LOCATION SHOBAN IDTentative Series
TAXONOMIC CLASS: Sandy, mixed, mesic Aquic Calcixerolls
TYPICAL PEDON: Shoban loamy sand, in a weedy pivot corner with a slope of less than 1 percent at 4,420 feet elevation. (When described on November 9, 1993, the soil was moist from the surface to a depth of 34 inches and saturated below. A water table was at a depth of 36 inches. Colors are for air-dry soil unless otherwise stated.)
Ap1--0 to 7 inches; brown (10YR 5/3) loamy sand, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and few fine, medium, and coarse roots; common very fine irregular and tubular pores; very slightly effervescent; moderately alkaline (pH 8.0); clear smooth boundary.
Ap2--7 to 11 inches; brown (10YR 5/3) loamy sand, dark brown (10YR 3/3) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; few very fine, fine, medium, and coarse roots; common very fine irregular and tubular pores; very slightly effervescent; moderately alkaline (pH 8.4); abrupt wavy boundary. (combined thickness of the Ap horizons is 7 to 14 inches)
A--11 to 16 inches; 70 percent brown (10YR 5/3) and 30 percent grayish brown (10YR 5/2) loamy sand, 70 percent dark brown (10YR 3/3) and 30 percent very dark gray (10YR 3/1) moist (colors are stratified); weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; few very fine, fine, medium, and coarse roots; many very fine irregular and common very fine tubular pores; very slightly effervescent; moderately alkaline (pH 8.4); abrupt smooth boundary. (0 to 8 inches thick)
BA--16 to 22 inches; pale brown (10YR 6/3) sand, brown (10YR 4/3) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine, fine, medium, and coarse roots; many very fine irregular and few very fine tubular pores; 1 percent gravel 2 to 10 mm in diameter; slightly effervescent; moderately alkaline (pH 8.3); clear smooth boundary. (0 to 10 inches thick)
Bk--22 to 37 inches; pale yellow (2.5Y 7/3) sand, light olive brown (2.5Y 5/3) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; many very fine irregular pores; common fine prominent gray (5Y 6/1) moist iron depletions and dark brown (10YR 4/3) moist masses of iron accumulation; violently effervescent, lime segregated as thin coats on sand grains; 17 percent calcium carbonate equivalent; 1 percent gravel 2 to 10 mm in diameter; moderately alkaline (pH 8.2); clear smooth boundary. (8 to 20 inches thick)
Bkg1--37 to 62 inches; light gray (2.5Y 7/2) sand, grayish brown (2.5Y 5/2) moist; single grain; loose; many very fine irregular pores; common fine prominent gray (5Y 6/1) moist masses of iron depletion and dark brown (10YR 4/3) moist masses of iron accumulation; violently effervescent, lime segregated as thin coats on sand grains; 14 percent calcium carbonate equivalent; moderately alkaline (pH 8.1); abrupt smooth boundary. (16 to 30 inches thick)
Bkg2--62 to 80 inches; 80 percent pale yellow (2.5Y 7/3) and 20 percent olive gray (5Y 4/2) stratified sand, loamy sand, and fine sandy loam, 80 percent light olive brown (2.5Y 5/3) and 20 percent dark olive gray (5Y 3/2) moist; dominantly massive with some strata being single grain; loose to slightly hard, loose to friable, nonsticky and nonplastic; many very fine irregular and few very fine tubular pores; common fine prominent yellowish brown (10YR 5/4) moist masses of iron accumulation; violently effervescent, lime segregated as thin coats on sand grains; 14 percent calcium carbonate equivalent; moderately alkaline (pH 8.2).
TYPE LOCATION: Bingham County, Idaho; about 2 miles west of Fort Hall; 2,470 feet west and 2,370 feet south of the northeast corner of sec. 33, T. 4S., R. 34E.; Fort Hall Quadrangle; Latitude - 43 degrees, 1 minute, 47 seconds North; Longitude - 112 degrees, 29 minutes, 1 second West.
RANGE IN CHARACTERISTICS:
Thickness of mollic epipedon - 10 to 19 inches
Depth to calcic horizon - 14 to 30 inches
Depth to redox concentrations - 20 to 30 inches
Depth to high water table - 24 to 40 inches in May through November Average annual soil temperature - 48 to 50 degrees F.
Particle-size control section
Clay content - 1 to 10 percent
Rock fragments - 0 to 5 percent
Ap and A horizons
Chroma - 2 or 3 dry, 1 through 3 moist
Reaction - slightly or moderately alkaline
Bk and Bkg1 horizons
Hue - 10YR or 2.5Y
Value - 6 or 7 dry, 4 or 5 moist
Chroma - 2 or 3 dry and moist
Texture - COS, S, LS
Calcium carbonate equivalent - 10 to 20 percent
Bkg2 horizon
Hue - 2.5Y, 5Y, 5GY
Value - 4 through 7 dry, 3 through 5 moist
Chroma - 1 through 3 dry and moist
Texture - COS, S, LCOS, LS, LFS, SL, or FSL (typically stratified) Calcium carbonate equivalent - 10 to 20 percent
COMPETING SERIES: There are no other series in this family. A closely related soil is the Maxey series which has an ochric epipedon.
GEOGRAPHIC SETTING: Shoban soils are on broad stream terraces with slopes from 0 to 2 percent. Elevation ranges from 4,400 to 4,500 feet. The soil formed in mixed sandy alluvium that has been modified by wind. The climate is semi-arid with warm dry summers and cold moist winters. The average annual precipitation is 9 to 11 inches. The average annual air temperature is 46 to 48 degrees F. The frost-free season is 110 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kukvey (T), Quincy, Tickason, and Tindahay soils. Kukvey, Tickason, and Tindahay soils are on similar landscape positions. Quincy soils are on dunes and terraces. All of these soils are well to excessively drained and do not have a high water table within a depth of 60 inches any time during the year.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; very slow runoff; very rapid permeability. A high water table is at a depth of 24 to 40 inches during May through November.
USE AND VEGETATION: Shoban soils are used primarily for irrigated cropland. They are also used for homesites. The major crops grown are potatoes, wheat, barley, and alfalfa.
DISTRIBUTION AND EXTENT: Southeastern Idaho. The series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Bingham County, Idaho, 1994. The name is taken from the Shoshone-Bannock Tribe.
REMARKS: Most areas of the Shoban series were mapped as the Tindahay series in the Fort Hall Area Soil Survey, 1977. The Shoban series is being differentiated by recognition of a mollic epipedon, a calcic horizon, and a high water table, all of which are not present in the Tindahay series. Drilling logs in the area where the Shoban series is mapped show a strata of clay is common at at a depth of 6 to 12 feet. This clay strata is the likely cause of the perched water table in the Shoban series.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from the surface to 16 inches (Ap1, Ap2, and A horizons)
Calcic horizon - the zone from 22 to 80 inches (Bk, Bkg1, and Bkg2 horizons)
Aquic subgroup - redox concentrations present below 22 inches and aquic conditions present within 30 inches during part of the year.
Particle-size control section - the zone from 10 to 40 inches (part of the Ap2 horizon, the A, BA, and Bk horizons, and part of the Bkg1 horizon)