LOCATION SAWFORK CO

Established Series
Rev. AMH/LC/TWH
01/2011

SAWFORK SERIES

The Sawfork series consists of deep, well drained soils formed in slope alluvium, colluvium, and residuum derived dominantly from tuff. Sawfork soils are on fan remnant side slopes and scarps of dissected pediments. Slopes range from 8 to 50 percent. The mean annual precipitation is about 15 inches and the mean annual temperature is about 42 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Vitrandic Argicryolls

TYPICAL PEDON: Sawfork very cobbly loam - on a 35 percent southwest-facing slope in an area of rangeland. When described on October 2, 1985 the soil was slightly moist throughout. (Colors are for dry soil unless otherwise noted.)

A--0 to 4 inches; grayish brown (10YR 5/2) very cobbly loam, very dark brown (10YR 2/2) moist; moderate fine granular structure; soft, very friable, slightly sticky and slightly plastic; 30 percent gravel, 20 percent cobbles, and 5 percent stones; neutral (pH 6.8); abrupt smooth boundary. (3 to 5 inches thick)

AB--4 to 8 inches; grayish brown (10YR 5/2) very cobbly loam, very dark brown (10YR 2/2) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; 30 percent gravel, 20 percent cobbles, and 5 percent stones; neutral (pH 7.0); abrupt wavy boundary. (0 to 4 inches thick)

Bt--8 to 14 inches; pale brown (10YR 6/3) very cobbly clay loam, brown (10YR 4/3) moist; moderate medium prismatic structure; hard, friable, moderately sticky and moderately plastic; common prominent clay films on ped faces; 30 percent gravel, 20 percent cobbles, 5 percent stones; neutral (pH 7.2); clear wavy boundary. (5 to 18 inches thick)

Bw--14 to 22 inches; pale brown (10YR 6/3) sandy clay loam, brown (10YR 4/3) moist weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; 10 percent gravel; slightly alkaline (pH 7.4); gradual wavy boundary. (0 to 8 inches thick)

2Bk1--22 to 30 inches; very pale brown (10YR 7/3) ashy sandy clay loam, brown (10YR 5/3) moist; weak medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; 10 percent moderately cemented tuff paragravel; few fine carbonate masses in the matrix; slightly effervescent; moderately alkaline (pH 8.0); clear wavy boundary.

2Bk2--30 to 39 inches; white (10YR 8/1) extremely paragravelly ashy sandy clay loam, light brownish gray (10YR 6/2) moist; massive; hard, friable, slightly sticky and slightly plastic; 60 percent moderately cemented tuff paragravel; few fine carbonate masses in the matrix; slightly effervescent; moderately alkaline (pH 8.2); clear wavy boundary.

2Bk3--39 to 48 inches; white (10YR 8/1) extremely paragravelly ashy sandy clay loam, light brownish gray (10YR 6/2) moist; massive; slightly hard, very friable, nonsticky and nonplastic; 75 percent moderately cemented tuff paragravel; few fine carbonate masses in the matrix; slightly effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (Combined thickness of the 2Bk horizons is 20 to 40 inches.)

2Cr--48 to 52 inches; moderately cemented tuff.

TYPE LOCATION: Fremont County, Colorado; about 15 miles northeast of Salida; 1,150 feet east and 550 feet south of the northwest corner of Sec. 5, T. 51 N., R. 11 E. USGS Gribbles Park quad.; Lat. 38 degrees, 41 minutes, 35 seconds N., and Long. 105 degrees, 47 minutes, 28 seconds W.

RANGE IN CHARACTERISTICS:
Soil moisture: The soil moisture control section is usually dry in late spring and early summer, moist in some part in late July and August, and intermittently dry in fall; ustic regime bordering on aridic.

Thickness of mollic epipedon: 7 to 13 inches
Depth to the base of the argillic horizon: 10 to 20 inches
Depth to disseminated calcareous material: 5 to 30 inches
Depth to lithologic discontinuity with layers of high volcanic glass content: 13 to 23 inches
Depth to paralithic contact: 40 to 60 inches
Mean annual soil temperature: 37 to 45 degrees F.
Mean summer soil temperature ranges: 51 to 58 degrees F.

Particle-size control section (weighted average):
Clay content: 18 to 35 percent
Sand content: 30 to 60 percent
Rock fragments: 35 to 60 percent

A and AB horizons (an AB is not in all pedons)
Hue: 10YR or 7.5YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 2 or 3, dry or moist
Clay content: 18 to 27 percent
Reaction: neutral or slightly alkaline

Bt horizon
Hue: 7.5YR or 10YR
Value: 4 through 6 dry, 3 through 5 moist
Chroma: 2 through 4, dry or moist
Rock fragment content: 35 to 60 percent, mainly gravel and cobbles
Texture, fine earth fraction: loam, clay loam, or sandy clay loam
Clay content: 18 to 35 percent
Silt content: 15 to 40 percent
Sand content: 30 to 60 percent
Reaction: neutral or slightly alkaline

2Bk horizons
Hue: 10YR through 5Y
Value: 6 through 8 dry, 5 through 7 moist
Chroma: 1 through 4, dry or moist
Rock fragment content: 0 to 10 percent, mainly gravel and cobbles
Texture: ashy loam, ashy sandy loam, ashy sandy clay loam, with or without paragravelly, very paragravelly, and extremely paragravelly modifiers
Paragravel content: 5 to 80 percent
Lithology of fragments: tuff
Coarse silt plus sand content: 60 to 80 percent
Glass content: 40 to 75 percent
Acid oxalate extractable Al + 1/2 Fe 0.00 to .05 percent
Reaction: slightly alkaline or moderately alkaline

COMPETING SERIES: These are the Edgway, Kiote, Rolldown, Trespass, and Tusel series.
The Edgway, Kiote, Rolldown, and Trespass soils do not have a paralithic contact.
The Tusel soils do not have accumulations of secondary carbonates.

GEOGRAPHIC SETTING: Sawfork soils are on fan remnant side slopes and scarps of dissected pediments. Slopes range from 8 to 50 percent. The soil formed in slope alluvium, colluvium, and residuum derived dominantly from tuff. Elevation ranges from 8,800 to 10,000 feet. The mean annual precipitation ranges from about 11 to 16 inches, and most areas have mean annual precipitation of 14 inches or less. Mean annual temperature ranges from 35 to 44 degrees F. The average frost-free period is about 50 to 85 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gebson, Morset, and Hodden soils. Gebson and Morset soils have less than 35 percent rock fragments throughout. Hodden soils have sandy-skeletal substrata and formed in alluvium.

DRAINAGE AND PERMEABILITY: Well drained; moderate to moderately slow permeability.

USE AND VEGETATION: These soils are used for rangeland. Principal native vegetation consists of mountain muhly, Arizona fescue, slimstem muhly, blue grama, western wheatgrass, prairie junegrass, and fringed sagebrush.

DISTRIBUTION AND EXTENT: Intermontane basins of central Colorado in areas of relatively low precipitation; MLRA 48B. The series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Fremont County (Fremont County Area), Colorado, 1988.

REMARKS: Diagnostic horizons and features recognized are:
Diagnostic horizons and features recognized in this pedon are:
Series control section: The zone from 0 to 58 inches.
Particle-size control section: the zone from 8 to 14 inches. (entire argillic horizon)
Mollic epipedon: from 0 to 8 inches. (A, AB horizons)
Argillic horizon: from 8 to 14 inches. (Bt horizon)
Lithologic discontinuity: at 22 inches (top of 2Bk1 horizon)
Vitrandic feature: high glass content from 22 to 30 inches (2Bk1 horizon)
Paralithic contact: at 48 inches (top of 2Cr layer)

The 01/2010 revision changes the subgroup classification from Ustic Argicryolls to Vitrandic Argicryolls. When established the classification was loamy-skeletal, mixed Argic Cryoborolls.

National Cooperative Soil Survey
U.S.A.