LOCATION TOCK                    ID

Established Series
Rev. KAB/DA/CLM
12/2019

TOCK SERIES

The Tock series consists of soils that are well drained and moderately deep to a hardpan that formed in old alluvium from welded tuff and volcanic ash. They are on terraces. Permeability is slow. Slopes range from 1 to 6 percent. The average annual precipitation is about 330 mm, and average annual temperature is about 6.7 degrees C.

TAXONOMIC CLASS: Fine, smectitic, frigid Xeric Argidurids

TYPICAL PEDON: Tock loam - on a slope of 2 percent under rangeland vegetation at 1,620 meters elevation. When described on September 24, 1979, the soil profile was dry throughout. (Colors are for dry soil unless otherwise noted.)

A--0 to 10 cm; pale brown (10YR 6/3) loam, dark brown (10YR 3/3) moist; moderate medium platy structure; soft, very friable, slightly sticky and slightly plastic; many very fine, fine and medium roots; many very fine and fine tubular pores; neutral (pH 6.7); clear smooth boundary. (8 to 18 cm thick)

Bt1--10 to 33 cm; brown (10YR 5/3) silty clay loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine, fine and medium roots; common very fine and fine tubular pores; common faint clay films on faces of peds and in pores; neutral (pH 7.2); clear smooth boundary. (10 to 28 cm thick)

Bt2--33 to 76 cm; yellowish brown (10YR 5/4) silty clay, yellowish brown (10YR 5/4) moist; moderate medium angular blocky structure; hard, firm, moderately sticky and moderately plastic; common very fine, fine and medium roots; common very fine and fine tubular pores; many distinct clay films on faces of peds and in pores; 5 percent gravel; neutral (pH 7.1); abrupt smooth boundary. (33 to 58 cm thick)

Bkqm--76 to 91 cm; light yellowish brown (10YR 6/4) indurated duripan, dark yellowish brown (10YR 4/4) moist; massive; extremely hard, extremely firm; many continuous silica laminations running between cemented sand and gravel; strongly effervescent; abrupt smooth boundary. (8 to 20 cm thick)

2C--91 to 152 cm; multi-colored loose sand and gravel; single grain.

TYPE LOCATION: Twin Falls County, Idaho; about 12 miles southeast of Rogerson, about 1,200 feet north and 1,600 feet east of the southeast corner, section 7, T. 16 S., R. 17 E.; USGS Magic Hot Springs 7.5-minute topographic quadrangle; latitude 42 degrees 2 minutes 42 seconds N and longitude 114 degrees 30 minutes 32 seconds W; WGS84 Decimal Degrees 42.0450000 latitude, -114.5088889 longitude.

RANGE IN CHARACTERISTICS:

Depth to duripan - 50 to 100 cm.
Clay content in control section average - 35 to 45 percent
Average annual soil temperature - 7.2 to 8.3 degrees C.
Soil moisture: Usually dry, moist in the winter and spring, dry from late June through October; aridic soil moisture regime bordering on xeric.
Depth to bedrock - more than 152 cm.

Bt horizon
Value - 5 or 6 dry, 3 through 5 moist.
Chroma - 3 or 4 dry or moist.
Texture - SICL or SIC
Structure - subangular blocky or angular blocky.

Bkqm horizon
Thickness of duripan - 8 to 25 cm thick.
Strength of cementation - indurated or strongly cemented (laminations)

COMPETING SERIES: These are the Larioscamp and Ratsow series. Larioscamp and Ratsow soils are moderately deep to bedrock.

GEOGRAPHIC SETTING: Tock soils are on terraces. The slope ranges from 1 to 6 percent. The soils formed in old alluvium from welded tuff and volcanic ash. Elevations are 1,590 to 1,710 meters. The average annual precipitation ranges from 300 to 360 mm. The average annual temperature is 6.1 to 7.2 degrees C. The (0 degrees C.) frost-free period is 90 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Arness, Chuska, and Oshone soils. Arness and Chuska soils occur on lower terraces and are shallow to a hardpan. Oshone soils occur on higher terraces, and have 45 to 55 percent clay in the Bt horizon.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; medium runoff; slow saturated hydraulic conductivity.

USE AND VEGETATION: Tock soils are used for rangeland. Native vegetation is bluebunch wheatgrass, western wheatgrass, Thurber needlegrass, Nevada bluegrass, and Wyoming big sagebrush.

DISTRIBUTION AND EXTENT: Tock soils are of small extent in south central Idaho.

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

SERIES ESTABLISHED: Twin Falls County, Idaho, 1992.

REMARKS: Clay percent by hydrometer: 10-33 cm - 36 percent; 33-76 cm - 40 percent.

Ochric epipedon - The zone from 0 to 10 cm (A horizon).
Argillic horizon - The zone from 10 to 61 cm (Bt1 and Bt2 horizons).
Duripan - The zone from 76 to 91 (Bkqm horizon).
The particle- size control section - The zone from 10 to 60 cm (The Bt1 and part of the Bt2 horizons).

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National Cooperative Soil Survey
U.S.A.