LOCATION PRAMISS COEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Typic Argiustolls
TYPICAL PEDON: Pramiss very cobbly loam, on a south facing, 14 percent slope in rangeland at an elevation of 7,280 feet. (Colors are for dry soil unless otherwise noted.)
The surface is covered by 25 percent gravel, 15 percent cobbles, and 10 percent stones.
A--0 to 3 inches; dark brown (7.5YR 4/4) very cobbly loam, dark brown (7.5YR 3/2) moist; strong thick platy vesicular crust overlying weak fine granular structure; soft, very friable, nonsticky and nonplastic; 25 percent gravel, 15 percent cobbles, and 10 percent stones; slightly alkaline (pH 7.5); clear wavy boundary. (3 to 7 inches)
AB--3 to 8 inches; dark brown (7.5YR 4/4) clay loam, dark reddish brown (5YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; 2 percent gravel; slightly alkaline (pH 7.4); gradual wavy boundary. (4 to 8 inches)
Bt--8 to 16 inches; reddish brown (5YR 5/4) clay, reddish brown (5YR 4/4) moist; strong coarse prismatic structure parting to strong coarse angular blocky; very hard, very firm, very sticky and very plastic; many distinct clay films on the faces of peds; 2 percent gravel; slightly alkaline (pH 7.4); gradual wavy boundary. (3 to 15 inches)
Btk1--16 to 22 inches; light reddish brown (5YR 6/4) clay, reddish brown (5YR 5/3) moist; moderate coarse prismatic structure parting to moderate medium angular blocky; very hard, very firm, moderately sticky and very plastic; common distinct clay films on the faces of peds; 2 percent gravel; few fine soft irregular masses of calcium carbonate; slightly effervescent; moderately alkaline (pH 8.0); clear wavy. (3 to 9 inches)
Btk2--22 to 31 inches; pink (5YR 7/4) clay, pinkish gray (5YR 6/2) moist; massive; hard, friable, moderately sticky and moderately plastic; few faint clay films on the faces of peds; 2 percent gravel; many fine irregular soft masses of calcium carbonate; violently effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (6 to 12 inches)
2Cr--31 inches; calcareous soft sandstone and shale.
TYPE LOCATION: Dolores County, Colorado; about 5 miles north of the community of Dove Creek; located about 1,850 feet east and 200 feet south of the northwest corner of sec. 7, T. 41 N., R. 18 W.; USGS quad; lat. 37 degrees 50 minutes 14 seconds N. and long. 108 degrees 53 minutes 50 seconds W., NAD 27
RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 43 to 47 degrees F
Particle-size control section: 35 to 60 percent clay
Depth to paralithic contact: 20 to 40 inches to calcareous soft sandstone and shale
Depth to secondary calcium carbonate: 15 to 30 inches
Thickness of the mollic epipedon: 7 to 16 inches
A horizon:
Hue: 5YR to 10YR
Value: 3 to 5 dry, 2 or 3 moist
Chroma: 2 to 4 dry or moist
Rock fragments: 0 to 60 percent
Reaction: neutral or slightly alkaline
Bt horizon:
Hue: 2.5YR to 7.5YR
Value: 4 to 6 dry, 4 or 5 moist
Chroma: 3 to 6 dry or moist
Texture: clay or clay loam
Rock fragments: 0 to 35 percent
Reaction: neutral to moderately alkaline
Bk horizon:
Hue: 5YR to 10YR
Rock fragments: 0 to 35 percent
Calcium carbonate equivalent: 5 to 15 percent
Reaction: slightly or moderately alkaline
COMPETING SERIES: These are the Absarokee, Acree, Brolliar, Delson, Herm, Morapos, Nortez, Peninsula, Reget, Ricot, Tamaneen, Tomasaki, Tukuhnik, and Work series.
The Absarokee, Brolliar, and Nortez soils have a lithic contact at depths of 20 to 40 inches.
The Acree, Delson, Herm, Morapos, Peninsula, Ricot, Tamaneen, Tomasaki, and Work soils do not have bedrock above a depth of 60 inches.
Reget soils have hues of 10YR or yellower in the argillic horizon.
Tukuhnik soils have a lithic contact at depths of 40 to 60 inches.
GEOGRAPHIC SETTING:
Parent material: reworked eolian material, eolian deposits and clayey slope alluvium over residuum derived from sandstone and shale
Landform: hills and ridges
Slopes: 2 to 25 percent
Elevation: 7,100 to 8,500 feet
Mean annual temperature: 43 to 47 degrees F
Mean annual precipitation: 15 to 20 inches
Precipitation is fairly evenly distributed throughout the year with July and August being slightly wetter and June being slightly dryer.
Frost-free period: 75 to 120 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Nortez soils, and the Granath, Ormiston, and Hesperus soils on similar positions. Granath, Ormiston, and Hesperus soils do not have paralithic contacts above a depth of 40 inches .
DRAINAGE AND PERMEABILITY: well drained, high or very high runoff, slow permeability
USE AND VEGETATION: Soils are used for grazing, wildlife habitat, and recreation. Native vegetation is sagebrush, Gambel's oak, squawapple, junegrass, and western wheatgrass. Nonstony surface areas are used to grow Pinto beans, alfalfa, and winter wheat.
DISTRIBUTION AND EXTENT: Southwest Colorado. LRR E, MLRA 48A. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Cortez Area, Colorado, Parts of Dolores and Montezuma Counties, 1997.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
mollic epipedon: The zone from 0 to 8 inches. (A and AB)
argillic horizon: The zone from 8 to 31 inches. (Bt)
paralithic contact: The contact with soft bedrock at 31 inches. (2Cr)
particle-size control section: The zone from 8 to 28 inches. (Bt, Btk1, Btk2)
Soil Taxonomy Second Edition, 1999
These soils are borderline mesic-frigid. Future temperature studies are needed to resolve this issue.