LOCATION EEP                     ID

Established Series
Rev. DL/DA/CLM/BKP
01/2019

EEP SERIES

The Eep series consists of well drained, very deep soils that formed in colluvium from volcanic ash and welded tuff. They are on breaks and scarps. Permeability is moderate. Slopes range from 6 to 75 percent. The average annual precipitation is about 460 mm, and the average annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Ashy-skeletal, glassy, frigid Vitrandic Argixerolls

TYPICAL PEDON: Eep very cobbly sandy loam - on a west facing slope of 25 percent under rangeland vegetation at 1,850 meter elevation. When described on April 15, 1981, the soil was slightly moist throughout. (Colors are for dry soil unless otherwise noted.)

A--0 to 23 cm; dark grayish brown (10YR 4/2) very cobbly ashy sandy loam, very dark brown (10YR 2/2) moist; weak medium granular structure; soft, very friable, nonsticky and nonplastic; many roots; many very fine tubular pores; 20 percent gravel, 30 percent cobbles, 5 percent stones; neutral (pH 6.6); gradual wavy boundary. (10 to 30 cm thick)

Bt1--23 to 43 cm; brown (10YR 5/3) very gravelly ashy loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; many roots; many very fine tubular pores; common distinct clay films on faces of peds and in pores; 40 percent gravel, 15 percent cobbles; slightly acid (pH 6.4); gradual wavy boundary. (13 to 38 cm thick)

Bt2--43 to 66 cm; brown (10YR 5/3) extremely cobbly ashy loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many roots; many very fine tubular pores; few faint clay films on faces of peds and in pores; 40 percent gravel, 20 percent cobbles, 5 percent stones; neutral (pH 6.6); gradual wavy boundary. (20 to 64 cm thick)

BC--66 to 97 cm; pale brown (10YR 6/3) very cobbly sandy ashy loam, brown (10YR 4/3) moist; massive; slightly hard, friable, nonsticky and nonplastic; common very fine to medium roots; many very fine tubular pores; 20 percent gravel, 30 percent cobbles; neutral (pH 7.0); clear wavy boundary. (0 to 36 cm thick)

C--97 to 193 cm; white (10YR 8/1) unconsolidated ashy loamy sand, light gray (10YR 7/2) moist; single grain; loose, nonsticky and nonplastic; few very fine roots; neutral (pH 7.2); abrupt wavy boundary. (76 to 152 cm thick)

Cr--193 to 198 cm; very pale brown (10YR 7/3) consolidated ash, light yellowish brown (10YR 6/4) moist; massive; very hard, very firm.

TYPE LOCATION: Twin Falls County, Idaho; about 21 miles southwest of Rogerson, Idaho; about 1,200 feet north and 430 feet west of the southeast corner section 7, T. 15 S., R. 13 E.; USGS Cedar Creek Reservoir 7.5 minute quadrangle; latitude 42 degrees 07 minutes 55 seconds N and longitude 114 degrees 58 minutes 14 seconds W; WGS84 Decimal Degrees 42.13944 latitude, -114.970556 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Moist in winter and spring, dry summer and fall; typic xeric soil moisture regime.
Average annual soil temperature: 6 to 7 degrees C.
Mollic epipedon: 25 to 50 cm.
Depth to a paralithic contact: greater than 152 cm.
Base saturation upper 100 cm: 65 to 75 percent

Particle-size control section - Clay content: 18 to 35 percent.
Rock fragments: 40 to 70 percent, gravel and cobbles.

A horizon
Chroma: 1 or 2 dry or moist.
Reaction: Slightly acid or neutral.
Volcanic glass content: 75 to 85 percent in the 0.02 to 2.0 mm fraction.

Bt1 horizon
Value: 5 or 4 dry, 3 or 2 moist.
Chroma: 2 or 3 dry or moist.
Texture: Loam or clay loam.
Rock fragments: 35 to 70 percent; gravel, cobbles and stones.
Volcanic glass content: 65 to 85 percent in the 0.02 to 2.0 mm fraction.
Reaction: Slightly acid or neutral.
Organic matter content: 1.5 through 3.0 percent.

Bt2 horizon (Bt3 horizon when present)
Value: 4 through 6 dry, 3 or 4 moist.
Chroma: 2 through 4 dry, 3 or 4 moist.
Texture: Loam or clay loam.
Rock fragments: 35 to 70 percent; gravel, cobbles and stones.
Volcanic glass content: 65 to 85 percent in the 0.02 to 2.0 mm fraction.
Reaction: Slightly acid or neutral.
Organic matter content: 0.5 through 1.5 percent, dropping rapidly below 50 cm in the profile.

BC horizon (when present)
Value: 5 through 8 dry, 3 through 7 moist.
Chroma: 1 through 4 dry or moist.
Rock fragments: 40 to 90 percent; mainly gravel and cobbles.
Volcanic glass content: 85 to 95 percent in the 0.02 to 2.0 mm fraction.

COMPETING SERIES: These are the Adamatt, Chesebro, Crazybird, Dawgbuffer, Epvip, Lyonman, Monasterio, Rancheria, Tourn, Vetash, Warnermount, and Willowak series.
Adamatt, Crazybird, Epvip, Rancheria soils are shallow.
Chesebro soils have an argillic horizon with a depth to the base of 114 to 150 cm.
Crazybird, Dawgbuffer soils are very shallow.
Lyonman, Monasterio, Tourn, Warnermount, and Willowak soils are moderately deep.
Vetash soils average less than 65 percent volcanic glass content throughout and receives less than 400 millimeters precipitation annually.

GEOGRAPHIC SETTING: Eep soils are on breaks, hillslopes, and scarps. The slope ranges from 6 to 75 percent. The soils formed in volcanic ash mixed with colluvium from welded tuff. Elevations are 1,770 to 2,075 meters. The average annual precipitation ranges from 400 to 560 mm. The average annual temperature is 4 to 7 degrees C. The frost free season is 60 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Amboat, Brose, Dehana, Howcree, Keman, and Mug soils. Amboat soils are clayey-skeletal and occur on summits. Brose soils are shallow to bedrock and occur on summits. Dehana soils are not skeletal, are cryic, and occur on the same landscape, but on wetter exposures. Keman soils are loamy-skeletal and occur on summits. Mug soils are moderately deep to bedrock. Howcree and Mug soils occur on terraces. Howcree soils are clayey-skeletal.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained, medium or rapid runoff; moderate permeability, moderately high saturated hydraulic conductivity.

USE AND VEGETATION: Eep soils are used for rangeland. Native vegetation is mountain big sagebrush, antelope bitterbrush, bluebunch wheatgrass, Sandberg bluegrass, needleandthread, Idaho fescue, lupine, and stoneseed.

DISTRIBUTION AND EXTENT: Eep soils are of moderate extent in south central Idaho. MLRA 25.

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

SERIES ESTABLISHED: Twin Falls County, Idaho, 1992.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from 0 to 66 cm (A and Bt1 horizons).
Argillic horizon - The zone from 23 to 66 cm (Bt1 and Bt2 horizons).

ADDITIONAL DATA: This soil has been sampled by the NSSL at Lincoln Lab. Sampled pedon ID numbers include: 81ID083001 and S2004ID083001.

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National Cooperative Soil Survey
U.S.A.