LOCATION FUGHES CO+UTEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Pachic Argiustolls
TYPICAL PEDON: Fughes loam - grassland. (Colors are for dry soil unless otherwise noted).
A--0 to 5 inches; very dark grayish brown (10YR 3/2) loam, very dark brown (10YR 2/2) moist; weak fine and medium granular structure; soft, very friable; many medium and fine roots; neutral; clear smooth boundary. (3 to 12 inches thick)
BA--5 to 18 inches; dark grayish brown (10YR 4/2) clay loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure parting to weak fine subangular blocks; slightly hard, friable, slightly sticky and slightly plastic; many medium and fine roots; neutral; clear wavy boundary. (4 to 16 inches thick)
Bt1--18 to 30 inches; reddish brown (5YR 5/4) clay, reddish brown (5YR 4/4) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; extremely hard, very firm, moderately sticky and moderately plastic; common fine and medium roots; many distinct clay films on faces of peds; neutral; gradual wavy boundary. (6 to 30 inches thick)
Bt2--30 to 44 inches; reddish brown (5YR 5/4) clay loam, reddish brown (5YR 5/4) moist; weak medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few faint clay films on faces of peds; neutral; gradual wavy boundary. (4 to 22 inches thick)
C--44 to 60 inches; light reddish brown (5YR 6/4) clay loam, reddish brown (5YR 5/4) moist; massive; hard, firm, moderately sticky and moderately plastic; neutral.
TYPE LOCATION: Gunnison County, Colorado; about 25 miles northeast of Paonia, on Jacobs Ranch; SE1/4 of Sec. 29, T. 11 S., R. 89 W.; Chair Mountain USGS quadrangle; NAD 27.
RANGE IN CHARACTERISTICS:
Soil moisture regime: ustic
Mean annual soil temperature: 41 to 47 degrees F.
Mean summer soil temperature: 59 to 64 degrees F.
Thickness of the mollic epipedon: 16 to 45 inches
Lithology of rock fragments: shale, sandstone
A horizon:
Hue: 5YR through 10YR
Value: 3 through 5 dry, 2 or 3 moist
Chroma: 1 through 3, dry or moist
Texture: loam, silt loam, sandy clay loam, or clay loam
Reaction: slightly acid to slightly alkaline
Bt horizon:
Hue: 5YR through 10YR
Value: 2 through 6 dry, 2 through 6 moist
Chroma: 2 through 6, dry or moist
Texture: clay loam, clay, silty clay, or silty clay loam
Clay content: 35 to 50 percent
Coarse fragment content: 0 to 15 percent, mainly gravel
Reaction: slightly acid to slightly alkaline.
C horizon (a BC horizon in some pedons):
Hue: 5YR through 2.5Y
Value: 5 through 7 dry, 4 through 6 moist
Chroma: 2 through 6, dry or moist
Coarse fragment content: 0 to 35 percent, mainly gravel
Texture: loam, clay, clay loam, or silty clay loam, including gravelly modifiers
Reaction: moderately acid to moderately alkaline
COMPETING SERIES: These are the
Chivington,
Hillery,
Kubler,
Savar,
Zeeland, and
Zoltay series.
Chivington (WY), Savar (WY), Zeeland (ND), Zoltay (CO)- have horizons of calcium carbonate accumulation above a depth of 40 inches.
Hillery (NM) - have rock fragments of basalt lithology and have greater than 50 percent clay in the particle-size control section.
Kubler (CO) - have more than 15 percent rock fragments in the particle-size control section, and have horizons of secondary carbonates.
GEOGRAPHIC SETTING:
Parent material: noncalcareous alluvium and slope alluvium derived principally from Wasatch and Mancos shales, and interbedded sandstone and shale.
Landform: alluvial fans, terraces, valley sides, draws, and drainageways.
Slopes: 0 to 65 percent.
Elevation: 6,500 to 9,200 feet.
Mean annual temperature: 39 to 46 degrees F. In the Cortez area, temperature ranges to 47 degrees F.
Mean annual precipitation: 18 to 24 inches.
Driest months: May and June
Frost-free period: 75 to 105 days. In southeastern Utah the frost-free period is 60 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cochetopa and Curecanti soils. Cochetopa soils are have a cryic temperature regime, and Curecanti soils are loamy-skeletal.
DRAINAGE AND PERMEABILITY: Well drained; medium to very high runoff; slow and very slow permeability.
USE AND VEGETATION: These soils are used principally as rangeland. Native vegetation is mainly Gambel's oak, big sagebrush, Arizona fescue, needleandthread, and western wheatgrass.
DISTRIBUTION AND EXTENT: Mountainous areas of western Colorado and southeastern Utah. MLRA 47 and 48A. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES ESTABLISHED: Paonia Area, Colorado, 1976.
REMARKS: Diagnostic horizons and features recognized in this pedon include:
Mollic epipedon, pachic feature: from the surface to 18 inches (A and BA horizons)
Argillic horizon: from 18 to 44 inches (Bt1 and Bt2 horizons)
Particle-size control section: the zone from 18 to 38 inches (the upper 20 inches of the argillic horizon)
Keys to Soil Taxonomy: Series classified according to Eighth Edition, 1998
This revision (7/00) deletes hills, mesas, structural benches, and mountain slopes landforms and colluvium parent material. Mean annual precipitation is revised from 15-24 inches to 18-24 inches. These changes bring the series concept in line with the original series concept.
The 2/99 revision changed the family mineralogy class name from montmorillonitic to smectitic, and changed the allowed depth to a lithic contact from greater than 40 inches to greater than 60 inches.