LOCATION COALBANK ID+UTEstablished Series
TAXONOMIC CLASS: Ashy, glassy, frigid Vitrandic Haploxerolls
TYPICAL PEDON: Coalbank fine sandy loam - rangeland. On a 42 percent smooth slope, north aspect, 5,100 feet 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 3 inches; grayish brown (10YR 5/2) fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, and very friable; many very fine roots; many very fine interstitial pores; mildly alkaline (pH 7.5 with phenol red, and 7.0 with sodium fluoride); abrupt smooth boundary. (3 to 8 inches thick)
A2--3 to 10 inches; grayish brown (10YR 5/2) fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak coarse and medium subangular blocky structure; soft and very friable; many very fine and common fine roots; many very fine tubular pores; mildly alkaline (pH 7.5 with phenol red, and 7.1 with sodium fluoride); clear smooth boundary. (5 to 10 inches thick)
Bw1--10 to 14 inches; brown (10YR 5/3) fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak coarse and very coarse subangular blocky structure; soft and very friable; common very fine and few fine roots; common very fine tubular pores; mildly alkaline (pH 7.5 with phenol red, and 7.1 with sodium fluoride); clear smooth boundary. (4 to 10 inches thick)
Bw2--14 to 21 inches; brown (10YR 5/3) fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak very coarse subangular blocky structure; soft and very friable; common very fine roots; common very fine tubular pores; mildly alkaline (pH 7.6 with phenol red, and 7.1 with sodium fluoride); gradual smooth boundary. (0 to 10 inches thick)
C1--21 to 46 inches; pale brown (10YR 6/3) fine sandy loam, dark brown (10YR 3/3) moist; massive; soft and very friable; few very fine roots; few very fine tubular pores; mildly alkaline (pH 7.6 with phenol red, and 7.0 with sodium fluoride); clear smooth boundary. (10 to 25 inches thick)
C2--46 to 55 inches; light gray (5Y 7/1) fine sand, olive gray (5Y 4/2) moist; massive; soft and very friable; 25 to 35 percent medium and coarse plates of Cr material that are hard and firm; mildly alkaline (pH 7.7 with phenol red, and 6.8 with sodium fluoride); abrupt smooth boundary. (9 to 22 inches thick)
Cr--55 to 60 inches; light gray (N7/0) weakly cemented volcanic ash, gray (5Y 7/1) moist; massive; very coarse plates can be broken out which are hard and firm; mildly alkaline (pH 7.8 with phenol red and 6.8 with sodium floride).
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.
RANGE IN CHARACTERISTICS:
Depth to paralithic contact - 40 to greater than 60 inches
Average annual soil temperature - 42 to 47 degrees F
Reaction - pH 6.8 to 8.0 with sodium floride
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 - FSL or VFSL
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 - FS, FSL, VFSL
Gravel - 0 to 10 percent - some pedons have a thin layer that contains 25 to 35 percent pebbles
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 4,800 to 6,000 feet. The soil formed in alluvium and residuum from weakly consolidated volcanic ash. Average annual precipitation is about 12 to 18 inches and the average annual air temperature is about 42 to 45 degrees F. Frost-free season is 70 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hardister (T), Tomsherry (T), and the competing Cottonthomas (T) and Trailcreek (T) soils. Hardister soils are mesic. Tomsherry soils have a duripan up to 20 to 40 inches. Hardister soils are on valley floors. Tomsherry and Cottomthomas soils are on fan terraces. Trailcreek soils are on convex sideslopes.
DRAINAGE AND PERMEABILITY: Well drained; runoff is medium; moderately rapid permeability.
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 inextensive in Idaho.
MLRA OFFICE RESPONSIBLE: Reno, Nevada
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 21 inches (A1, A2, Bw1, and Bw2 horizons)
Cambic horizon - the zone from 10 to 21 inches (Bw1 and Bw2 horizons)
Particle size control section - 10 to 40 inches (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 floride pH is less than 10.