LOCATION READINGPEAK CAEstablished Series
The Readingpeak series consists of deep, well drained soils that formed in tephra over colluvium and residuum weathered from andesite, dacite and rhyodacite. Readingpeak soils are on glaciated mountain slopes, volcanic domes and roche moutonnees in hanging valleys in the Southern Cascade mountains. Slopes range from 5 to 95 percent. The mean annual precipitation is about 117 inches (2972 mm) and the mean annual temperature is about 39 degrees F (4 degrees C).
TAXONOMIC CLASS: Ashy-skeletal, amorphic Xeric Vitricryands
TYPICAL PEDON: Readingpeak very gravelly ashy sandy loam, on a south facing (195 degrees) slope of 52 percent, under a cover of mountain hemlock, western white pine, lupine, and pinemat manzanita at an elevation of 8507 feet, (2594 m). When described on 9/19/06, the soil was dry throughout. (Colors are for dry soil unless otherwise noted).
A1--0 to 2 inches (0 to 4 cm); grayish brown (10YR 5/2) very gravelly ashy sandy loam, very dark grayish brown (10YR 3/2) moist; 3 percent clay; single grain; loose, nonsticky, nonplastic; common very fine and fine roots; many very fine and fine interstitial pores; 17 percent angular fine gravel, 17 percent angular medium and coarse gravel, 10 percent angular cobbles, and 5 percent angular stones; strongly acid, pH 5.6 by Hellige-Truog; NaF pH 10.5; clear smooth boundary.
A2--2 to 7 inches (4 to 19 cm); light brownish gray (10YR 6/2) very gravelly ashy sandy loam, dark grayish brown (10YR 4/2) moist; 3 percent clay; weak fine and medium subangular blocky structure parting to single grain; loose, nonsticky, nonplastic; few very coarse and many very fine to coarse roots; many very fine and fine interstitial pores; 17 percent angular fine gravel, 21 percent angular medium and coarse gravel, 10 percent angular cobbles, and 5 percent angular stones; moderately acid, pH 5.7 by Hellige-Truog; NaF pH 11.0; clear smooth boundary. (Combined thickness of the A horizon is 5 to 9 inches (13 to 23 cm) thick)
2Bq1--7 to 14 inches (19 to 36 cm); light yellowish brown (10YR 6/4) extremely gravelly ashy loamy sand, dark yellowish brown (10YR 4/4) moist; 3 percent clay; single grain; loose, partially weakly cemented by silica, nonsticky, nonplastic; few coarse roots and many very fine to medium roots; many very fine interstitial pores; 20 percent threadlike silica masses around rock fragments; 15 percent angular fine gravel, 38 percent angular medium and coarse gravel, 20 percent angular cobbles, and 5 percent angular stones; slightly acid, pH 6.3 by Hellige-Truog; NaF pH 11.6; clear smooth boundary.
2Bq2--14 to 26 inches (36 to 65 cm); very pale brown (10YR 7/3) extremely cobbly ashy loamy coarse sand, dark yellowish brown (10YR 4/4) moist; 3 percent clay; single grain; loose, partially very weakly cemented by silica, nonsticky, nonplastic; few very fine to medium roots; many very fine interstitial pores; 15 percent threadlike silica masses around rock fragments; 21 percent subangular fine gravel, 35 percent subangular medium and coarse gravel, 20 percent subangular cobbles, and 10 percent subangular stones; slightly acid, pH 6.3 by Hellige-Truog; NaF pH 11.5; clear smooth boundary. (Combined thickness of the 2Bq horizon is 17 to 21 inches (43 to 53 cm) thick)
2Bq3--26 to 35 inches (65 to 88 cm); very pale brown (10YR 8/2) extremely cobbly ashy loamy sand, yellowish brown (10YR 5/4) moist; 3 percent clay; moderate fine and medium subangular blocky structure; slightly hard, friable, partially extremely weakly cemented, nonsticky, nonplastic; few very fine to medium roots; many very fine to medium interstitial and many very fine to coarse irregular pores; 14 percent subangular fine gravel, 28 percent subangular medium and coarse gravel, 20 percent subangular cobbles, and 10 percent subangular stones, slightly acid, pH 6.4 by Hellige-Truog; NaF pH 11.4; gradual wavy boundary.
2Bq4--35 to 50 inches (88 to 127 cm); light gray (10YR 7/2) extremely stony ashy loamy sand, brown (10YR 4/3) moist; 2 percent clay; moderate fine and medium subangular blocky structure; slightly hard, friable, partially very weakly cemented, nonsticky, nonplastic; few fine to coarse roots; many medium and coarse irregular and many very fine to medium interstitial pores; 9 percent subangular fine gravel, 18 percent subangular medium and coarse gravel, 25 percent subangular cobbles, and 30 percent subangular stones; slightly acid, pH 6.6 by Hellige-Truog; NaF pH 11.3; clear smooth boundary. (Combined thickness of the 2C horizon is 22 to 26 inches (55.5 to 66 cm) thick)
2R--50 to 60 inches (127 to 152 cm); indurated bedrock
TYPE LOCATION: Shasta County, California, about 0.2 miles west-southwest from the southernmost corner of the Lassen Peak Trail parking lot, approximately 1,900 feet north and 1,600 feet east from the southwest corner of sec 11, T. 30 N, R. 4 E, 40 degrees, 28 minutes, 24 seconds north latitude and 121 degrees, 30 minutes, 34 seconds west longitude, NAD83; USGS Quad: Lassen Peak, California.
RANGE IN CHARACTERISTICS:
Depth to restrictive feature: Lithic contact 40 to 60 inches (102 to 152 cm).
Mean annual soil temperature: 40 to 43 degrees F (4.4 to 6.0 degrees C).
Soil moisture control section is dry: July to October (about 90 days).
Particle-size control section (thickest part): 2 to 3 percent clay, and 72 to 86 percent rock fragments.
Surface fragments: 20 to 30 percent gravel, 25 to 35 percent cobbles, 15 to 30 percent stones, and 0 to 15 percent boulders.
A horizon:
Color dry: 10YR 5/2, 6/2
Color moist: 10YR 3/2, 4/2
Texture: very gravelly ashy sandy loam
Clay content: 2 to 4 percent
Rock fragments: 15 to 20 percent fine gravel, 15 to 25 percent medium and coarse gravel, 30 to 45 percent total gravel, 5 to 15 percent cobbles, 0 to 10 percent stones, 35 to 60 percent total rock fragments
Organic matter: 4 to 5.5 percent
Acid oxalate extractable Al plus 1/2 Fe: 0.35 to 0.50
P retention: 30 to 50 percent
Glass content: 20 to 30 percent
NaF pH: 10.5 to 11.0
Soil reaction: moderately acid
Upper 2Bq horizon:
Color dry: 10YR 7/3, 6/4
Color moist: 10YR 4/4
Texture: extremely gravelly ashy loamy coarse sand, extremely gravelly ashy loamy sand, extremely cobbly ashy loamy coarse sand
Clay content: 2 to 4 percent
Cementation class: extremely weakly cemented to strongly cemented in less than 10 percent of horizon
Rock fragments: 15 to 25 percent fine gravel, 30 to 40 percent medium and coarse gravel, 45 to 65 total gravel, 15 to 25 percent cobbles, 0 to 15 percent stones, 60 to 85 percent total rock fragments
Organic matter: 3 to 5 percent
Acid oxalate extractable Al plus 1/2 Fe: 1.4 to 1.8
P retention: 60 to 85 percent
Glass content: 18 to 25 percent
NaF pH: 11.5 to 11.6
Soil reaction: slightly acid
Lower 2Bq horizon:
Color dry: 10YR 7/2, 8/2
Color moist: 10YR 4/3, 5/4
Texture: extremely gravelly ashy loamy sand, extremely stony ashy loamy sand, extremely cobbly ashy loamy sand
Clay content: 2 to 3 percent
Cementation class: extremely weakly cemented to strongly cemented in less than 10 percent of horizon
Rock fragments: 5 to 15 percent fine gravel, 15 to 30 percent medium and coarse gravel, 25 to 45 percent total gravel, 15 to 30 percent cobbles, 5 to 35 percent stones, 45 to 85 percent total rock fragments
Organic matter: 2 to 4 percent
Acid oxalate extractable Al plus 1/2 Fe: 1.4 to 1.8
P retention: 70 to 95 percent
Glass content: 18 to 25 percent
NaF pH: 11.3 to 11.4
Soil reaction: slightly acid or neutral
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: Readingpeak soils are on glaciated mountain slopes, volcanic domes and roche moutonnees in hanging valleys in the Southern Cascade mountains. Slopes are 5 to 95 percent. These soils formed in tephra over colluvium and residuum weathered from andesite, dacite and rhyodacite. Elevation is 6675 to 10450 feet (2035 to 3186 m). Mean annual precipitation is 69 to 125 inches (1753 to 3175 mm). The mean annual temperature is 39 to 41 degrees F (4 to 5 degrees C). Frost free season is 50 to 85 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Emeraldlake and Terracelake soils. The Emeraldlake soils are very deep and formed in ash mixed with colluvium on cirque walls and mountain slopes. The Terracelake soils are moderately deep to bedrock.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; saturated hydraulic conductivity is high in the A horizons, and high to very high in the 2Bq horizons.
USE AND VEGETATION: This soil is used for wildlife habitat, recreation, ecosystem management and watershed. Vegetation is mountain hemlock, western white pine, lupine, and pinemat manzanita.
DISTRIBUTION AND EXTENT: The soils are inextensive and are mapped in MLRA: 22B. Southern Cascade Mountains
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Shasta County, California. Source of name from Reading Peak in Lassen Volcanic National Park.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: 0 to 7 inches, (0 to 19 cm)
Andic soil properties: 7 to 50 inches, (19 to 127 cm)
Particle-size control section: 0 to 40 inches, (0 to 102 cm)
Soil moisture control section: 40 to 50 inches, (102 to 127 cm)
ADDITIONAL DATA: Classification and properties inferred from lab data from lab pedon number 08N0485 NSSL, Lincoln, NE. NASIS User Pedon ID in Davis, MLRA Office: 789173.