LOCATION POWMENT                 NV

Established Series
Rev. JVC/JBF
06/2017

POWMENT SERIES

The Powment series consist of very shallow, somewhat excessively drained soils that formed in colluvium and residuum derived from granitic rock. Powment soils are on mountains. Slopes are 50 to 75 percent. The mean annual precipitation is about 360 mm and the mean annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Sandy-skeletal, mixed, frigid, shallow Xeric Torriorthents

TYPICAL PEDON: Powment very gravelly sand--rangeland. (Colors are for dry soil unless otherwise noted.) The surface is partially covered by about 70 percent gravel pavement.

A--0 to 5 cm; light brownish gray (10YR 6/2) very gravelly sand, very dark grayish brown (10YR 3/2) moist; single grain; loose, nonsticky and nonplastic; many very fine roots; many very fine interstitial pores; 50 percent gravel; neutral (pH 6.8); abrupt smooth boundary. (3 to 10 cm thick)

C1--5 to 15 cm; pale brown (10YR 6/3) extremely gravelly sand, dark grayish brown (10YR 4/2) moist; single grain; loose, nonsticky and nonplastic; many very fine roots; many very fine interstitial pores; 80 percent gravel; neutral (pH 6.8); clear smooth boundary. (5 to 15 cm thick)

C2--15 to 25 cm; pale brown (10YR 6/3) extremely gravelly sand, dark grayish brown (10YR 4/2) moist; single grain; loose, nonsticky and nonplastic; many very fine roots; many very fine interstitial pores; 80 percent gravel; neutral (pH 6.8); abrupt smooth boundary. (0 to 18 cm thick)

Cr--25 to 56 cm; highly fractured and weathered granitic bedrock (grus).

TYPE LOCATION: Mineral County, Nevada; approximately 15 miles south of Hawthorne in the Wassuk Range; about 2,200 feet east of the southwest corner of section 33 along the line between townships, T. 6 N., R. 30 E.; USGS Powell Mountain 7.5 minute topographic quadrangle; latitude 38 degrees 19 minutes 41 seconds N and longitude 118 degrees 38 minutes 32 seconds W; WGS84 Decimal Degrees 38.3280556 latitude, -118.6422222 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in winter and spring, dry in summer and fall except for 10 to 20 days cumulative in some part between July and October due to convection storms; aridic (torric) moisture regime that borders on xeric.
Mean annual soil temperature: 7 to 8 degrees C.
Ochric epipedon thickness: 3 to 10 cm.
Depth to bedrock: 10 to 36 cm to a paralithic contact. The paralithic materials below the contact are weathered granitic rock such as granodiorite.
Reaction: Slightly acid or neutral.

Particle-size control section - Rock fragments: Averages 50 to 80 percent, mainly fine gravel.

C horizons
Texture: Very gravelly sand or extremely gravelly sand.
Rock fragments: 50 to 80 percent gravel.
Clay content: 0 to 10 percent.
Other features: The C2 horizon takes on grus-like characteristics in some pedons with pararock fragments present.

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

GEOGRAPHIC SETTING: Powment soils are on mountains. They formed in colluvium and residuum derived from granitic rock. Slopes are 50 to 75 percent. Elevations range from 1,950 to 2,380 meters. The climate is semiarid with cool, moist winters and warm dry summers. The mean annual precipitation is 300 to 400 mm, mean annual temperature is 7 to 8 degrees C, and the frost-free period is 60 to 90 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Lazan and Nupart soils. Lazan soils are mesic. Nupart soils have mollic epipedons.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat excessively drained; low surface runoff; rapid permeability; high saturated hydraulic conductivity.

USE AND VEGETATION: Powment soils are used for rangeland and wildlife habitat. The present vegetation is singleleaf pinyon, Utah juniper, Indian ricegrass, mountain big sagebrush, and antelope bitterbrush.

DISTRIBUTION AND EXTENT: Western Nevada. These soils are moderately extensive. MLRA 26.

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

SERIES ESTABLISHED: Mineral County, Area, Nevada, 1985.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 18 cm (A, C1 and part of the C2 horizons).
Paralithic contact - The boundary at 25 cm to underlying weathered bedrock (Cr layer).
Particle-size control section - The zone from the soil surface to 25 cm (A, C1, and C2 horizons).

ADDITIONAL DATA: The revision of October 2002 updates the taxonomic class, from Sandy-skeletal, mixed, frigid, shallow Typic Xerorthents, because of a change in concept for moisture regime.
Previous authors include HBS-JFR-WED.

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National Cooperative Soil Survey
U.S.A.