LOCATION BIGCOW OR
Established Series
Rev. JLW/RJO/DAL
11/2018
BIGCOW SERIES
Landscape--plateaus, mountains
Landform--plateaus, mountain slopes, mountain base slopes
Slope--0 to 60 percent
Parent material--thin mantle of volcanic ash over colluvium derived from andesite or basalt
Mean annual precipitation--about 750 mm
Mean annual air temperature--about 3 degrees C
Depth class--very deep
Drainage class--well drained
Soil moisture regime--xeric
Soil temperature regime--frigid
Soil moisture subclass--typic
TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Andic Haploxerepts
TYPICAL PEDON: Bigcow gravelly ashy silt loam, forested, on a 30-percent, planar, northeast-facing slope at an elevation of 1750 m
Oi--0 to 5 cm; slightly decomposed needles and twigs
A--5 to 10 cm; gravelly ashy silt loam, brown (10YR 5/3) dry, brown (10YR 4/3) moist; weak very fine and fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and fine and common medium roots; common fine irregular pores; 15 percent gravel; neutral (pH 7.0); clear smooth boundary
Bw1--10 to 18 cm; gravelly ashy silt loam, very pale brown (10YR 7/4) dry, yellowish brown (10YR 5/4) moist; weak very fine and fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and fine and few medium and coarse roots; common fine tubular pores; 15 percent gravel; neutral (pH 7.0); clear smooth boundary
Bw2--18 to 33 cm; gravelly ashy silt loam, very pale brown (10YR 8/4) dry, light yellowish brown (10YR 6/4) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many fine, medium, and coarse roots; common fine tubular pores; 15 percent gravel; neutral (pH 7.0); abrupt wavy boundary
2Eb--33 to 51 cm; very gravelly loam, very pale brown (10YR 7/3) dry, brown (10YR 5/3) moist; weak very fine and fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many fine and common medium and coarse roots; few fine irregular pores; 40 percent gravel and 5 percent cobbles; slightly acid (pH 6.5); clear smooth boundary
2Bwb--51 to 89 cm; very gravelly loam, very pale brown (10YR 7/3) dry, light yellowish brown (10YR 6/4) moist; weak very fine and fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many fine and common medium and coarse roots; common fine irregular pores; 45 percent gravel and 10 percent cobbles; slightly acid (pH 6.5); gradual smooth boundary
2BCb--89 to 160 cm; extremely gravelly loamy sand, pale brown (10YR 6/3) dry, light yellowish brown (10YR 6/4) moist; single grain; loose, nonsticky and nonplastic; common fine and few medium roots; many fine, common medium, and few coarse irregular pores; 60 percent gravel, 15 percent cobbles, and 10 percent stones; neutral (pH 7.0)
TYPE LOCATION: Baker County, Oregon; in the SE1/4SE1/4NE1/4 of section 13, T. 13 S., R. 35 1/2 E.; latitude 44.4393346, longitude -118.3544004 WGS 84 (Coordinate source unknown)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--4 to 7 degrees C
Soil moisture--dry 45 to 60 consecutive days in summer
Thickness of ash-influenced layers--23 to 33 cm
Depth to lithic contact--100 to 200 cm
Estimated properties of layers influenced by volcanic ash
*Ammonium oxalate extractable Al + 1/2 Fe-1.0- to 2.8 percent
*0.02- to 2.0-mm fraction--40 to 60 percent
*Volcanic ash content in 0.02- to 2.0-mm fraction--50 to 85 percent
*1/3-bar bulk density--0.65 to 1.00 g/cm3
*Phosphate retention--50 to 80 percent
Particle-size control section
*Clay content--9 to 16 percent
*Total rock fragment content--45 to 65 percent
A horizon
Moist color--7.5YR 4/2, 10YR 3/2, 10YR 3/3, 10YR 4/2, 10YR 4/3
Dry color--7.5YR 5/2, 10YR 5/3, 10YR 6/3, 10YR 6/4
Fine-earth texture--ashy silt loam
Clay content--4 to 7 percent
Total rock fragment content--15 to 25 percent
Gravel content--15 to 25 percent
Cobble content--0 to 5 percent
Reaction--6.1 to 7.0
Thickness--3 to 10 cm
Bw horizon
Moist color--7.5YR 5/4, 10YR 4/3, 10YR 4/4, 10YR 5/3, 10YR 5/4, 10YR 6/4
Dry color--7.5YR 6/4, 10YR 5/4, 10YR 6/4, 10YR 7/4, 10YR 8/4
Fine-earth texture--ashy silt loam
Clay content--4 to 7 percent
Total rock fragment content--15 to 30 percent
Gravel content--15 to 30 percent
Cobble content--0 to 5 percent
Stone content--0 to 5 percent
Reaction--6.1 to 7.0
Combined thickness--20 to 28 cm
2Eb horizon
Moist color--7.5YR 4/3, 10YR 4/2, 10YR 4/4, 10YR 5/3, 10YR 5/4
Dry color--7.5YR 6/2, 10YR 6/3, 10YR 6/4, 10YR 7/3
Fine-earth texture--loam
Clay content--9 to 16 percent
Total rock fragment content--35 to 50 percent
Gravel content--30 to 40 percent
Cobble content--5 to 10 percent
Stone content--0 to 5 percent
Reaction--6.1 to 7.0
Thickness--15 to 38 cm
2Bwb horizon
Moist color--7.5YR 4/2, 7.5YR 4/4, 10YR 4/4, 10YR 6/4
Dry color--7.5YR 5/4, 7.5YR 6/4, 10YR 5/4, 10YR 6/3, 10YR 7/3
Fine-earth texture--loam, sandy loam
Clay content--10 to 17 percent
Total rock fragment content--40 to 60 percent
Gravel content--25 to 50 percent
Cobble content--5 to 15 percent
Stone content--0 to 15 percent
Reaction--6.1 to 7.0
Thickness--30 to 46 cm
2BCb horizon
Moist color--7.5YR 4/4, 7.5YR 5/4, 10YR 4/4, 10YR 6/4
Dry color--7.5YR 5/3, 7.5YR 6/4, 10YR 5/3, 10YR 5/4, 10YR 6/3
Fine-earth texture--sandy loam, loamy sand, loam
Clay content--5 to 20 percent
Total rock fragment content--55 to 90 percent
Gravel content--35 to 60 percent
Cobble content--5 to 15 percent
Stone content--0 to 15 percent
Reaction--6.1 to 7.0
COMPETING SERIES:
Hondu--formed in argillite colluvium; averages 3 to 9 percent clay in particle-size control section
Inkler--deep or very deep (100 to 150 cm or more) to lithic contact (metamorphic or volcanic); formed in glacial till or colluvium and residuum derived from volcanic and metamorphic rock; dry 60 to 75 consecutive days in summer
Juandefuca--very deep (more than 150 cm); formed in colluvium derived from marine basalt; ash mantle that has more than 12 percent (air-dried samples) water content at 1500 kPa (i.e., medial) and is less than 30 percent volcanic glass
McCree--deep (100 to 150 cm) to lithic contact (rhyolite); 5 to 20 percent volcanic glass in ash mantle; dry 60 to 75 consecutive days in summer
Newhorn--moderately deep (50 to 100 cm) to densic contact (till); dry 60 to 75 consecutive days in summer
Oxerine--moderately deep (50 to 100 cm) to lithic contact (gneiss); dry 60 to 75 consecutive days in summer
Piutespring--moderately deep (50 to 100 cm) to lithic contact (granitic rock); averages 2 to 9 percent clay in particle-size control section
Redriver--moderately deep (50 to 100 cm) to lithic contact (basalt); dry 75 to 90 consecutive days in summer
Tunnelcreek--moderately deep (50 to 100 cm) to paralithic contact underlain by metavolcanic rock; ash mantle that has more than 12 percent (air-dried samples) water content at 1500 kPa (i.e., medial)
Veridge--moderately deep (50 to 100 cm) to lithic contact (sandstone); 30 to 60 percent volcanic glass in thin volcanic ash mantle; less than 10 percent clay in particle-size control section; dry 60 to 75 consecutive days in summer
Wilma--moderately deep (50 to 100 cm) to lithic contact (granite); 2C or 2BC horizon that has hue of 2.5Y; dry 60 to 75 consecutive days in summer
Wonder--moderately deep (50 to 100 cm) to lithic contact (andesitic basalt)
GEOGRAPHIC SETTING:
Elevation--1050 to 2200 m
Climate--cool, wet winters; cool to warm, dry summers
Mean annual precipitation--470 to 1110 mm
Mean annual air temperature--1 to 6 degrees C
Frost-free period--25 to 75 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Bennettcreek--on lower backslopes and footslopes; moderately deep to bedrock; mixed mantle of ash and colluvium over a loamy-skeletal argillic horizon; under grand fir,
Douglas-fir, ponderosa pine, birchleaf spirea, and pinegrass
Cherrycreek--on north-facing mid slopes of plateaus and canyons; deep to bedrock; mixed ash and loess mantle over colluvium; thick mollic epipedon; under Idaho fescue, bluebunch wheatgrass, and snowberry
Larabee--on backslopes and shoulders of hills and in canyons of dissected basalt plateaus; mollic epipedon and argillic horizon; under
Douglas-fir, ponderosa pine, mallow ninebark, common snowberry, and elk sedge
Linecreek--on hillslopes; very deep; volcanic ash mixed with basalt colluvium; mollic epipedon; cambic horizon; skeletal; under
Douglas-fir, ponderosa pine, mallow ninebark, pinegrass, and elk sedge
McWillis--on planar to concave, lower backslopes; deep to bedrock; thick volcanic ash mantle and argillic horizon; under grand fir or
Douglas-fir and birchleaf spirea
Olot--on plateaus and side slopes of mountains; moderately deep; thick volcanic ash mantle over loamy-skeletal material; under
Douglas-fir forest
Wonder--on ridges and shoulder slopes; moderately deep to bedrock; thin volcanic ash mantle and loamy-skeletal particle-size control section; under grand fir or
Douglas-fir forest
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Saturation during normal years--none
Flooding--none
Ponding--none
Saturated hydraulic conductivity (Ksat)--moderately high over high
USE AND VEGETATION:
Use--timber production, domestic livestock grazing, watershed, wildlife habitat, recreation
Potential native vegetation--grand fir, ponderosa pine, Douglas-fir, western larch, lodgepole pine, subalpine fir, pinegrass, big huckleberry, elk sedge, heartleaf arnica, white hawkweed, woodland strawberry, tailcup lupine, lupine, Virginia strawberry, showy aster, Piper's anemone, common snowberry, common yarrow, western fescue, low Oregon grape, longstalk clover
DISTRIBUTION AND EXTENT: MLRA 10; small extent
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Wallowa-Whitman National Forest, Oregon; 2012
REMARKS:
Diagnostic horizons and other features recognized in this pedon
*Ochric epipedon
*Upper cambic horizon--zone from 10 to 33 cm
*Buried cambic horizon--zone from 51 to 89 cm
*Volcanic glass--zone from 5 to 33 cm
*Andic soil properties--zone from 5 to 33 cm
*Depth to lithologic discontinuity--33 cm
*Particle-size control section--zone from 30 to 105 cm
National Cooperative Soil Survey
U.S.A.