LOCATION MCVEGAS                 NV

Established Series
Rev. WED/CEJ/GJS/JBF
03/2016

MCVEGAS SERIES

The McVegas series consists of shallow, well drained soils that formed in residuum derived from metavolcanic and volcanic rocks. These soils are on hills. Slopes are 8 to 30 percent. The mean annual precipitation is about 180 mm and the mean annual temperature is about 9 degrees C.

TAXONOMIC CLASS: Clayey-skeletal, smectitic, mesic, shallow Natrargidic Natridurids

TYPICAL PEDON: McVegas very cobbly loam--rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is partially covered by approximately 30 percent cobbles and 10 percent gravel.

Al--0 to 5 cm; light brownish gray (10YR 6/2) very cobbly loam, dark grayish brown (10YR 4/2) moist; weak thin platy structure; soft, very friable, nonsticky and nonplastic; few medium roots; many fine vesicular pores; 30 percent cobbles and 20 percent gravel; moderately alkaline (pH 8.4); abrupt smooth boundary. (3 to 10 cm thick)

A2--5 to 13 cm; light brownish gray (10YR 6/2) cobbly loam, brown (10YR 4/3) moist; weak thin platy structure; slightly hard, very friable, nonsticky and slightly plastic; few medium roots; many very fine tubular pores; 15 percent gravel and 15 percent cobbles; moderately alkaline (pH 8.4); abrupt smooth boundary. (5 to 13 cm thick)

Btn--13 to 25 cm; brown (10YR 5/3) very gravelly silty clay, dark brown (10YR 3/3); brown (10YR 4/3) crushed, moist; weak medium prismatic structure parting to strong fine and medium angular blocky; very hard, very, firm, very sticky and very plastic; few medium roots; common fine tubular pores; thick continuous clay films on peds; 25 percent gravel and 15 percent cobbles; strongly alkaline (pH 8.8); clear wavy boundary. (8 to 18 cm thick)

Btnk--25 to 48 cm; light yellowish brown (10YR 6/4) very cobbly silty clay, dark yellowish brown (10YR 3/4); dark yellowish brown l0YR 4/4) crushed, moist; moderate fine angular blocky structure; very hard, very firm, very sticky and very plastic; few medium roots; common very fine tubular pores; thick continuous clay films on peds; 25 percent gravel, 20 percent cobbles; common medium lime filaments and threads; strongly effervescent; strongly alkaline (pH 9.0); abrupt irregular boundary. (10 to 25 cm thick)

Bqkm--48 to 56 cm; very pale brown (10YR 7/4) strongly cemented duripan capping bedrock and in cracks in the bedrock with some discontinuous laminar indurated deposits; 50 percent gravel, 30 percent cobbles essentially in place; strongly effervescent; abrupt smooth boundary. (3 to 48 cm thick)

R--56 cm; hard volcanic bedrock.

TYPE LOCATION: Lander County, Nevada; approximately 30 miles northwest of Austin about 1,200 feet south and 1,100 feet west of the approximate northeast corner of section 30, T. 24 N., R. 42 E.; USGS Gilbeert Creek NE 7.5 minute topographic quadrangle; latitude 39 degrees 55 minutes 39 seconds N and longitude 117 degrees 17 minutes 12 seconds W; WGS84 Decimal Degrees 39.9275000 latitude, -117.2866667 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry, moist in some part for short periods from October through May; typic aridic soil moisture regime.
Mean annual soil temperature: 8 to 11 degrees C.
Depth to strongly cemented duripan: 36 to 50 cm.
Depth to bedrock: 38 to 90 cm.
Reaction: Moderately alkaline through very strongly alkaline usually increasing with depth.

Particle-size control section - Clay content: 35 to 45 percent.
Rock fragments: 35 to 60 percent, mainly cobbles and gravel.

A horizons
Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 2 or 3.
Structure: Weak to moderate, thin or medium platy.

Btn horizon
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 3 or 4.
Texture: Very cobbly silty clay, very cobbly clay, very cobbly silty clay loam, or very cobbly clay loam.
Structure: Weak to strong fine to medium prismatic.
Consistence: Hard to very hard dry, friable to very firm moist.

Btnk horizon
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 4 or 6.
Texture: Very cobbly silty clay, very cobbly clay, very cobbly
silty clay loam, or very cobbly clay loam.
Structure: Moderate or strong, fine or medium, angular blocky or prismatic structure.
Consistence: Hard or very hard, friable to very firm.

COMPETING SERIES: There are no other series in this family.

GEOGRAPHIC SETTING: McVegas soils are on hills. These soils formed in residuum derived from metavolcanic and volcanic rocks. Slopes are 8 to 30 percent. Elevations are 1,620 to 2,135 meters. The climate is cool, semiarid with hot, dry summers and cool, moist winters. The mean annual precipitation is 150 to 200 mm, mean annual temperature is 8 to 11 degrees C, and the frost-free season is l00 to l20 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Atlow, Colbar, Jung, Newpass and Stingdorn soils. Atlow, Colbar and Jung soils lack a strongly cemented duripan over the bedrock. Newpass soils have a clayey particle-size control section. Stingdorn soils have a loamy-skeletal particle-size control section.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; medium or rapid runoff; moderately low saturated hydraulic conductivity.

USE AND VEGETATION: Rangeland and wildlife habitat. The present vegetation is mainly shadscale, bud sagebrush, bottlebrush squirreltail, Indian ricegrass and small rabbitbrush.

DISTRIBUTION AND EXTENT: These soils are not extensive.

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

SERIES ESTABLISHED: Lander County, Nevada, South Part, 1985.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 13 cm (A1 and A2 horizons).
Natric horizon - The zone from 13 to 48 cm (the Btn and Btnk horizons).
Duripan - The zone from 48 to 56 cm (the Bqkm horizon).
Lithic contact - The boundary at about 56 cm.
Particle-size control section - The zone from 13 to 48 cm (the Btn and Btnk horizons).

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National Cooperative Soil Survey
U.S.A.