LOCATION OCASHE                  CA+NV

Established Series
Rev. EWB-JVC-JBF
04/2017

OCASHE SERIES

The Ocashe series consists of very shallow and shallow, well drained soils that formed in residuum and colluvium derived from volcanic rocks with surficial additions of eolian volcanic ash. Ocashe soils are on mountains. Slopes are 15 to 75 percent. The mean annual precipitation is about 330 mm and the mean annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Ashy-skeletal, glassy, mesic Aridic Lithic Argixerolls

TYPICAL PEDON: Ocashe extremely gravelly ashy sandy loam--forest land. (Colors are for dry soil unless otherwise noted.) The soil surface is covered with 40 percent gravel, 5 percent cobbles, and 5 percent stones.

A1--0 to 3 cm; grayish brown (10YR 5/2) extremely gravelly ashy sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; few very fine roots; many very fine interstitial pores; 60 percent gravel; slightly acid (pH 6.3); clear wavy boundary. (3 to 13 cm thick)

A2--3 to 8 cm; brown (10YR 5/3) extremely gravelly ashy sandy loam, dark brown (10YR 3/3) moist; moderate fine and medium subangular blocky structure; soft, very friable, slightly sticky and nonplastic; common very fine and fine roots; common very fine and fine interstitial and tubular pores; 60 percent gravel; neutral (pH 6.7); clear wavy boundary. (5 to 13 cm thick)

Bt1--8 to 18 cm; brown (10YR 5/3) extremely gravelly ashy sandy loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure; hard, very friable, slightly sticky and slightly plastic; common very fine, fine and medium roots; common very fine tubular and interstitial pores; 60 percent gravel; common faint clay bridges between sand grains; slightly acid (pH 6.5); clear irregular boundary. (8 to 15 cm thick)

Bt2--18 to 33 cm; pale brown (10YR 6/3) extremely gravelly ashy sandy clay loam, brown (10YR 4/3) moist; moderate fine subangular blocky structure; hard, very friable, moderately sticky and moderately plastic; few very fine roots; common very fine tubular and interstitial pores; common faint clay bridges between sand grains; 65 percent gravel; neutral (pH 6.8); clear irregular boundary. (0 to 15 cm thick)

R--33 cm; hard, fractured and altered volcanic rock.

TYPE LOCATION: Mono County, California; on the Toiyabe National Forest about 2.5 miles southwest of Devils Gate; approximately 900 feet south and 1,700 feet west of the northeast corner of section 11, T. 6 N., R. 25 E.; USGS Sweetwater Creek 7.5 minute topographic quadrangle; latitude 38 degrees 23 minutes 14.4 seconds N and longitude 119 degrees 11 minutes 37.5 seconds W; WGS84 Decimal Degrees 38.3873333 latitude, -119.1937500 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in winter and spring, dry from July through October; aridic moisture regime that borders on xeric.
Mean annual soil temperature: 8 to 10 degrees C.
Mollic epipedon thickness: 18 to 30 cm; includes part or all of the argillic horizon.
Depth to bedrock: 18 to 36 cm to a lithic contact.

Particle-size control section - Clay content: Averages 15 to 25 percent.
Rock fragments: Averages 60 to 80 percent, mainly gravel. Lithology of fragments is volcanic rock such as andesite or tuff; Volcanic glass content: Averages 30 percent or more in coarse silt through very coarse sand fractions.

A horizons
Chroma: 2 or 3, dry or moist.
Organic matter content: 1 to 3 percent.
Reaction: Slightly acid or neutral.
Volcanic glass content: 35 to 60 percent in coarse silt through fine sand fractions.

Bt1 horizon
Hue: 10YR or 7.5YR.
Chroma: 2 or 3, dry or moist.
Texture: Extremely gravelly ashy sandy clay loam, extremely gravelly ashy loam, or extremely gravelly ashy sandy loam.
Clay content: 18 to 27 percent.
Rock fragments: 60 to 80 percent.
Organic matter content: 1 to 3 percent.
Reaction: Slightly acid or neutral.
Volcanic glass content: 35 to 60 percent in coarse silt through fine sand fractions.

Bt2 horizon
Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 2 or 3, dry or moist.
Texture: Extremely gravelly ashy sandy clay loam, extremely gravelly ashy loam, or extremely gravelly ashy sandy loam.
Clay content: 18 to 27 percent.
Rock fragments: 60 to 80 percent.
Organic matter content: 0.5 to 2 percent.
Reaction: Slightly acid or neutral.
Volcanic glass content: 15 to 40 percent in coarse silt through fine sand fractions.
Oxalate aluminum plus one-half oxalate iron: 0.2 to 0.4 percent.

COMPETING SERIES: These are the Corbaley and Marepas series.

Corbaley soils have 10 to 30 percent coarse sand and very coarse sand-sized (0.5 to 2.0 mm in diameter) pumiceous ash grains and 35 to 60 percent rock fragments in the particle-size control section. Marepas soils have 35 to 60 percent rock fragments in the particle-size control section.

GEOGRAPHIC SETTING: Ocashe are on mountains. They typically occur on backslope positions. They formed in residuum and colluvium derived from volcanic rocks such as andesite and tuff with surficial additions of eolian volcanic ash. The probable sources of the volcanic ash are the Mono Craters and Long Valley Caldera in eastern California. Slopes are 15 to 75 percent. Elevations range from 1,955 to 2,445 meters. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 300 to 360 mm, the mean annual temperature is 6 to 7 degrees C., and the frost-free period is 70 to 90 days.

GEOGRAPHICALLY ASSOCIATED SOILS: This is the Hardnut soil. Hardnut soils have a frigid soil temperature regime and have lithic contacts at depths of 25 to 50 cm.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; very high surface runoff; moderate permeability; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: Ocashe soils are used for forest land, recreation, watershed, and wildlife habitat. The native vegetation is mainly a forest canopy of singleleaf pinyon with an understory of mountain big sagebrush, antelope bitterbrush, and Thurber's needlegrass.

DISTRIBUTION AND EXTENT: Eastern California and western Nevada, in the western part of the Great Basin. These soils are not extensive.MLRA 26.

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

SERIES ESTABLISHED: Mineral County Area, Nevada, 2005. The series was proposed in Mono County (Toiyabe National Forest Area), California, 2004.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 18 cm (A1, A2, and Bt1 horizons).
Argillic horizon - The zone from 8 to 33 cm (Bt1 and Bt2 horizons).
Vitrandic intergrade feature - The zone from the soil surface to 33 cm (A1, A2, Bt1, and Bt2 horizons).
Lithic contact - The boundary at 33 cm to underlying hard bedrock (R layer).
Particle-size control section and ashy substitute class with glassy mineralogy - The zone from the soil surface to 33 cm (A1, A2, Bt1, and Bt2 horizons).

Classification was updated to 11th edition on 07/2011 changed from Lithic Argixerolls to Aridic Lithic Argixerolls.

ADDITIONAL DATA: Volcanic glass content determined locally by optical grain count with a polarizing petrographic microscope.
User Pedon ID: 2004CA051001.

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National Cooperative Soil Survey
U.S.A.