep (greater than 60 inches deep) formed in colluvium; mollic epipedon 10 to 25 inches thick; dry 90 to 105 consecutive days in summer
Wagberg soils - greater than 40 inches deep (till); mollic epipedon 10 to 18 inches thick; dry 90 to 105 consecutive days in summer

GEOGRAPHIC SETTING:
Landform: backslopes of canyons and plateaus
Slope gradient: 40 to 90 percent
Parent material: Mazama volcanic ash mixed with loess and colluvium
Lithology: metavolcanic rock or argillite
Elevation: 2,000 to 2,800 feet
Climate: cool, moist winters and hot, dry summers
Mean annual precipitation: 10 to 15 inches
Mean annual air temperature: 47 to 49 degrees F
Frostfree period: 95 to 200 days

GEOGRAPHICALLY ASSOCIATED SOILS:
Cabincreek: on concave slopes and lower backslopes; deep to a lithic contact (metavolcanic); mixed ash and loess mantle, and mollic epipedon 20 to 40 inches thick; under common snowberry, rose, ninebark, silky lupine, mouse-ear, Idaho fescue and bluebunch wheatgrass

DRAINAGE AND PERMEABILITY:
Drainage: well drained
Permeability: moderate

USE AND VEGETATION:
Use: recreation, wildlife habitat, livestock grazing and watershed
Potential natural vegetation: Idaho fescue, bluebunch wheatgrass, silky lupine, arrowleaf balsamroot, yarrow and deerhorn.
Plant association: FEID-AGSP (Idaho fescue-bluebunch wheatgrass); may include FEID-AGSP/LUSE(Idaho fescue-bluebunch wheatgrass/ silky lupine) or FEID-AGSP/BASA(Idaho fescue-bluebunch wheatgrass/ arrowleaf balsamroot)

DISTRIBUTION AND EXTENT:
Distribution: MLRA: 9; Palouse and Nez Perce Prairies
Extent: small

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

SERIES ESTABLISHED: Wallowa-Whitman National Forests, Oregon, 2012

REMARKS: Diagnostic horizons and features recognized in this pedon are:
mollic epipedon: 0 to 24 inches; A, AB horizons
vitrandic subgroup properties (ash influenced layer): 0 to 13 inches; A horizon
particle-size control section: 10 to 35 inches; A, AB, BC horizons

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National Cooperative Soil Survey
U.S.A.