LOCATION POWLEY NV+CAInactive Series
TAXONOMIC CLASS: Clayey, smectitic, mesic, shallow Vitritorrandic Durixerolls
TYPICAL PEDON: Powley gravelly ashy fine sandy loam--rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 1 inch; grayish brown (10YR 5/2) gravelly ashy fine sandy loam, very dark brown (10YR 2/2) moist; weak medium platy structure; soft, very friable, slightly sticky and nonplastic; root crowns only; many very fine interstitial pores; slightly acid (pH 6.4); abrupt broken boundary. (1 or 2 inches thick)
A2--1 to 3 inches; light brownish gray (10YR 6/2) ashy fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak medium platy structure; slightly hard, friable, slightly sticky and nonplastic; few very fine and fine roots; many very fine and fine vesicular pores; neutral (pH 6.6); clear wavy boundary. (1 to 3 inches thick)
A3--3 to 9 inches; grayish brown (10YR 5/2) ashy fine sandy loam, dark brown (10YR 3/3) moist; moderate thick platy structure parting to moderate medium subangular blocky; slightly hard, very friable, slightly sticky and slightly plastic; many very fine, many fine, and few medium roots; many very fine interstitial pores; neutral (pH 6.6); clear smooth boundary. (4 to 8 inches thick)
Bt and E--9 to 11 inches; pale brown (10YR 6/3) ashy sandy clay loam, dark brown (10YR 3/3) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; many very fine, many fine, and few medium roots; many very fine interstitial and few fine tubular pores; few faint clay films on faces of peds and lining pores (Bt part); common uncoated sand grains (skeletans) in few to common fine and medium very pale brown (10YR 7/3) zones of clay depletion (E part); neutral (pH 6.8); clear smooth boundary. (1 to 4 inches thick)
Bt--11 to 15 inches; brown (10YR 5/3) clay, brown (7.5YR 4/3) moist and crushed; weak medium prismatic structure parting to moderate medium subangular blocky; hard, friable, very sticky and very plastic; many very fine, many fine, and few medium roots; common very fine and fine tubular pores; common to many prominent brown (7.5YR 4/3) pressure cutans on faces of peds and many distinct clay films lining pores; neutral (pH 6.8); clear smooth boundary. (4 to 6 inches thick)
Btq--15 to 19 inches; pale brown (10YR 6/3) clay, brown (10YR 4/3) moist; weak medium prismatic structure parting to moderate medium subangular blocky; hard, friable, very sticky and very plastic; common very fine and fine roots between peds; few very fine and fine tubular pores; many distinct and common prominent light yellowish brown (10YR 6/4) pressure cutans on faces of peds and common distinct clay films lining pores; 10 percent subangular blocky durinodes that are very hard, firm, and brittle; neutral (pH 6.8); abrupt smooth boundary. (3 to 6 inches thick.)
Bqm--19 to 27 inches; pale brown (10YR 6/3) duripan, very dark grayish brown (10YR 3/2) moist; strong medium and thick platy structure; extremely hard, extremely firm; strongly cemented by secondary silica; light yellowish brown (10YR 6/4) and very pale brown (10YR 7/4) laminae of secondary silica on faces of peds; common very fine and fine roots matted on plate surfaces; few very fine discontinuous tubular pores; neutral (pH 6.8); gradual smooth boundary. (6 to 10 inches thick.)
Bqkm--27 to 32 inches; grayish brown (10YR 5/2) duripan, brown (10YR 4/3) moist; massive; extremely hard, extremely firm; moderately to strongly cemented by secondary silica; light yellowish brown (10YR 6/4) and very pale brown (10YR 7/4) laminae of silica; few coarse dark brown (10YR 3/3) coats of organic matter; no roots apparent; few very fine tubular pores; secondary carbonates segregated as common coarse very pale brown (10YR 8/3) coats along fractures; noneffervescent matrix and violently effervescent coats; matrix is neutral (pH 6.8) and coats are moderately alkaline (pH 8.4).
TYPE LOCATION: Washoe County, Nevada; southwest of Nellie Spring Mountain between Fern Spring and Americum Reservoir; about 1,200 feet west and 1,625 feet south of the northeast corner of section 21, T. 40 N., R. 21 E.; USGS Hart Mountain 7.5 minute topographic quadrangle; 41 degrees 22 minutes 23.5 seconds north latitude and 119 degrees 37 minutes 7.7 seconds west longitude, NAD 27.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually moist in the moisture control section during winter and spring, dry in summer and fall; aridic moisture regime that borders on xeric.
Mean annual soil temperature - 47 to 49 degrees F.
Mollic epipedon thickness - 7 to 13 inches, includes the Bt and E horizon.
Depth to base of argillic horizon - 15 to 20 inches.
Depth to duripan - 15 to 20 inches.
Depth to bedrock - More than 60 inches.
Particle-size control section - Clay content: Averages 35 to 55 percent; Rock fragments: 5 to 15 percent, mainly pebbles. Lithology of fragments are volcanic rocks such as tuff and basalt.
A1 horizon - Value: 4 through 6 dry, 2 or 3 moist; The upper 7 inches mixed has a dry value of 4 or 5.
Chroma: 2 or 3, dry or moist.
Rock fragments: 15 to 25 percent pebbles, 0 to 5 percent cobbles.
Structure: Weak or moderate, thin to thick platy.
Consistence: Soft or slightly hard dry.
Reaction: Slightly acid or neutral.
Organic matter content: 1 to 3 percent.
Volcanic glass content: 30 to 60 percent in coarse silt through fine sand fractions.
A2 and A3 horizons - Value: 6 or 7 dry, 3 or 4 moist.
Chroma: 1 through 3, dry or moist.
Rock fragments: 0 to 15 percent pebbles.
Structure: Platy parting to moderate or strong, very fine to medium subangular blocky or granular.
Reaction: Slightly acid or neutral.
Organic matter content: 1 to 3 percent.
Volcanic glass content: 30 to 60 percent in coarse silt through fine sand fractions.
Bt and E horizon - Texture: Ashy sandy clay loam, ashy loam, or ashy clay loam.
Clay content: 27 to 40 percent.
Rock fragments: 0 to 15 percent pebbles.
Organic matter content: 1 to 3 percent.
Volcanic glass content: 30 to 60 percent in coarse silt through fine sand fractions.
Bt and Btq horizons - Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 3 through 5 moist.
Chroma: 3 or 4, dry or moist.
Clay content: 40 to 60 percent.
Rock fragments: 5 to 15 percent pebbles.
Structure: Weak to strong, fine or medium prismatic, or medium or coarse subangular blocky; Weak grades of structure are normally accompanied by a stronger secondary grade of structure.
Durinodes: 0 to 20 percent.
Bqm and Bqkm horizons - Value: 5 through 7 dry, 3 through 5 moist.
Chroma: 2 or 3, dry or moist; Silica laminae have chroma of 3 through 6.
Structure: Moderate or strong platy, medium to thick platy or the horizon is massive.
Cementation class: Moderately cemented or strongly cemented.
COMPETING SERIES: At present, there are no other series in this family.
GEOGRAPHIC SETTING: Powley soils are on fan remnants. They formed in alluvium derived from volcanic rocks such as tuff and basalt and in eolian material derived from volcanic ash. Slopes are 2 to 15 percent. Elevations range from 5,500 to 6,000 feet. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 10 to 12 inches that comes mostly as snow. The mean annual temperature is 45 to 47 degrees F. The frost-free period is 80 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Espil, Hart Camp, and Mascamp soils. Espil soils are shallow to duripans. Hart Camp soils are shallow to paralithic contacts. Mascamp soils are loamy-skeletal and are shallow to lithic contacts.
DRAINAGE AND PERMEABILITY: Well drained; very high surface runoff; very slow permeability above the duripan.
USE AND VEGETATION: Powley soils are used for livestock grazing. The dominant vegetation consists of Wyoming big sagebrush, Douglas rabbitbrush, bluebunch wheatgrass, Thurber's needlegrass, bottlebrush squirreltail, and annual forbs.
DISTRIBUTION AND EXTENT: Northwestern Nevada and adjacent parts of northeastern California. These soils are moderately extensive. MLRA 23.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Washoe County (Surprise Valley-Home Camp Area), Nevada, 1968.
REMARKS: This series was inactivated in 2007 as a result of the update and recorrelation of the Soil Survey of Surprise Valley-Home Camp Area, California and Nevada in 2006.
The revision of May 2001 updated the type location to the probable correct location of the typical pedon. A prior revision in March 2001 updated the taxonomic class from Clayey, smectitic, frigid, shallow Aridic Durixerolls and recognized the influence of volcanic ash on the upper horizons.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 11 inches (A1, A2, A3, and Bt and E horizons).
Argillic horizon - The zone from 9 to 19 inches (Bt and E, Bt, and Btq horizons).
Vitrandic intergrade feature - The zone from the soil surface to 11 inches (A1, A2, A3, and Bt and E horizons).
Durinodes- The zone from 15 to 19 inches (Btq horizon).
Duripan- The zone from 19 to 32 inches (Bqm and Bqkm horizons).
Particle-size control section - The zone from 9 to 19 inches (Bt and E, Bt, and Btq horizons).
ADDITIONAL DATA: A pedon is sampled for full characterization by the Soil Survey Laboratory (SSL), Lincoln, NE, as soil survey sample number S88NV-031-001 (pedon # 88P0686).