LOCATION ERASTRA                 NV

Established Series
Rev. JBF/EWB/TM/JVC
03/2017

ERASTRA SERIES

The Erastra series consists of shallow, well drained soils that formed in residuum and colluvium derived from granodiorite. Erastra soils are on mountains and hills. Slopes are 8 to 75 percent. The mean annual precipitation is about 360 mm and the mean annual temperature is about 8 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic, shallow Aridic Argixerolls

TYPICAL PEDON: Erastra extremely stony coarse sandy loam--forestland. (Colors are for dry soil unless otherwise noted.) The soil surface is covered with 20 percent gravel, 10 percent cobbles, 25 percent stones, and 10 percent boulders.

A--0 to 8 cm; brown (10YR 5/3) extremely stony coarse sandy loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and nonplastic; common very fine and fine roots; common very fine interstitial pores; 25 percent gravel, 10 percent cobbles, and 25 percent stones; neutral (pH 6.8); clear wavy boundary. (8 to 23 cm thick)

Bt1--8 to 18 cm; brown (10YR 5/3) extremely stony sandy clay loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure; hard, friable, moderately sticky and moderately plastic; common fine and medium roots; common very fine tubular and interstitial pores; common distinct clay films on faces of peds and lining pores; 25 percent gravel, 10 percent cobbles, and 25 percent stones; neutral (pH 6.8); clear wavy boundary. (8 to 25 cm thick)

Bt2--18 to 28 cm; yellowish brown (10YR 5/4) extremely stony sandy clay loam, dark yellowish brown (10YR 4/4) moist; moderate fine and medium subangular blocky structure; very hard, friable, moderately sticky and moderately plastic; common fine through coarse roots; common very fine tubular and interstitial pores; common distinct clay films on faces of peds and lining pores; 40 percent gravel, 10 percent cobbles, and 20 percent stones; neutral (pH 6.8); clear wavy boundary. (0 to 23 cm thick)

Bt3--28 to 36 cm; light yellowish brown (10YR 6/4) extremely stony sandy clay loam, yellowish brown (10YR 5/4) moist; weak medium subangular blocky structure; very hard, friable, moderately sticky and moderately plastic; few fine through coarse roots; common very fine tubular and interstitial pores; common distinct clay films on faces of peds and lining pores; 40 percent gravel, 10 percent cobbles, and 20 percent stones; slightly acid (pH 6.4) clear irregular boundary. (0 to 13 cm thick)

Cr--36 to 61 cm; slightly weathered granodiorite.

TYPE LOCATION: Douglas County, Nevada; about 14.5 miles east of Gardnerville in the Pine Nut Mountains; 1,100 feet south and 800 feet west of the northeast corner of section 2, T. 12 N., R. 22 E.; USGS Pine Nut Valley 7.5 minute topographic quadrangle; latitude 38 degrees 56 minutes 10.62 seconds N and longitude 119 degrees 28 minutes 33.54 seconds W; WGS84 Decimal Degrees 38.9362833 latitude, -119.4759833 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry; moist in winter and spring, dry in summer and fall; aridic soil moisture regime that borders on xeric.
Mean annual soil temperature: 8 to 11 degrees C.
Mollic epipedon thickness: 18 to 30 cm, includes the Bt1 horizon.
Depth to base of argillic horizon: 36 to 50 cm.
Depth to bedrock: 36 to 50 cm to a paralithic contact. The paralithic materials below the contact are weathered granodiorite.
Reaction: Slightly acid or neutral.

Particle-size control section - Clay content: 18 to 27 percent.
Sand content: 50 to 75 percent, mainly medium through very coarse sands.
Rock fragments: averages 60 to 75 percent, mainly stones and cobbles. Lithology of fragments is granodiorite.

A horizon
Hue: 10YR or 7.5YR.
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Organic matter content: 2 or 3 percent.

Bt1 horizon
Hue: 10YR or 7.5YR.
Texture: Extremely stony coarse sandy loam or extremely stony sandy clay loam.
Organic matter content: 1 or 2 percent.

Bt2 and Bt3 horizons (when present)
Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 3 or 4, dry or moist.
Texture: Extremely stony coarse sandy loam or extremely stony sandy clay loam.
Organic matter content: 0.5 to 1 percent.

COMPETING SERIES: These are the Acrelane, Koontz, Roloc, Tulecan, and Ubehebe series.

Acrelane, Roloc, and Tulecan soils average between 35 and 60 percent rock fragments in the particle-size control section and rock fragments are mainly fine gravel. In addition, Roloc soils have 10 to 18 percent clay in the particle-size control section. Koontz soils have argillic horizons with loam or clay loam texture, do not have significant amounts of medium or coarser sands, have rock fragments which are mainly gravel, and have paralithic materials of metamorphic (metavolcanic) rocks in the series control section. Ubehebe soils have paralithic materials of siltstone in the series control section, are moist in some part for 10 to 20 days cumulative between July and October, and have rock fragments which are mainly coarse gravel.

GEOGRAPHIC SETTING: Erastra soils are on mountains and hills. They typically occur on backslope positions. These soils formed in residuum and colluvium derived from granodiorite. Slopes are 8 to 75 percent. Elevations range from 1,950 to 2,440 meters. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 300 to 400 mm, mean annual temperature is 7 to 9 degrees C, and the frost-free period is 75 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dotsolot and Nutval soils. Dotsolot soils are frigid. Nutval soils are very deep and have mollic epipedons more than 50 cm thick.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; very high surface runoff; moderately low saturated hydraulic conductivity.

USE AND VEGETATION: Erastra soils are used for livestock grazing, wood products, and wildlife habitat. The present vegetation is a forest canopy of singleleaf pinyon with an understory of mountain big sagebrush, antelope bitterbrush, curlleaf mountainmahogany, muttongrass, prairie junegrass, and Thurber's needlegrass.

DISTRIBUTION AND EXTENT: Western Nevada. These soils are not extensive. MLRA 26.

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

SERIES ESTABLISHED: Douglas County, Nevada, 1999.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 18 cm (A and Bt1 horizons).
Argillic horizon - The zone from 8 to 36 cm (Bt1, Bt2, and Bt3 horizons).
Paralithic contact - The boundary at 36 cm to underlying soft, weathered bedrock (Cr layer).
Particle-size control section - The zone from 8 to 36 cm (Bt1, Bt2, and Bt3 horizons).

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National Cooperative Soil Survey
U.S.A.