LOCATION INFERNO IDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Vertic Palexeralfs
TYPICAL PEDON: Inferno-Grouseville association -- on a steep mountain sideslope at 7,000 feet elevation. (Colors are for dry soil unless otherwise noted. When described on June 4, 1986, the soil was dry throughout.
A1--0 to 7 inches; brown (10YR 5/3) gravelly clay loam, dark brown (10YR 3/3) moist; moderate fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine roots; 15 percent gravel and 1 percent cobbles; slightly alkaline (pH 7.4); abrupt smooth boundary.
A2--7 to 12 inches; brown (7.5YR 5/4) gravelly clay loam, dark brown (7.5YR 4/4) moist; moderate fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and few fine roots; many very fine tubular pores; 10 percent gravel and 5 percent cobbles; slightly alkaline (pH 7.6); abrupt smooth boundary. (Combined thickness of the A horizons is 10 to 14 inches)
Bt1--12 to 28 inches; strong brown (7.5YR 4/6) gravelly clay, strong brown (7.5YR 4/6) moist; moderate coarse prismatic structure parting to moderate medium subangular blocky; hard, firm, very sticky and very plastic; common very fine, and few fine and medium roots; common very fine tubular pores; many distinct clay films lining pores and on faces of peds; 15 percent gravel and 1 percent cobbles; moderately alkaline (pH 7.9); clear irregular boundary.
Bt2--28 to 36 inches; pink (7.5YR 7/4) gravelly clay, brown (7.5YR 5/4) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; very hard, firm, very sticky and very plastic; common very fine, and few fine and medium roots; common very fine tubular pores; common distinct clay films lining pores and on faces of peds; 15 percent gravel and 5 percent cobbles; moderately alkaline (pH 7.9); clear irregular boundary. (Combined thickness of the Bt horizons is 20 to 28 inches)
Btk1--36 to 54 inches; pink (7.5YR 8/4) gravelly clay, strong brown (7.5YR 5/6) moist; moderate fine subangular blocky structure; very hard, firm, moderately sticky and moderately plastic; few fine roots; common very fine tubular pores; few thin clay films lining pores and on faces of peds; 10 percent gravel, 5 percent cobbles, and 2 percent stones; lime coatings, less than 1 mm thick, on undersides and side of rock fragments; slightly effervescent; moderately alkaline (pH 8.1), clear irregular boundary. (16 to 22 inches thick)
Btk2--54 to 60 inches; pink (7.5YR 8/4) extremely gravelly clay, reddish yellow (7.5YR 6/6) moist; strong fine and medium subangular blocky structure; very hard, firm, moderately sticky and moderately plastic; few very fine tubular pores; few thin clay films lining pores and on faces of peds; 60 percent gravel, 5 percent cobbles, and 5 percent stones; lime coatings, fragments; strongly effervescent; moderately alkaline (pH 8.1).
TYPE LOCATION: Custer County, Idaho; about 3 miles southwest of Mackay, Idaho; about 2,500 feet south and 500 feet east from the northwest corner of sec. 5.T.6N., R.24E. Latitude - 43 degrees, 52 minutes, 52 seconds N. Longitude - 113 degrees, 38 minutes, 10 seconds W.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 39 to 41 degrees F.
Depth to argillic horizon - 10 to 14 inches
particle-size control section
Clay content - 35 to 50 percent
Rock fragment content - 15 to 30 percent
A horizons:
Hue - 7.5YR to 10YR
Value - 5 or 6 dry and 3 or 4 moist with 3 moist always occurring in the upper 4 to 7 inches.
Chroma - 2 through 4 dry or moist
Reaction - neutral or slightly alkaline
Bt horizons:
Hue - 10YR or 7.5YR
Value - 4 through 7 dry, 3 through 5 moist
Chroma - 3 through 6 dry and moist
Texture - GR-CL or GR-C
Rock fragment content - 15 to 80 percent
Reaction - slightly or moderately alkaline
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Inferno series are on ridges and mountains. These soils formed in alluvium and colluvium from volcanic rocks. Slopes are 15 to 35 percent. Elevation ranges from 6,000 to 8,000 feet. The average annual precipitation is 13 to 16 inches. Average annual air temperature is 40 to 44 degrees F. Frost-free period is 60 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ike and Jimbee series. Ike soils are on concave positions on mountainsides and have loamy-skeletal particle-size control sections. Jimbee soils are in convex positions on mountainsides and have loamy-skeletal particle-size control sections.
DRAINAGE AND PERMEABILITY: Well drained; rapid runoff; slow permeability.
USE AND VEGETATION: Rangeland. The principle native vegetation is bluebunch wheatgrass and low sagebrush.
DISTRIBUTION AND EXTENT: East-central Idaho. This series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Custer County, Idaho, 1999.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric peipedon - the zone from 0 to 12 inches (A1 and A2 horizons)
Argillic horizon - the zone from 12 to 60 inches (Bt1, Bt2, Btk1 and Btk2 horizons)
Particle-size control section - the zone from 12 to 32 inches (Bt1 and part of the Bt2 horizons)