LOCATION ZEPHAN NV+CAEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic, mesic Xeric Haplargids
TYPICAL PEDON: Zephan stony sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.)
Al--0 to 2 inches; brown (l0YR 5/3) stony sandy loam, brown (l0YR 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 pores; 20 percent pebbles, 2 percent stones, 5 percent cobbles; medium acid (pH 6.0); clear smooth boundary. (l to 4 inches thick)
A2--2 to 8 inches; pale brown (l0YR 6/3) gravelly loam, dark yellowish brown (l0YR 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 pores; 25 percent pebbles; medium acid (pH 6.0); clear smooth boundary. (0 to 8 inches thick)
Btl--8 to ll inches; light yellowish brown (l0YR 6/4) gravelly clay loam, dark yellowish brown (l0YR 4/4) moist; weak fine subangular blocky structure; hard, friable, sticky and slightly plastic; common fine and very fine roots; common fine and very fine pores; few thin clay films on peds; l5 percent pebbles; slightly acid (pH 6.3); clear wavy boundary. (0 to 8 inches thick)
Bt2--ll to 26 inches; brown (7.5YR 5/4) very cobbly clay, dark yellowish brown (l0YR 4/4) moist; weak coarse prismatic structure; very hard, firm, sticky and plastic; few medium and coarse roots; few medium pores; common moderately thick clay films on peds; 40 percent decomposing coarse fragments; slightly acid (pH 6.l); clear wavy boundary. (l0 to 20 inches thick)
Bt3--26 to 35 inches; brown (7.5YR 5/4) extremely cobbly clay, strong brown (7.5YR 5/6) moist; massive; very hard, firm, sticky and plastic; very few roots; very few pores; few moderately thick clay films in pores; 60 percent decomposing coarse fragments; slightly acid (pH 6.2); gradual irregular boundary. (8 to l4 inches thick)
Cr--35 to 42 inches; weathered rhyolite. (3 to 20 inches thick)
R--42 inches; 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 2,500 feet east and l00 feet south of the northwest corner of section 26, T. 20 N., R. 20 E.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually dry, moist in winter and spring.
Soil temperature - 49 to 53 degrees F.
Control section - Percent clay: 35 to 45.
Rock fragments: 35 to 60 percent.
Depth to paralithic contact - 25 to 40 inches.
Depth to hard bedrock - 40 to 50 inches.
A horizon - Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 2 through 4.
Reaction: Medium acid commonly, but ranges to neutral in some pedons.
B horizon - 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, Havingdon, Pula, Pulcan, Surgen, Tenmile and Vanwyper series. Berning, Bilbo, Pula and Tenmile soils lack bedrock within 40 inches. Havingdon, Surgen, and Vanwyper soils have a lithic contact within 40 inches. Pulcan soils have moderately alkaline Bk horizons.
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 4,500 to 6,500 feet. The climate is semiarid. The mean annual precipitation is 8 to l2 inches; mean annual temperature is 47 to 5l degrees F.; mean January temperature is 30 to 32 degrees F.; mean July temperature is 67 to 69 degrees F.; and the frost-free season is 80 to ll0 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 PERMEABILITY: Well drained; medium or rapid runoff; slow permeability.
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 OFFICE RESPONSIBLE: Reno, Nevada
SERIES ESTABLISHED: Washoe County, South Part, Nevada, l980.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the surface to about 8 inches. (A1 and A2 horizon)
Argillic horizon - The zone from about 8 to 35 inches. (Bt1, Bt2 and Bt3 horizons)
Paralithic contact - The boundary at about 35 inches.
Particles-size control section - The zone from about 8 to 28 inches. (Bt1, Bt2 and upper Bt3 horizons)