LOCATION BEARTRAP IDEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Aridic Calcixerolls
TYPICAL PEDON: Beartrap loam on a 3 percent slope at an elevation of 5,000 feet in rangeland. When described on July 17, 1979, the pedon was dry throughout. (Colors are for dry soil unless otherwise noted)
A1--0 to 2 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; weak fine and medium granular structure; soft, very friable; many very fine, fine, and medium roots; many very fine and fine irregular pores; strongly effervescent (15 percent calcium carbonate equivalent); slightly alkaline (pH 7.6); abrupt smooth boundary. (2 to 5 inches thick)
A2--2 to 16 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; moderate fine and medium granular structure; soft, friable; many very fine, fine, and medium roots; many very fine and fine irregular pores; slightly effervescent (5 percent calcium carbonate equivalent); slightly alkaline (pH 7.4); clear smooth boundary. (7 to 14 inches thick)
Bk1--16 to 19 inches; light yellowish brown (10YR 6/4) fine sandy loam, brown (10YR 4/3) moist; moderate fine and medium subangular blocky structure; slightly hard, firm; many very fine, fine, and medium roots; many very fine and fine tubular pores; about 5 percent cobbles; strongly effervescent (15 percent calcium carbonate equivalent); slightly alkaline (pH 7.8); abrupt wavy boundary. (3 to 20 inches thick)
Bk2--19 to 43 inches; light gray (10YR 7/2) fine sandy loam, brown (10YR 5/3) moist; moderate medium subangular blocky structure; slightly hard, firm; common very fine and fine roots; common very fine and fine tubular pores; about 10 percent cobbles; violently effervescent (30 percent calcium carbonate equivalent); moderately alkaline (pH 8.4); gradual wavy boundary. (10 to 34 inches thick)
Bk3--43 to 52 inches; white (10YR 8/2) fine sandy loam, pale brown (10YR 6/3) moist; massive; slightly hard, friable; common very fine and fine roots; common very fine tubular pores; about 10 percent cobbles; violently effervescent (30 percent calcium carbonate equivalent); moderately alkaline (pH 8.4). (5 to 15 inches thick)
R--52 inches; basalt.
TYPE LOCATION: Blaine County, Idaho, about 2,800 feet south and 2,500 feet west of the northeast corner of sec. 31, T. 2 S., R. 28 E. Latitude - 43 degrees, 12 minutes, 09 seconds North; Longitude - 113 degrees, 13 minutes, 47 seconds West.
RANGE IN CHARACTERISTICS:
Depth to basalt bedrock - 40 to 60 inches
Average annual soil temperature - 42 to 47 degrees F.
Reaction - slightly alkaline to moderately alkaline
Thickness of mollic epipedon and depth to the calcic horizon - 10 to 16 inches
A horizon
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3 moist or dry
Rock fragments - 0 to 5 percent
Bk1 horizon
Value - 5 or 6 dry, 4 or 5 moist
Chroma - 3 or 4 moist or dry
Texture - loam, fine sandy loam
Clay content - 12 to 18 percent
Rock fragments - 0 to 5 percent
Bk2 and Bk3 horizons
Value - 6 through 8 dry and 5 or 6 moist
Chroma - 2 or 3 moist or dry
Texture - fine sandy loam and silt loam
Clay content - 12 to 18 percent
Rock fragments - 5 to 15 percent
COMPETING SERIES: This is the Stan series. Stan soils lack bedrock above 60 inches.
GEOGRAPHIC SETTING: Beartrap soils are on basalt plains on mounds 10 to 30 feet in diameter. Slopes range from 2 to 30 percent. Elevation ranges from 4,600 to 5,500 feet. The soil formed in eolian deposits and alluvium from eolian material. The average annual precipitation is 10 to 14 inches, most of which falls as snow and early spring rains. The average annual air temperature is 41 degrees to 45 degrees F. The frost free season is 70 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: They are the Atomic, Splittop, and McCarey soils. Atomic and Splittop soils have ochric epipedons. McCarey soils are moderately deep and have more than 18 percent clay in the control section.
DRAINAGE AND PERMEABILITY: Well drained. Medium runoff. Permeability is moderate.
USE AND VEGETATION: Mainly used for rangeland. Vegetation is basin big sagebrush, basin wildrye, bluebunch wheatgrass, and cheatgrass brome.
DISTRIBUTION AND EXTENT: Beartrap soils are of moderate extent in south-central Idaho.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Blaine County, Idaho, 1993.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from 0 to 16 inches (A1 and A2 horizon)
Calcic horizon - the zone from 16 to 52 inches (Bk1, Bk2, and Bk3 horizons)
Particle-size control section - the zone from 10 to 40 inches (part of the A2, the Bk1, and part of the Bk2 horizon)