LOCATION ORMISTON COEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic, frigid Calcic Haplustalfs
TYPICAL PEDON: Ormiston extremely stony loam, in rangeland (Colors are for dry soil unless otherwise noted.)
The surface is covered by 10 percent stones from sandstone.
A1--0 to 3 inches; brown (7.5YR 4/4) extremely stony loam, dark brown (7.5YR 3/2) moist; weak thick platy structure; soft, very friable, nonsticky and nonplastic; 20 percent gravel, 20 percent cobbles, and 25 percent stones from sandstone; neutral; clear wavy boundary. (2 to 6 inches thick)
A2--3 to 7 inches; brown (7.5YR 5/4) very stony clay loam, dark brown (7.5YR 3/4) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky and moderately plastic; 10 percent gravel, 15 percent cobbles, and 20 percent stones from sandstone; neutral, clear wavy boundary. (0 to 7 inches thick)
Bt1--7 to 24 inches; reddish brown (5YR 5/4) very stony clay loam, reddish brown (5YR 4/4) moist; strong medium prismatic structure parting to moderate medium angular blocky; very hard, very firm, moderately sticky and moderately plastic; many distinct clay films on the faces of peds; 10 percent gravel, 20 percent cobbles, and 20 percent stones from sandstone; slightly alkaline; clear irregular boundary. (15 to 20 inches thick)
Bt2--24 to 32 inches; reddish brown (5YR 5/4) stony clay loam, yellowish red (5YR 5/6) moist; strong medium angular blocky structure; very hard, very firm, moderately sticky and moderately plastic; many distinct clay films on the faces of peds; 5 percent gravel, 15 percent cobbles, and 10 percent stones from sandstone; slightly alkaline; abrupt wavy boundary. (0 to 20 inches thick)
Bk--32 to 44 inches; pinkish white (5YR 8/2) stony clay loam, pink (5YR 7/3) moist; massive; hard, firm, slightly sticky and slightly plastic; many large masses of calcium carbonate; 5 percent gravel, 5 percent cobbles, and 5 percent stone from sandstone; violently effervescent, 33 percent calcium carbonate equivalent; moderately alkaline; clear smooth boundary. (6 to 15 inches thick)
2R--44 inches; hard Dakota sandstone.
TYPE LOCATION: Dolores County, Colorado; about 5 miles east of the community of Dove Creek; located about 2,400 feet east and 400 feet north of the southwest corner of sec. 36, T. 41 N., R. 18 W.; Secret Canyon, Colorado USGS quad; lat. 37 degrees 45 minutes 57 seconds N. and long. 108 degrees 48 minutes 15 seconds W., NAD 27
RANGE IN CHARACTERISTICS:
Soil moisture regime: ustic
Mean annual soil temperature: 43 to 47 degrees F
Surface rock fragments: 3 to 15 percent
Depth to lithic contact: 40 to 60 inches to hard sandstone
Depth to calcic horizon: 30 to 40 inches
Depth to secondary calcium carbonate: 20 to 40 inches
Particle-size control section: 35 to 60 percent clay
A horizon:
Hue: 5YR to 10YR
Value: 3 to 5 dry, 2 to 4 moist
Chroma: 2 to 4 dry or moist
Rock fragments: 35 to 80 percent sandstone fragments, mostly stones with lesser amounts of cobble and gravel
Reaction: neutral or slightly alkaline
Bt horizon:
Hue: 2.5YR to 7.5YR
Value: 4 to 6 dry, 3 to 5 moist
Chroma: 4 to 6 dry or moist
Texture: clay loam or clay
Rock fragments: 25 to 80 percent sandstone fragments, mostly stones with lesser amounts of cobble and gravel
Calcium carbonate equivalent: 0 to 5 percent
Reaction: neutral to moderately alkaline
Bk horizon:
Hue: 5YR or 7.5YR
Value: 7 or 8 dry, 6 or 7 moist
Chroma: 2 to 4 dry or moist
Texture: loam or clay loam
Rock fragments: 15 to 80 percent sandstone fragments, mostly stones with lesser amounts of cobble and gravel
Calcium carbonate equivalent: 15 to 40 percent
Reaction: moderately or strongly alkaline
COMPETING SERIES: There are no competing series. Similar soils are the Ceek, Fishers, and Pleioville soils. These soils lack calcic horizons.
GEOGRAPHIC SETTING:
Parent material: slope alluvium and colluvium from eolian material, and colluvium and residuum from sandstone
Landform: hills and mesas
Slopes: 0 to 30 percent
Elevation: 7,100 to 8,600 feet
Mean annual temperature: 40 to 45 degrees F
Mean annual precipitation: 15 to 25 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 110 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Granath, and Nortez soils on similar positions. These soils all have non-skeletal particle size control sections and mollic epipedons.
DRAINAGE AND PERMEABILITY: well drained, medium to very high runoff, slow permeability
USE AND VEGETATION: These soils are used for grazing and wildlife habitat. Native vegetation is Gambel's oak, Utah serviceberry, mountain brome, elk sedge, and junegrass.
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:
ochric epipedon: The zone from 0 to 7 inches. (A1, A2)
argillic horizon: The zone from 7 to 32 inches. (Bt1 and Bt2)
calcic horizon: The zone from 32 to 44 inches. (Bk)
lithic contact feature: The contact with hard sandstone at 44 inches. (R)
particle-size control section: The zone from 7 to 27 inches. (Bt1 and Bt2)
Soil Taxonomy Second Edition, 1999