LOCATION SEVENMILE               NV

Established Series
Rev. JBF-TRM-JVC
06/2016

SEVENMILE SERIES

The Sevenmile series consist of very deep, well drained soils that formed in alluvium derived from welded tuff with minor components of limestone and quartzite. Sevenmile soils are on stream terraces, drainageways, and inset fans. Slopes are 0 to 8 percent. The mean annual precipitation is about 250 mm and the mean annual temperature is about 10 degrees C.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Vitritorrandic Haploxerolls

TYPICAL PEDON: Sevenmile ashy fine sandy loam--rangeland. (Colors are for dry soil unless otherwise noted.)

A1--0 to 7 cm; brown (10YR 5/3) ashy fine sandy loam, dark brown (10YR 3/3) moist; weak moderately thick platy structure; soft, very friable, slightly sticky and slightly plastic; few very fine roots; few fine vesicular pores; 5 percent gravel; slightly alkaline (pH 7.8); clear smooth boundary. (5 to 15 cm thick)

A2--7 to 24 cm; brown (10YR 5/3) ashy fine sandy loam, dark brown (10YR 3/3) moist; moderate fine and medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common fine and medium roots; common very fine and fine tubular pores; 5 percent gravel; slightly alkaline (pH 7.7); clear smooth boundary. (8 to 25 cm thick)

Bw1--24 to 42 cm; brown (10YR 5/3) ashy fine sandy loam, dark brown (10YR 3/3) moist; moderate fine and medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common fine and medium roots; common very fine and fine tubular pores; 5 percent gravel; moderately alkaline (pH 7.9); clear smooth boundary. (15 to 60 cm thick)

Bw2--42 to 87 cm; pale brown (10YR 6/3) sandy loam, brown (10YR 4/3) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common fine and medium roots; common very fine and fine tubular pores; 10 percent gravel; moderately alkaline (pH 8.1); clear smooth boundary. (15 to 60 cm thick)

C1--87 to 120 cm; pale brown (10YR 6/3) very gravelly loamy coarse sand, brown (10YR 4/3) moist; massive; soft, very friable, slightly sticky and slightly plastic; few fine roots; common fine interstitial pores; about 35 percent gravel; slightly alkaline (pH 7.8); slightly effervescent; clear smooth boundary. (25 to 50 cm thick)

C2--120 to 154 cm; pale brown (10YR 6/3) very gravelly loamy sand, brown (10YR 4/3) moist; massive; soft, very friable, slightly sticky and nonsticky and slightly plastic and nonplastic; few fine roots; many fine and medium interstitial pores; about 50 percent gravel; slightly alkaline (pH 7.6).

TYPE LOCATION: Nye County, Nevada; in Ralston Valley east of the Toquima Range; about 150 feet south and 1,500 feet west of the northeast corner of section 29, T. 8 N., R. 45 E.; USGS Belmont West 7.5 minute topographic quadrangle; latitude 38 degrees 31 minutes 16 seconds N and longitude 116 degrees 56 minutes 05 seconds W; WGS84 Decimal Degrees 38.5211111 latitude, -116.9347222 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Moist in winter and spring, dry in summer and fall except for 10 to 20 days cumulative between July to October due to convection storms; aridic soil moisture regime that borders on xeric.
Mean annual soil temperature: 11 to 14 degrees C.
Mollic epipedon thickness: 25 to 45 cm.
Cambic horizon thickness: 15 to 60 cm.
Depth to base of cambic horizon: 60 to 90 cm.
Sodium fluoride pH: 8.5 to 10.0.

Particle-size control section - Clay content: Averages 6 to 18 percent.
Rock fragments: Averages 10 to 35 percent, mainly gravel. Lithology of fragments are dominantly volcanic.

A horizons
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Reaction: Neutral through moderately alkaline.
Organic matter content: 1 to 3 percent.
Volcanic glass content: 15 to 25 percent in coarse silt through fine sand fractions; Acid oxalate extractable aluminum plus one-half the acid oxalate extractable iron: 0.1 to 0.3 percent.

Bw1 horizon
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 3 or 4, dry or moist.
Texture: Ashy fine sandy loam, ashy very fine sandy loam, or ashy loam.
Rock fragments: 5 to 15 percent.
Organic matter content: 1 or 2 percent.
Consistence: Soft or slightly hard, dry; very friable or friable, moist, slightly sticky or moderately sticky and slightly plastic or moderately plastic, wet.
Reaction: Neutral through moderately alkaline.
Volcanic glass content: 15 to 25 percent in coarse silt through fine sand fractions; Acid oxalate extractable aluminum plus one-half the acid oxalate extractable iron: 0.1 to 0.3 percent.

Bw2 horizon
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 3 or 4, dry or moist.
Texture: Sandy loam, very fine sandy loam, or gravelly loam.
Rock fragments: 5 to 35 percent
Consistence: Soft to moderately hard, dry; very friable or friable, moist.
Reaction: Neutral through moderately alkaline.

C horizons
Value: 6 or 7 dry, 3 through 5 moist.
Chroma: 3 or 4, dry or moist.
Texture: Stratified and dominated by loamy coarse sand, loamy sand, fine sandy loam, sandy loam, or very fine sandy loam but includes strata of loamy coarse sand to silt loam in some pedons.
Rock fragments: Averages 10 to 50 percent, mainly gravel; individual strata range from 0 to 65 percent.
Structure: Subangular blocky or massive.
Consistence: Soft to moderately hard, dry, nonsticky or slightly sticky and nonplastic or slightly plastic, wet.
Reaction: Slightly alkaline or moderately alkaline.
Effervescence: Noneffervescent through violently effervescent.
Calcium carbonate equivalent: 0 to 3 percent in the material less than 2 mm.

COMPETING SERIES: These are the Caphealy, Deschutes, Era, Houstake and Lafollette series.

Caphealy and Deschutes soils are moderately deep to bedrock. Era soils have carbonates at 50 to 90 cm. Houstake soils have firm brittle layer at 50 to 100 cm. Lafollette soils hae C horizons with 35 to 60 percent rock fragments.

GEOGRAPHIC SETTING: Sevenmile soils are on stream terraces, drainageways and inset fans. These soils formed in alluvium derived from welded tuff with minor components of limestone and quartzite. Slopes are 0 to 8 percent. Elevations range from 1,480 to 2,270 meters. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 200 to 350 mm, mean annual temperature is 8 to 13 degrees C, and the frost-free period is 100 to 130 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Mosida, Penoyer, and Rebel soils. Mosida soils are coarse-loamy, have ochric epipedons, and an irregular decrease in organic carbon. Penoyer soils are coarse-silty and have ochric epipedons. Rebel soils are coarse-loamy and have ochric epipedons.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; very low or low surface runoff; high saturated hydraulic conductivity. These soils are susceptible to rare flooding for very brief periods year-round.

USE AND VEGETATION: Sevenmile soils are used for livestock grazing and wildlife habitat. The vegetation is mainly Wyoming big sagebrush, rabbitbrush, Indian ricegrass, thickspike wheatgrass, and basin wildrye.

DISTRIBUTION AND EXTENT: Central Nevada. These soils are not extensive. MLRAs 28B, 28A and 29.

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

SERIES ESTABLISHED: Nye County (Northwest Part), Nevada, 1994.

REMARKS: This revision updates the taxonomic classification from Coarse-loamy, mixed, superactive, mesic Aridic Haploxerolls.

Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 43 cm (A1, A2, and Bw1 horizons).
Vitritorrandic feature - The zone from the soil surface to 43 cm (A1, A2, and Bw1 horizons).
Cambic horizon - The zone from 43 to 86 cm (Bw2 horizon).
Particle-size control section - The zone from 25 to 100 cm (Bw2 horizon and parts of the Bw1 and C1 horizons).

ADDITIONAL DATA: The typical pedon at the series type location was sampled for full characterization by the Soil Survey Laboratory (SSL), Lincoln, NE, as soil survey sample number S92nv-023-006 (pedon # 92P0575). The 10/2009 update changed the classification from isotic to mixed, superactive to better reflect the series concept.

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National Cooperative Soil Survey
U.S.A.