LOCATION STEPTOE                 NV

Established Series
Rev. CWL/PWB/JBF
11/2016

STEPTOE SERIES

The Steptoe series consists of very deep, well drained soils that formed in alluvium from limestone with admixtures of quartzite. Steptoe soils occur on stream terraces and drainageways in mountains. Slopes range from 4 to 15 percent. The mean annual precipitation is about 450 mm and the mean annual temperature is about 5 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Cumulic Haploxerolls

TYPICAL PEDON: Steptoe gravelly loam, rangeland. (Colors are for dry soils unless otherwise noted.) The soil surface is covered with approximately 10 percent gravel and 10 percent cobbles.

A1--0 to 12 cm; grayish brown (10YR 5/2) gravelly loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure parting to moderate medium granular; soft, very friable, nonsticky and nonplastic; many very fine and fine roots; many very fine and fine tubular pores; 20 percent gravel and 5 percent cobbles; very slightly effervescent; moderately alkaline (pH 8.0); clear smooth boundary. (10 to 20 cm thick)

A2--12 to 30 cm; dark grayish brown (10YR 4/2) very gravelly sandy loam, very dark brown (10YR 2/2) moist; moderate medium subangular blocky structure parting to moderate medium granular; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine tubular pores; 30 percent gravel and 10 percent cobbles; slightly effervescent; moderately alkaline (pH 8.1); clear smooth boundary. (10 to 30 cm thick)

ABk--30 to 54 cm; brown (10YR 5/3) very gravelly sandy loam, dark brown (10YR 3/3) moist; moderate coarse subangular blocky structure parting to weak medium subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; many very fine and common fine roots; many very fine and fine tubular pores; 35 percent gravel and 10 percent cobbles; common (5 percent) secondary calcium carbonate concretions on bottom of rock fragments; strongly effervescent; strongly alkaline (pH 8.5); clear smooth boundary. (20 to 30 cm thick)

Bk1--54 to 99 cm; yellowish brown (10YR 5/4) very gravelly sandy clay loam, dark yellowish brown (10YR 3/4) moist; strong coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; many very fine tubular pores; 35 percent gravel and 20 percent cobbles; common (10 percent) secondary calcium carbonate concretions on bottom of rock fragments; common (10 percent) fine secondary calcium carbonate threads; violently effervescent; strongly alkaline (pH 8.6); gradual smooth boundary. (30 to 50 cm thick)

Bk2--99 to 152 cm; light brownish gray (10YR 6/2) very gravelly sandy clay loam, dark grayish brown (10YR 4/2) moist; moderate coarse prismatic structure parting to strong coarse subangular; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; common very fine tubular pores; 35 percent gravel and 15 percent cobbles; common (15 percent) secondary calcium carbonate concretions on bottom of rock fragments; common (10 percent) fine secondary calcium carbonate threads; violently effervescent; strongly alkaline (pH 8.6).

TYPE LOCATION: White Pine County, Nevada; about 3 miles east of Cave Lake and 3 miles west of Cave Mountain and 100 feet south of the road; about 1,780 feet north and 1,400 feet west of the southwest corner, section 10, T 15 N., R 65 E.; USGS Cave Creek 7.5 minute quadrangle; 39 degrees 10 minutes 39.8 seconds north latitude 114 degrees 39 minutes and 28.0 seconds west longitude; WGS84 Decimal Degrees 39.1777222 latitude, -114.6577778 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in winter, spring, and early summer, dry in all parts at least 45 consecutive days following the summer solstice (July and August); Xeric soil moisture regime.
Soil temperature: 5.5 to 7 degrees C.
Mollic epipedon thickness: 50 to 100 cm.
Depth to cambic horizon: 50 to 100 cm.
Cambic horizon thickness: 30 to 50 cm.

Particle-size control section - Clay content; Averages 18 to 27 percent.
Rock fragment content; Averages 35 to 60 percent. Lithology of rock fragments is mainly limestone.

A horizons
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Effervescence: Very slightly effervescent through slightly effervescent.
Reaction: Slightly alkaline or moderately alkaline.

ABk and Bk horizons
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 2 to 4, dry or moist.
Clay content: 18 to 27 percent.
Rock fragments: 35 to 60 percent.
Effervescence: Strongly effervescent to violently effervescent.
Reaction: Moderately alkaline or strongly alkaline.
Calcium carbonate equivalence: 5 to 15 percent.

COMPETING SERIES: This is the Ripcon (NV) and Tierney (NV) series.
Ripcon soils have 12 to 18 percent clay in the particle-size control section, are moderately well drained, and have a seasonal high water table within 100 cm of the surface for brief periods in the spring. Tierney soils have 10 to 18 percent clay in the particle-size control section.

GEOGRAPHIC SETTING: Steptoe soils are in mountains and occur on stream terraces and drainageways. These soils formed in alluvium from limestone with admixtures of quartzite. Slopes are 4 to 15 percent. Elevations are 2,300 to 2,500 meters. The climate is dry-subhumid, with cool moist winters and warm dry summers. The mean annual precipitation is 400 to 500 mm. The mean annual temperature is 4 to 6 degrees C. The frost-free season is 40 to 70 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bigwash, Brokit, and Lehmandow series.
Bigwash soils contain 5 to 15 percent rock fragments in the particle-size control section. Brokit soils have a strongly contrasting particle-size control section with 12 to 20 percent clay in the upper part and 3 to 10 percent clay in the lower part. Lehmandow soils are very poorly drained.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; medium to high runoff; moderately high saturated hydraulic conductivity. These soils are susceptible to very rare flooding for very brief periods between March and September.

USE AND VEGETATION: Livestock grazing, recreation, and wildlife habitat. The potential native vegetation is mainly slender wheatgrass, basin wildrye, and chokecherry. This site is correlated to Ecological Site R28BY103NV Streambank Type B, Chokecherry community.

DISTRIBUTION AND EXTENT: East Central Nevada. These soils are not extensive. MLRA 28B.

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

SERIES ESTABLISHED: White Pine County, Humboldt-Toiyabe National Forest, South Part, 2013.

REMARKS: Diagnostic horizons and features recognized in the pedon are:
Mollic epipedon - The zone from the soil surface to 54 cm (A1, A2, and ABk, horizons).
Particle-size control section - The zone from 25 to 100 cm (lower part of the A2, ABk, Bk1, and upper part of the Bk2 horizons).

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National Cooperative Soil Survey
U.S.A.