LOCATION ZEPHAN NV+CA
Established Series
Rev. WED/JBF
01/2023
ZEPHAN SERIES
The Zephan series consist of moderately deep, well drained soils that formed in residuum and colluvium derived from rhyolite and altered andesite. Zephan soils are on plateaus, hills and mountains. Slopes are 4 to 50 percent. The mean annual precipitation is about 250 mm and the mean annual temperature is about 9 degrees C.
TAXONOMIC CLASS: Clayey-skeletal, smectitic, mesic Xeric Haplargids
TYPICAL PEDON: Zephan gravelly sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 5 cm; brown (10YR 5/3) gravelly sandy loam, brown (10YR 4/3) moist; moderate fine subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; many very fine, fine, and medium roots; many very fine, fine, and medium interstitial pores; 20 percent gravel, 5 percent cobbles and 2 percent stones; moderately acid (pH 6.0); clear smooth boundary. (3 to 10 cm thick)
A2--5 to 20 cm; pale brown (10YR 6/3) gravelly loam, dark yellowish brown (10YR 4/4) moist; moderate fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine tubular pores; 25 percent gravel; moderately acid (pH 6.0); clear smooth boundary. (0 to 20 cm thick)
Bt1--20 to 28 cm; light yellowish brown (10YR 6/4) gravelly clay loam, dark yellowish brown (10YR 4/4) moist; weak fine subangular blocky structure; hard, friable, moderately sticky and slightly plastic; common fine and very fine roots; common fine and very fine tubular pores; few faint clay films on peds; l5 percent gravel; slightly acid (pH 6.3); clear wavy boundary. (0 to 20 cm thick)
Bt2--28 to 66 cm; brown (7.5YR 5/4) very cobbly clay, dark yellowish brown (10YR 4/4) moist; weak coarse prismatic structure; very hard, firm, moderately sticky and moderately plastic; few medium and coarse roots; few medium tubular pores; common distinct clay films on peds; 40 percent decomposing coarse fragments; slightly acid (pH 6.1); clear wavy boundary. (25 to 50 cm thick)
Bt3--66 to 89 cm; brown (7.5YR 5/4) extremely cobbly clay, strong brown (7.5YR 5/6) moist; massive; very hard, firm, moderately sticky and moderately plastic; very few medium roots; very few fine tubular pores; few distinct clay films in pores; 60 percent decomposing coarse fragments; slightly acid (pH 6.2); gradual irregular boundary. (20 to 36 cm thick)
Cr--89 to 107 cm; weathered rhyolite; clear wavy boundary. (8 to 50 cm thick)
R--107 cm; hard rhyolite.
TYPE LOCATION: Washoe County, Nevada; about l50 yards south above the railroad tracks and 300 yards north of the water tank in a little valley just south of Panther Valley; about 1,850 feet east and 270 feet south of the northwest corner of section 26, T. 20 N., R. 20 E.; USGS Reno 7.5 minute topographic quadrangle; latitude 39 degrees 34 minutes 38 seconds N and longitude 119 degrees 49 minutes 11 seconds W; WGS84 Decimal Degrees 39.5772222 latitude, -119.8197222 longitude.
RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry, moist in winter and spring, aridic soil moisture regime bordering on xeric.
Mean annual soil temperature: 9 to 12 degrees C.
Depth to paralithic contact: 64 to 100 cm.
Depth to hard bedrock: 100 to 125 cm.
Particle-size control section - Clay content: 35 to 45 percent.
Rock fragments: 35 to 60 percent.
A horizons
Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 2 through 4.
Reaction: Moderately acid through neutral.
Bt horizons
Hue: 10YR or 7.5YR.
Value: 4 through 6 dry, 4 or 5 moist.
Chroma: 3 or 4 dominantly, but may be as high as 6 in the lower part of some pedons.
Textures: Clay, sandy clay, subhorizons may be sandy clay loam or heavy clay loam.
C horizon
Other features: A thin medium acid or strongly acid C horizon occurs above bedrock in some pedons.
COMPETING SERIES: These are the
Berning,
Bilbo,
Clenage,
Havingdon,
Lambranch,
Maderbak,
Pula,
Surgem,
Tanawit,
Tenmile and
Vanwyper series.
Berning,
Bilbo,
Lambranch,
Pula,
Tanawit, and
Tenmile soils lack bedrock within 100 cm.
Clenage,
Havingdon,
Maderbak,
Surgem, and
Vanwyper soils have hard bedrock within 100 cm.
GEOGRAPHIC SETTING: Zephan soils are on plateaus, hills and mountains. These soils formed in residuum and colluvium from rhyolite and altered andesite. Slopes are 4 to 50 percent. Elevations are 1,370 to 1,980 meters. The climate is semiarid. The mean annual precipitation is 200 to 300 mm, mean annual temperature is 8 to 11 degrees C and the frost-free season is 80 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Manogue,
Mizel,
Wedekind, and
Xman soils. Manogue soils are Vertisols. Mizel soils are shallow and lack an argillic horizon. Wedekind soils are loamy, shallow, and have a mollic epipedon. Xman soils have less than 30 percent rock fragments in the particle-size control section and are shallow to bedrock.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; medium or rapid runoff; slow permeability; moderately low saturated hydraulic conductivity.
USE AND VEGETATION: Zephan soils are used for wildlife habitat, recreation, and urban development. Vegetation is primarily horsebrush, cheatgrass, bottlebrush squirreltail, ephedra, big sagebrush, and low sagebrush.
DISTRIBUTION AND EXTENT: Western Nevada. These soils are of small extent. MLRA 26.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Washoe County, South Part, Nevada, 1980.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the surface to 20 cm (A1 and A2 horizon).
Argillic horizon - The zone from 20 to 89 cm (Bt1, Bt2 and Bt3 horizons).
Paralithic contact - The boundary at 89 cm (Cr layer).
Lithic contact - The boundary at 107 cm (R layer).
Particles-size control section - The zone from about 20 to 70 cm (Bt1, Bt2 and upper Bt3 horizons).
ADDITIONAL DATA: User Pedon ID: 2006NV031148.
National Cooperative Soil Survey
U.S.A.