LOCATION PENAGUL IDEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic, frigid, shallow Typic Haplargids
TYPICAL PEDON: Penagul very gravelly clay loam--on a 60 percent smooth, northeast aspect in rangeland at 5,550 feet elevation. (Colors are for dry soil unless otherwise noted. When described on September 18, 1985, the soil was dry to 2 inches and moist below this depth.)
E--0 to 2 inches; very pale brown (10YR 7/3) very gravelly clay loam, brown (10YR 5/3) moist; moderate fine angular blocky structure; slightly hard, firm, moderately sticky and moderately plastic; common very fine and fine roots; many very fine and fine interstitial pores; 50 percent pebbles; neutral (pH 7.3); clear smooth boundary. (1 to 3 inches thick)
Bt--2 to 8 inches; pale brown (10YR 6/3) very gravelly clay loam, brown (10YR 5/3) moist; moderate fine and medium angular blocky structure; slightly hard, firm, very sticky and moderately plastic; many very fine and fine roots; many very fine and fine tubular pores; common distinct clay films lining pores and on faces of peds; 40 percent pebbles; slightly alkaline (pH 7.4); clear wavy boundary. (4 to 8 inches thick)
Cr1--8 to 12 inches; fractured tuff; 4 to 6 inches between fractures and root mats on rock fragments and penetrating into fractures; tuff is soft when moist and can be excavated easily with tiling spade; tuff is hard when dry and fractures when struck with tiling spade; some interstices are not filled with soil material; gradual wavy boundary. (3 to 6 inches thick)
Cr2--12 inches; fractured tuff; 4 to 6 inches between fractures; many interstices are not filled with soil material; tuff is soft when moist and hard when dry.
TYPE LOCATION: Custer County, Idaho; Penal Gulch Area and 4 miles northeast of Challis, Idaho; about 1,600 feet west and about 1,000 feet south of the northeast corner of section 12, T.14N., R.19E.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 39 to 43 degrees F
Control section - Percent clay: 35 to 45
Rock fragments: 35 to 50 percent
Depth to paralithic - 6 to 10 inches
E horizon
Value - 6 or 7 dry, 4 or 5 moist
Bt horizon
Value - 6 or 7 dry, 4 or 5 moist
Chroma - 3 or 4 dry or moist
Texture - GRV-CL, GRV-C
Reaction - neutral or slightly alkaline
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Penagul soils are on foothills and ridges. These soils formed in residuum and slope alluvium from tuff. Slopes are 20 to 60 percent. Elevations are 5,000 to 6,000 feet. Climate is cold and moist in winter and dry in summer. The average annual precipitation is 6 to 8 inches; average annual temperature is 37 to 41 degrees F. The frost-free period is 60 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dawtonia, Rosebriar, Sactus and Venum soils. Dawtonia soils are on mountains and are very deep. Rosebriar soils are on ridges and are shallow to aparalithic contact. Sactus soils are on ridges and are very shallow to a lithic contact. Venum soils are on mountains and are very deep.
DRAINAGE AND PERMEABILITY: Well drained. Medium runoff; slow permeability.
USE AND VEGETATION: Rangeland. Vegetation is mainly Shadscale, Salmon wildrye and Indian ricegrass.
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:
Ochic epipedon
Argillic horizon - The zone from 2 to 8 inches (Bt horizon).
Paralithic contact - The boundary at 8 inches.
Particle-size control section - The zone from the surface to the paralithic contact (A and Bt horizons).