LOCATION PERWASO                 NV

Established Series
Rev. CS/RLB/JBF
05/2016

PERWASO SERIES

The Perwaso series consists of very deep, well drained soils that formed in alluvium derived from mixed rocks. The Perwaso soils are on alluvial flats. Slopes are 0 to 2 percent. The mean annual precipitation is about 150 mm and the mean annual temperature is about 11 degrees C.

TAXONOMIC CLASS: Fine-loamy over sandy or sandy-skeletal, mixed, superactive, calcareous, mesic Typic Torrifluvents

TYPICAL PEDON: Perwaso silt loam--rangeland. (Colors are for dry soils unless otherwise noted.)

A--0 to 8 cm; light brownish gray (10YR 6/2) silt loam, dark grayish brown (10YR 4/2) moist; strong medium platy structure parting to strong very fine angular blocky; hard, very friable, slightly sticky and slightly plastic; many very fine roots; violently effervescent; strongly alkaline (pH 9.0); abrupt smooth boundary. (3 to 10 cm thick)

C1--8 to 30 cm; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; massive; slightly hard, very friable, moderately sticky and slightly plastic; few very fine and fine roots; common very fine tubular pores; violently effervescent; strongly alkaline (pH 8.6); clear smooth boundary. (18 to 46 cm)

C2--30 to 64 cm; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; massive; slightly hard, very friable, moderately sticky and slightly plastic; few very fine and fine roots; common very fine tubular pores; violently effervescent; strongly alkaline (pH 8.9); clear smooth boundary. (25 to 40 cm thick)

C3--64 to 91 cm; pale brown (10YR 6/3) sandy clay loam, brown (10YR 4/3) moist; massive; slightly hard, very friable, moderately sticky and moderately plastic; few very fine and fine roots; common very fine tubular pores; strongly effervescent; strongly alkaline (pH 8.9); abrupt smooth boundary. (23 to 33 cm thick)

2C--91 to 157 cm; pale brown (10YR 6/3) gravelly loamy coarse sand, brown (10YR 4/3) moist; massive; slightly hard, very friable, nonsticky and nonplastic; few very fine roots; many very fine interstitial pores; 15 percent gravel; strongly effervescent; strongly alkaline (pH 8.6).

TYPE LOCATION: Pershing County, Nevada; approximately 9 miles north of Gerlach, about 2,400 feet south of the northeast corner of section 36, T. 35 N., R. 23 E.; latitude 40 degrees 52 minutes, 35 seconds N and longitude 119 degrees 18 minutes 33 seconds W; TYPE LOCATION: Pershing County, Nevada; approximately 9 miles north of Gerlach; about 2,400 feet south of the northeast corner of section 31, T. 35 N., R. 24 E.; USGS Haulapai Flat North, NV 7.5 minute topographic quadrangle; latitude 40 degrees 52 minutes, 35 seconds N and longitude 119 degrees 18 minutes 33 seconds W; WGS84 Decimal Degrees 40.8765000 latitude, -119.309166 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry, moist in some part for short periods during the winter and early spring and dry from May through November; typic aridic soil moisture regime.
Mean annual soil temperature: 12 to 14 degrees C.
Depth to discontinuity: 76 to 99 cm.

Particle-size control section - Clay content: 18 to 27 percent in the upper part and 3 to 7 percent in the lower part.

A horizon
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 2 or 3 dry or moist.
Structure: Platy, angular blocky or subangular blocky.
Reaction: Strongly alkaline or very strongly alkaline.
Sodicity (SAR): 30 to 50.

C horizon
Hue: 10YR 2.5Y.
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 2 or 3 dry or moist.
Texture: Stratified silt loam, loam, clay loam and sandy clay loam.
Reaction: Moderately alkaline or strongly alkaline.
Sodicity (SAR): 30 to 175.

2C horizon
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 2 or 3 dry or moist.
Texture: Stratified gravelly loamy coarse sand through fine sand.
Rock fragments: 5 to 20 percent, mainly gravel.
Reaction: Moderately alkaline or strongly alkaline.
Sodicity (SAR): 30 to 50.

COMPETING SERIES: This is the Joraibi series. Joraibi has Hues of 5YR or 7.5YR and is intermittently moist July through September..

GEOGRAPHIC SETTING: Perwaso soils are on alluvial flats. These soils formed in alluvium derived from mixed rocks. Elevations are 1,130 to 1,280 meters. Slopes are 0 to 2 percent. The climate is cool, arid with hot, dry summers and cool, moist winters. The mean annual precipitation is 100 to 200 mm; mean annual temperature is 10 to 12 degrees C.,and the frost-free season is 120 to 130 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Benin, Dedmount, Juva, Slaw and Umberland soils. Benin, Dedmount and Umberland soils have more than 35 percent clay in the particle-size control section. Juva soils have less than 18 percent clay in the particle-size control section and lack a discontinuity with contrasting particle sizes. Slaw soils have less than 15 percent fine sand or coarse in the particle-size control section and lack a discontinuity with contrasting particle sizes.

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

USE AND VEGETATION: Livestock grazing, cropland and wildlife habitat. The present vegetation is black greasewood, Torry quailbush, seepweed, shadscale, rubber rabbitbrush, inland saltgrass and basin wildrye.

DISTRIBUTION AND EXTENT: Northwest Nevada. MLRA 27.

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

SERIES ESTABLISHED: Pershing County, Nevada, West Part, 1986.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the surface to 18 cm (A and part of the C1 horizons).
Fluvent feature - Irregular decrease in organic carbon.
Particle-size control section - The zone from 25 to 100 cm (C2, C3 and part of the C1 and 2C4 horizons).

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National Cooperative Soil Survey
U.S.A.