LOCATION SHEEPPASS               NV

Established Series
REV: LJL/CAH/ET
12/2015

SHEEPPASS SERIES

The Sheeppass series consists of very shallow, well drained soils that formed in residuum and colluvium derived from limestone and dolomite. Sheeppass soils are on mountains. Slope ranges from 15 to 75 percent. The mean annual precipitation is about 200 millimeters and the mean annual temperature is about 12 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, carbonatic, mesic Lithic Torriorthents

TYPICAL PEDON: Sheeppass very gravelly sandy loam, rangeland and wildlife habitat. (Colors are for dry soil unless otherwise noted.) The soil surface is covered by approximately 70 percent gravel, 6 percent cobbles and 4 percent stones.

A--0 to 6 centimeters (0 to 2 inches); pale brown (10YR 6/3) very gravelly sandy loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; few very fine roots; many very fine interstitial and few fine tubular pores; 50 percent gravel, 3 percent cobbles, and 1 percent stones; violently effervescent(55 percent calcium carbonate equivalent in the fine earth fraction); moderately alkaline (pH 8.2); abrupt smooth boundary. (2 to 7 centimeters thick)

Bk--6 to 23 centimeters (2 to 9 inches); pale brown (10YR 6/3) very gravelly fine sandy loam, brown (10YR 4/3) moist; moderate coarse subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; 1 percent fine, prominent, white (10YR 8/1), very strongly cemented calcium carbonate pendants on bottom surfaces of rock fragments; 30 percent prominent, white (10YR 8/1), calcium carbonate coats on bottom surfaces of rock fragments; 35 percent gravel and 3 percent cobbles; violently effervescent (40 percent calcium carbonate equivalent in the fine earth fraction); moderately alkaline (pH 8.2); very abrupt wavy boundary. (5 to 20 centimeters thick)

R--23 centimeters (9 inches); gray (10YR 5/1) indurated limestone bedrock, very dark gray (10YR 3/1) moist; fractures 10 to 45 centimeters apart.

TYPE LOCATION: Clark County, Nevada; about 11 kilometers north and 22 kilometers east of Corn Creek, Nevada located on the north end of Peek-a-boo Canyon; approximately 2 kilometers east and 4 kilometers south of Searles Reservoir; 400 feet south and 2020 feet east of the northwest corner of section 23, T. 16 S., R. 61 E.; USGS Hayford Peak SE, NV 7.5 minute quadrangle; 36 degrees, 32 minutes, 2.4 seconds north latitude and 115 degrees, 6 minutes, 50.7 seconds west longitude; UTM 11S 668829e 4044833n; (DATUM: NAD83).

RANGE IN CHARACTERISTICS:

Soil moisture control section- usually dry, moist in some part for short periods during winter and early spring. The soils have a Typic-aridic moisture regime.

Soil temperature: 11 to 15 degrees C (52 to 59 degrees F).

Depth to lithic contact: 10 to 25 centimeters.


Control section -
Rock fragments: 35 to 70 percent, mainly gravel with 0 to 10 percent cobbles and 0 to 3 percent stones.
Clay content: 6 to 12 percent.


A horizon
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 2 or 3, dry.
Structure: weak through strong, fine through coarse.
Consistence: soft through moderately hard, nonsticky or slightly sticky, nonplastic or slightly plastic.
Calcium carbonate equivalence of the fine earth: 30 to 60 percent.

Bk or Bkq horizons
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 3 or 4, dry or moist.
Texture: sandy loam, fine sandy loam, or loam.
Structure: weak through strong, fine through coarse, subangular blocky or massive.
Consistence: soft through moderately hard, nonsticky or slightly sticky, nonplastic or slightly plastic.
Rock fragments: 35 to 70 percent, mainly gravel with 0 to 10 percent cobbles.
Calcium carbonate equivalence of the fine earth: 30 to 50 percent.
Sodium Adsorption Ratio: 0 to 5.
Electrical conductivity: 0 to 2.
Other features: Some pedons have 0 to 5 percent secondary silica coats on bottoms of rock fragments.

COMPETING SERIES: These are the Koynik, Potosi, and Theriot series. Koynick soils have a MAST of 8 to 11 degrees C (47 to 52 degrees F). Potosi soils have 15 to 30 percent calcium carbonate equivalent in the fine earth fraction. Theriot soils are dominated by cobbles and stones.

GEOGRAPHIC SETTING: Sheeppass soils are on mountains. Slope ranges from 15 to 75 percent. These soils formed in residuum and colluvium derived from limestone and dolomite. Elevations are 1,220 to 2,100 meters (4,000 to 6,900 feet). The climate is semiarid with cool, moist winters and warm, intermittently moist summers. Precipitation is greatest in the winter with lesser secondary peak in the summer, typical of the Mojave Desert transitional to Great Basin. The mean annual precipitation is 175 to 225 millimeters; mean annual air temperature is 9 to 13 degrees C. (48 to 55 degrees F.), and the frost-free season is 130 to 180 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are Boxspring and Mormonwell soils. Boxspring soils are on mountains, are shallow (36 to 50 centimeters, 14 to 20 inches) to limestone bedrock and have an aridic bordering on ustic moisture regime. Mormonwell soils are on upper elevation mountains and have mollic epipedons.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat excessively drained; very high runoff; moderately high and high saturated hydraulic conductivity above the bedrock and are low throughout the bedrock.

USE AND VEGETATION: These soils are used for rangeland and wildlife habitat. The present vegetation is mainly blackbrush, Stansbury cliffrose, and desert needlegrass.

DISTRIBUTION AND EXTENT: Mojave Desert of southern Nevada, U.S.A.; MLRA 30. These soils are not extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: PHOENIX, ARIZONA

SERIES ESTABLISHED: Desert National Wildlife Refuge Area, Nevada, South Part, Clark County, Nevada, 2011. The name is coined from Sheep Pass located in the Desert National Wildlife Refuge.

REMARKS: Diagnostic horizons and features recognized in the profile are:
Ochric epipedon - 0 to 18 centimeters (0 to 7 inches) (A and part of the Bk horizons).
Lithic contact - 23 centimeters (9 inches) (R horizon).
Particle-size control section - 0 to 23 centimeters (0 to 9 inches) (A and Bk horizons).

Responsibility for this series was transferred from Davis to Phoenix 12/2015. The last revision to the series was 6/2011. ET

---

National Cooperative Soil Survey
U.S.A.