LOCATION ALZOLA                  ID

Established Series
Rev. RDR/ALH/CLM
02/2018

ALZOLA SERIES

The Alzola series consists of very deep, well drained soils with moderately slow permeability that formed in mixed alluvium from extrusive rocks and volcanic ash. Alzola soils are on outwash terraces. Slopes range from 1 to 20 percent. The average annual precipitation is about 250 mm and the average annual temperature is about 6.7 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Durinodic Xeric Calciargids

TYPICAL PEDON: Alzola silt loam -- on a southeast-facing slightly convex slope of 4 percent, in seeded rangeland at 1,600 meter elevation. (When described on October 27, 1983, the soil was dry throughout. Colors are for air-dry soil unless otherwise stated.)

A1--O to 5 cm; light gray (10YR 7/2) silt loam, brown (10YR 4/3) moist; moderate medium and thick platy structure parting to moderate thin platy; slightly hard, very friable, slightly sticky and slightly plastic; many fine and very fine, few medium roots; common very fine, fine, and medium, few coarse vesicular and interstitial pores; 10 percent gravel; moderately alkaline (pH 8.4); abrupt smooth boundary. (5 to 10 cm thick)

A2--5 to 10 cm; very pale brown (10YR 7/3) silt loam, dark yellowish brown (10YR 4/4) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common fine and very fine, few medium roots; common very fine and fine, few medium vesicular pores; 10 percent gravel; strongly alkaline (pH 8.6); abrupt smooth boundary. (0 to 13 cm thick)

Bt--10 to 23 cm; pale brown (10YR 6/3) cobbly silty clay loam, dark yellowish brown (10YR 4/4) moist; moderate fine subangular blocky structure; hard, friable, very sticky and moderately plastic; common fine and very fine, few medium roots; common fine and medium tubular pores; many faint clay films on faces of peds and in pores; 10 percent gravel, 10 percent cobbles; strongly alkaline (pH 8.7); clear wavy boundary. (10 to 28 cm thick)

Btkq--23 to 36 cm; light yellowish brown (10YR 6/4) extremely cobbly clay loam, yellowish brown (10YR 5/4) moist; moderate fine subangular block structure; hard, friable, moderately sticky and moderately plastic; few fine, very fine, and medium roots; few fine and medium tubular pores; common faint clay films on faces of peds and in pores; 25 percent gravel, 40 percent cobbles (thick silica/carbonate pendants are common); strongly effervescent; strongly alkaline (pH 9.0); clear smooth boundary. (0 to 20 cm thick)

Bkq1--36 to 56 cm; very pale brown (10YR 7/3) weakly cemented extremely cobbly sandy loam, pale brown (10YR 6/3) moist; massive; very hard, firm, nonsticky and nonplastic; few fine roots; common fine interstitial pores; 25 percent gravel, 45 percent cobbles (secondary silica and calcium carbonates commonly completely engulf rock fragments to form medium and coarse discontinuous, indurated plates); violently effervescent; very strongly alkaline (pH 9.1); clear wavy boundary. (15 to 23 cm thick)

Bkq2--56 to 152 cm; very pale brown (10YR 8/3) extremely cobbly loamy sand, very pale brown (10YR 7/4) moist; single grain; loose, nonsticky and nonplastic; few fine roots; 30 percent gravel, 50 percent cobbles; violently effervescent; very strongly alkaline (pH 9.4).

TYPE LOCATION: Owyhee County, Idaho; about 8 1/2 miles east and 16 miles south of Grasmere; 2,000 feet west and 150 feet north of the southeast corner of section 2, T. 15 S., R. 6 E.; USGS Triguero Lake 7.5 minute topographic quadrangle; 42 degrees, 08 minutes, 38 seconds North Latitude and 115 degrees, 42 minutes, 55 seconds West Longitude; WGS84 Decimal Degrees 42.1438889 latitude, -115.7152778 longitude.

RANGE IN CHARACTERISTICS:

Depth to base of argillic horizon - 25 to 38 cm.
Depth to weakly cemented calcic horizon - 36 to 61 cm. Particle-size control section - 35 to 50 percent rock fragments; 27 to 34 percent clay.
Average annual soil temperature - 6.7 to 8.3 degrees C. Average summer soil temperature - 17.8 to 19.4 degrees C.
Aridic moisture regime bordering on xeric.

A horizon
Value - 6 or 7 dry, 3 or 4 moist
Chroma - 2 through 4 dry or moist
Rock fragments - 5 to 35 percent
Reaction (pH) - slightly or moderately alkaline

Bt horizon
Value - 6 or 7 dry, 4 or 5 moist
Chroma - 3 or 4 dry or moist
Texture - CB-SICL or CB-CL
Clay content - 27 to 34 percent
Rock fragments - 15 to 35 percent
Reaction (pH) - slightly through strongly alkaline

Btkq horizon
Value - 6 or 7 dry, 4 or 5 moist
Chroma - 3 or 4 dry or moist
Texture - CBV-CL or CBX-CL
Clay content - 27 to 34 percent
Rock fragments - 40 to 80 percent
Calcium carbonate equivalent - 3 to 15 percent
Reaction (pH) - slightly through strongly alkaline

Bkq horizon
Value - 7 or 8 dry, 6 or 7 moist
Chroma - 1 through 4 dry or moist
Texture - CBX-SL, CBV-SL, or CBX-LS
Clay content - 5 to 15 percent clay
Rock fragments - 50 to 90 percent
Calcium carbonate equivalent - 15 to 30 percent
Reaction (pH) - strongly or very strongly alkaline

COMPETING SERIES: These are the Cyan and Gabel series. Cyan soils average more than 45 percent sand in the argillic horizon and lack calcium carbonates throughout. Gabel soils are 22 to 32 inches deep to bedrock.

GEOGRAPHIC SETTING: Alzola soils are undulating to hilly on outwash terraces atop structural benches at elevations of 1,525 to 1,770 meters. Slopes range from 1 to 20 percent. These soils formed in mixed alluvium from extrusive rocks and volcanic ash. The climate is cool and moist in the winter and warm and dry in summer. Average annual precipitation ranges from 250 to 330 mm. Average annual temperature ranges from 5.6 to 7.2 degrees C. Frost-free period is 75 to 90 days.

GEOGRAPHICALLY ASSOCIATED SOILS: This is the Freshwater series. Freshwater soils have indurated duripans over bedrock and are on lower landscape positions.

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

USE AND VEGETATION: Alzola soils are used mainly for rangeland and wildlife habitat. The dominant natural vegetation is Wyoming big sagebrush, bluebunch wheatgrass, and Thurber needlegrass. Extensive areas have been seeded to crested wheatgrass.

DISTRIBUTION AND EXTENT: Southwestern Idaho. Alzola soils are of moderate extent. MLRA 25.

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

SERIES ESTABLISHED: Owyhee County Area, Idaho, 1992.

REMARKS: This revision (6/95) changes the classification from Durixerollic Haplargids to Durinodic Xeric Calciargids according to the 1994 edition of Keys to Soil Taxonomy. The remainder of the OSD has not been updated since 6/93.

Diagnostic horizons and other features recognized in this pedon:
Ochric epipedon - zone 0 to 10 cm (A1 and A2 horizons)
Argillic horizon and particle-size control section - zone 10 to 36 cm
(Bt and Btkq horizons)
Calcic horizon - The zone from 36 to 152 cm (Bkq1 and Bkq2 horizons)
Weakly cemented layer - The zone from 36 to 56 cm (Bkq1 horizon)

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.