LOCATION SHEEPCREEK OR
Established Series
Rev. RLW/KMS
11/2018
SHEEPCREEK SERIES
Landscape--mountains
Landform--plateaus, mountain slopes
Slope--0 to 15 percent
Parent material--thin mantle of volcanic ash mixed with loess over colluvium derived from basalt
Mean annual precipitation--about 810 mm
Mean annual air temperature--about 6 degrees C
Depth class--moderately deep to lithic bedrock
Drainage class--moderately well drained
Soil moisture regime--xeric
Soil temperature regime--frigid
Soil moisture subclass--oxyaquic
TAXONOMIC CLASS: Fine-loamy, isotic, frigid Andic Haploxerolls
TYPICAL PEDON: Sheepcreek ashy silt loam, forested, on a slope of 6 percent at an elevation of 1521 m
A1--0 to 23 cm; ashy silt loam, brown (7.5YR 4/2) dry, very dark brown (7.5YR 2.5/2) moist; weak very fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine, fine, and medium roots throughout; common very fine irregular pores; 1 percent gravel; slightly acid (pH 6.5); clear wavy boundary
2A2--23 to 43 cm; silt loam, brown (7.5YR 5/3) dry, dark brown (7.5YR 3/3) moist; moderate fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine, fine, and medium roots throughout; common fine irregular pores; 1 percent gravel; slightly acid (pH 6.5); clear wavy boundary
2Bw1--43 to 66 cm; silt loam, brown (7.5YR 5/4) dry, dark brown (7.5YR 3/4) moist; moderate fine subangular blocky structure; slightly hard, friable, moderately sticky and slightly plastic; common very fine, fine, and medium roots throughout; common fine irregular and tubular pores; 5 percent gravel; neutral (pH 7.3); clear wavy boundary
2Bw2--66 to 74 cm; very gravelly silt loam, yellowish brown (10YR 5/4) dry, brown (10YR 4/3) moist; weak fine subangular blocky structure; slightly hard, friable, moderately sticky and slightly plastic; common fine irregular pores; 5 percent fine prominent iron-manganese masses; 35 percent gravel and 5 percent cobbles; neutral (pH 7.3); abrupt wavy boundary
2R--74 cm; indurated basalt
TYPE LOCATION: Wallowa County, Oregon; about 70 m east and 75 m south of the northwest corner of section 18, T. 5 N., R. 41 E., latitude 45.9187622 , longitude -117.7487183, datum WGS 84 (coordinates most likely determined from a GPS)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--3 to 8 degrees C
Soil moisture--dry 45 to 60 consecutive days following summer solstice
Depth to lithic contact--50 to 100 cm
Thickness of mollic epipedon--25 to 50 cm
Thickness of layers influenced by volcanic ash--18 to 35 cm
Estimated properties of layers influenced by volcanic ash
*Ammonium oxalate extractable Al + 1/2 Fe--0.4 to 2.0 percent
*0.02- to 2.0-mm fraction--more than 30 percent
*Glass content in 0.02- to 2.0-mm fraction--25 to 45 percent
*1/3-bar bulk density--0.8 to 1.0 g/cm3
*Phosphate retention--25 to 50 percent
*15-bar water retention--less than 30 percent (undried samples), 5 to 10 percent (dried samples)
Particle-size control section
*Clay content--18 to 27 percent
*Total rock fragment content--less than 35 percent
A1 horizon
Fine-earth texture--ashy silt loam
Clay content--10 to 20 percent
Sand content--10 to 30 percent
Organic matter content--3 to 7 percent
Total rock fragment content--0 to 5 percent
Gravel content--0 to 5 percent
Reaction--6.1 to 6.5
2A2 horizon
Fine-earth texture--silt loam
Clay content--15 to 27 percent
Sand content--5 to 20 percent
Organic matter content--2 to 4 percent
Total rock fragment content--0 to 5 percent
Gravel content--0 to 5 percent
Reaction--6.1 to 6.5
2Bw1 horizon
Fine-earth texture--silt loam
Clay content--18 to 27 percent
Sand content--5 to 20 percent
Organic matter content--1 to 2 percent
Total rock fragment content--0 to 5 percent
Gravel content--0 to 5 percent
Reaction--6.6 to 7.3
2Bw2 horizon
Fine-earth texture--silt loam
Clay content--18 to 27 percent
Sand content--10 to 20 percent
Organic matter content--0 to 2 percent
Total rock fragment content--25 to 55 percent
Gravel content--25 to 45 percent
Cobble content--0 to 10 percent
Reaction--6.6 to 7.3
COMPETING SERIES: None
GEOGRAPHIC SETTING:
Elevation--910 to 1520 m
Climate--cool, wet winters; hot, dry summers
Mean annual precipitation--530 to 1090 mm
Mean annual air temperature--5 to 7 degrees C
Frost-free season--40 to 130 days
GEOGRAPHICALLY ASSOCIATED SOILS: None given
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Saturation during normal years--saturated in the layer directly above the bedrock in March through June
Flooding--none
Ponding--none
Saturated hydraulic conductivity (Kstat)--moderately high
USE AND VEGETATION:
Use--timber production, wildlife habitat, water supply, livestock grazing
Potential natural vegetation--tufted hairgrass, Baltic rush, smallwing sedge, beauty cinquefoil, Kentucky bluegrass, American bistort
DISTRIBUTION AND EXTENT: Eastern Oregon; MLRA 10; small extent
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Wallowa-Whitman National Forest, Oregon; 2018
REMARKS:
Diagnostic horizons and other features recognized in this pedon
*Mollic epipedon--zone from the surface to a depth of 43 cm
*Cambic horizon--zone from 43 to 74 cm
*Volcanic glass--zone from the surface to a depth of 23 cm
*Depth to lithologic discontinuity--23 cm
*Andic soil properties--zone from the surface to a depth of 23 cm
*Particle-size control--zone from 25 to 74 cm
*Oxyaquic feature--zone from 66 to 74 cm; saturated in March through June
National Cooperative Soil Survey
U.S.A.