LOCATION BOTHWELL IDEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, frigid Pachic Argixerolls
TYPICAL PEDON: Bothwell silt loam in nonirrigated cropland on a 0 percent slope at 5,000 feet elevation. When described on July 7, 1986, the soil was moist below seven inches. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 9 inches; brown (10YR 5/3) silt loam, very dark grayish brown (10YR 3/2) moist; moderate very fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; few very fine tubular pores; slightly alkaline (pH 7.8); abrupt smooth boundary. (6 to 12 inches thick)
Bt1--9 to 20 inches; grayish brown (10YR 5/2) silt loam, very dark brown (10YR 2/2) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, sticky and plastic; many very fine roots; many very fine tubular pores; few faint clay films on faces of peds and in pores; slightly alkaline (pH 7.6); gradual smooth boundary. (12 to 20 inches thick)
Bt2--20 to 26 inches; brown (10YR 5/3) silty clay loam, dark brown (10YR 3/2) moist; moderate very fine subangular blocky structure; hard, friable, sticky and plastic; many very fine roots; many very fine and fine irregular and few very fine tubular pores; common distinct clay films on faces of peds and in pores; slightly alkaline (pH 7.6); gradual smooth boundary. (4 to 10 inches thick)
Bt3--26 to 45 inches; brown (10YR 5/3) silty clay loam, dark brown (7.5YR 3/2) moist; moderate very fine subangular blocky structure; hard, friable, sticky and plastic; common very fine roots; common very fine tubular pores; many faint clay films on faces of peds and in pores; slightly alkaline (pH 7.8); gradual smooth boundary. (15 to 25 inches thick)
Bk--45 to 60 inches; pale brown (10YR 6/3) silt loam, brown (7.5YR 4/2) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; strongly effervescent; moderately alkaline (pH 8.0).
TYPE LOCATION: Oneida County, Idaho; about 16 miles southwest of Malad, Idaho; 2,700 feet east and 100 feet north of the southwest corner of sec. 23, T. 16 S., R. 34 E. Latitude - 42 degrees, 30 seconds North; 112 degrees, 26 minutes, 59 seconds West.
RANGE IN CHARACTERISTICS:
Mollic epipedon - 20 to 50 inches thick
Depth to lime - 44 to greater than 60 inches
Control section average - 22 to 27 percent clay in the upper part and 28 to 35 percent in the lower part
Average annual soil temperature - 44 to 47 degrees F.
A horizon
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 1 through 4 dry, 1 through 3 moist
Reaction - slightly acid through slightly alkaline
Bt horizon
Color hue - 10YR or 7.5YR
Value - 4 through 7 dry, 2 through 4 moist
Chroma - 1 through 3 dry or moist
Texture - SIL, SICL
Coarse fragments - 0 to 3 percent rounded gravel
Reaction - slightly acid through moderately alkaline
Bk horizon (absent in some pedons)
Color hue - 10YR or 7.5YR
Value - 4 through 7 dry, 3 or 4 moist
Chroma 2 through 4 dry or moist
Texture - SIL, SICL, SI
Coarse fragments - 0 to 5 percent rounded gravel
Reaction - neutral through moderately alkaline
COMPETING SERIES: These are the Marystown and Smelter series. Marystown soils have buried argillic horizons that have strong structure and slow permeability. Smelter soils have average annual soil temperature of less than 44 degrees F. and have strong structure in the argillic horizon.
GEOGRAPHIC SETTING: Bothwell soils are on lake terraces, fan terraces, and hillsides, and have slopes of 0 to 30 percent. Elevation ranges from 4,900 to 6,000 feet. The soil formed in lacustrine sediments and silty alluvium influenced by loess. Average annual precipitation is 14 to 20 inches and average annual air temperature is 42 to 45 degrees F. The frost free period is 70 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bancroft, Buckboard, Elevator, and Povirt soils. Bancroft soils have calcic horizons. Buckboard soils do not have an argillic horizon. Elevator and Povirt soils have mollic epipedons less than 20 inches thick. Bancroft soils are on loess covered fan terraces. Buckboard and Elevator soils are on lake terraces. Povirt soils are on playas.
DRAINAGE AND PERMEABILITY: Well drained; slow to very rapid runoff; moderately slow permeability.
USE AND VEGETATION: Nonirrigated cropland. Used mostly for small grains and alfalfa.
DISTRIBUTION AND EXTENT: Southeastern Idaho. These soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Box Elder County, Utah, 1941.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from the surface to 45 inches (Ap, Bt1, Bt2, and Bt3 horizons)
Argillic horizon - the zone from 9 to 45 inches (Bt1, Bt2, and Bt3 horizons)
Particle-size control section - the upper 20 inches of the argillic horizon (Bt1, Bt2, and part of Bt3 horizons)
Classification based on Keys to Soil Taxonomy, Eighth Edition, 1998.
CEC activity class is a tentative placement and is based on NASIS interpretive estimates for clay total and CEC-7.