LOCATION SHEEPSKIN IDTentative Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Torrifluventic Haploxerolls
TYPICAL PEDON: Sheepskin gravelly loamy sand, in a weedy pivot corner with a southeast facing slope of 4 percent at 4,445 feet elevation. (When described on November 10, 1993 the soil was dry from 0 to 3 inches and slightly moist below. Colors are for air-dry soil unless otherwise stated.)
Ap1--0 to 4 inches; brown (10YR 5/3) gravelly loamy sand, very dark brown (10YR 2/2) moist; moderate thick and very thick platy structure; soft, very friable, nonsticky and nonplastic; common very fine and few fine roots; common very fine irregular and common fine and medium tubular pores; 15 percent gravel; slightly alkaline (pH 7.4); abrupt wavy boundary.
Ap2--4 to 12 inches; grayish brown (10YR 5/2) gravelly loamy sand, very dark brown (10YR 2/2) moist; weak moderate and coarse subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and few fine roots; common very fine irregular and few fine tubular pores; 20 percent gravel; slightly alkaline (pH 7.5); clear wavy boundary. (combined thickness of the Ap horizons is 0 to 14 inches)
Bw1--12 to 21 inches; pale brown (10YR 6/3) gravelly sandy loam, very dark grayish brown (10YR 3/2) moist; very friable, nonsticky and nonplastic; weak medium and coarse subangular blocky structure; slightly hard, common very fine and few fine roots; common very fine irregular and tubular pores and few fine tubular pores; 50 percent basalt sand grains; 15 percent gravel; slightly alkaline (pH 7.6); gradual wavy boundary.
Bw2--21 to 27 inches; pale brown (10YR 6/3) gravelly sandy loam, very dark grayish brown (10YR 3/2) moist; weak medium and coarse subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; common very fine roots; common very fine irregular and tubular pores; 50 percent basalt sand grains; 15 percent gravel; slightly alkaline (pH 7.6); clear wavy boundary. (combined thickness of the Bw horizons is 10 to 19 inches)
C1--27 to 32 inches; pale brown (10YR 6/3) gravelly fine sandy loam, dark grayish brown (10YR 3/3) moist; massive; slightly hard, friable, nonsticky and nonplastic; common very fine roots; common very fine irregular and tubular pores and few fine tubular pores; 25 percent gravel; slightly alkaline (pH 7.6); clear smooth boundary. (4 to 12 inches thick)
C2--32 to 53 inches; pale brown (10YR 6/3) very gravelly loamy sand, very dark grayish brown (10YR 3/2) moist; single grain; loose; common very fine roots; many very fine irregular pores; matrix is noneffervescent, slightly effervescent on bottom of rock fragments; very few very thin lime and silica coatings on bottom of rock fragments; 65 percent basalt sand grains; 50 percent gravel, 5 percent cobbles; slightly alkaline (pH 7.6); abrupt wavy boundary. (12 to 33 inches thick)
C3--53 to 57 inches; dark multicolored very gravelly sand; single grain; loose; few very fine roots; many very fine irregular pores; matrix is noneffervescent, slightly effervescent on bottom of rock fragments; very few very thin lime and silica coatings on bottom of rock fragments; 80 percent basalt sand grains; 45 percent gravel; slightly alkaline (pH 7.6); abrupt wavy boundary. (0 to 8 inches thick)
Ck1--57 to 63 inches; pale brown (10YR 6/3) very fine sandy loam, dark grayish brown (10YR 4/2) moist; weak thick platy rock structure; slightly hard, friable, nonsticky and nonplastic; few very fine roots; common very fine and few fine tubular pores; slightly effervescent; lime segregated as few fine soft masses; 5 percent gravel; slightly alkaline (pH 7.7); abrupt wavy boundary. (0 to 12 inches thick)
Ck2--63 to 80 inches; pale brown (10YR 6/3) very gravelly sand, dark grayish brown (10YR 4/2) moist; single grain; loose; many very fine irregular pores; strongly effervescent; lime and silica coatings on bottom of rock fragments 0.1 to 2 mm thick; 50 percent gravel; moderately alkaline (pH 7.9).
TYPE LOCATION: Bingham County, Idaho; about 3 miles north northeast of Fort Hall; 2450 feet north and 150 feet east of the southwest corner of sec. 18, T. 4S., R. 35E.; Fort Hall Quadrangle; Latitude - 43 degrees, 4 minutes, 46 seconds North; Longitude - 112 degrees, 24 minutes, 57 seconds West.
RANGE IN CHARACTERISTICS:
Thickness of mollic epipedon - 10 to 19 inches
Average annual soil temperature - 49 to 51 degrees F.
Particle-size control section
Clay content - 5 to 12 percent (average)
Rock fragments - 20 to 35 percent (average)
Ap or A horizons
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3 dry and moist
Rock fragments - 0 to 20 percent rounded pebbles
Reaction - neutral or slightly alkaline
Bw horizons
Hue - 10YR or 2.5Y
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 2 through 4 dry and moist
Texture - GR-LFS, LFS, GR-SL, GR-FSL, FSL
Rock fragments - 5 to 25 percent rounded pebbles
Reaction - neutral or slightly alkaline
C horizons
Hue - 10YR or 2.5Y
Value - 5 through 7 dry, 3 through 5 moist
Chroma - 2 or 3 dry and moist
Texture - Stratified GRX-S to VFSL
CaCO3 equivalent - 0 to 5 percent
Rock fragments - 2 to 75 percent rounded pebbles
Reaction - slightly or moderately alkaline
COMPETING SERIES: These are the Cleman, Kimberly, and Mosida series. Cleman and Kimberly soils average less than 15 percent rock fragments in the particle-size control section and they are well drained. Mosida soils appear to be misclassified and are too poorly defined to compete.
GEOGRAPHIC SETTING: Sheepskin soils are on stream and fan terraces with slopes from 0 to 8 percent. Elevation ranges from 4,400 to 4,500 feet. The soil formed in mixed coarse and moderately coarse alluvium. 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, Shoban (T), Tickason, and Tindahay soils. Kukvey soils are on stream and fan terraces and are sandy throughout. Quincy soils are on dunes and terraces, have an ochric epipedon and are sandy throughout. Shoban soils are on stream terraces and have a water table at a depth of 24 to 40 inches during May through November. Tickason soils are on stream terraces and have a calcic horizon at a depth of 12 to 23 inches. Tindahay soils are on stream terraces and have a sandy particle-size control section.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; very slow or slow runoff; moderately rapid permeability.
USE AND VEGETATION: Sheepskin soils are used primarily for irrigated cropland. They are also used for homesites and rangeland. 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, 1993. The name is taken from Sheepskin Road in the Fort Hall Indian Reservation.
REMARKS: Most areas of the Sheepskin series were mapped as the Tindahay series in the Fort Hall Area Soil Survey, 1977. The Sheepskin Soils are being differentiated by having a coarse-loamy particle-size control section.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from the surface to 12 inches (Ap1 and Ap2 horizons)
Torrifluventic subgroup - Sheepskin soils occur within an area with an aridic moisture regime that is bordering on xeric. The soil is assumed to have an irregular decrease in organic carbon with depth based on stratification of texture and soil color within the profile.
Particle-size control section - the zone from 10 to 40 inches (part of the Ap2 horizon, the Bw1, Bw2, and C1 horizons, and part of the C2 horizon)