LOCATION BRADFIELD COEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Udic Haplusterts
TYPICAL PEDON: Bradfield clay loam, on a southeast facing, simple, 2 percent slope in rangeland at an elevation of 8,350 feet. (Colors are for dry soil unless otherwise noted.) When described on May 10,1990 the soil was saturated from 4 to 48 inches.
A--0 to 7 inches; grayish brown (10YR 5/2) clay loam, very dark grayish brown (10YR 3/2) moist; moderate medium granular structure; hard, firm, moderately sticky and moderately plastic; many fine and medium roots; neutral (pH 7.2); clear smooth boundary. (6 to 20 inches thick)
Bss1--7 to 15 inches; brown (10YR 4/3) clay loam, dark brown (10YR 3/3) moist, moderate coarse prismatic structure parting to moderate medium angular and subangular blocky; extremely hard, firm, moderately sticky and moderately plastic; common prominent pressure faces and slickensides; cracks are 1/2 inch wide or more; few fine roots; neutral (pH 7.0); gradual smooth boundary. (7 to 20 inches thick)
Bss2--15 to 28 inches; dark grayish brown (10YR 4/2) clay, very dark grayish brown (10YR 3/2) moist; moderate coarse prismatic structure parting to moderate medium angular and subangular blocky; extremely hard, very firm, very sticky and very plastic; many prominent intersecting pressure faces and slickensides; wedge shaped aggregates are present; cracks are 1/2 inch wide or more; neutral (pH 7.2); clear smooth boundary. (10 to 30 inches thick)
Bss3--28 to 36 inches; brown (10YR 5/3) and yellowish brown (10YR 5/4) clay, dark brown (10YR 3/3) and yellowish brown (10YR 5/4) moist; massive; extremely hard, very firm, very sticky and very plastic; many prominent pressure faces and slickensides; slightly alkaline (pH 7.4); gradual wavy boundary. (0 to 12 inches thick)
BCy--36 to 60 inches; light yellowish brown (10YR 6/4) clay, yellowish brown (10YR 5/4) moist; massive; very hard, very firm, very sticky and very plastic; few fine secondary gypsum crystals in the lower part of this horizon; neutral ( pH 7.2).
TYPE LOCATION: Dolores County, Colorado; about 28 miles north or Dolores, Colorado; located about 1,600 feet west and 1,200 feet south of the northeast corner of sec. 4, T. 40 N., R. 16 W.; Glade Mountain USGS quad.; lat. 37 degrees, 45 minutes, 44 seconds N.; long. 108 degrees, 30 minutes, 00 seconds W.
RANGE IN CHARACTERISTICS:
Soil moisture regime: ustic.
Mean annual soil temperature: 40 to 46 degrees F.
Mean summer soil temperature: 60 to 65 degrees F.
Depth to secondary calcium carbonate: 35 to 60 inches or more
Depth to secondary gypsum: 35 to 60 inches or more
Vertic features: The soil has cracks extending to the surface when dry. Cracks are 1/2 to 1 inch wide, 20 inches or more deep, and 12 inches or more long. At a 20 inch depth the cracks remain open for 90 to 150 cumulative days in most years, though at the surface they may be open for shorter periods. The COLE value is about 0.07 in the surface layer and .06 in the Bss horizons. Pressure faces and slickensides are evident in the particle-size control section. Wedge shaped aggregates are present in most pedons.
Particle-size control section:
Clay content: 35 to 60 percent
Silt content: 10 to 45 percent
Sand content: 10 to 45 percent
Pararock fragment content: 0 to 10 percent parachanners (shale chips)
A horizon:
Hue: 10YR or 2.5Y
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 1 to 3, dry and moist
Reaction: neutral or slightly alkaline
Bss1 and Bss2 horizons:
Hue: 10YR or 2.5Y
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 1 to 3, and moist
Texture: C or CL
Parachanner content: 0 to 10 percent
Reaction: neutral or slightly alkaline
Bss3 horizon:
Hue: 10YR or 2.5Y
Value: 5 or 6 dry, 3 to 5 moist
Chroma: 3 or 4, dry and moist
Texture: C or CL
Parachanner content: 0 to 10 percent
Reaction: neutral or slightly alkaline
Cy horizon:
Hue: 10YR or 2.5Y
Gypsum: 0 to 5 percent
Reaction: neutral to moderately alkaline
COMPETING SERIES: These are the
Wildrose and
Lawther series.
Wildrose: have carbonates above a depth of 30 inches
Lawther: have a mollic epipedon less than 20 inches thick; have horizons of secondary carbonate above 30 inches.
GEOGRAPHIC SETTING:
Parent material: alluvium and slope alluvium derived mostly from shale.
Landform: mesas and alluvial fans.
Slopes: 0 to 5 percent
Elevation: 7,600 to 8,500 feet
Mean annual air temperature: 40 to 44 degrees F.
Mean annual precipitation: 18 to 25 inches.
Wettest months: July and August receive slightly more precipitation than other months.
Driest months: May and June receive the least precipitation, however the soils are still moist from snowmelt through mid June.
Frost-free period: 70 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Fardraw, Lonecone, and Narraguinnep series.
Fardraw soils contain more than 35 percent rock fragments in the particle-size control section.
Lonecone soils are fine-loamy and moderately deep over bedrock.
Narraguinnep soils have carbonates at depths of 12 to 24 inches and have horizons of calcium carbonate accumulation.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; slow permeability.
USE AND VEGETATION: These soils are used for livestock grazing and wildlife habitat. Native vegetation consists of western wheatgrass, Arizona fescue, mountain brome, mountain muhly, Columbia needlegrass, and sagebrush.
DISTRIBUTION AND EXTENT: Southwestern Colorado. LRR E, MLRA 48A. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Dolores County, Animas-Dolores Area, Colorado, 2002. Series proposed in 1990. The name is taken from bridge across the Dolores River.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: The zone from 0 to 28 inches. (A, Bss1, and Bss2 horizons)
Cambic horizon: The zone from 7 to 28 inches. (Bss1 and Bss2 horizons)
Vertic features: Pressure faces, slickensides, and wedge shaped aggregates are in part of the particle size control section. The soil has cracks 1/2 inch wide or more.
Keys to Soil Taxonomy: Classified according to the Eighth Edition, 1998