LOCATION LAROSS                  NV

Established Series
Rev. DJM/RLB/JBF
03/2011

LAROSS SERIES

The Laross series consists of deep, well drained soils that formed in residuum and colluvium derived from volcanic tuff. The Laross soils are on mountain slopes. Slopes are 30 to 75 percent. The mean annual precipitation is about 400 mm and the mean annual temperature is about 10 degrees C.

TAXONOMIC CLASS: Ashy-skeletal, glassy, mesic Vitrandic Haplustolls

TYPICAL PEDON: Laross cobbly loam--woodland. (Colors are for dry soil unless otherwise noted.) The surface is partially covered with 20 percent cobbles and 10 percent gravel.

A1--0 to 8 cm; dark grayish brown (10YR 4/2) cobbly loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and fine roots; many very fine and fine interstitial and common fine tubular pores; 20 percent cobbles and 10 percent gravel; neutral (pH 7.2); clear smooth boundary. (3 to 10 cm thick)

A2--8 to 20 cm; dark grayish brown (10YR 4/2) gravelly loam, dark brown (10YR 3/3) moist; moderate fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine and fine and common medium roots; many very fine and fine interstitial and common fine tubular pores; 5 percent cobbles and 20 percent gravel; neutral (pH 7.2); gradual smooth boundary. (10 to 15 cm thick)

2Bw1--20 to 33 cm; pale brown (10YR 6/3) extremely gravelly loam, brown (10YR 4/3) moist; moderate fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many fine and medium and common coarse roots; common fine and medium interstitial and common medium tubular pores; 20 percent cobbles and 45 percent gravel; neutral (pH 7.0); clear wavy boundary. (10 to 18 cm thick)

2Bw2--33 to 48 cm; light gray (10YR 7/2) extremely cobbly loam, brown (10YR 5/3) moist; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and medium roots; common fine and medium interstitial and common medium tubular pores; 30 percent cobbles and 35 percent gravel; neutral (pH 7.0); clear wavy boundary. (13 to 20 cm thick)

2C--48 to 132 cm; light gray (10YR 7/2) extremely cobbly sandy loam, pale brown (10YR 6/3) moist; massive; slightly hard, very friable, nonsticky and nonplastic; common very fine and fine and few medium roots; many very fine and fine interstitial and few fine tubular pores; 40 percent cobbles and 30 percent gravel; neutral (pH 7.0). (50 to 100 cm thick)

2R--132 cm; volcanic tuff.

TYPE LOCATION: Lincoln County, Nevada; approximately 1600 feet southeast of the Ella Mountain Lookout; about 1.75 miles southwest of the southwest corner of section 31, T. 5 S., R. 68 E.; latitude 37 degrees 27 minutes 23 seconds N and longitude 114 degrees 27 minutes 49 seconds W; NAD 83.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist, moist in some part of the moisture control section from early July to early October and during the winter and early spring months.
Mean annual soil temperature: 8 to 11 degrees C.
Thickness of mollic epipedon; 18 to 25 cm
Depth to bedrock: 100 to 150 cm.
Other features: Strong influence from volcanic glass with a bulk density of 0.90 to 1.2 gram/cubic cm.

Particle-size control section - Clay content: 10 to 18 percent.
Rock fragments: 35 to 60 percent, dominantly gravel and cobbles.

A horizons
Value: 4 or 5 dry, 3 or 4 moist.
Chroma: 2 or 3.

2Bw horizons
Value: 6 or 7 dry, 4 through 6 moist.
Chroma: 2 or 3.
Texture: Loam or sandy loam.
Rock fragments: 35 to 75 percent gravel and cobbles.
Structure: Weak or moderate subangular blocky.
Consistence: Slightly hard or soft.
Other features: The Bw horizons average 30 to 50 percent volcanic glass by weight within the very fine sand fraction.

2C horizon
Value: 6 or 7 moist or dry.
Chroma: 2 or 3.
Texture: Loam or sandy loam.
Rock fragments: 60 to 85 percent gravel and cobbles.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Laross soils are on mountain slopes. These soils formed in residuum and colluvium derived from volcanic tuffs with a strong influence from volcanic glass. Slopes are 30 to 75 percent. Elevations are 1,895 to 2,230 meters. The climate is cool continental with warm moist summers. The mean annual precipitation is 350 to 460 mm; the mean annual temperature is 7 to 10 degrees C and the frost free season is 90 to 120 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Turba and Faleria soils. Turba soils have a paralithic contact within 36 cm and have a loamy-skeletal control section. Faleria soils have an argillic horizon and a mean annual soil temperature less than 8 degrees C.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; rapid runoff; moderate permeability; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: Woodland and wildlife habitat. The present vegetation is mainly singleleaf pinyon, mountain big sagebrush, mountain snowberry, Utah serviceberry, and pine bluegrass.

DISTRIBUTION AND EXTENT: Southeastern Nevada. These soils are of small extent. MLRA 29.

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

SERIES ESTABLISHED: Lincoln County, Nevada, South Part, 1992.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the surface to 20 cm (A1 and A2 horizons).
Cambic horizon - The zone from 20 to 48 cm (2Bw1 and 2Bw2 horizons).
Vitrandic subgroup - The sand fraction makes up more than 30 percent of the fine earth and it contain more than 30 percent volcanic glass.
Particle-size control section - The zone from 25 to 100 cm (2Bw1, 2Bw2 and upper part of the 2C horizons).

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National Cooperative Soil Survey
U.S.A.