LOCATION SUNSETCONE              ID

Established Series
Rev. RW/TDT
01/2011

SUNSETCONE SERIES

The Sunsetcone series consists of very deep, well-drained soils that formed in volcanic tephra. Sunsetcone soils are on north-facing slopes on cinder cones. Slopes are 30 to 60 percent. The permeability is moderately rapid. The mean annual precipitation is about 16 inches, and the mean annual temperature is about 42 degrees F.

TAXONOMIC CLASS: Medial over pumiceous or cindery, amorphic over glassy Humic Xeric Vitricryands

TYPICAL PEDON: Sunsetcone gravelly medial loam - on a 40 percent slope at an elevation of 5,960 feet in forestland. When described on November 9, 1997, the soil was dry throughout. (Colors are for dry soil unless otherwise noted.)

Oi--0 to 1 inch; Slighly decomposed Douglas-fir needles and twigs, fibric. (1 to 4 inches thick)

Oe--1 to 2 inches; Moderately decomposed Douglas-fir needles and root mat, hemic. (1 to 3 inches thick)

A1--2 to 6 inches; brown (10YR 4/3) gravelly medial loam, very dark brown (10YR 2/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine and fine and common medium and coarse roots; many very fine interstitial pores; about 20 percent gravel-size cinders; moderately alkaline (pH 7.9); clear smooth boundary. (1 to 4 inches thick)

A2--6 to 8 inches; dark grayish brown (10YR 4/2) gravelly medial loam, black (10YR 2/1) moist; moderate fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine and fine and common medium and coarse roots; common very fine tubular pores; about 15 percent gravel-size cinders; moderately alkaline (pH 7.9); gradual wavy boundary. (1 to 4 inches thick)

AB--8 to 12 inches; 70 percent brown (10YR 5/3) and 30 percent grayish brown (10YR 5/2) very gravelly medial loam, black (10YR 2/1) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and fine and common medium and coarse roots; common very fine tubular pores; about 35 percent gravel-size cinders; moderately alkaline (pH 7.9); gradual smooth boundary. (3 to 7 inches thick)

Bw--12 to 26 inches; brownish yellow (10YR 6/6) very gravelly medial sandy loam, dark yellowish brown (10YR 4/4) moist; single grained; loose; many very fine and fine and common medium and coarse roots; common very fine tubular pores; about 35 percent gravel-size cinders; moderately alkaline (pH 8.0); abrupt wavy boundary. (8 to 15 inches thick)

2C1--26 to 32 inches; dark brown (10YR 3/3) cobbles, black (10YR 2/1) moist; single-grained; loose; many very fine and fine and common medium and coarse roots; common medium and coarse interstitial pores; 70 percent cobble-size cinders and 20 percent gravel-size cinders; gradual wavy boundary. (8 to 15 inches thick)

2C2--32 to 62 inches; dark brown (10YR 3/3) gravel, black (10YR 2/1) moist; single-grained; loose; many very fine, fine, and medium and few coarse interstitial pores; 85 percent gravel-size cinders and 10 percent cobble-size cinders.

TYPE LOCATION: Butte County, Idaho about 1/2 mile north of Crater of Moon Headquarters; 1,900 feet north and 2,000 feet east of the southwest corner of sec. 26, T. 2 N., R. 24 E. Latitude - 113 degrees, 34 minutes, 00 seconds north; Longitude - 43 degrees, 28 minutes, 19 seconds west.

RANGE IN CHARACTERISTICS:

The soil moisture control section is dry for 60 to 90 consecutive days.
Depth to cinders or 2C horizons - 14 to 40 inches
Mean annual soil temperature - 40 to 44 degrees F.
Mean summer soil temperature is 45 to 47 degrees.
Andic soil properties
Glass content is 5 to 30 percent
Phosphate retention is 50 to 80 percent
Acid oxalate aluminum plus one-half the acid oxalate iron is 1.0 to 2.0
15-bar water, dry is 12 to 15 and moist is 20 to 30 percent
Mollic epipedon is 7 to 15 inches thick
The upper part of the particle-size control section averages 20 to 35 percent cinders

A and AB horizons
Chroma - 1 through 3 moist or dry
Rock fragments - 15 to 35 percent cinders
Organic matter - 1 to 4 percent

Bw horizon
Value - 5 or 6 dry, 2 through 4 moist
Textures - GRV-SL, GRV-L
Chroma - 1 through 6 moist or dry
Rock fragments - 35 to 45 percent cinders

2C horizons
Rock fragments - 90 to 100 percent cinders

COMPETING SERIES: These are the no competing series.

GEOGRAPHIC SETTING: Sunsetcone soils are on north-facing slopes on cinder cones. Slopes range from 30 to 60 percent. Elevation ranges from 5,500 to 6,500 feet. The soil formed in wind deposited volcanic tephra and loess. The mean annual precipitation is 16 to 20 inches, most of which falls as snow and early spring rain. The mean annual air temperature is about 37 to 43 degrees F. The frost-free season is 30 to 70 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hal and Grassycone soils. Grassycone and Hal soils lack the cinders above 40 inches.

DRAINAGE AND PERMEABILITY: Well drained. Rapid runoff. Moderately rapid over very rapid permeability.

USE AND VEGETATION: Mainly used for wildlife and limited rangeland. Vegetation is Douglas fir, mountain big sagebrush, snowberry, bitterbrush and scattered limber pine.

DISTRIBUTION AND EXTENT: South-central Idaho. This series is small extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Craters of the Moon Area, Idaho, 1999.

REMARKS: Depths to diagnostic horizons and features start from the mineral soil surface.

Diagnostic horizons and features recognized in this pedon are:

Andic soil properties from 2 to 26 inches
Mollic epipedon from 2 to 12 inches
Cambic horizon from 12 to 26 inches
Particle-size control section from 2 to 42 inches; upper part from 2 to 26 inches is medial with weighted average of 32 percent cinders and lower part from 26 to 42 inches is cinders with less than 10 percent fine earth material

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National Cooperative Soil Survey
U.S.A.