LOCATION SILENTCONE IDEstablished Series
TAXONOMIC CLASS: Ashy-skeletal, glassy, frigid Humic Vitrixerands
TYPICAL PEDON: Silentcone very gravelly ashy loam - on a 3 percent slope at an elevation of 5,700 feet in rangeland. When described in Nov. 1997, the soil was dry throughout. (Colors are for dry soil unless otherwise noted.)
A1--0 to 4 inches; dark grayish brown (10YR 4/2) very gravelly ashy loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; common very fine and fine roots; many very fine interstitial pores; about 35 percent gravel-size cinders; neutral (pH 7.3); clear smooth boundary. (2 to 6 inches thick)
A2--4 to 10 inches; brown (10YR 4/3) very gravelly ashy loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; common very fine, fine medium and coarse roots; common very fine tubular pores; about 35 percent gravel-size cinders; slightly alkaline (pH 7.4); clear wavy boundary (4 to 9 inches thick)
Bw--10 to 24 inches; brown (10YR 5/3) very gravelly ashy loam, dark yellowish brown (10YR 4/4) moist; single grained; loose; common very fine, fine medium and coarse roots; common very fine tubular pores; about 45 percent gravel-size cinders; slightly alkaline (pH 7.4); clear wavy boundary (4 to 15 inches thick).
2R--24 to 48 inches; basalt with vertical fractures 0.5 to 2 cm wide (1 to 3 meters apart) with B material in fractures, few very fine, fine and medium roots in fractures.
TYPE LOCATION: Butte County, Idaho about 1 mile south of Craters of Moon Headquarters; 200 feet south and 1,400 feet west of the northeast corner of sec. 25, T. 2 N., R. 24 E. Latitude - 113 degrees, 32 minutes, 24 seconds north; Longitude - 42 degrees, 28 minutes, 50 seconds west.
RANGE IN CHARACTERISTICS:
The soil moisture control section is dry for 90 to 100 consecutive days.
Depth to basalt bedrock - 20 to 30 inches
Mean annual soil temperature - 42 to 47 degrees F.
Mollic epipedon - 7 to 12 inches thick
Andic soil properties
Glass content - 30 to 50 percent
Phosphate retention - 25 to 50 percent
Acid oxalate aluminum plus one-half the acid oxalate iron is 0.4 to 1.0
15-bar water, dry is 5 to 12 and moist is 10 to 20 percent.
A horizon
Value - 4 or 5 dry
Chroma - 2 or 3 moist or dry
Rock fragments - 35 to 50 percent cinders
Bw horizon
Value - 4 or 5 dry, 3 or 4 moist
Chroma - 3 or 4 moist or dry
Rock fragments - 40 to 60 percent cinders
COMPETING SERIES: These are the Fryrear, McCumber, Pipp and Yapoah Series. Fryrear soils are dry for 45 to 90 consecutive days and rock fragments are basalt. McCumber soils are very deep, have an umbric epipedon and have surface O horizons. Pipp soils are deep to bedrock and have surface O horizons. Yapoah soils are very deep.
GEOGRAPHIC SETTING: Silentcone soils are on recent basalt plains and associated with lava flows. Slopes range from 2 to 15 percent. Elevation ranges from 4,800 to 6,000 feet. The soil formed in wind deposited volcanic tephra. The mean annual precipitation is 14 to 18 inches, most of which falls as snow and early spring rain. The mean annual air temperature is about 40 to 45 degrees F. The frost-free season is 60 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Treemold and Cinderhurst soils. Cinderhurst and Treemold soils are very shallow to bedrock.
DRAINAGE AND PERMEABILITY: Well drained. Rapid runoff. Moderate permeability.
USE AND VEGETATION: Mainly used for wildlife and limited rangeland. Vegetation is mountain big sagebrush, lava fernbush, snowberry, bitterbrush, and bluegrass.
DISTRIBUTION AND EXTENT: South-central Idaho. This series is of small extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Craters of the Moon Area, Idaho, 1999.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Andic soil properties throughout the profile.
Mollic epipedon - 0 to 10 inches
Cambic horizon - 10 to 24 inches