LOCATION ISLANDPARK IDEstablished Series
TAXONOMIC CLASS: Coarse-silty, isotic Vitrandic Palecryalfs
TYPICAL PEDON: Islandpark ashy silt loam, on a 3 percent concave south slope in a area of lodgepole pine/grouse whortleberry community type at an elevation of 5,980 feet. (Colors are for dry soil unless otherwise stated.)
A--0 to 6 inches; grayish brown (10YR 5/2) ashy silt loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine, fine and medium roots; few very fine irregular pores; very strongly acid (pH 4.8); abrupt wavy boundary. (4 to 8 inches thick)
E1--6 to 14 inches; pale brown (10YR 6/3) ashy silt loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; common fine and medium tubular pores; strongly acid (pH 5.4); gradual smooth boundary. (1 to 11 inches thick)
E2--14 to 36 inches; very pale brown (10YR 7/3) ashy silt loam, dark grayish brown (10YR 4/2) moist; strong coarse subangular blocky structure; soft, very friable, nonsticky and nonplastic; common fine and medium roots; few fine tubular pores; strongly acid (pH 5.4); clear smooth boundary. (9 to 23 inches thick)
E/Bt1--36 to 51 inches; very pale brown (10YR 7/3) ashy silt loam, brown (10YR 4/3) moist; about 5 percent brown (10YR 5/3) very fine veins and tonguing of Bt material, dark grayish brown (10YR 4/2) moist; moderate coarse subangular blocky structure; soft, very friable, nonsticky and nonplastic; few medium roots; few fine and medium tubular pores; moderately acid (pH 5.8); clear wavy boundary. (15 to 43 inches thick)
E/Bt2--51 to 65 inches; very pale brown (10YR 7/3) ashy loam, dark grayish brown (10YR 4/2) moist; 15 percent yellowish brown (10YR 5/4) very fine veins and tonguing of Bt material, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure; soft, very friable, slightly sticky and moderately plastic; common fine roots; few fine and medium tubular pores; moderately acid (pH 5.8); abrupt wavy boundary. (0 to 18 inches thick)
2Bt--65 to 75 inches; brown (7.5YR 5/4) clay loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine roots; few very fine tubular pores; common faint clay films bridging mineral grains; 10 percent pebbles; common uncoated sand grains on faces of peds; slightly acid (pH 6.2); abrupt wavy boundary. (9 to 37 inches thick)
2R--75 inches; basalt
TYPE LOCATION: Fremont County, Idaho; about 10 miles northeast of Ashton; about 500 feet south and 2300 feet west of the northeast corner of section 13, T. 10 N., R. 43 E.; Latitude - 44 degrees, 12 minutes, 2 seconds North; Longitude - 111 degrees, 19 minutes, 23 seconds West.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 39 to 42 degrees F.
Average summer soil temperature - 43 to 46 degrees F. (With an 0 horizon) - 50 to 54 degrees F. (Without an O horizon)
Average clay percent for the particle-size control section - 8 to 12 percent
Depth to argillic horizon - 40 to 70 inches
Depth to hard bedrock - 60 to 100 inches
The soil is dry for 30 to 45 consecutive days following the summer solstice.
A horizon
Value - 5 or 6 dry; 2 to 4 moist
Chroma - 2 to 4 dry or moist
Color - value after mixing the upper 7 inches is greater than 5 dry and 3 moist
Reaction - very strongly or strongly acid
Volcanic glass in the 0.02 to 2.0 mm fraction - 50 to 80 percent
Acid-oxalate extractable aluminum plus one-half iron - less than 0.4 percent
Phosphate retention - 20 to 50 percent Base saturation (NH4OAC) - 20 to 50 percent.
E horizons
Value - 6 or 7 dry, 3 or 4 moist
Chroma - 2 or 3 dry or moist
Texture - ashy silt loam
Reaction - very strongly to moderately acid
Rock fragments - 0 to 15 percent
Pebbles - 0 to 10 percent
Cobbles - 0 to 10 percent
Stones - 0 to 5 percent
Volcanic glass in the 0.02 to 2.0 mm fraction - 5 to 30 percent
Acid-oxalate extractable aluminum plus one-half iron - 0.1 percent
Phosphate retention - 20 to 50 percent
E/Bt horizons
E portion
Value - 6 or 7 dry; 4 or 5 moist
Chroma - 2 or 3 dry or moist
B portion
Hue - 10YR or 7.5YR
Value - 5 or 6 dry, 4 or 5 moist
Chroma - 2 to 4 dry or moist
Volume of Bt material - 5 to 15 percent
Texture - ashy silt loam, loam
Reaction - strongly or moderately acid
Rock fragments - 0 to 15 percent
Pebbles - 0 to 10 percent
Cobbles - 0 to 15 percent
Stones - 0 to 5 percent
Volcanic glass content in the 0.02 to 2.0 mm fraction - 5 to 30 percent
Acid-oxalate extractable aluminum plus one-half iron - 0.1 to 1 percent
Phosphate retention - 20 to 50 percent
Base saturation (NH4OAC) - 60 to 100 percent
Other - 85 to 95 percent E material
2Bt horizon
Hue - 10YR or 7.5YR
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 3 or 4 dry or moist
Reaction - moderately to slightly acid
Texture - loam, clay loam, clay loam
Rock fragments - 0 to 20 percent
Pebbles - 0 to 20 percent
Cobbles - 0 to 15 percent
Stones - 0 to 5 percent
Volcanic glass content in the 0.02 to 2.0 mm fraction - less than 5 percent
Base saturation (NH4OAC) - 60 to 100 percent
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Islandpark soils are formed in loess over residuum from basalt. They are on caldera floors. The Islandpark soils are on the sideslopes and in the swales. Slopes range from 0 to 20 percent. Elevations range from 5,900 to 6,400 feet. Average annual precipitation is 20 to 28 inches, average annual temperature is 37 to 40 degrees F., the frost free period is less than 70 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Spliten and Potrmound series. Spliten soils are shallow to hard bedrock and are on basalt plains and terraces. Potrmound soils have loamy-skeletal particle-size control sections, are moderately deep to hard bedrock, have an Umbric epipedon, and are on basalt pressure ridges and domes.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderate permeability.
USE AND VEGETATION: Islandpark soils are used for timber production, woodland grazing, recreation, and wildlife habitat. These soils commonly support lodgepole pine/elk sedge, lodgepole pine/pinegrass, and lodgepole pine/grouse whortleberry community types. The potential native vegetation is a subalpine fir/grouse whortleberry plant association.
DISTRIBUTION AND EXTENT: Southeastern Idaho. The soils of this series are of large extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Targhee National Forest, Fremont County, Idaho, 1997.
REMARKS: Location coordinates determined by Global Positioning System.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon
Albic horizon - The zone from 14 to 51 inches (the E and E/Bt1 horizons).
Glossic horizon - The zone from 51 to 65 inches (E/Bt2 horizon)
Argillic horizon - The zone from 65 to 75 inches (the 2Bt horizon).
Vitrandic subgroup feature - The zone from the mineral soil surface to 65 inches (A, E1, E2, E/Bt1, E/Bt2 horizons)
Particle-size control section - The zone from 10 to 40 inches (lower part of the E1, the E2, and upper part of the E/Bt1 horizons)
Lithologic discontinuities - Occur at a depth of 65 inches.
Soil temperature regime - cryic
Soil moisture regime - udic
ADDITIONAL DATA: Reference sample: full characterization for Pedon #95P-152, samples 95P 1039-1044; National Soil Survey Laboratory, Lincoln, NE 8/96