LOCATION COALBANK ID+UT

Established Series
Rev. FRK-CLM-GHL-GAM
01/2019

COALBANK SERIES

The Coalbank series consists of deep and very deep, well drained moderately rapidly permeable soils that are formed in alluvium and residuum from weakly consolidated volcanic ash. They are on mesa sides, mountain sides, hill sides, and terraces and have slopes of 4 to 75 percent. The average annual temperature is about 6.1 degrees C. and the average annual precipitation is about 360 mm.

TAXONOMIC CLASS: Ashy, glassy, frigid Vitrandic Haploxerolls

TYPICAL PEDON: Coalbank ashy fine sandy loam - rangeland. On a 42 percent smooth slope, north aspect, 1,555 meter elevation. (The profile was dry to 10 inches and moist below. Colors are for air-dry soil unless otherwise noted. This profile was described on August 7, 1980.)

A1--0 to 8 cm; grayish brown (10YR 5/2) ashy fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine roots; many very fine interstitial pores; slightly alkaline (pH 7.5 with phenol red, and 7.0 with sodium fluoride); abrupt smooth boundary. (8 to 20 cm thick)

A2--8 to 25 cm; grayish brown (10YR 5/2) ashy fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak coarse and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and common fine roots; many very fine tubular pores; slightly alkaline (pH 7.5 with phenol red, and 7.1 with sodium fluoride); clear smooth boundary. (13 to 25 cm thick)

Bw1--25 to 36 cm; brown (10YR 5/3) ashy fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak coarse and very coarse subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and few fine roots; common very fine tubular pores; slightly alkaline (pH 7.5 with phenol red, and 7.1 with sodium fluoride); clear smooth boundary. (10 to 25 cm thick)

Bw2--36 to 53 cm; brown (10YR 5/3) ashy fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak very coarse subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine roots; common very fine tubular pores; slightly alkaline (pH 7.6 with phenol red, and 7.1 with sodium fluoride); gradual smooth boundary. (0 to 25 cm thick)

C1--53 to 117 cm; pale brown (10YR 6/3) ashy fine sandy loam, dark brown (10YR 3/3) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine roots; few very fine tubular pores; slightly alkaline (pH 7.6 with phenol red, and 7.0 with sodium fluoride); clear smooth boundary. (25 to 64 cm thick)

C2--117 to 140 cm; light gray (5Y 7/1) ashy fine sand, olive gray (5Y 4/2) moist; massive; soft, very friable, nonsticky and nonplastic; 25 to 35 percent medium and coarse plates of Cr material that are hard and firm; slightly alkaline (pH 7.7 with phenol red, and 6.8 with sodium fluoride); abrupt smooth boundary. (23 to 56 cm thick)

Cr--140 to 165 cm; light gray (N 7/0) weakly cemented volcanic ash, gray (5Y 7/1) moist; massive; very thick plates can be broken out which are hard and firm; slightly alkaline (pH 7.8 with phenol red and 6.8 with sodium fluoride).

TYPE LOCATION: Cassia County, Idaho; about 6 miles west and 16 miles south of Oakley; 200 feet east and 500 feet south of the northwest corner, sec. 34, T. 16 S., R. 21 E.; USGS Pole Creek 7.5 minute topographic quadrangle; latitude 42 degrees 00 minutes 17 seconds N and longitude 113 degrees 59 minutes 22 seconds W; WGS84 Decimal Degrees 42.0047222 latitude, -113.9894444 longitude.

RANGE IN CHARACTERISTICS:

Depth to paralithic contact - 100 to greater than 152 cm.
Average annual soil temperature - 5.6 to 8.3 degrees C.
Reaction - pH 6.8 to 8.0 with sodium fluoride
Typic xeric moisture regime.

A horizon
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3
Reaction - slightly acid through mildly alkaline

Bw horizon
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 2 or 3
Texture - ashy fine sandy loam or ashy very fine sandy loam
Reaction - slightly acid through mildly alkaline

C horizon
Hue - N, 5Y, 2.5Y, 10YR
Value - 6 to 8 dry, 3 to 6 moist
Chroma - 0 to 3
Texture - ashy fine sand, ashy fine sandy loam or ashy very fine sandy loam
Gravel - 0 to 10 percent - some pedons have a thin layer that contains 25 to 35 percent gravel
Reaction - neutral to moderately alkaline

COMPETING SERIES: These are the Cottonthomas and Trailcreek series. Cottonthomas soil have a Bk horizon. Trailcreek soils are moderately deep to a paralithic contact.

GEOGRAPHIC SETTING: Coalbank soils are on mountain slopes, hillslopes, and terraces. Slopes range from 4 to 75 percent. Elevation ranges from 1,465 to 1,830 meters. The soil formed in alluvium, colluvium and residuum from weakly consolidated volcanic ash. Average annual precipitation is about 300 to 460 mm and the average annual air temperature is about 5.6 to 7.2 degrees C. Frost-free season is 70 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hardister, Tomsherry, and the competing Cottonthomas and Trailcreek soils. Hardister soils are mesic. Tomsherry soils have a duripan up to 50 to 100 cm. Hardister soils are on valley floors. Tomsherry and Cottomthomas soils are on fan terraces. Trailcreek soils are on convex sideslopes.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; runoff is medium; moderately rapid saturated hydraulic conductivity.

USE AND VEGETATION: Coalbank soils are used for rangeland. The natural vegetation is mountain big sagebrush, Idaho fescue, prairie junegrass, and needleandthread.

DISTRIBUTION AND EXTENT: Southcentral Idaho and inferred in northwestern Utah and northeastern Nevada. This series is not extensive in Idaho. MLRA 25.

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

SERIES ESTABLISHED: Bannock County, Idaho, 1983.

REMARKS: Diagnostic horizons and other features recognized in this pedon are:
Mollic epipedon - the zone from the surface to 53 cm (A1, A2, Bw1, and Bw2 horizons).
Cambic horizon - the zone from 25 to 53 cm (Bw1 and Bw2 horizons).

Particle size control section - 25 to 100 cm (Bw1, Bw2, and part of the C1 horizon).
Vitric feature - has greater than 60 percent ashy material in the control section.

Bulk density is greater than 0.85glcc and the sodium fluoride pH is less than 10.

National Cooperative Soil Survey
U.S.A.