LOCATION NEEDAVAR                CA

Established Series
Rev. EWB-AMB-JBF-TM
04/2017

NEEDAVAR SERIES

The Needavar series consists of moderately deep, well drained soils that formed in alluvium derived from volcanic rocks with additions of aeolian volcanic ash. Needavar soils are on lake terraces. Slopes are 2 to 8 percent. The mean annual precipitation is about 330 mm and the mean annual temperature is about 6 degrees C.

TAXONOMIC CLASS: Fine, smectitic, frigid Vitritorrandic Durixerolls

TYPICAL PEDON: Needavar ashy coarse sand--rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is covered with 20 percent gravel and 1 percent cobbles.

A1--0 to 3 cm; light gray (10YR 7/2) ashy coarse sand, grayish brown (10YR 5/2) moist; single grain; loose, nonsticky and nonplastic; few very fine roots; many very fine interstitial pores; 5 percent gravel; neutral (pH 6.8); clear wavy boundary. (3 to 5 cm thick)

A2--3 to 13 cm; brown (10YR 5/3) ashy sandy loam, dark brown (10YR 3/3) moist; moderate medium platy structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; many very fine vesicular pores; 5 percent gravel; neutral (pH 6.8); clear wavy boundary. (5 to 15 cm thick)

A3--13 to 25 cm; brown (10YR 5/3) ashy sandy loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure; soft, very friable, slightly sticky and nonplastic; common very fine and fine roots; common very fine tubular and interstitial pores; 10 percent gravel; neutral (pH 6.8); clear wavy boundary. (8 to 16 cm thick)

Bt1--25 to 38 cm; brown (7.5YR 5/3) clay loam, brown (7.5YR 4/3) moist; strong fine and medium angular blocky structure; very hard, firm, very sticky and very plastic; few very fine and fine roots; common very fine tubular pores; 50 percent prominent pressure faces on all faces of peds; 10 percent gravel; neutral (pH 7.2); clear wavy boundary. (13 to 25 cm thick)

Bt2--38 to 64 cm; light brown (7.5YR 6/4) clay, brown (7.5YR 4/4) moist; moderate medium prismatic structure; extremely hard, very firm, very sticky and very plastic; few very fine and fine roots; few very fine interstitial and tubular pores; 50 percent prominent pressure faces on all faces of peds; 10 percent gravel; slightly alkaline (pH 7.4); clear wavy boundary. (15 to 30 cm thick)

Bt3--64 to 79 cm; light brown (7.5YR 6/4) gravelly clay loam, brown (7.5YR 4/4) moist; massive; very hard, friable, moderately sticky and moderately plastic; few very fine roots; few very fine interstitial and tubular pores; 25 percent distinct clay films on surfaces along pores; 25 percent gravel; slightly alkaline (pH 7.4); clear wavy boundary. (8 to 30 cm thick)

2Bqm--79 to 102 cm; moderately silica cemented material; massive; extremely hard, very firm; 15 percent gravel; slightly alkaline (pH 7.5); clear wavy boundary. (20 to 30 cm thick)

2Bq--102 to 152 cm; light brown (7.5YR 6/3) very gravelly ashy sandy loam, brown (7.5YR 4/3) moist; massive; hard, friable, nonsticky and nonplastic; common very fine interstitial and tubular pores; 10 percent cobbles and 40 percent gravel; slightly alkaline (pH 7.6).

TYPE LOCATION: Mono County, California; in the Bodie Hills about 10 kilometers northeast of Kirkwood Spring; about 1,500 feet north and 2,100 feet east of the southwest corner, section 16, T. 4 N., T 28 E.; USGS Kirkwood Spring 7.5 minute topographic quadrangle; latitude 38 degrees 12 minutes 11.8 seconds N and longitude 118 degrees 53 minutes 42.3 seconds W; WGS84 Decimal Degrees 38.2032778 latitude, -118.8950833 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in winter and spring, dry from July through October; aridic moisture regime that borders on xeric.
Mean annual soil temperature: 7 to 8 degrees C.
Mollic epipedon thickness: 25 to 36 cm thick.
Depth to moderately cemented duripan: 50 to 100 cm.

Particle-size control section - Clay content: Averages 35 to 50 percent.
Rock fragments: Averages 0 to 15 percent, mainly gravel. Lithology of rock fragments is mainly andesite and related volcanic rocks.

A horizons
Value: 5 dry, 3 moist, may be 6 or 7 dry and 4 or 5 moist in A1 horizon. High values are due to the high volume of volcanic glass. Value is 5 or less dry and 3 or less moist in the upper 18 cm when mixed.
Chroma: 2 or 3 dry, or moist.
Organic matter content: 1 to 2 percent.
Volcanic glass content: 50 to 75 percent in coarse silt through medium sand fractions.
Reaction: Slightly acid or neutral.

Bt horizons
Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 3 or 4 dry, or moist.
Texture: Clay loam, clay or gravelly clay loam.
Clay content: 35 to 50 percent.
Rock fragments: Less than 15 percent.
Organic matter content: 0.5 to 1 percent.
Reaction: Neutral or slightly alkaline.

2Bqm horizon
Cementation: Moderately cemented, but broken in some places by burrowing animals.

2Bq horizons
Hue: 10YR or 7.5YR.
Texture: Very gravelly ashy sandy loam.
Clay content: Averages 8 to 12 percent.
Rock fragments: 35 to 60 percent.
Silica cementation: 30 to 50 percent moderately cemented durinodes or lenses.
Volcanic glass content: 30 to 75 percent in coarse silt through fine sand fractions.
Reaction: Neutral or slightly alkaline.

COMPETING SERIES: These are the Babala and Pinchey series. Babala soils have bedrock within depths of 56 to 160 cm, have less than 40 percent volcanic glass in their A horizons and have secondary calcium carbonate in their duripan. Pinchey soils have 25 to 35 percent rock fragments in their particle-size control section, have less than 50 percent volcanic glass in their A horizons and have an indurated duripan.

GEOGRAPHIC SETTING: Needavar soils are on lake terraces. They typically occur on summit positions. They formed in alluvium derived from mixed rock sources with additions of Aeolian volcanic ash. Slopes are 2 to 8 percent. Elevations range from 2,100 to 2,320 meters. The climate is semi-arid with cool, moist winters and warm, dry summers. The mean annual precipitation is 300 to 360 mm, mean annual temperature is 6 to 8 degrees C., and the frost-free period is 50 to 70 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Adamatt, Bodiehill and Domehill series. Adamatt, Bodiehill and Domehill soils have less than 35 percent clay and more than 35 percent rock fragments in their particle-size control section, and do not have a duripan.

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

USE AND VEGETATION: Needavar soils are used for livestock grazing, recreation, watershed and wildlife habitat. The native vegetation is mainly mountain big sagebrush, antelope bitterbrush, western needlegrass, basin wildrye and needleandthread.

DISTRIBUTION AND EXTENT: Eastern California, east of the Sierra Nevada Range. These soils are not extensive. MLRA 26.

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

SERIES ESTABLISHED: Mono County (Coleville-Bridgeport Area), California, 2010.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 25 cm (A1, A2 and A3 horizons).
Argillic horizon - The zone from 25 to 79 cm (Bt1, Bt2 and Bt3
horizons).
Duripan - The zone from 79 to 102 cm (2Bqm horizon).
Particle-size control section - The zone from 25 to 75 cm (Bt1, Bt2 and upper Bt3 horizons).

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National Cooperative Soil Survey
U.S.A.