LOCATION ALPINEPEAK IDEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Oxyaquic Haplocryepts
TYPICAL PEDON: Alpinepeak very gravelly sandy loam--on a 2 percent slightly concave, south to southwest-facing slope at 6,420 feet elevation in irrigated pasture. (Colors are for dry soil unless other wise noted. When described on September 16, 1986, the soil was moist throughout. An induced water table was at 32 inches on this date.)
A--0 to 3 inches; brown (10YR 5/3) very gravelly sandy loam, dark brown (10YR 3/3) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and common fine roots; common very fine and fine irregular pores; 40 percent fine gravel; slightly acid (pH 6.2); clear smooth boundary. (2 to 4 inches thick)
AB--3 to 7 inches; yellowish brown (10YR 5/4) very gravelly sandy loam, dark yellowish brown (10YR 3/4) moist; weak medium subangular blocky structure; soft, friable, nonsticky and nonplastic; common very fine and fine roots ; common very fine and fine irregular pores; 50 percent gravel; moderately acid (pH 6.0); clear wavy boundary. (2 to 6 inches thick)
Bw1--7 to 14 inches; yellowish brown (10YR 5/4) very gravelly sandy loam, dark yellowish brown (10YR 4/4) moist; weak fine subangular blocky structure; soft, friable, nonsticky and nonplastic; common very fine roots; common very fine and fine tubular and irregular pores; 50 percent gravel; moderately acid (pH 6.0); clear wavy boundary. (5 to 9 inches thick)
Bw2--14 to 25 inches; yellowish brown (10YR 5/4) extremely gravelly sandy loam, dark yellowish brown (10YR 4/4) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; few very fine roots; common very fine and fine and few medium tubular and irregular pores; 60 percent gravel; slightly acid (pH 6.2); clear wavy boundary. (8 to 15 inches thick)
Bw3--25 to 32 inches; yellowish brown (10YR 5/4) extremely gravelly sandy loam, dark yellowish brown (10YR 4/4) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; few very fine roots; common very fine and fine tubular and irregular pores; 60 percent gravel; slightly acid (pH 6.2); clear wavy boundary. (7 to 10 inches thick)
2C--32 to 60 inches; light yellowish brown (10YR 6/4) extremely gravelly coarse sand, light yellowish brown (10YR 6/4) moist; single grain; loose, nonsticky and nonplastic; common medium and coarse irregular pores; 65 percent gravel, 20 percent cobbles; slightly acid (pH 6.2).
TYPE LOCATION: Custer County, Idaho; approximately 1.5 miles northeast of the Idaho Highway 21 and Stanley Lake Road junction; about 1200 feet south and 1600 feet west of the northeast corner of section 24, T. 11 N., R. 12 E.
RANGE IN CHARACTERISTICS:
Xeric soil moisture regime
Average annual soil temperature - 35 to 39 degrees F.
Average summer soil temperature - 44 to 49 degrees F.
Control section - Percent clay: 6 to 15.
Coarse fragments: 40 to 75 percent.
Solum thickness: 20 to 40 inches.
A horizon
Chroma - 3 or 4, dry or moist.
Reaction - slightly acid or moderately acid.
Bw horizon
Hue - 2.5Y or 10YR
Value - 5 or 6 dry, 3 through 5 moist.
Chroma - 3 or 4, dry or moist.
Texture - GRV-SL, GRX-SL.
Coarse fragments - 45 to 85 percent.
Reaction - slightly acid or moderately acid.
2C horizon
Texture - GRX-COS, GRX-LCOS, GRX-COSL, CBX-COS
Coarse fragments - 60 to 90 percent.
COMPETING SERIES: This is the Elvick series. Elvick soils have an E horizon, do not have a lithologic discontinuity, are somewhat poorly drained, have an ustic moisture regime and have an O horizon.
GEOGRAPHIC SETTING: Alpinepeak soils are on outwash fans and stream terraces. These soils formed in outwash and stream alluvium dominantly from granite. Slopes are 1 to 4 percent. Elevations are 6,200 to 6,600 feet. The climate is cold and moist in winter and spring and cool in summer. The average annual precipitation is 12 to 16 inches. Average annual temperature is 34 to 38 degrees F. The frost-free period is 5 to 30 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Castlepeak, Fezip, Lilylake, Redfish, and Yankeefork soils. Castlepeak soils are on outwash fans, fan terraces, and stream terraces. They have sandy-skeletal particle-size control sections and are excessively drained. Fezip soils are on flood plains and have mollic epipedons, sandy particle-size control sections, and are poorly drained. Lilylake soils are on floodplains and have histic epipedons and are very poorly drained. Redfish soils are on floodplains and have sandy-skeletal particle-size control sections and are poorly drained. Yankeefork soils are on outwash fans, fan terraces and stream terraces and are well drained.
DRAINAGE AND PERMEABILITY: Moderately well drained. Slow runoff; moderately rapid permeability in the upper part and very rapid in the lower part of the profile. There is a water table at a depth of 2.5 to 3.5 feet from June through September.
USE AND VEGETATION: Irrigated native pasture. The natural vegetation is bluegrass, Idaho fescue, and sedges.
DISTRIBUTION AND EXTENT: Central Idaho. These soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Custer County, Idaho, 1999.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 0 to 7 inches (A and AB horizons)
Cambic horizon - The zone from 7 to 32 inches (the Bw1, Bw2, and the Bw3 horizons).
Xeric soil moisture regime
Particle-size control section - The zone from 10 to 40 inches (part of the Bw1, the Bw2, the Bw3, and part of the 2C horizons).
The 3/2008 description reflects a change in classification from Loamy-skeletal, mixed, superactive Oxyaquic Eutrocryepts to Loamy-skeletal, mixed, superactive Oxyaquic Haplocryepts. The competing series section was not updated and should be reviewed after all the cryepts have been re-classified.