LOCATION COWTRACK                CA

Established Series
Rev. ET/CEJ/MAV/GAM
03/2017

COWTRACK SERIES

The Cowtrack series consists of deep, somewhat excessively drained soils that formed in volcanic ash over buried loamy soils from volcanic bedrock. Cowtrack soils are on hills and mountain sideslopes. Slopes are 2 to 30 percent. The mean annual precipitation is about 330 mm and the mean annual temperature is about 4.4 degreesC.

TAXONOMIC CLASS: Ashy over loamy, glassy over mixed, superactive, nonacid, frigid Vitrandic Torriorthents

TYPICAL PEDON: Cowtrack loamy sand - on a 9 percent east slope at 2,515 meters elevation under big sagebrush, antelope bitterbrush, and rabbitbrush vegetation. Colors are for dry soil unless otherwise stated. When described on June 4, 1980, the soil was moist below 3 cm. About 10 percent of the soil surface is partially covered with fine and medium pumice gravel.

A--0 to 5 cm; light brownish gray (10YR 6/2) ashy loamy sand, dark grayish brown (10YR 4/2) moist; single grain; loose, nonsticky and nonplastic; few very fine roots; many very fine interstitial pores; 5 percent fine pumice gravel; slightly acid (pH 6.1); abrupt smooth boundary. (5 to 8 cm thick)

C1--5 to 64 cm; light brownish gray (10YR 6/2) ashy loamy sand, dark grayish brown (10YR 4/2) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; many very fine interstitial pores; 1 percent fine pumice gravel; slightly acid (pH 6.3); abrupt wavy boundary. (20 to 64 cm thick)

C2--64 to 97 cm; light brownish gray (10YR 6/2) ashy loamy sand, dark grayish brown (10YR 4/2) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; common very fine interstitial pores; 1 percent fine pumice gravel; slightly acid (pH 6.4); gradual wavy boundary. (15 to 25 cm thick)

2Btb1--97 to 112 cm; light brownish gray (10YR 6/2) sandy loam, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; few very fine tubular and common very fine interstitial pores; 1 percent gravel, 1 percent cobbles, and 1 percent stones; common faint clay bridges between mineral grains; neutral (pH 6.6); clear wavy boundary. (15 to 30 cm thick)

2Btb2--112 to 127 cm; light brownish gray (2.5Y 6/2) sandy loam, dark grayish brown (2.5Y 4/2) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; few very fine tubular and interstitial pores; 5 percent gravel, 1 percent cobbles, and 1 percent stones; common faint clay films in pores and on ped faces, and many faint clay bridges between mineral grains; neutral (pH 6.8); clear wavy boundary. (8 to 15 cm thick)

2Cr--127 to 147 cm; mixed light gray (2.5Y 7/2) and pale yellow (2.5Y 7/4) weathered and fractured dacite, light brownish gray (2.5Y 6/2) and light yellowish brown (2.5Y 6/4) moist; average fracture spacing is 8 cm; gradual wavy boundary. (0 to 25 cm thick)

2R--147 cm; hard, fractured dacite.

TYPE LOCATION: Mono County, California. About 15 1/2 miles east of Lee Vining on Cowtrack Mountain; 20 feet northwest of dirt road, just before last bend in road before going down to the intersection; about 1,000 feet north and 500 feet east of the southwest corner of section 18, T. 1 N., R. 29 E.; USGS Cowtrack Mountain 7.5 minute topographic quadrangle; latitude 37 degrees 56 minutes 29 seconds N and longitude 118 degrees 49 minutes 46 seconds W; WGS84 Decimal Degrees 37.9413889 latitude, -118.8294444 longitude.

RANGE IN CHARACTERISTICS: Depth to hard bedrock is 100 to 152 cm. The ashy overburden ranges from 60 to 97 cm thick. The soil is usually dry in all parts from late May to mid-November, and is usually moist in some or all parts the rest of the time. The soil temperature is above 5 degrees C. from April 15 to December 1, and is above 8.3 degrees C. from April 30 to November 15. Summer thunderstorms occur, but are sporadic and usually do not wet the control section. The mean annual soil temperature is 6.7 to 8.3 degrees C. Mean summer soil temperatures are 15 to 17.8 degrees C. Base saturation is 90 to 100 percent. Ash content is 60 to 100 percent in the ashy over-burden. Dry bulk density of the ashy overburden is 1.1 to 1.25 g/cc. The moist bulk density is 1.30 to 1.45 g/cc. The soil surface is partially covered with 5 to 15 percent pumice gravel. The soil is slightly acid or neutral. Aridic moisture regime bordering on xeric.

The A horizon color is 10YR 6/2, 6/3 or 7/1, and moist color is 10YR 4/2, 4/3 or 5/1. The soil contains 0 to 5 percent fine pumice gravel. The organic carbon content is 0.45 to 0.55 percent.

The C horizon colors and texture are similar to the A horizon.

The buried B horizon color is 10YR 5/3, 5/4, 6/2, 6/4 or 2.5Y 6/2, and moist color is 10YR 3/3, 3/4, 4/2, 4/4 or 2.5Y 4/2. Textures are sandy loam or loam. Rock fragment content is 3 to 15 percent consisting of 0 to 10 percent gravel and 1 to 5 percent cobbles and stones.

COMPETING SERIES: There are no other series in this family.

GEOGRAPHIC SETTING: Cowtrack soils are on hills and mountain sideslopes at elevations of 2,380 to 2,685 meters. Slopes are 2 to 30 percent. The soils formed in volcanic ash showered on top of buried loamy soils from dacite, andesite, granitic, or basaltic bedrock. The mean annual precipitation is 300 to 360 mm, mostly as snow. Mean annual snowfall is 100 to 130 inches. Mean January temperature is about -3.3 degrees C; mean July temperature is about 13.9 degrees C. The mean annual temperature is 3.9 to 5.6 degrees C. Frost-free period is 75 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: This is the Zono series. Zono soils have mesic soil temperature regimes.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat excessively drained: very slow runoff; moderately rapid permeability; high saturated hydraulic conductivity.

USE AND VEGETATION: Used principally for livestock grazing and wildlife habitat. Vegetation is mainly mountain big sagebrush, antelope bitterbrush, Douglas rabbitbrush, Indian ricegrass, needleandthread, western needlegrass and blue wildrye.

DISTRIBUTION AND EXTENT: The higher elevations in the mountains surrounding Mono Lake in east-central California. The soils are moderately extensive in MLRA is 26.

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

SERIES PROPOSED: Mono County, California; Benton-Owens Valley Soil Survey, 1987.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 0 to 18 cm (A horizon and part of the C1 horizon).
Particle-size control section - The zone from 25 to 100 cm. (C2 and part of the C1 and 2Btb1 horizons)

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National Cooperative Soil Survey
U.S.A.