LOCATION ATOM IDEstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, frigid Sodic Xeric Haplocalcids
TYPICAL PEDON: Atom silt loam; rangeland; on a 3 percent southwest slope at 5,286 feet elevation with Wyoming big sagebrush and bluebunch wheatgrass. When described on July 11, 1979, the soil was slightly moist below 30 inches. (Color is for dry soil unless otherwise noted.)
A1--0 to 3 inches; pale brown (10YR 6/3) silt loam, dark brown (10YR 3/3) moist; moderate very thin platy structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine roots; many fine vesicular pores; slightly effervescent (5 percent calcium carbonate equivalent); 2 percent basalt gravel; slightly alkaline (pH 7.6); clear smooth boundary.
A2--3 to 10 inches; pale brown (10YR 6/3) silty clay loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure; slightly hard, very friable, slightly sticky and moderately plastic; common fine and very fine roots; common very fine tubular pores; slightly effervescent (7 percent calcium carbonate equivalent); 1 percent basalt gravel; slightly alkaline (pH 7.8); clear smooth boundary. (combined thickness of the A horizons is 7 to 12 inches)
Bkq--10 to 29 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; weak fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine roots; common very fine irregular pores; common coarse hard rounded nodules or cicada krotovinas; violently effervescent (25 percent calcium carbonate equivalent); common 1 mm thick lime and silica coats on undersides of rock fragments; 1 percent basalt gravel; strongly alkaline (pH 8.5); clear wavy boundary. (0 to 20 inches thick)
Bk1--29 to 39 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; few very fine roots; common very fine tubular pores; violently effervescent (20 percent calcium carbonate equivalent); common 1 mm thick lime coats on undersides of rock fragments; 1 percent basalt gravel; strongly alkaline (pH 9.0); clear smooth boundary. (8 to 36 inches thick)
Bk2--39 to 60 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; few very fine roots; common very fine tubular pores; violently effervescent (20 percent calcium carbonate equivalent); common 1 mm thick lime coats on undersides of rock fragments; 5 percent basalt gravel; strongly alkaline (pH 9.0).
TYPE LOCATION: Bingham County, Idaho; about one-half mile northeast of Middle Butte, about 4 miles northwest of Atomic City; approximately 2,400 feet north and 700 feet east of the southwest corner of sec. 16, T.2N., R.32E. Latitude - 43 degrees, 29 minutes, 57 seconds north. Longitude - 112 degrees, 42 minutes, 55 seconds west.
RANGE IN CHARACTERISTICS:
The soil moisture control section is dry for one-half to three-fourths of the time when the soil temperature is above 41 degrees; dry for 70 to 85 consecutive days.
Profile
Mean annual soil temperature - 44 to 47 degrees F.
Mean summer soil temperature - 62 to 66 degrees F.
Depth to calcic horizon and secondary carbonates - 7 to 12 inches BA or Bw horizons are present in some pedons
Particle-size control section
Total clay content - 12 to 35 percent
Carbonate free clay content - 10 to 18 percent
Silt plus very fine sand is 70 to 85 percent
Rock fragment content - 0 to 5 percent
A horizon
Value - 5 or 6 dry and 3 or 4 moist
Reaction - slightly or moderately alkaline The upper part of the A horizon is non effervescent in some pedons
Bkq and Bk horizons
Value - 6 or 7 dry and 4 through 6 moist
Chroma - 2 or 3 dry
Texture - SIL to a depth of 40 inches and ranging to SICL below 40 inches.
Rock fragment content - 0 to 5 percent
Reaction - strongly or very strongly alkaline
SAR - 13 to 30
Calcium carbonate - 15 to 40 percent
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Atom soils are typically on lava plains, but are also on terraces and alluvial fans that join lava plains. Elevations range from 4,500 to 5,800 feet. Slopes range from 0 to 20 percent. The parent material is mixed alluvium. The average annual precipitation ranges from 9 to 11 inches. The average annual air temperature is about 43 to 45 degrees F. The frost free season is 70 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Coffee, Deuce, Pancheri, Polatis, Menan, Nargon and Techicknot series. Nargon and Polatis soils are moderately deep soils on higher positions. Coffee soils are deep to basalt on similar positions. Deuce soils are shallow to basalt bedrock on higher positions near to rock outcrop. Pancheri soils are in similar positions and are coarse-silty. Menan and Techicknot soils are in basin positions with argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderately slow permeability.
USE AND VEGETATION: Used primarily for range and wildlife habitat. Vegetation is mainly Wyoming big sagebrush and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: Southeastern Idaho. These soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Bingham County, Idaho, 1997; part of the Butte County Area Soil Survey.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 10 inches (The A1 and A2 horizons) Carbonates decrease from 28 percent at about 12 inches to 17 percent at 40 inches.
Calcic horizon - the zone from 10 to 60 inches (The Bkq, Bk1 and Bk2 horizons)
Sodic- SAR of over 20 from about 10 inches to over 60 inches.
Particle-size control section - the zone from 10 to 40 inches (the Bkq, Bk1 and part of the Bk2 horizons) averages 17 percent total clay, 4 percent carbonate clay and 81 percent silt and very fine sand.
ADDITIONAL DATA: Lab data available from official series type location, S94ID-011-006. The nomenclature and depth associated with the laboratory data do not match the series description. The series description was made in 1979 and the description with the laboratory data was made in 1994.