LOCATION SHELLROCK IDEstablished Series
TAXONOMIC CLASS: Mixed, frigid Typic Xeropsamments
TYPICAL PEDON: Shellrock loamy coarse sand, forested. (Colors are for dry soil unless otherwise noted.)
A1--0 to 2 inches; dark grayish brown (10YR 4/2) loamy coarse sand, very dark grayish brown (10YR 3/2) moist; weak fine and very fine granular structure; loose, very friable; few coarse roots; many very fine and coarse interstitial pores; slightly acid (pH 6.4); abrupt smooth boundary. (1 to 3 inches thick)
A2--2 to 6 inches; dark grayish brown (10YR 4/2) loamy coarse sand, very dark grayish brown (10YR 3/2) moist; weak fine and medium granular structure; loose, very friable; few very fine and common fine roots; many very fine and coarse interstitial pores; neutral (pH 6.6); clear smooth boundary. (2 to 4 inches thick)
C1--6 to 40 inches; brown (10YR 5/3) loamy coarse sand, dark brown (10YR 4/3) moist; massive; loose; few very fine and common fine roots; many very fine and coarse interstitial pores; slightly acid (pH 6.4); gradual smooth boundary. (20 to 50 inches thick)
C2--40 to 56 inches; white (10YR 8/2) and very pale brown (10YR 8/4) gravelly coarse sand; singly grained; loose; slightly acid; gradual smooth boundary.
Cr--56 inches; weathered granite.
TYPE LOCATION: Valley County, Idaho; about 3 miles southeast of Donnelly on Goldfork Creek; 1,600 feet west, 2,000 feet south of the NE corner sec. 32, T.16N., R.4E.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 40 to 44 degrees F.
Average summer soil temperature - 59 to 63 degrees F.
Depth to paralithic contact - 40 to 60 inches
A horizons
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3 dry and moist
C horizons
Value - 5 through 8 dry, 4 through 6 moist
Chroma - 2 through 4 dry or moist
COMPETING SERIES: These are the Corbett, Juniperbute, Lowercreek(T), Sacheen and Sisters(T) series. Corbett soils have a paralithic contact at depths of 24 to 40 inches. Juniperbute soils are fine sand throughout the profile. Lowercreek and Sacheen soils have 0 horizons. Danz soils are strongly and medium acid throughout the soil profile and are moderately deep over glacial till. Maxson soils have very strongly acid A horizons and strongly acid C horizons. Sisters soils formed in mixed alluvium high in volcanic ash and have 30 to 50 percent rock fragments in the lower part of the control section.
GEOGRAPHIC SETTING: Shellrock soils are on ridgetops and south-facing slopes in rolling to very steep granitic mountains at elevations of 4,200 to 7,000 feet. Slopes are 12 to 60 percent. Average annual precipitation is 24 to 30 inches and includes 10 to 12 feet of snowfall. July and September are the driest months. The average frost-free period is 70 to 90 days. Average annual temperature is 38 to 42 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Jugson, Moscow and Takeuchi soils. Jugson soils have O and Bs horizons. Moscow soils have an O horizon and are over weathered bedrock at depths of 20 to 40 inches. Takeuchi soils have a dark surface horizon over 10 inches thick and have a weak Bt horizon.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; medium to rapid runoff; rapid permeability.
USE AND VEGETATION: Used for timber, range, wildlife, and watershed, Vegetation is ponderosa pine, scattered Douglas-fir, Ceanothus species, Idaho fescue, Stipa species, and pinegrass.
DISTRIBUTION AND EXTENT: Widely distributed in the granitic mountains of the Idaho Batholith. The soil is extensive.
MLRA OFFICE RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Valley Area, Idaho, 1977.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 6 inches (A1 and A2 horizons)