LOCATION SPRABAT IDEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Typic Haplocalcids
TYPICAL PEDON: Sprabat gravelly sandy loam--on a 4 percent convex, southwest-facing slope in rangeland at 5,300 feet elevation. (Colors are for dry soil unless otherwise noted. When described on August 16, 1984 the soil was dry to 29 inches and moist below this depth.)
A--0 to 5 inches; brown (10YR 5/3) gravelly sandy loam, brown (10YR 4/3) moist; weak thick platy structure parting to weak fine subangular blocky; soft, very friable, nonsticky and nonplastic; many very fine and fine and few medium roots; many very fine and fine interstitial pores; 15 percent pebbles; slightly effervescent; moderately alkaline (pH 8.2); abrupt smooth boundary. (3 to 6 inches thick)
Bw--5 to 7 inches; light yellowish brown (10YR 6/4) sandy loam, brown (10YR 4/3) moist; weak medium and coarse subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; many very fine and fine roots; many very fine and fine interstitial pores; 10 percent fine pebbles; strongly effervescent; moderately alkaline (pH 8.3); clear smooth boundary. (0 to 4 inches thick)
Bk1--7 to 14 inches; light yellowish brown (10YR 6/4) gravelly sandy loam, brown (10YR 5/3) moist; weak coarse subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; many very fine and fine roots; many very fine and fine interstitial pores; 25 percent fine pebbles; calcium carbonate coatings 1 mm thick on undersides of coarse fragments; violently effervescent; moderately alkaline (pH 8.4); clear smooth boundary. (5 to 10 inches thick)
Bk2--14 to 29 inches; light yellowish brown (10YR 6/4) gravelly sandy loam, yellowish brown (10YR 5/4) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and fine roots; many very fine and fine interstitial pores; 25 percent fine pebbles; calcium carbonate coatings 1mm thick on undersides of coarse fragments; violently effervescent; strongly alkaline (pH 8.9); clear wavy boundary. (10 to 18 inches thick)
Bk3--29 to 41 inches; pale brown (10YR 6/3) gravelly sandy loam, brown (10YR 4/3) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; many fine and medium interstitial pores; 30 percent fine pebbles; calcium carbonate coatings 1 to 2 mm thick on sides and undersides of coarse fragments; strongly effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (10 to 20 inches thick)
Bk4--41 to 53 inches; yellowish brown (10YR 5/4) gravelly loamy coarse sand, brown (10YR 4/3) moist; single grain; loose; few very fine and fine roots; many very fine, fine and medium interstitial pores; 30 percent fine pebbles; calcium carbonate coatings 1 mm thick on all sides of coarse fragments; strongly effervescent; moderately alkaline (pH 8.4); clear wavy boundary. (6 to 15 inches thick)
Bk5--53 to 60 inches; light yellowish brown (10YR 6/4) gravelly sandy loam, dark yellowish brown (10YR 4/4) moist; weak fine and medium subangular blocky structure; soft, very friable, slightly sticky; and nonplastic; many very fine and fine interstitial pores; 25 percent fine pebbles; calcium carbonate coatings 1 mm thick on all sides of coarse fragments; slightly effervescent; strongly alkaline (pH 8.6).
TYPE LOCATION: Custer County, Idaho; approximately 1 mile southeast of Challis Hot Springs, about 2,600 feet south and about 1,300 feet west of the northeast corner of section 25, T. 14 N., R. 20 E.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 39 to 43 degrees F.
Control section; percent clay - 8 to 15 percent
Coarse fragments - 20 to 30 percent, mainly fine pebbles
Depth to calcic horizon - 4 to 8 inches
A horizon
Value - 5 or 6 dry, 3 or 4 moist
Bk horizon
Value - 5 through 7 dry
Texture - GR-SL, GR-LCOS
Other features - 1 to 2 mm thick coatings of silica are present on some coarse fragments.
Reaction - Moderately or strongly alkaline
COMPETING SERIES: This is the McGinty series. McGinty soils have depth to calcic horizon of 10 to 40 inches and average annual soil temperatures of 43 to 46 degrees F.
GEOGRAPHIC SETTING: Sprabat soils are on fan terraces. They formed in alluvium from tuff. Slopes are 0 to 8 percent. Elevations are 5,000 to 5,500 feet. The climate is cold and moist in winter and cool and dry in summer. Average annual precipitation is 6 to 8 inches; average annual temperature is 38 to 41 degrees F. The frost free period is 60 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dawtonia, Farvant, Sactus, and Snowslide soils. Dawtonia soils are on mountains and ridges. Dawtonia soils are very deep and have argillic horizons. Farvant and Sactus soils are on ridges. Farvant soils are shallow to a paralithic contact. Sactus soils are very shallow to hard bedrock. Snowslide soils are on fan terraces and have loamy-skeletal particle-size control section.
DRAINAGE AND PERMEABILITY: Well drained. Slow runoff; moderately rapid permeability.
USE AND VEGETATION: Rangeland. Vegetation is mainly shadscale, Indian ricegrass, bottlebrush squirreltail and sand dropseed.
DISTRIBUTION AND EXTENT: East-central Idaho. This series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Custer County, Idaho, 1999.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Calcic horizon - The zone from 7 to 29 inches (Bk1, Bk2 horizons).
Particle-size control section - The zone from 10 to 40 inches (part of Bk1, the Bk2, and part of Bk3 horizons).