LOCATION COTTLE                  ID

Established Series
Rev. CWT/ALH/CLM
01/2019

COTTLE SERIES

The Cottle series consists of shallow, well drained soils on foothills. They formed in residuum and colluvium from welded rhyolitic tuff or related rocks. Permeability is moderately slow. Slopes range from 2 to 40 percent. The average annual precipitation is about 250 mm and the average annual temperature is about 10 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Lithic Xeric Haplargids

TYPICAL PEDON: Cottle very cobbly loam -- on a southwest-facing slope of 27 percent, in native rangeland at 1,250 meters elevation. The surface has 1 to 3 percent cover of stones. (Colors are for air dry soil unless otherwise noted.)

A--0 to 13 cm; light brownish gray (10YR 6/2, 10YR 7/2 rubbed) very cobbly 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; slightly alkaline (pH 7.6); clear smooth boundary. (5 to 20 cm thick)

AB--13 to 20 cm; 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 and few fine tubular pores; 35 percent gravel, 10 percent cobbles, 5 percent stones; neutral (pH 7.3); clear wavy boundary. (0 to 13 cm thick)

Bt--20 to 28 cm; 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 faint brown (10YR 5/3) clay films on faces of peds and in pores; neutral (pH 7.0); clear wavy boundary. (8 to 18 cm thick)

Btkq--28 to 41 cm; 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, moderately sticky and moderately plastic; common fine roots; few very fine tubular pores; 65 percent gravel, 10 percent cobbles, 10 percent stones; many faint and distinct clay films on faces of peds and in pores; thin carbonate and silica coatings on rock fragments; slightly alkaline (pH 7.8); abrupt broken boundary. (5 to 15 cm thick)

R--41 cm; 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.; USGS Reynolds 7.5 minute topographic quadrangle; latitude 43 degrees 12 minutes 50 seconds N and longitude 116 degrees 44 minutes 02 seconds W; WGS84 Decimal Degrees 43.2138889 latitude, -116.7338889 longitude.

RANGE IN CHARACTERISTICS:

Average annual soil temperature - 8 to 12 degrees c.
Depth to bedrock - 25 to 50 cm.
Aridic moisture regime that borders on xeric.

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 12 to 15 degrees C. 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 855 to 1,555 meters. 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 230 to 330 mm and the average annual temperature is 7 to 11 degrees C. 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 SATURATED HYDRAULIC CONDUCTIVITY: Well drained; medium to very rapid runoff; moderately slow saturated hydraulic conductivity. .

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 11 and 25.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Elmore County Area, Idaho, 1986.

REMARKS: Diagnostic horizons and other features recognized in this pedon:
Ochric epipedon - The zone from 0 to 20 cm (A and AB horizons).
Argillic horizon - The zone from 20 to 41 cm (Bt and Btk horizons).
Lithic contact - The boundary at 41 cm (R layer).

Particle-size control section - The zone from 20 to 41 cm (Bt and Btk horizons).

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National Cooperative Soil Survey
U.S.A.