LOCATION OLDGRADE                CA

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

OLDGRADE SERIES

The Oldgrade series consists of very deep, moderately well drained soils that formed in colluvium derived from volcanic rocks such as andesite, with additions of eolian volcanic ash. Oldgrade soils are on mountains and plateaus. Slopes are 0 to 4 percent. The mean annual precipitation is about 400 mm and the mean annual temperature is about 6 degrees C.

TAXONOMIC CLASS: Ashy, glassy Vitrandic Argicryolls

TYPICAL PEDON: Oldgrade ashy sandy loam--rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is covered with 5 percent gravel.

A1--0 to 8 cm; grayish brown (10YR 5/2) ashy sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine to medium roots; common very fine and fine interstitial pores; 10 percent nonflat subangular andesite gravel; neutral (pH 6.6); clear smooth boundary. (5 to 13 cm thick)

A2--8 to 25 cm; brown (10YR 5/3) ashy sandy loam, dark brown (10YR 3/3) moist; weak fine and medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine and fine roots; few fine interstitial and tubular pores; 5 percent nonflat subangular andesite gravel; slightly acid (pH 6.4); clear smooth boundary. (10 to 30 cm thick)

Bt1--25 to 38 cm; brown (10YR 5/3) gravelly ashy sandy loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine and fine roots; few fine interstitial and tubular pores; 10 percent faint clay bridges between sand grains; 15 percent nonflat subangular andesite gravel; neutral (pH 6.6); clear smooth boundary. (10 to 20 cm thick)

Bt2--38 to 61 cm; yellowish brown (10YR 5/4) gravelly ashy loam, dark yellowish brown (10YR 3/4) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, , slightly sticky, slightly plastic; common very fine and fine roots; few fine interstitial and tubular pores; 20 percent distinct clay films on surfaces along pores and 20 percent distinct clay films on all faces of peds; 15 percent nonflat subangular andesite gravel; neutral (pH 6.6); clear smooth boundary. (15 to 30 cm thick)

Bt3--61 to 81 cm; yellowish brown (10YR 5/4) very gravelly ashy loam, dark yellowish brown (10YR 3/4) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine roots; few fine interstitial and tubular pores; 20 percent distinct clay films on all faces of peds and 20 percent distinct clay films on surfaces along pores; 10 percent nonflat subangular andesite cobbles and 25 percent nonflat subangular andesite gravel; neutral (pH 6.7); clear smooth boundary. (10 to 38 cm thick)

Bt4--81 to 109 cm; pale brown (10YR 6/3) very gravelly ashy loam, brown (10YR 4/3) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; few very fine and fine roots; common fine tubular pores; 10 percent faint clay bridges between sand grains; 5 percent strong brown (7.5YR 4/6), moist, masses of oxidized iron; 10 percent nonflat subangular andesite cobbles and 25 percent nonflat subangular andesite gravel; neutral (pH 6.8); clear smooth boundary. (0 to 28 cm thick)

C1--109 to 140 cm; pale brown (10YR 6/3) gravelly ashy loam, brown (10YR 4/3) moist; massive; slightly hard, very friable, very sticky and moderately plastic; few very fine roots; common fine tubular pores; 2 percent strong brown (7.5YR 4/6), moist, masses of oxidized iron; 5 percent nonflat subangular andesite cobbles and 15 percent nonflat subangular andesite gravel; neutral (pH 6.8); clear smooth boundary. (15 to 38 cm thick)

C2--140 to 152 cm; yellowish brown (10YR 5/4) gravelly ashy loam, dark yellowish brown (10YR 3/4) moist; massive; slightly hard, very friable, very sticky and moderately plastic; few fine roots; few fine tubular pores; 2 percent black (N 2.5/), moist, masses of oxidized manganese; 5 percent nonflat subangular andesite cobbles and 15 percent nonflat subangular andesite gravel; neutral, (pH 6.8);

TYPE LOCATION: Mono County, California; in the Bodie Hills about 2 miles east of the town of Bodie; about 2,400 feet north and 1,700 feet west of the southeast corner of section 15, T. 4 N., R. 27 E.; Kirkwood Spring USGS 7.5 minute topographic quadrangle; latitude 38 degrees 12 minutes 17.8 seconds N and longitude 119 degrees 58 minutes 56.7 seconds W; WGS84 38.20494 latitude, -118.98242 longitude.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in the moisture control section; moist fall, winter and spring; usually dry July through early October; xeric moisture regime, bordering on aridic. Saturated for short periods within a depth of 61 to 100 cm during spring and early summer.
Mean annual soil temperature: 7 to 8 degrees C.
Mean summer soil temperature: 12 to 15 degrees C.
Mollic epipedon thickness: 25 to 50 cm.
Depth to bedrock: 150 to 200 cm to a paralithic contact. The paralithic materials below the contact are weathered andesitic rock.

Particle-size control section - Clay content: Averages 12 to 18 percent.
Rock fragments: Averages 15 to 35 percent, mainly gravel. Lithology of rock fragments is volcanic rock such as andesite.

A horizons
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3 dry or moist.
Reaction: Slightly acid or neutral.
Organic matter content: 1 to 3 percent.
Volcanic glass content: 30 to 75 percent in coarse silt through fine sand fractions.

Bt1 and Bt2 Horizons
Value: 5 dry in upper part, 5 or 6 dry in lower part, 3 moist in upper part, 3 or 4 moist in lower part.
Texture: Gravelly ashy sandy loam.
Clay content: Averages 12 to 18 percent or gravelly ashy loam.
Rock fragments: 15 to 35 percent.
Reaction: Slightly acid or neutral.
Organic matter content: 1 to 3 percent.
Volcanic glass content: 30 to 75 percent in coarse silt through fine sand fractions.

Bt3 and Bt4 Horizons
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 3 or 4 dry or moist.
Texture: Very gravelly ashy loam or very gravelly ashy sandy clay loam.
Clay content: Averages 18 to 25 percent.
Rock fragments: 35 to 60 percent.
Reaction: Slightly acid or neutral.
Organic matter content: 0.5 to 1 percent.
Volcanic glass content: 30 to 75 percent in coarse silt through fine sand fractions.
Redoximorphic features: Redox concentrations may occur as masses of iron accumulation in the lower part.

C Horizons
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 3 or 4 dry or moist.
Texture: Gravelly ashy loam or gravelly ashy sandy loam.
Clay content: Averages 18 to 25 percent.
Rock fragments: 12 to 25 percent.
Reaction: Slightly acid or neutral.
Volcanic glass content: 30 to 75 percent in coarse silt through fine sand fractions.
Redoximorphic features: Redox concentrations occur as masses of iron or manganese accumulation.

COMPETING SERIES: These are the Atastra, Denpark, Hashwoods and Nissler soils.

Atastra and Hashwoods soils have a mollic epipedon more than 76 cm thick. Denpark soils are moderately deep. Nissler soils have a mollic epipedon 7 to 12 cm thick, have a lithic contact at 150 to 200 cm, and are not saturated within 100 cm.

GEOGRAPHIC SETTING: Oldgrade soils are on mountains and plateaus. They typically occur on toeslope positions. They formed in colluvium derived from volcanic rocks such as andesite, with additions of eolian volcanic ash. Slopes are 0 to 4 percent. Elevations range from 2,200 to 2,850 meters. The climate is semi-arid with cool, moist winters and warm, dry summers. The mean annual precipitation is 350 to 450 mm, mean annual temperature is 6 to 7 degrees C., and the frost-free period is 30 to 60 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Adamatt, Bodiehill and Lastsummer series. Adamatt soils have bedrock within 50 cm and have more than 35 percent rock fragments in their particle-size control section. Bodiehill soils have more than 60 percent rock fragments in their particle-size control section, and have a frigid soil temperature regime. Lastsummer soils have more than 35 percent rock fragments in their particle-size control section, and have a mollic epipedon more than 50 cm thick.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Moderately well drained; Endosaturation is present with an apparent seasonal high water table between 1 and 100 cm (moderately deep free water occurrence classes) during spring months in some years. Cumulative annual duration class is Transitory; low surface runoff; moderate permeability; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: Oldgrade soils are used for livestock grazing, recreation, watershed and wildlife habitat. The native vegetation is mainly silver sagebrush, sedge, western needlegrass, mat muhly, and lupine.

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 38 cm (A1, A2 and Bt1 horizons).
Argillic horizon - The zone from 25 to 109 cm (Bt1, Bt2, Bt3 and Bt4 horizons).
Vitrandic intergrade feature -- High volcanic glass content in the .02 to 2mm fraction from the mineral soil surface to 152 cm (A1, A2, Bt1, Bt2, Bt3, Bt4, C1 and C2 horizons).
Particle-size control section - The zone from 25 to 75 cm (Bt1, Bt2 and upper Bt3 horizons).

ADDITIONAL DATA: User Pedon ID: 2006CA051001.

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National Cooperative Soil Survey
U.S.A.