LOCATION GRANATH COEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, frigid Typic Argiustolls
TYPICAL PEDON: Granath loam on a 4 percent southwest facing slope in rangeland at an elevation of 7,560 feet. (Colors are for dry soil unless otherwise noted.)
A--0 to 2 inches; brown (7.5YR 4/2) loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, nonsticky and slightly plastic; many very fine and common fine roots; many very fine vesicular and tubular pores; neutral (pH 6.9); clear smooth boundary. (1 to 12 inches thick)
BA--2 to 10 inches; brown (7.5YR 4/2) loam, dark brown (7.5YR 3/2) moist; weak coarse subangular blocky structure parting to weak medium subangular blocky; slightly hard, friable, moderately sticky and moderately plastic; common fine and few coarse roots; common very fine vesicular and tubular pores; very few faint clay films on faces of peds; slightly alkaline (pH 7.4); clear wavy boundary. (0 to 12 inches thick)
Bt1--10 to 15 inches; brown (7.5YR 4/4) loam, dark brown (7.5YR 3/2) moist; moderate coarse subangular blocky structure parting to moderate medium subangular blocky; hard, firm, moderately sticky and moderately plastic; common fine and few medium roots; common very fine vesicular tubular and common medium vesicular and tubular pores; few distinct clay films on faces of peds; slightly alkaline (pH 7.4); clear wavy boundary. (3 to 10 inches thick)
Bt2--15 to 20 inches; reddish brown (5YR 4/4) loam, reddish brown (5YR 4/3) moist; moderate coarse subangular blocky structure parting to moderate medium subangular blocky; very hard, firm, moderately sticky and moderately plastic; few fine and few medium roots; common very fine vesicular and tubular and tubular and common medium vesicular and tubular pores; common distinct clay films on faces of peds; slightly alkaline (pH 7.5); clear wavy boundary. (0 to 12 inches thick)
Bt3--20 to 28 inches; reddish brown (5YR 4/4) clay loam, reddish brown (5YR 4/4) moist; strong coarse prismatic structure parting to strong medium subangular blocky, extremely hard, very firm, moderately sticky and moderately plastic; few fine and few medium roots; few very fine vesicular and tubular and few fine vesicular and tubular pores; many prominent clay films on faces of peds; slightly alkaline (pH 7.4); clear wavy boundary. (0 to 12 inches thick)
Bt4--28 to 40 inches; reddish brown (5YR 4/4) clay loam, yellowish red (5YR 4/6) moist; strong coarse prismatic structure parting to strong medium subangular blocky; extremely hard, very firm, moderately sticky and moderately plastic; few fine and few medium roots; few very fine continuous tubular pores, many prominent clay films on faces of peds; slightly alkaline (pH 7.8); clear smooth boundary. (0 to 14 inches thick)
Btkl--40 to 49 inches; reddish brown (5YR 4/4) clay loam, reddish brown (5YR 4/4) moist; strong coarse prismatic structure parting to strong coarse angular blocky; extremely hard, very firm, moderately sticky and moderately plastic; few fine roots; few very fine discontinuous pores; many prominent clay films on faces of peds; few fine filaments of calcium carbonate; 1 percent calcium carbonate equivalent; slightly effervescent; moderately alkaline (pH 8.1); clear smooth boundary. (4 to 20 inches thick)
Btk2--49 to 60 inches; reddish brown (5YR 4/4) clay loam; reddish brown (5YR 5/4) moist; strong medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few medium roots; few fine discontinuous tubular pores; common prominent clay films on faces of peds; common medium masses of calcium carbonate; 19 percent calcium carbonate equivalent; strongly effervescent; moderately alkaline (pH 8.2). (0 to 20 inches thick)
TYPE LOCATION: Montezuma County, Colorado; about 2,200 feet west and 750 feet south of the northeast corner of sec. 2, T. 39 N., R. 17 W.; Doe Canyon, Colorado USGS quad; Lat. 37 degrees 40 minutes 30 seconds N. and long. 108 degrees 41 minutes 25 seconds W., NAD 27.
RANGE IN CHARACTERISTICS:
Soil moisture regime: ustic
Depth to secondary calcium carbonate: 30 to 50 inches
Depth to calcic horizon: 40 to 70 inches
Depth to the base of the argillic horizon: 40 to more than 70 inches
Thickness of the mollic epipedon: 10 to 16 inches
Particle-size control section (weighted averages):
Clay content: 18 to 35 percent
Content of fine sand and coarser sand plus gravel: 1 to 15 percent
A horizon:
Hue: 5YR to 10YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 1 to 3 dry or moist
Texture: loam, fine sandy loam, very fine sandy loam
Rock fragments: 0 to 5 percent sandstone gravel
Reaction: slightly acid to slightly alkaline
Bt horizon:
Hue: 5Y or 7.5YR
Value: 5 to 7 dry, 3 to 6 moist
Chroma: 2 to 6 dry or moist
Texture: silty clay loam, loam, or clay loam with 10 to 70 percent silt, 10 to 70 percent sand with 1 to 15 percent being fine or coarser sand
Clay content: 18 to 40 percent
Rock fragments: 0 to 5 percent sandstone gravel
Reaction: slightly acid to slightly alkaline
Btk horizon:
Hue: 5YR or 7.5YR
Texture: loam, clay loam, or sandy clay loam
Rock fragments: 0 to 5 percent sandstone gravel
Calcium carbonate equivalent: 1 to 25 percent
Reaction: moderately alkaline or strongly alkaline
COMPETING SERIES: These are the
Blackdog,
Farland,
Morton, and
Xavier series.
Soils that may be competitors when the classification is updated are the:
Dingle and
Hanaker series.
Blackdog,
Farland,
Hanaker, and Xavier: have hues of 10YR or yellower in all horizons.
Morton: have a paralithic contact at 20 to 40 inches.
Dingle: are calcareous throughout and formed in stratified lacustrine deposits.
GEOGRAPHIC SETTING:
Parent material: eolian deposits derived from sandstone
Landform: mesas, hills, and stable alluvial fans
Slopes: 0 to 15 percent
Elevation: 7,100 to 8,500 feet
Mean annual air temperature: 43 to 47 degrees F
Mean annual precipitation: 15 to 22 inches
Precipitation is fairly evenly distributed throughout the year with July and August being slightly wetter and June being slightly dryer.
Frost-free period: 80 to 100 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ilex and Ricot soils. Ilex soils have more than 35 percent clay in their argillic horizons and lack mollic epipedons. Ricot soils have more than 35 percent clay in their argillic horizon and have more than 10 percent rock fragments in the lower part of the profile. Both are on similar landscapes.
DRAINAGE AND PERMEABILITY: Well drained, medium to very high runoff, moderately slow permeability.
USE AND VEGETATION: They are used as grazing land or for dry and irrigated cropland. Native vegetation is mainly oakbrush and scattered ponderosa pine with an understory of native bluegrass and needlegrass.
DISTRIBUTION AND EXTENT: Southwest Colorado. LRR E, MLRA 48A. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Cortez Area, Colorado, Parts of Dolores and Montezuma Counties, 1997. The type location is in the Animas-Dolores Area, Colorado.
REMARKS: Type location moved to 1997 NSSL sampling site (2/99). This provides more information about this series.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: The zone from 0 to 10 inches. (A, BA horizons)
Argillic horizon: The zone from 10 to 60 inches. (Bt1, Bt2, Bt3, Bt4, Btk1, Btk2 horizons)
Calcic horizon: The zone from 49 to 60 inches (Btk2 horizon)
Particle-size control section: The zone from 10 to 30 inches. (Bt1, Bt2, Bt3, Bt4 horizons)
Keys to Soil Taxonomy: Series classified according to Eighth Edition, 1998.
ADDITIONAL DATA: Lab Sample S86CO-033-002.