LOCATION SCARPAL OR
Tentative Series
IRD. JRD/DAL
03/2013
SCARPAL SERIES
The Scarpal series consists of very deep well drained soils formed in volcanic ash over colluvium from basalt, rhyolite, pyroclastic tuffs and Mesozoic marine sediments on upland escarpments and steep, north and east-facing mountain sideslopes. Slope gradients are 20 to 70 percent. Mean annual precipitation is about 23 inches; mean annual temperature is about 43 degrees F.
TAXONOMIC CLASS: ashy-skeletal over loamy-skeletal, glassy over isotic, frigid Humic Vitrixerands
TYPICAL PEDON: Scarpal extremely stony ashy sandy loam - upland forest, on a 40 percent convex slope at an elevation of 5800 feet. (Colors are for air dry unless otherwise noted.)
Oi--0 to 2 inches, slightly decomposed fir litter
A1--2 to 8 inches, yellowish brown (10YR 5/4) extremely stony ashy sandy loam, dark brown (10YR 3/3) moist; weak medium platy structure; very soft, very friable, slightly sticky and non-plastic; many very fine, fine and medium roots; many very fine irregular pores; 10 percent gravel, 25 percent cobbles and 30 percent stones; moderately acid (pH 5.8); clear smooth boundary.
A2--8 to 16 inches, yellowish brown (10YR 5/4) extremely stony ashy sandy loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; very soft, very friable, slightly sticky and slightly plastic; many very fine, fine and medium, and common coarse roots; common very fine to medium irregular pores; 10 percent gravel, 25 percent cobbles and 30 percent stones; moderately acid (pH 5.6); clear smooth boundary.
A3--16 to 24 inches; brown (10YR 4/3) extremely stony ashy sandy loam, dark brown (10YR 3/3) moist; weak medium subangular blocky structure, soft, friable, slightly sticky and slightly plastic; many fine and medium, and common coarse roots; common very fine irregular pores; 10 percent gravel, 30 percent cobbles and 20 percent stones; moderately acid (pH 5.8); abrupt smooth boundary. (Combined thickness of the A horizons is 14 to 24 inches.)
2A--24 to 31 inches; dark yellowish brown (10YR 4/4) extremely cobbly sandy clay loam, dark yellowish brown (10YR 3/4) moist; moderate medium subangular blocky structure, slightly sticky, and slightly plastic; many very fine, fine, medium and coarse roots; common very fine irregular pores; 15 percent gravel, 30 percent cobbles and 20 percent stones; moderately acid (pH 6.0); clear smooth boundary. (7 to 9 inches thick)
2Bw1--31 to 42 inches; dark yellowish brown (10YR 4/6) extremely cobbly sandy clay loam, dark yellowish brown (10YR 3/4) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine to very coarse roots; few very fine tubular pores; 20 percent gravel, 35 percent cobble and 25 percent stones; moderately acid (pH 6.0); clear smooth boundary. (10 to 12 inches thick)
2Bw2--42 to 62 inches; dark yellowish brown (10YR 4/6) extremely cobbly sandy clay loam, dark yellowish brown (10YR 3/4) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine to coarse roots; few very fine tubular pores; 20 percent gravel, 35 percent cobbles and 25 percent stones; moderately acid (ph 6.0).
TYPE LOCATION: Crook County, Oregon; central Maury Mountains, NE of Drake Butte, on a convex slope, at 5800 feet elevation.
SE 1/4 of Sec. 31, T. 17 S, R. 20 E.
Latitude 44 degrees, 2 minutes, 50.78 seconds;
Longitude 120 degrees, 22 minutes, 20.78 seconds
UTM Coordinates: Zone: 10; Northing: 4880505.5; Easting: 710492.1
RANGE IN CHARACTERISTICS:
Soil Temperature Regime: frigid
Mean Annual Soil Temperature: 37 to 41 degrees
Mean Summer Soil Temperature: 44 to 49 degrees
Mean Winter Soil Temperature: 32 to 36 degrees
Soil Moisture: Xeric regime, dry 45 to 60 days in summer and early fall
Particle-size control section: mineral surface to 40 inches below the mineral surface
Upper part (ashy-skeletal): 18 to 24 inches thick
Clay content (weighted average): 7 to 18 percent
Rock fragment content (weighted average): 35 to 75 percent
Lower part (loamy-skeletal):
Clay content (weighted average): 18 to 35 percent
Rock fragment content (weighted average): 65 to 85 percent
Diagnostic horizons and features:
andic soil properties: upper boundary at the mineral surface; 18 to 24 inches thick
Al+1/2Fe (aox): 0.4 to 1.0 percent
P retention: 25 to 50 percent
0.2 to 2.0 mm fraction: 60 to 80 percent of fine earth
volcanic glass in the 0.2 to 2.0 mm fraction: 30 to 60 percent
water content at 1500 kPa (air dry): 8 to 12 percent
mollic epipedon: 14 to 24 inches thick
lithic contact: over 60 inches
Major horizons:
A horizon
color moist: hue 10YR value 3 chroma 2 or 3
color dry: hue 10YR value 4 or 5 chroma 3 or 4
clay content: 7 to 18 percent
rock fragments: 35 to 85 percent
gravel: 0 to 15 percent
cobbles: 15 to 35 percent
stones: 15 to 35 percent
boulders: 0 to 15 percent
reaction: moderately acid to slightly acid; pH: 5.6 to 6.5
2Bw horizon
color moist: hue 10YR value 3 chroma 3 or 4
color dry: hue 10YR value 4 chroma 4 or 6
texture: loam, clay loam, sandy clay loam
rock fragment modifier: very stony, very cobbly, extremely stony, extremely cobbly
clay content: 18 to 35 percent
rock fragments: 65 to 90 percent
gravel: 10 to 20 percent
cobbles: 15 to 40 percent
stones: 20 to 30 percent
boulders: 0 to 10 percent
reaction: moderately acid to slightly acid, pH: 5.6 to 6.5
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform: upland escarpments and steep mountain sideslopes
Aspect: northern and eastern
Slope gradient: 20 to 70 percent
Parent material: volcanic ash over colluvium from basalt, rhyolite, pyroclastic tuffs and Mesozoic marine sediments
Elevation: 4,000 to 7,000 feet
Climate: cold, wet winters and hot, dry summers
Mean annual precipitation: 20 to 25 inches
Mean annual temperature: 40 to 45 degrees F.
Frost-free period: 45 to 60 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Normauk (T) - occur on less steep slope positions and are ashy over clayey-skeletal
DRAINAGE AND PERMEABILITY:
Drainage: well drained
Permeability: rapid in ashy mantle, moderate in loamy subsoil
USE AND VEGETATION:
Use: timber production, range, wildlife habitat and water supply
Natural vegetation: grand fir, Douglas fir, ponderosa pine and western larch, pachistima and pinegrass
DISTRIBUTION AND EXTENT:
Distribution--Central Oregon
MLRA--10
Extent--moderate
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Crook County, Oregon, 2005
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
andic soil material (ash): 2 to 24 inches A1, A2, A3
mollic epipedon: 2 to 24 inches A1, A2, A3
Plant Association, CWG1-13, Grand fir/pinegrass
Plant Association group: Douglas fir (moist) or grand fir (moist)
National Cooperative Soil Survey
U.S.A.