LOCATION GRAYLOCK                ID+CA NV

Established Series
Rev. TWP/ALH/CLM/JBF
12/2011

GRAYLOCK SERIES

The Graylock series consists of deep, well or somewhat excessively drained soils on mountainsides. They formed in alluvium and colluvium derived from intermediate intrusive rocks. Slopes are 20 to 80 percent. The average annual precipitation is about 760 mm and the average annual temperature is about 2 degrees C.

TAXONOMIC CLASS: Sandy-skeletal, mixed Typic Cryorthents

TYPICAL PEDON: Graylock stony loamy coarse sand -- at about 2,475 meters elevation--rangeland. (Colors are for air dry soil unless otherwise noted.)

A--0 to 5 cm; brown (10YR 4/3)and brown (10YR 5/3) crushed stony loamy coarse sand, very dark grayish brown (10YR 3/2) moist; weak very fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine and fine, few medium roots; common very fine and fine tubular pores; 15 percent angular fine gravel and 5 percent stones; moderately acid (pH 5.7); clear smooth boundary. (3 to 10 cm thick)

Bw1--5 to 15 cm; light yellowish brown (10YR 6/4) or pale brown (10YR 6/3) crushed gravelly loamy coarse sand, dark yellowish brown (10YR 4/4) or brown (10YR 4/3) crushed moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and fine, few medium roots; many very fine and fine tubular pores; 30 percent angular fine gravel and 5 percent stones; strongly acid (pH 5.3); gradual wavy boundary. (8 to 18 cm thick)

Bw2--15 to 53 cm; light yellowish brown (10YR 6/4) very gravelly loamy coarse sand, dark yellowish brown (10YR 4/4), brown 10YR 4/3 crushed moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and fine, few medium roots; many very fine and fine tubular pores; 40 percent angular fine gravel, 5 percent cobbles and stones; very strongly acid (pH 4.8); gradual irregular boundary. (10 to 50 cm thick)

C1--53 to 107 cm; very pale brown (10YR 8/3) and very pale brown (10YR 7/4) extremely gravelly loamy coarse sand, light yellowish brown (2.5Y 6/4) and brown (10YR 5/3) moist; massive; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; common very fine and fine tubular pores; 50 percent angular gravel, 10 percent cobbles and stones, some stones are highly weathered; very strongly acid (pH 4.8); clear irregular boundary. (25 to 64 cm thick)

C2--107 to 142 cm; white (10YR 8/1) extremely stony coarse sand, light gray (10YR 7/1) moist; common yellow (10YR 7/6), very pale brown (10YR 7/4), and reddish yellow (7.5YR 7/6) stains; single grain; loose, nonsticky and nonplastic; few very fine and fine roots; few very fine tubular pores; 30 percent angular gravel, 50 percent angular cobbles and stones; very strongly acid (pH 5.0). (5 to 50 cm thick)

R--142 cm; unweathered granite.

TYPE LOCATION: Boise County, Idaho; near Scott Mountain lookout; NE1/4 SE1/4 section 20, T. 10 N., R. 6 E.; latitude 44 degrees 11 minutes 2 seconds N and longitude 115 degrees 45 minutes 49 seconds W; NAD 83.

RANGE IN CHARACTERISTICS:
Soil moisture: Moist in winter and early spring and continuously dry in all parts for significant periods in summer and fall; xeric soil moisture regime.
Mean annual soil temperature: 1 to 7 degrees C.
Mean summer soil temperature: 10 to 15 degrees C.
Depth to bedrock: 100 to 150 cm.
Reaction: Moderately acid through very strongly acid.
Other features: O horizons up to 5 cm thick are present in some pedons

Particle-size control section - Clay content: Less than 5 percent.
Rock fragments: 35 to 60 percent.

A horizon
Value: 4 through 6 dry; 3 through 5 moist
Chroma: 2 or 3 dry or moist

B horizon
Value: 6 through 8 dry; 4 through 7 moist
Chroma: 3 or 4 dry or moist
Texture: Loamy sand, loamy coarse sand, loamy sand and coarse sand.
Modifiers: Very gravelly or very cobbly.

COMPETING SERIES: These are the Alflack, Castlepeak, Chena, Mirror Lake, Nataga, Nazina, Obscurity, Ovando, Polepatch, Stecum, and Studebaker series.

Alflack and Stecum soils have bedrock at 50 to 100 cm. Castlepeak soils have 60 to 90 percent rock fragments in the particle-size control section. Chena and Nizina soils have a mean annual soil temperature less than 1 degrees C. Mirror Lake soils have 35 to 70 percent quartzite and sandstone fragments and hue of 5YR or 7.5YR. Nataga soils lack Bw horizons. Obscurity soils have 15 to 50 percent volcanic ash in the particle-size control section. Ovanda soils have E horizons and lamellae. Polepatch soils formed in material weathered from basalt and have basalt rock fragments throughout the particle-size control section. Studebaker soils have basalt fragments and 15 to 50 percent volcanic glass and glass aggregates in the particle-size control section.

GEOGRAPHIC SETTING: Graylock soils are on mountainsides at elevations of 1,525 to 2,595 meters. They formed in alluvium, residuum, and colluvium derived from intermediate intrusive rocks. Slopes are 20 to 80 percent. Aspects are northerly at lower elevations but may be any direction at higher elevations. Average annual precipitation is 635 to 1,000 mm and comes mostly as snow. Average annual temperature is 0 to 6 degrees C. Frost-free period is 20 to 70 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These include the Broad Canyon, Bryan, Hanks, Pyle, and Whitecap series. Broad Canyon soils have a mollic epipedon and are loamy-skeletal. Bryan soils have a umbric epipedon. Hanks soils are coarse-loamy. Pyle soils have bedrock at 50 to 100 cm. Whitecap soils have bedrock at 50 cm or less. These soils are on landscape positions similar to Graylock soils.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well or somewhat excessively drained; medium or rapid runoff; very high saturated hydraulic conductivity.

USE AND VEGETATION: Graylock soils are used mainly for forestry, wildlife habitat, recreation, and grazing. The dominant natural vegetation consists of subalpine fir, Douglas fir or lodgepole pine with an understory of huckleberry, pinegrass or rocky mountain maple.

DISTRIBUTION AND EXTENT: The Idaho Batholith. The series is moderately extensive.

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

SERIES ESTABLISHED: Middle Fork Payette River Area, Boise and Valley Counties, Idaho, 1966.

REMARKS: Diagnostic horizons and other features recognized in this pedon:
Ochric epipedon - The zone from the surface to 18 cm (A Bw1 and part of the Bw2 horizons)
Particle-size control section - the zone from 25 to 100 cm (part of the Bw2 and C1 horizons).

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National Cooperative Soil Survey
U.S.A.