LOCATION BIGLOST IDEstablished Series
TAXONOMIC CLASS: Coarse-loamy over sandy or sandy-skeletal, mixed, superactive Aquic Cumulic Haplocryolls
TYPICAL PEDON: Biglost gravelly fine sandy loam--on a 2 percent smooth, south aspect at 6,310 feet elevation in rangeland. (Colors are for dry soil unless otherwise noted. When described on August 1, 1985, the soil was moist throughout.)
A--0 to 5 inches; brown (10YR 5/3) gravelly fine sandy loam, very dark grayish brown (10YR 3/2) moist; moderate medium and platy structure; soft, very friable, slightly sticky and nonplastic; many very fine and fine, common medium roots; common very fine and fine tubular and interstitial pores; 15 percent pebbles; slightly alkaline (pH 7.5); clear wavy boundary. (4 to 9 inches thick)
AB--5 to 9 inches; brown (10YR 5/3) very fine sandy loam, dark brown (10YR 3/3) moist; moderate thin platy structure; soft, very friable, nonsticky and nonplastic; common very fine, fine and medium roots; common very fine and fine tubular and interstitial pores; 5 percent pebbles; minor lenses of sandy material with single grain structure within this horizon; neutral (pH 7.0); clear wavy boundary. (3 to 12 inches thick)
Bw--9 to 23 inches; brown (10YR 5/3) very fine sandy loam, dark brown (10YR 3/3) moist; few fine distinct redox concentrations and depletions, gray (10YR 5/1) and yellowish brown (10YR 5/4) moist; moderate medium and thick platy structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; many very fine and fine tubular and interstitial pores; 5 percent pebbles; slightly alkaline (pH 7.5); clear wavy boundary. (9 to 16 inches thick)
2C1--23 to 37 inches; multicolored extremely gravelly loamy sand; single grain; loose; common very fine and fine roots; common fine and medium interstitial pores; 65 percent pebbles, 10 percent cobbles; slightly alkaline (pH 7.4); clear wavy boundary. (12 to 18 inches thick)
3C2--37 to 43 inches; grayish brown (10YR 5/2) extremely gravelly loamy fine sand, dark brown (10YR 3/3) moist; single grain; loose; few very fine and fine roots; common fine and medium interstitial pores; 65 percent pebbles, 20 percent cobbles; slightly alkaline (pH 7.4); clear wavy boundary. (4 to 10 inches thick)
4C3--43 to 60 inches; multicolored extremely gravelly loamy coarse sand; single grain; loose; few fine roots; common fine and medium interstitial pores; 50 percent pebbles, 30 percent cobbles, 5 percent stones; slightly alkaline (pH 7.4).
TYPE LOCATION: Custer County, Idaho; approximately 1 mile southwest of the Highway 93 - Trail Creek Road junction, about 300 feet south and 500 feet east from the northwest corner of section 4, T.8N., R.22E. Latitude - 44 degrees, 03 minutes, 35 seconds North; Longitude - 113 degrees, 51 minutes, 40 seconds West.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 37 to 42 degrees F
Average summer soil temperature - 52 to 55 degrees F
Mollic epipedon thickness - 16 to 25 inches
Depth to redox features - 7 to 20 inches
Depth to strongly contrasting textures - 20 to 30 inches
Depth to high water table - 2.5 to 6 feet
A horizon
Hue - 2.5Y or 10YR
Value - 4 or 5 dry
Chroma - 2 to 4 dry, 2 or 3 moist
Bw horizon
Value - 4 or 5 dry
Chroma - 3 or 4 dry
Texture - VFSL, FSL, SIL
Percent clay - 8 to 15
Coarse fragments - 0 to 15 percent
C horizons
Texture - GRX-LS, GRX-LFS, GRX-LCOS
Percent clay - 0 to 5
Rock fragments - 60 to 90 percent
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Biglost soils are on floodplains and stream terraces. These soils formed in coarse-textured alluvium over flood deposited gravels. Slopes are 0 to 4 percent. Elevations are 4,8000 to 6,600 feet. The climate is cold and moist in winter and spring and cool in summer. The average annual precipitation is 8 to 13 inches. Average annual temperature is 33 to 40 degrees F. Frost-free period is 30 to 60 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Copperbasin and Whiskeysprings soils. Copperbasin soils are on flood plains. They have thin mollic epipedons and sandy-skeletal particle-size control sections. Whiskeysprings soils are on flood plains, are poorly drained and have 18 to 25 percent clay.
DRAINAGE AND PERMEABILITY: Moderately well drained. Slow runoff; moderate or moderately rapid permeability through the upper part and very rapid permeability in the lower part. The soil floods occasionally for brief periods from March to June.
USE AND VEGETATION: Rangeland. The natural vegetation is basin big sagebrush and wheatgrasses.
DISTRIBUTION AND EXTENT: East-central Idaho. These soils are 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:
Mollic epipedon - The zone from 0 to 23 inches (the A, AB, and Bw1 horizons).
Particle-size control section - The zone from 10 to 40 inches (part of the Bw, the 2C1, and part of the 3C2 horizons).
A wet phase of this soil is recognized. It has a water table due to irrigation.