LOCATION POWLOW                  NV

Established Series
Rev. JBF/TM
01/2020

POWLOW SERIES

The Powlow series consists of shallow to a duripan, well drained soils that formed in alluvium derived from volcanic rocks. Powlow soils are on fan remnants. Slopes are 2 to 15 percent. The mean annual precipitation is about 280 mm and the mean annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Clayey, smectitic, mesic, shallow Argidic Durixerolls

TYPICAL PEDON: Powlow very gravelly loam--rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is partially covered with approximately 40 percent gravel and 2 percent cobbles.

A1--0 to 5 cm; grayish brown (10YR 5/2) very gravelly loam, very dark grayish brown (10YR 3/2) moist; moderate thin and medium platy structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine roots; many very fine and fine vesicular pores; 45 percent gravel; neutral (pH 6.8); abrupt wavy boundary. (5 to 10 cm thick)

A2--5 to 15 cm; grayish brown (10YR 5/2) gravelly loam, dark brown (10YR 3/3) moist; strong very thin and thin platy structure; slightly hard, very friable, moderately sticky and moderately plastic; many very fine and common fine roots; many very fine vesicular pores; 30 percent gravel; neutral (pH 7.0); abrupt wavy boundary. (8 to 15 cm thick)

Bt1--15 to 25 cm; brown (10YR 5/3) gravelly clay loam, dark brown (10YR 3/3) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine and fine roots; common fine tubular pores; many distinct clay films on faces of peds and lining pores; 20 percent gravel; neutral (pH 7.0); clear wavy boundary. (10 to 18 cm thick)

Bt2--25 to 38 cm; strong brown (7.5YR 5/6) gravelly clay, strong brown (7.5YR 4/6) moist; moderate fine prismatic structure parting to strong fine and medium subangular blocky; very hard, friable, very sticky and very plastic; common very fine and few fine roots; common fine tubular pores; many distinct clay films on faces of peds and lining pores; 20 percent gravel; slightly alkaline (pH 7.4); abrupt wavy boundary. (8 to 23 cm thick)

Bqm--38 to 64 cm; pink (7.5YR 7/4) cemented material, yellowish brown (10YR 5/6) moist; strong thick platy structure; extremely hard, extremely firm; strongly cemented by secondary silica; common very fine roots matted on plate surfaces; alternate horizontal light brown (7.5YR 6/4) 1 to 2 mm thick silica laminae on tops of plates, brown (7.5YR 4/4) moist; slightly alkaline (pH 7.8); clear smooth boundary. (20 to 46 cm thick)

Bqkm1--64 to 91 cm; reddish yellow (7.5YR 7/6) cemented material, strong brown (7.5YR 5/6) moist; massive; extremely hard, extremely firm; strongly cemented by secondary silica; secondary carbonates segregated as common medium and coarse horizontal masses; many thin (<0.5 mm) coats of silica and secondary carbonates on bottoms of rock fragments within cemented matrix; violently effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (23 to 38 cm thick)

Bqkm2--91 to 152 cm; pink (7.5YR 8/4) cemented material, strong brown (7.5YR 5/6) moist; massive; very hard, extremely firm and very firm; strongly to weakly cemented by secondary silica; common alternate horizontal discontinuous 0.5 to 2 mm silica laminae; secondary carbonates segregated as few fine and medium horizontal masses; strongly effervescent; moderately alkaline (pH 8.0).

TYPE LOCATION: Washoe County, Nevada; southeast of Bitner Table near the Sheldon Antelope Refuge; about 2,850 feet south and 210 feet south of the northwest corner of section 23, T. 43 N., R. 22 E.; USGS Badger Mountain NW 7.5 minute topographic quadrangle; latitude 41 degrees 37 minutes 59 seconds N and longitude 119 degrees 28 minutes 49 seconds W; WGS84 Decimal Degrees 41.6330556 latitude, -119.4791667 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in winter and spring, dry from mid-June through October; aridic soil moisture regime that borders on xeric.
Mean annual soil temperature: 8 to 11 degrees C.
Mollic epipedon thickness: 23 to 38 cm, includes the Bt1 horizon.
Depth to duripan: 36 to 50 cm.
Reaction: Neutral through moderately alkaline.

Particle-size control section - Clay content: 35 to 50 percent.
Rock fragments: 10 to 25 percent, mainly gravel. Lithology of fragments is volcanic rocks such as basalt or tuff.

A horizon
Value: 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Clay content: 10 to 18 percent.
Organic matter content: 1 to 3 percent.

Bt horizons
Hue: 7.5YR or 10YR.
Value: 4 through 6 dry, 3 or 4 moist.
Chroma: 3 through 6, dry or moist.
Texture: Clay, gravelly clay, or gravelly clay loam.
Clay content: 35 to 50 percent.
Rock fragments: 10 to 25 percent.
Structure: Subangular blocky, angular blocky, or prismatic parting to subangular blocky or angular blocky.
Organic matter content: 1 or 2 percent in the Bt1 horizon.

Bqm and Bqkm horizons
Hue: 7.5YR or 10YR.
Value: 6 through 8 dry, 4 or 5 moist.
Chroma: 4 through 6, dry or moist.
Cementation class: Strongly cemented or moderately cemented. Lenses of weakly cemented material are in the lower part of most pedons.

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

GEOGRAPHIC SETTING: Powlow soils are on fan remnants. They typically occur on shoulder positions. These soils formed in alluvium derived from volcanic rocks. Slopes are 2 to 15 percent. Elevations range from 1,710 to 2,000 meters. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 250 to 300 mm, mean annual temperature is 7 to 8 degrees C, and the frost-free period is 80 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: This is the Esmod soil. Esmod soils have ochric epipedons and an abrupt textural change between the A and Bt horizons.

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

USE AND VEGETATION: Powlow soils are used for rangeland and wildlife habitat. The present vegetation is mainly Wyoming big sagebrush, bluebunch wheatgrass, and Thurber's needlegrass.

DISTRIBUTION AND EXTENT: Northwestern Nevada. These soils are not extensive with about 5,300 acres of the series mapped to date. MLRA 23.

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

SERIES ESTABLISHED: Washoe County (North Part), Nevada, 1995.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 25 cm (A1, A2 and Bt1 horizons).
Argillic horizon - The zone from 15 to 38 cm (Bt1 and Bt2 horizons).
Duripan - The zone from 38 to 152 cm (Bqm, Bqkm1 and Bqkm2 horizons).
Particle-size control section - The zone from 15 to 38 cm (Bt1 and Bt2 horizons).

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National Cooperative Soil Survey
U.S.A.