LOCATION GRANDRIDGE CA+NV

Established Series
Rev. EWB-JVC
03/2017

GRANDRIDGE SERIES

The Grandridge series consists of shallow, well drained soils that formed in residuum and colluvium derived from granitic rock. Grandridge soils are on mountains. Slopes are 4 to 50 percent. The mean annual precipitation is about 500 mm and the mean annual temperature is about 4.4 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid, shallow Typic Argixerolls

TYPICAL PEDON: Grandridge very gravelly coarse sandy loam--rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is covered with 75 percent gravel, 5 percent cobbles, and 2 percent stones.

A--0 to 3 cm; dark grayish brown (10YR 4/2) very gravelly coarse sandy loam, very dark brown (10YR 2/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine roots; many very fine interstitial pores; 40 percent gravel; neutral (pH 6.6); clear wavy boundary. (3 to 8 cm thick)

Bt1--3 to 13 cm; brown (10YR 5/3) very gravelly loam, very dark grayish brown (10YR 3/2) moist; weak fine and medium subangular blocky structure; soft, very friable, moderately sticky and moderately plastic; many very fine and fine roots; common very fine tubular and interstitial pores; few faint clay bridges between sand grains; 35 percent gravel; neutral (pH 6.6); clear wavy boundary. (5 to 13 cm thick)

Bt2--13 to 25 cm; brown (10YR 5/3) very gravelly sandy clay loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; common very fine and fine roots; common very fine tubular and interstitial pores; common faint clay bridges between sand grains and few distinct clay films on faces of peds and lining pores; 50 percent gravel and 5 percent cobbles; neutral (pH 6.7); clear wavy boundary. (10 to 15 cm thick)

Bt3--25 to 46 cm; brown (7.5YR 5/4) very gravelly sandy clay loam, dark brown (7.5YR 3/4) moist; moderate fine subangular blocky structure; hard, very friable, moderately sticky and moderately plastic; few very fine and fine roots; common very fine tubular and interstitial pores; common distinct clay films on faces of peds and lining pores; 50 percent gravel and 5 percent cobbles; neutral (pH 6.8); clear irregular boundary. (15 to 23 cm thick)

Cr--46 cm; weathered granitic rock.

TYPE LOCATION: Mono County, California; on the Toiyabe National Forest in the Sweetwater Mountains about 2.7 miles northwest of Lobdell Lake; approximately 150 feet north and 1,750 feet west of the southeast corner of section 1, T. 7 N., R. 23 E.; USGS Chris Flat 7.5 minute topographic quadrangle; 38 degrees 28 minutes 21.69 seconds north latitude and 119 degrees 23 minutes 57.18 seconds west longitude; WGS84 Decimal Degrees 38.4726917 latitude, -119.3992167 longitude.

RANGE IN CHARACTERISTICS:

Soil moisture: Usually moist in the moisture control section during late fall, winter, and spring; dry from July through early October for 75 to 90 consecutive days in the four months following the summer solstice; xeric moisture regime that borders on aridic.
Mean annual soil temperature: 7 to 8 degrees C.
Mean summer soil temperature: 15 to 20 degrees C.
Mean winter soil temperature: 0 to 2.2 degrees C.
Mollic epipedon thickness: 18 to 25 cm; includes the Bt1 and Bt2 horizons.
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 granitic rock.

Particle-size control section - Clay content: Averages 18 to 25 percent; Rock fragments: Averages 35 to 60 percent, mainly fine gravel (2 to 5 mm diameter). Lithology of fragments are granitic rocks such as granodiorite.

A horizons
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Organic matter content: 2 to 4 percent.
Reaction: Slightly acid or neutral.

Bt1 and Bt2 horizons
Hue: 10YR or 7.5YR.
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Texture: Very gravelly loam, very gravelly coarse sandy loam, or very gravelly sandy clay loam.
Clay content: 18 to 25 percent.
Rock fragments: 35 to 60 percent.
Organic matter content: 1 to 3 percent.
Reaction: Slightly acid or neutral.

Bt3 horizon
Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 3 or 4, dry or moist.
Texture: Very gravelly loam, very gravelly coarse sandy loam, or very gravelly sandy clay loam.
Clay content: 18 to 25 percent.
Rock fragments: 35 to 60 percent.
Reaction: Slightly acid or neutral.

COMPETING SERIES: These are the Crispy, Cucamungo, Pinew, Quopant, and Trailamp series.

Crispy soils are dominated by medium and coarse gravel (5 to 75 mm diameter) in the particle-size control section, have rock fragments which are metamorphic rocks, and have paralithic materials of weathered schist or gneiss in the series control section. Cucamungo soils are intermittently moist for 10 to 20 days during the summer due to convection storms. Pinew soils are dominated by medium and coarse gravel (5 to 75 mm diameter) in the particle-size control section, have rock fragments which are volcanic rocks, and have paralithic materials of weathered tuff or andesite in the series control section. Quopant soils have 2C horizons below the argillic horizon and have paralithic materials of weathered ash-flow tuff in the series control section. Trailamp soils are slightly alkaline or moderately alkaline, have paralithic contacts at depths of 18 to 36 cm, have paralithic materials of siltstone or shale in the series control section, and are intermittently moist during the summer due to convection storms.

GEOGRAPHIC SETTING: Grandridge soils are on mountains. They typically occur on summit and shoulder positions. They formed in residuum and colluvium derived from granitic rock. Slopes are 4 to 50 percent. Elevations range from 2,450 to 3,350 meters. The climate is subhumid-continental with cold, moist winters and warm, dry summers. The mean annual precipitation is 400 to 750 mm, mean annual temperature is 2 to 7 degrees C, and the frost-free period is 30 to 60 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Delhew and Granhogany soils. Delhew soils are very deep, have thick mollic epipedons, and a cryic temperature regime. Granhogany soils are sandy-skeletal and do not have diagnostic subsurface horizons.

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

USE AND VEGETATION: Grandridge soils are used for rangeland, recreation, watershed, and wildlife habitat. The native vegetation is mainly low sagebrush, pine needlegrass, bluegrass, prairie junegrass, Eriogonum, and scattered curl-leaf mountain mahogany. This pedon is correlated to R022AY011NV, Mountain ridge 30"+ P.Z.

DISTRIBUTION AND EXTENT: Eastern California and western Nevada, on the east side of the Sierra Nevada Range. These soils are not extensive with about 6,000 acres of the series mapped to date. MLRAS 22A and 26.

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

SERIES ESTABLISHED: Mono County (Toiyabe National Forest Area), California, 2006.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 25 cm (A, Bt1, and Bt2 horizons).
Argillic horizon - The zone from 3 to 46 cm (Bt1, Bt2, and Bt3 horizons).

Paralithic contact - The boundary at 46 cm to underlying soft, weathered bedrock (Cr layer).
Particle-size control section - The zone from 3 to 46 cm (Bt1, Bt2, and Bt3 horizons).

ADDITIONAL DATA: User pedon ID: 2002CA051002.

National Cooperative Soil Survey
U.S.A.