LOCATION COULTERG COEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Entic Haplustolls
TYPICAL PEDON: Coulterg loam, in coniferous forest. (Colors are for dry soil unless otherwise noted.)
A1--0 to 14 inches; dark grayish brown (10YR 4/2) loam, very dark grayish brown (10YR 3/2) moist; moderate medium granular structure; soft, very friable, nonsticky and nonplastic; 5 percent channers; slightly effervescent moderately alkaline (pH 8.0); clear smooth boundary. (10 to 15 inches thick.)
A2--14 to 19 inches; grayish brown (10YR 5/2) loam, dark grayish brown (10YR 4/2) moist; moderate medium granular structure; soft, very friable, nonsticky and nonplastic; 5 percent channers; strongly effervescent (7 percent calcium carbonate equivalent); moderately alkaline (pH 8.0); clear smooth boundary. (4 to 10 inches thick)
Bky1--19 to 30 inches; grayish brown (10YR 5/2) loam, brown (10YR 4/3) moist; massive; soft, friable, slightly sticky and slightly plastic; 5 percent channers; violently effervescent (10 percent calcium carbonate equivalent); common fine gypsum crystals; moderately alkaline (pH 8.2); clear wavy boundary. (10 to 20 inches thick)
Bky2--30 to 60 inches; grayish brown (10YR 5/2) loam, brown (10YR 4/3) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; 3 percent cobbles, 3 percent flagstones; violently effervescent (14 percent calcium carbonate equivalent); common fine gypsum crystals; moderately alkaline (pH 8.2).
TYPE LOCATION: Eagle County, Colorado; about 15 miles east of Glenwood Springs, Colorado; located about 2,500 feet north and 2,000 feet west of the southwest corner of sec. 34, T. 5 S., R. 86 W.; Cottonwood Pass USGS quad; lat. 39 degrees 34 minutes 19 seconds N. and long. 107 degrees 01 minutes 04 seconds W., NAD 27.
RANGE IN CHARACTERISTICS:
Soil moisture regime: ustic.
Mean annual soil temperature: 41 to 45 degrees F.
Mean summer soil temperature: 59 to 62 degrees F.
Depth to secondary calcium carbonate: 0 to 10 inches
Thickness of the mollic epipedon: 8 to 15 inches; in some pedons the mollic epipedon includes part or all of a Bw horizon.
Particle-size control section:
Clay content: 18 to 30 percent
Rock fragment content: 0 to 20 percent
A horizon:
Hue: 5Y to 10YR
Value: 4 or 5 dry, 2 to 4 moist (2 or 3 moist in the mollic epipedon)
Chroma: 1 to 3, dry and moist
Texture, fine earth fraction: L, CL
Rock fragment content: 0 to 20 percent
Calcium carbonate equivalent: 0 to 5 percent
Reaction: neutral to moderately alkaline
Bw horizon: (present in some pedons)
Hue: 5Y to 10YR
Value: 4 to 7 dry, 3 or 6 moist
Chroma: 2 to 4, dry and moist
Texture, fine earth fraction: L, CL
Rock fragment content: 0 to 20 percent
Calcium carbonate equivalent: 5 to 15 percent
Gypsum: 0 to 5 percent
Reaction: slightly alkaline or moderately alkaline
Bky horizon (a Bk in some pedons):
Hue: 2.5Y or 10YR
Value: 5 to 7 dry, 4 to 6 moist
Chroma: 2 to 4, dry and moist
Texture, fine earth fraction: L, SCL, or CL
Rock fragment content: 0 to 20 percent
Calcium carbonate equivalent: 5 to 15 percent
Gypsum: 0 to 5 percent
Reaction: slightly alkaline or moderately alkaline
COMPETING SERIES: These are the
Barvon,
Mavreeso, and
Rottulee series.
The Azar,
Minnimaud,
Roundup, and
Twin Creek series may be competitors when their classification is updated.
Azaar: has a lithic contact at depths of 20 to 40 inches.
Barvon and Minnimaud: have a paralithic contact at depths of 20 to 40 inches.
Mavreeso, and Twin Creek: have hue of 7.5YR or redder.
Rottulee: have limestone bedrock at 20 to 40 inches.
Roundup: have a paralithic contact at 20 to 40 inches.
GEOGRAPHIC SETTING:
Parent material: slope alluvium or alluvium derived from calcareous and gypsiferous shale, and from sandstone, siltstone, and limestone.
Landform: hills, mountain slopes, and alluvial fans.
Slopes: 10 to 60 percent
Elevation: 7,200 to 9,500 feet
Mean annual air temperature: 39 to 43 degrees F.
Mean annual precipitation: 16 to 18 inches.
Wettest months: July and August receive slightly more precipitation than other months.
Driest months: May and June receive the least precipitation.
Frost-free period: 70 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Antrobus,
Anvik,
Brownsto,
Cochetopa,
Forelle, and
Tridell soils.
Antrobus, Anvik, Cochetopa soils are at higher elevations and have a cryic temperature regime.
Brownsto and Forelle soils lack mollic epipedons.
Tridell soils have a calcic horizon.
DRAINAGE AND PERMEABILITY: Well drained; medium or high runoff; moderate permeability.
USE AND VEGETATION: Used mainly for wildlife habitat, timber production, and limited livestock grazing. Native vegetation is Rocky Mountain Douglas fir, lodgepole pine, ponderosa pine, and some Rocky Mountain juniper. Understory plants include mountain snowberry, oregongrape, Gambel's oak, dwarf blueberry, slender wheatgrass, and elk sedge.
DISTRIBUTION AND EXTENT: Western and southwestern Colorado. LRR E, MLRA 48A. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Eagle County, (Aspen-Gypsum Soil Survey Area), Colorado, 1982.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: The zone from 0 to 14 inches. (A1 horizon)
Particle size control section: The zone from 10 to 40 inches. (Part of the A1, the A2, the Bky1, and part of the Bky2 horizons)
Entic feature: free carbonates in the lower part of the mollic epipedon (lower part of A1 horizon).
Keys to Soil Taxonomy: Classified according to the Eighth Edition, 1998
Activity class is presumed based on the general trend of other soils in the area.