LOCATION DUFFYMONT CO+UTEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Lithic Haplustolls
TYPICAL PEDON: Duffymont very stony fine sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 4 inches; brown (10YR 4/3) very stony fine sandy loam, brown (10YR 3/3) moist; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; 20 percent cobbles, 30 percent stones; slightly alkaline (pH 7.4); abrupt wavy boundary. (3 to 6 inches thick)
A2--4 to 11 inches; brown (10YR 4/3) extremely stony fine sandy loam, dark brown (10YR 3/3) moist; weak medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; 20 percent cobbles, 50 percent stones; slightly alkaline (pH 7.4); abrupt wavy boundary. (0 to 14 inches thick)
R--11 inches; hard sandstone.
TYPE LOCATION: Moffat County, Colorado; approximately 10 miles west of Hamilton, about 400 feet north and 400 feet west of the southeast corner of Sec. 23, T. 5 N., R. 93 W. Axial Basin quad; Longitude: 107 degrees, 47 minutes, 32 seconds west; latitude: 40 degrees, 21 minutes, 47 seconds north. NAD 27
RANGE IN CHARACTERISTICS:
Soil moisture regime: The smcs is moist in all parts for 45 or more consecutive days after April 1. It is dry in all parts for 45 consecutive days immediately following July 1. Ustic soil moisture regime bordering on aridic.
Soil temperature regime: frigid
Mean annual soil temperature: 40 to 44 degrees F.
Mean summer soil temperature: 59 to 64 degrees F.
Depth to the lithic contact: 4 to 20 inches to sandstone
Some pedons have C horizons
Particle-size control section (weighted averages):
Clay content: 10 to 18 percent
Rock fragment content: 40 to 75 percent, dominantly stones
and flagstones
Content of fine and coarser sand: 35 to 80 percent
A horizon:
Hue: 5YR through 10YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 1 through 3 dry or moist
Fine earth texture: fine sandy loam or sandy loam
Reaction: neutral or slightly alkaline
C horizon (when present)
Hue: 5YR through 10YR
Value: 5 or 6 dry, 3 to 5 moist
Chroma: 3 or 4 dry or moist
Fine earth texture: fine sandy loam, loam, or sandy loam
Reaction: neutral or slightly alkaline
COMPETING SERIES: Currently, the only competitor is the Castner series. Castner series have accumulations of secondary calcium carbonate.
Competitors prior to the Seventh Edition, 1996 Keys to Soil Taxonomy were the:
Catgulch,
Cathedral,
Celeste,
Comodore,
Firo,
Nivean,
Onaqui,
Paunsaugunt,
Pendant,
Reedpoint,
Vershal, and
Whitlash series.
Catgulch soils have cambic horizons and formed in material derived from granite.
Cathedral soils have rock fragments dominantly smaller than 10 inches in diameter.
Celeste, Comodore, Firo, and Onaqui soils have greater than 18 percent clay in their particle-size control section.
Nivean soils have a paralithic contact overlying a lithic contact with welded tuff.
Paunsaugunt and Pendant soils are calcareous.
Reedpoint, Vershal, and Whitlash soils are moist during June and July.
GEOGRAPHIC SETTING: Duffymont soils are on plateaus, mesas, hills, and mountain slopes. Slopes range from 1 to 65 percent. The soil formed in slope alluvium and colluvium derived from sandstone. Elevation ranges from 6,500 to 8,500 feet. The mean annual precipitation ranges from 14 to 20 inches with June and July being the driest months. Mean annual temperature ranges from 40 to 45 degrees F. The frost-free period is about 60 to 95 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Tolman, Maudlin, Morapos, and Regent soils. Maudlin, Regent, and Morapos soils are greater than 20 inches to bedrock. Tolman soils have an argillic horizon.
DRAINAGE AND PERMEABILITY: Well to somewhat excessively drained; very low to medium runoff; moderately rapid permeability.
USE AND VEGETATION: These soils are used for livestock grazing and wildlife habitat. Native vegetation consists of wheatgrasses, needleandthread, Indian ricegrass, antelope bitterbrush, Gambel oak, serviceberry, and mountain big sagebrush.
DISTRIBUTION AND EXTENT: Duffymont soils are in northwestern Colorado and northeastern Utah. The series is of moderate extent. LRR D, MLRA 34 and LRR E, MLRA 47, 48A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Moffat County (Moffat County Area), Colorado, 1991.
REMARKS: Diagnostic horizon and features recognized in this pedon are:
Mollic epipedon: The zone from 0 to 11 inches. (A1 and A2 horizons)
Lithic contact: The contact at 11 inches with sandstone bedrock. (R horizon)
Particle-size control section extends from 0 to 11 inches.
The classification was changed from Lithic Haploborolls to frigid Lithic Haplustolls 12/98.
Taxonomic version of the Keys to Soil Taxonomy: Eighth Edition, 1998.
CEC activity class is estimated