LOCATION AVTABLE                 ID

Established Series
Rev. JR/ALH/CLM
12/2022

AVTABLE SERIES

The Avtable series consists of shallow, well drained soils that formed in residuum and alluvium from welded rhyolitic tuff. They are on summits and sideslopes of foothills and structural benches. Permeability is moderately slow. Slopes are 2 to 15 percent. The average annual precipitation is about 380 mm and the average annual temperature is about 6.1 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Lithic Mollic Haploxeralfs

TYPICAL PEDON: Avtable gravelly loam -- on a south-facing slope of 2 percent, in native rangeland at 1,775 meters elevation. The surface has about 1 to 3 percent stone cover. (When described on September 23, 1980, the soil was moist to a depth of 28 cm and dry below. Colors are for air dry soil unless otherwise stated.)

A--0 to 10 cm; yellowish brown (10YR 5/4) gravelly loam, dark yellowish brown (10YR 3/4) moist; moderate medium subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; many very fine, common fine, few medium and coarse roots; many fine and very fine vesicular and interstitial pores; 20 percent fine gravel, 3 percent stones; neutral (pH 6.7); clear smooth boundary. (5 to 13 cm thick)

Bt1--10 to 25 cm; yellowish brown (10YR 5/4) gravelly loam, brown (10YR 4/3) moist; moderate fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine, fine, medium and coarse roots; many very fine tubular and interstitial pores; few faint clay films on faces of peds and few faint clay bridges between sand grains; 25 percent gravel, 5 percent cobbles; neutral (pH 6.7); clear smooth boundary. (8 to 23 cm thick)

Bt2--25 to 48 cm; light yellowish brown (10YR 6/4) extremely stony clay loam, dark yellowish brown (10YR 4/4) moist; strong fine subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine and fine, few medium and coarse roots; many very fine tubular pores; common faint clay films on faces of peds; 15 percent gravel, 30 percent cobbles, 35 percent stones; slightly acid (pH 6.5); abrupt irregular boundary. (3 to 9 inches thick)

R--48 cm; fractured welded rhyolitic tuff.

TYPE LOCATION: Owyhee County, Idaho; about 1 3/4 miles southwest of Mud Flat BLM Administrative Site; 1,600 feet west and 400 feet north of the southeast corner of section 33, T. 9 S., R. 2 W.; USGS Wagon Box Basin 7.5 minute topographic quadrangle; latitude 42 degrees 35 minutes 24 seconds N and longitude 116 degrees 34 minutes 24 seconds W; WGS84 Decimal Degrees 42.5900000 latitude, -116.5733333 longitude.

RANGE OF CHARACTERISTICS:

Depth to bedrock - 36 to 50 cm.
Reaction (pH) - slightly acid or neutral
Average annual soil temperature - 6.1 to 8.3 degrees C.
Average summer soil temperature - 17.2 to 19.4 degrees C.
Soil moisture control section - dry less than 90 days cumulative.
Aridic moisture regime bordering on xeric.

A horizon
Hue - 7.5YR or 10YR
Value - 5 or 6 dry
Chroma - 2 to 4 dry or moist
Rock fragments - 15 to 35 percent

Bt horizon
Hue - 7.5YR or 10YR
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 3 to 6 dry or moist
Texture (upper part) - GR-L, GRV-L, or CB-CL
Texture (lower part) - STX-CL, CBV-L, or GRX-L
Clay content - 20 to 30 percent
Rock fragments (average) - 35 to 85 percent
Other features - clay commonly occurs in bedrock fractures

COMPETING SERIES: These are the Blackspar, Cinderhurst, Thorn (T), and Wassit series. Blackspar soils are dry 90 to 120 days cumulative. Cinderhurst soils are less than 10 inches deep to bedrock. Thorn soils have volcanic ash and pumice in the upper part. Wassit soils are less than 36 cm deep to bedrock.

GEOGRAPHIC SETTING: Avtable soils are on undulating to hilly summits and sideslopes of foothills and structural benches. Slopes range from 2 to 15 percent. Elevations range 1,525 to 1,955 meters. These soils formed in residuum and alluvium from welded rhyolitic tuff. The climate is cool and moist in winter and warm and dry in summer. Average annual precipitation is 330 to 410 mm, and average annual temperature is 5.0 to 7.2 degrees C. The frost-free period is 70 to 95 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cleavage, Hat (T), Hurryback, Monasterio, and Hawksy soils. Cleavage soils have mollic epipedons and are on similar landscape positions. Hat soils are 50 to 100 cm deep and on similar landscape positions. Hurryback and Monasterio soils have mollic epipedons and are on less exposed aspects. Hawksy soils have more than 35 percent clay in the control section and are on similar landscape positions.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; medium or rapid runoff; moderately slow permeability.

USE AND VEGETATION: Avtable soils are used mainly for rangeland and wildlife habitat. The dominant natural vegetation is low sagebrush, Idaho fescue, and bluebunch wheatgrass. Western juniper is occasionally present.

DISTRIBUTION AND EXTENT: Southwestern Idaho. This series is moderately extensive. MLRA 25.

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

SERIES ESTABLISHED: Owyhee County Area, Idaho, 1992.

REMARKS: Diagnostic horizons and other features recognized in this pedon:

Ochric epipedon - zone 0 to 10 cm (A horizon).
Argillic horizon and particle-size control section - zone 10 to 48 cm (Bt1 and Bt2 horizons).
Lithic contact - the boundary at 48 cm (R layer).
The superactive cation exchange activity class was added in 03/2003 to the taxonomic classification by the National Soil Survey Center on request of the Reno MLRA office, without review of the soil series property data. The remainder of this document has not been updated.

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National Cooperative Soil Survey
U.S.A.