LOCATION SCOTCH COEstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive Lithic Haplocryalfs
TYPICAL PEDON: Scotch loam, on a west facing, simple, 55 percent slope in spruce-fir woodland at an elevation of 10,200 feet. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 2 inches; Organic mat of roots, needles, leaves and twigs. (0 to 3 inches thick)
E--2 to 7 inches; pale red (2.5YR 6/2) loam, reddish brown (2.5YR 5/4) moist; moderate medium granular structure; soft, friable, nonsticky and nonplastic; 5 percent gravel; strongly acid (pH 5.2); clear smooth boundary. (3 to 7 inches thick)
Bt--7 to 17 inches; reddish brown (2.5YR 5/4) clay loam, reddish brown (2.5YR 4/4) moist; moderate medium subangular blocky structure parting to moderate medium granular; hard, friable, moderately sticky and moderately plastic; 2 percent gravel; few distinct clay films on faces of peds; strongly acid (pH 5.2); clear wavy boundary. (5 to 15 inches thick)
R--17 inches; hard sandstone, weathered in top few inches.
TYPE LOCATION: San Juan County, Colorado, along Hotel Draw road about 35 miles north of Durango, Colorado; about 1,000 feet north and 2,300 feet west of the southeast corner of Sec. 10, T. 39 N., R. 10 W.; Hermosa Peak USGS quad; lat. 37 degrees 39 minutes 31 seconds N. and long. 107 degrees 57 minutes 10 seconds W., NAD 27
RANGE IN CHARACTERISTICS: (depths given are measured from the mineral soil surface)
Soil moisture regime: udic; dry in some part of the moisture control section for less than 45 cumulative days (typic udic subclass)..
Mean annual soil temperature: 35 to 40 degrees F.
Mean summer soil temperature: 41 to 46 degrees F. with an O horizon
Depth to lithic contact: 10 to 20 inches to sandstone
Particle-size control section:
Clay content: 18 to 35 percent
Rock fragment content: 0 to 25 percent
E horizon:
Hue: 2.5YR or 5YR
Value: 5 to 7 dry, 4 or 5 moist
Chroma: 2 to 4, dry and moist
Rock fragment content: 0 to 15 percent
Reaction: very strongly acid or strongly acid
Base saturation: 50 to 70 percent (by ammonium acetate, estimated)
Bt horizon:
Hue: 2.5YR to 5YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 to 6, dry and moist
Texture, fine earth fraction: L, CL, or SCL
Reaction: very strongly acid or strongly acid
Base saturation: 50 to 70 percent (by ammonium acetate, estimated)
COMPETING SERIES: This is the
Silex series.
Silex: have hue of 7.5YR or 10YR and have rock fragments of limestone and sandstone..
GEOGRAPHIC SETTING:
Parent material: slope alluvium and residuum derived principally from sandstone and interbedded shale.
Landform: mountain slopes and ridges.
Slopes: 30 to 60 percent
Elevation: 9,000 to 11,500 feet
Mean annual air temperature: 30 to 38 degrees F.
Mean annual precipitation: 35 to 45 inches.
Wettest months: July and August receive slightly more monthly precipitation than other months.
Driest months: May and June receive the least precipitation, however, the soils are still moist from snowmelt.
Frost-free period: 50 to 70 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Graysill, Needleton, and Haviland series. All are on mountain slopes.
Graysill soils are moderately deep over sandstone.
Needleton and
Haviland soils are very deep.
DRAINAGE AND PERMEABILITY: Well drained; medium to high runoff; moderate or moderately slow permeability.
USE AND VEGETATION: These soils are used for timber production, livestock grazing, and wildlife habitat. Principal native vegetation is subalpine fir, Rocky Mountain Douglas fir, Engelmann's spruce, Quaking aspen, whortleberry, kinnickinnick, snowberry, sedges, mountain brome, and forbs.
DISTRIBUTION AND EXTENT: Southwestern Colorado. LRR E, MLRA 48A. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: San Juan County, Colorado, Animas-Dolores Soil Survey Area, 1984. The name is taken from a creek in the area.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: The zone from 2 to 7 inches. (E horizon)
Argillic horizon: The zone from 7 to 17 inches. (Bt horizon)
Lithic contact: sandstone bedrock at 17 inches.
Particle size control section: The zone from 7 to 17 inches. (Bt horizon)
Keys to Soil Taxonomy: Classified according to the Eighth Edition, 1998
Activity class is presumed based on general trend of other soils in the area.