LOCATION MORMONWELL              NV

Established Series
Rev: LJL/CAH/ET
11/2015

MORMONWELL SERIES

The Mormonwell series consists of shallow, well drained soils that formed in residuum and colluvium derived from limestone and dolomite. Mormonwell soils are on mountains. Slope ranges from 30 to 75 percent. The mean annual precipitation is about 225 millimeters and the mean annual temperature is about 8 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Aridic Lithic Haplustolls

TYPICAL PEDON: Mormonwell extremely gravelly loam, on an east facing (115 degrees), 56 percent slope at an elevation of 2046 meters (6714 feet). When described on 8/5/2009 the soil was dry throughout. Colors are for dry soil unless otherwise noted. The soil surface is covered by approximately 70 percent gravel, 8 percent cobbles and 7 percent stones.

A--0 to 5 centimeters (0 to 2 inches); brown (10YR 5/3), extremely gravelly loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine roots; many very fine vesicular pores; 65 percent gravel, 3 percent cobbles, 1 percent stones; violently effervescent (25 percent calcium carbonate equivalent in the fine earth fraction); slightly alkaline (pH 7.8); clear smooth boundary. (4 to 7 centimeters thick)

Bk1--5 to 19 centimeters (2 to 7 inches); brown (10YR 5/3), extremely gravelly loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; moderately hard, very friable, slightly sticky and slightly plastic; common very fine, few fine and medium roots; common very fine and few fine tubular pores; 25 percent prominent, white (10YR 8/1), calcium carbonate coats on bottom surfaces of rock fragments; 60 percent gravel, 2 percent cobbles; violently effervescent (17 percent calcium carbonate equivalent in the fine earth fraction); moderately alkaline (pH 8.0); clear smooth boundary.

Bk2--19 to 46 centimeters (7 to 18 inches); brown (10YR 5/3), extremely gravelly loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; moderately hard, very friable, slightly sticky and slightly plastic; common very fine and few fine through coarse roots; common very fine and few fine tubular pores; 25 percent prominent, white (10YR 8/1), calcium carbonate coats on bottom surfaces of rock fragments; 50 percent gravel, 15 percent cobbles, 2 percent stones; violently effervescent (17 percent calcium carbonate equivalent in the fine earth fraction); moderately alkaline (pH 8.0); very abrupt broken boundary. (Combined thickness of the Bk horizons is 18 to 46 centimeters.)

R--46 centimeters (18 inches); indurated limestone bedrock; fractures are 10 to 45 centimeters apart; strongly effervescent.

TYPE LOCATION: Clark County, Nevada; about 24 kilometers north and 24 kilometers east of Corn Creek, Nevada on the eastside of the Sheep Mountain Range; approximately 670 meters east and 500 meters north of Mormon Well; 1030 feet south and 1320 feet west of the northeast corner of sec. 12, T. 15 S., R. 61 E.; USGS Mormon Well, NV 7.5 minute topographic quadrangle; 36 degrees, 38 minutes, 54.6 seconds north latitude and 115 degrees, 5 minutes, 22.8 seconds west longitude; UTM 11S 0670763e 4057581n; (DTM: NAD83).

RANGE IN CHARACTERISTICS:

Soil moisture control section- usually dry, moist in late winter and early spring and intermittently moist in the upper part following summer convection storms; The soils have a ustic-aridic soil moisture regime.

Soil temperature: 8 to 12 degrees C.

Depth to base of mollic epipedon: 25 to 50 centimeters.
Depth to lithic contact: 25 to 50 centimeters.

Control section -
Rock fragments: 50 to 70 percent, mainly gravel with 0 to 15 percent cobbles, and 0 to 3 percent stones.
Clay content: 8 to 12 percent.
Calcium carbonate equivalence of the less than 20 millimeter fraction: 30 to 40 percent.

A horizon
Value: 4 or 5, dry.
Calcium carbonate equivalence of the fine earth: 15 to 30 percent.

Bk1 horizon
Value: 4 or 5 dry.
Texture: loam or silt loam.
Structure: moderate or strong, medium or coarse.
Rock fragments: 50 to 70 percent, mainly gravel with 0 to 5 percent cobbles, and 0 to 3 percent stones.
Calcium carbonate equivalence of the fine earth: 10 to 20 percent.

Bk2 horizon
Chroma: 2 or 3, dry or moist.
Texture: loam or silt loam.
Structure: weak or moderate, medium or coarse.
Consistence: slightly hard or moderately hard.
Rock fragments: 50 to 70 percent, mainly gravel with 7 to 15 percent cobbles, and 0 to 3 percent stones.
Calcium carbonate equivalence of the fine earth: 10 to 20 percent.

COMPETING SERIES: These are the Arbol, Faraway, Oro Grande, Rotagilla, Seralin, and Yaquican series. Arbol soils have MAST of 55 to 59 degrees F., 18 to 27 percent clay, moderately acid to slightly acid reaction classes, and a paralithic contact at 8 to 15 inches. Faraway soils have moderately acid to neutral reaction classes. Oro Grande soils averages 18 to 35 clay. Rotagilla soils have MAST of 55 to 59 degrees F., 18 to 27 percent clay, and moderately acid to slightly acid reaction classes. Seralin soils have 1 to 5 percent calcium carbonate equivalent in the fine earth fraction and 20 to 30 percent calcium carbonate equivalent in the less than 20 millimeter fraction. Yaquican soils have 20 to 25 percent clay, 35 to 50 percent rock fragments, and slightly acid to neutral reaction classes.

GEOGRAPHIC SETTING: Mormonwell soils are on mountains. Slope ranges from 30 to 75 percent. These soils formed in residuum and colluvium derived from limestone and dolomite. Elevations are 1,570 to 2,500 meters (5,150 to 8,200). 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 200 to 250 millimeters; mean annual air temperature is 6 to 10 degrees C., and the frost-free season is 90 to 135 days.

GEOGRAPHICALLY ASSOCIATED SOILS: This is Boxspring soils. The Boxspring soils occur on mountains and do not have a mollic epipedon.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; very high runoff; moderately high saturated hydraulic conductivity above the bedrock.

USE AND VEGETATION: These soils are used for rangeland and wildlife habitat. The present vegetation is mainly mountain big sagebrush, spiny greasebush, Stansbury cliffrose, desert globemallow, Indian ricegrass, and bottlebrush squirreltail.

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 Mormon Well located in the Desert National Wildlife Refuge.

REMARKS: Diagnostic horizons and features recognized in the profile are:

Mollic epipedon - 0 to 46 centimeters (0 to 18 inches) (A, Bk1 and Bk2 horizons).
Lithic contact - 46 centimeters (18 inches) (R horizon).
Particle-size control section - 25 to 46 centimeters (10 to 18 inches) (part of the Bk2 horizon).

ADDITIONAL DATA: The USER PEDON ID is 09NV786031LL and was described on 8/5/2009. The ecological site is Loamy Slope 9-11 PZ (R030XC046NV).

Responsibility for this series was transferred from Davis to Phoenix 11/2015. The last revision to the series was 6/2011. ET

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National Cooperative Soil Survey
U.S.A.