LOCATION COTTLE IDEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Lithic Xeric Haplargids
TYPICAL PEDON: Cottle stony loam -- on a southwest-facing slope of 27 percent, in native rangeland at 4100 feet elevation. The surface has 1 to 3 percent cover of stones. (Colors are for air dry soil unless otherwise noted.)
A--0 to 5 inches; light brownish gray (10YR 6/2, 10YR 7/2 rubbed) stony loam, dark grayish brown (10YR 4/2) moist; moderate thin platy structure parting to weak very fine granular; soft, friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine vesicular and tubular pores; 35 percent gravel, 15 percent cobbles, 5 percent stones; mildly alkaline (pH 7.6); clear smooth boundary. (2 to 8 inches thick)
AB--5 to 8 inches; light brownish gray (10YR 6/2) very gravelly loam, dark grayish brown (10YR 4/2) moist; weak medium platy structure parting to weak very fine granular; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine, few medium roots; common very fine, few fine tubular pores; 35 percent gravel, 10 percent cobbles, 5 percent stones; neutral (pH 7.3); clear wavy boundary. (0 to 5 inches thick)
Bt--8 to 11 inches; pale brown (10YR 6/3) very gravelly loam, brown (10YR 4/3) moist; moderate very fine and fine subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common fine, few medium roots; common very fine tubular pores; 35 percent gravel, 10 percent cobbles, 10 percent stones; few thin brown (10YR 5/3) clay films on faces of peds and in pores; neutral (pH 7.0); clear wavy boundary. (3 to 7 inches thick)
Btkq--11 to 16 inches; brown (7.5YR 4/4) extremely gravelly clay loam, dark brown (7.5YR 3/3) moist; moderate very fine and fine subangular blocky structure; very hard, firm, sticky and plastic; common fine roots; few very fine tubular pores; 65 percent gravel, 10 percent cobbles, 10 percent stones; many thin and moderately thick clay films on faces of peds and in pores; thin carbonate and silica coatings on rock fragments; mildly alkaline (pH 7.8); abrupt broken boundary. (2 to 6 inches thick)
R--16 inches; rhyolite.
TYPE LOCATION: Owyhee County, Idaho; Northwest Hydrology Research Watershed, Reynolds Creek Area; about 1 mile northeast of Reynolds; 1,250 feet west and 250 feet north of the southeast corner of section 30, T. 2 S., R. 3 W.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 47 to 54 degrees F.
Depth to bedrock - 10 to 20 inches
A horizon
Value - 6 to 8 dry, 4 or 5 moist
Chroma - 2 or 3 dry or moist
Bt and Btkq horizons
Hue - 7.5YR or 10YR
Value - 4 to 8 dry, 3 to 6 moist
Chroma - 3 or 4 dry or moist
Texture - GRV-L, GRV-CL, GRX-L, GRX-CL
Clay content - 22 to 35 percent
Rock fragments - 35 to 85 percent
Reaction (pH) - neutral or mildly alkaline in the Bt horizon
Other features - bedrock is highly fractured in the upper part in some pedons
COMPETING SERIES: These are the Atlow, Boomstick, Checkett, Gabbvally, Hooplite, Olac, Old Camp, Phliss, Rowel, Soughe, Stewval, and Thike series. Atlow soils are moderately to strongly alkaline in the argillic horizon and lack evidence of secondary silica. Boomstick, Olac and Soughe soils are noncalcareous in all parts. Checkett, Hooplite, and Stewval soils are calcareous in all parts. Gabbvally soils are noncalcareous throughout and have average annual soil temperatures of 53 to 59 degrees F. Old Camp soils receive summer moisture in the form of convection storms. Phliss soils are calcareous in all parts of the argillic horizon and lack secondary silica. Rowel soils have an argillic horizon with 40 to 55 percent clay. Thike soils have less than 18 percent clay in the argillic.
GEOGRAPHIC SETTING: Cottle soils are on summits, shoulders, and backslopes of foothills at elevations of 2,800 to 5,100 feet. These soils formed residuum and colluvium from welded rhyolitic tuff and related rocks. Slopes range from 2 to 40 percent. The average annual precipitation is 9 to 13 inches and the average annual temperature is 45 to 52 degrees F. The frost-free period is 90 to 140 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Mackey, Sidlake, and Willhill series. Mackey and Willhill soils are moderately deep to bedrock. Sidlake soils are fine-loamy and moderately deep. All of these soils are on similar landscape positions.
DRAINAGE AND PERMEABILITY: Well drained; medium to very rapid runoff; moderately slow permeability.
USE AND VEGETATION: Cottle soils are used mainly for rangeland and wildlife habitat. The dominant natural vegetation is Wyoming big sagebrush, low sagebrush, Thurber needlegrass, and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: Southwest Idaho. Cottle soils are moderately extensive.
MLRA OFFICE RESPONSIBLE: Reno, Nevada
SERIES ESTABLISHED: Elmore County Area, Idaho, 1986.
REMARKS: Diagnostic horizons and other features recognized in this pedon:
Argillic horizon and particle-size control section - zone 8 to 16 inches (Bt and Btk horizons)