LOCATION ACROPH CAEstablished Series
The Acroph series consists of shallow, well drained soils that formed in tephra over residuum from andesite, dacite and rhyodacite. Acroph soils are on scoured glacial-valley walls and floors and roche moutenees in the southern Cascade mountains. Slopes range from 5 to 80 percent. The mean annual precipitation is about 107 inches (2718 mm) and the mean annual temperature is about 40 degrees F (5 degrees C).
TAXONOMIC CLASS: Ashy-skeletal, glassy Lithic Vitricryands
TYPICAL PEDON: Acroph ashy highly organic sand, on a south facing (180 degrees) slope of 18 percent, under a cover of pinemat manzanita, California red fir, western white pine, and mountain hemlock at an elevation of 7958 feet, (2426 m). When described on 7/24/2007, the soil was dry throughout. (Colors are for dry soil unless otherwise noted).
Oi--0 to 1 inches (0 to 3 cm); slightly decomposed twigs, cones, needles and leaf litter; abrupt smooth boundary.
A1--1 to 2 inches (3 to 6 cm); dark grayish brown (10YR 4/2) ashy highly organic sand, very dark gray (10YR 3/1) moist; 1 percent clay; moderate thick and very thick platy parting to weak very fine and fine granular structure; soft, very friable, nonsticky, nonplastic; common very fine and fine, and few medium to very coarse roots; common fine tubular and many very fine and fine interstitial and irregular pores; 2 percent subangular fine gravel; strongly acid, pH 5.6 by Hellige-Truog; NaF pH 9.0; abrupt smooth boundary.
A2--2 to 5 inches (6 to 12 cm); grayish brown (10YR 5/2) ashy highly organic loamy sand, very dark grayish brown (10YR 3/2) moist; 3 percent clay; moderate thick and very thick platy parting to weak very fine and fine granular structure; soft, very friable, nonsticky, nonplastic; many very fine to very coarse roots; many very fine irregular and interstitial pores; 1 percent subangular medium and coarse gravel and 3 percent subangular fine gravel; strongly acid, pH 5.6 by Hellige-Truog; NaF pH 9.2; abrupt wavy boundary. (Combined thickness of the A horizon is 2 to 6 inches (5 to 15 cm) thick).
2Bw1--5 to 11 inches (12 to 29 cm); light yellowish brown (2.5Y 6/3) very cobbly ashy loamy sand, brown (10YR 4/3) moist; 2 percent clay; weak thick and very thick platy parting to weak very fine and fine subangular blocky structure; soft, very friable, nonsticky, nonplastic; common very fine and many fine to very coarse roots; many very fine and fine irregular and common fine vesicular pores; 7 percent subangular fine gravel, 11 percent subangular medium and coarse gravel, 15 percent subangular cobbles, and 5 percent subangular stones; moderately acid, pH 5.9 by Hellige-Truog; NaF pH 11.5; abrupt wavy boundary.
2Bw2--11 to 15 inches (29 to 37 cm); pale yellow (2.5Y 7/4) extremely cobbly ashy loamy sand, brown (10YR 4/3) moist; 3 percent clay; weak very fine subangular blocky structure parting to single grain; loose, nonsticky, nonplastic; common fine and medium roots and few very fine roots; many very fine and fine irregular and interstitial and few fine vesicular pores; 10 percent subangular fine gravel, 20 percent subangular medium and coarse gravel, 25 percent subangular cobbles, and 5 percent subangular stones; moderately acid, pH 6.0 by Hellige-Truog; NaF pH 11.5; abrupt wavy boundary. (Combined thickness of the Bw horizon is 8 to 12 inches (20 to 30 cm) thick)
2R--15 inches (37 cm); andesite bedrock
TYPE LOCATION: Shasta County, California, about 0.5 miles northeast of Soda Lake, approximately 950 feet south and 450 feet east of the northwest corner of sec 10, T. 30N, R. 4E, 40 degrees, 28 minutes, 47 seconds north latitude and 121 degrees, 31 minutes, 57 seconds west longitude, NAD83; USGS Quad: Lassen Peak, California.
RANGE IN CHARACTERISTICS:
Depth to restrictive feature: Lithic contact 10 to 20 inches (25 to 51 cm).
Mean annual soil temperature: 38 to 42 degrees F (3 to 6 degrees C).
Mean summer soil temperature: 43 to 46 degrees F (6 to 8 degrees C).
Soil moisture control section is dry: July to October (about 90 days).
Particle-size control section (thickest part): 2 to 5 percent clay, and 35 to 62 percent rock fragments.
Surface fragments: 5 to 66 percent gravel, 3 to 15 percent cobbles, 2 to 6 percent stones, and 2 to 5 percent boulders.
A horizon:
Color dry: 10YR 4/2, 5/2, 6/2
Color moist: 10YR 3/1, 3/2
Texture: ashy highly organic sand, ashy highly organic loamy sand, gravelly ashy highly organic sandy loam, gravelly ashy highly organic coarse sandy loam
Clay content: 1 to 3 percent
Rock fragments: 2 to 13 percent fine gravel, 0 to 6 percent medium to coarse gravel, 2 to 19 percent total gravel
Organic matter: 13 to 35 percent
Base saturation by ammonium acetate: 8 to 20 percent
Acid oxalate extractable Al plus 1/2 Fe: 0.30 to 0.75
P retention: 40 to 100 percent
Glass content: 55 to 65 percent
NaF pH: 9.0 to 11.2
Soil reaction: moderately acid to neutral
2Bw horizon:
Color dry: 10YR 7/3, 2.5Y 6/3, 7/4
Color moist: 10YR 4/3, 5/3
Texture: gravelly ashy sandy loam, very cobbly ashy loamy sand, extremely cobbly ashy loamy sand
Clay content: 2 to 5 percent
Rock fragments: 7 to 22 percent fine gravel, 8 to 20 percent medium to coarse gravel, 18 to 30 percent total gravel, 5 to 25 percent cobbles, 0 to 5 percent stones, 30 to 70 percent total rock fragments
Organic matter: 1.2 to 2.5 percent
Base saturation by ammonium acetate: 3 to 10 percent
Acid oxalate extractable Al plus 1/2 Fe: 0.82 to 0.93
P retention: 45 to 55 percent
Glass content: 65 to 75 percent
NaF pH: 11.0 to 11.5
Soil reaction: moderately acid to neutral
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: Acroph soils are on scoured glacial-valley walls and floors and roche moutenees in the southern Cascade mountains. Slopes are 5 to 80 percent. These soils formed in tephra over residuum weathered from andesite, dacite and rhyodacite. Elevation is 5720 to 8512 feet (1744 to 2595 m). Mean annual precipitation is 55 to 117 inches (1397 to 2972 mm). The mean annual temperature is 39 to 43 degrees F (4 to 6 degrees C). Frost free season is 50 to 85 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Terracelake and Shadowlake soils. The Terracelake soils are moderately deep to bedrock and are on similar glacially scoured positions. Shadowlake soils are deep to dense till, and are on linear and concave positions where glacial till was deposited.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; high to very high saturated hydraulic conductivity.
USE AND VEGETATION: This soil is used for wildlife habitat, recreation, ecosystem management and watershed. Vegetation is pinemat manzanita, California red fir, western white pine, and mountain hemlock.
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: 2009 Shasta County, California. Source of name is coined.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon 1 to 5 inches, (3 to 12 cm)
Andic soil properties: 1 to 15 inches, (3 to 37 cm)
Lithic contact: 15 inches, (37 cm)
Particle-size control section: 1.2 to 15 inches, (3 to 37 cm)
Soil moisture control section: 15 inches, (37 cm)
ADDITIONAL DATA: Classification and properties inferred from lab data from lab pedon number 07N0143, NSSL, Lincoln NE. NASIS User Pedon ID in Davis, MLRA Office: 789314.