LOCATION BLUEGULCH IDEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Xeric Haplocalcids
TYPICAL PEDON: Bluegulch gravelly loam--on a southwest-facing slope of 10 percent under rangeland vegetation at 3,800 feet elevation. (Colors are for dry soil unless otherwise stated.) When described on August 31, l983, the soil profile was dry throughout.
A--0 to 4 inches; brown (10YR 5/3) gravelly loam, dark brown (10YR 3/3) moist; weak medium granular structure; soft, friable, slightly sticky and slightly plastic; common very fine, fine and medium roots; many very fine and fine tubular pores; 25 percent gravel; neutral (pH 7.1); clear smooth boundary. (4 to 6 inches thick)
Bw1--4 to 12 inches; pale brown (10YR 6/3) gravelly loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine and medium roots; many very fine and fine tubular pores; 15 percent gravel; neutral (pH 6.7); gradual wavy boundary. (0 to 10 inches thick)
Bw2--12 to 20 inches; pale brown (10YR 6/3) very gravelly loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine, and few medium roots; common very fine and fine tubular pores; 45 percent gravel and 5 percent cobbles; slightly alkaline (pH 7.4); clear smooth boundary (0 to 22 inches thick)
Bk--20 to 44 inches; light gray (10YR 7/2) extremely gravelly sandy loam, grayish brown (10YR 5/2) moist; massive; slightly hard, friable; few very fine and fine roots; few very fine and fine irregular pores; 45 percent gravel and 25 percent cobbles; strongly effervescent, carbonates and silica coating on underside of coarse fragments; slightly alkaline (pH 7.5); abrupt wavy boundary. (19 to 28 inches thick)
R--44 inches; welded tuff bedrock.
TYPE LOCATION: About 12 miles southwest of Buhl, Twin Falls County, Idaho; in the southwest 1/4, northwest 1/4, northwest 1/4 of section 12, T. 10 S., R. 12 E.
RANGE IN CHARACTERISTICS:
Depth to bedrock - 40 to 60 inches
Average coarse fragments in control section - 50 to 70 percent
Depth to carbonates - 18 to 35 inches
Average annual soil temperature - 51 to 53 degrees F.
A horizon
Value - 5 or 6 dry, 3 or 4 moist
Gravel - 15 to 30 percent
Bw horizon
Value - 3 or 4 moist
Gravel - 15 to 45 percent
Cobbles - 0 to 5 percent
Clay - 18 to 24 percent
Bk horizon
Value - 4 or 5 moist
Chroma - 2 or 3 dry or moist
Textures - GRX-SL, GRX-L
Gravel - 45 to 55 percent
Cobbles - 10 to 25 percent
CaCO3 equivalent 5 to 15 percent
COMPETING SERIES: These are the Graveya , Mackey, Sitar, Tupper, and Waycup series. Graveya soils are greater than 60 inches deep, have 24 to 30 percent clay in the Bw horizon and have moderately alkaline or strongly alkaline 2Bkq horizons. Mackey soils are 20 to 40 inches deep to bedrock. Sitar soils are greater than 60 inches deep, are 2 to 12 inches deep to a calcic horizon, and have 15 to 25 percent CaCO3 equivalent in the calcic horizon. Tupper soils are greater than 60 inches deep, are 20 to 36 inches deep to stratified sand and rock fragments, and have 15 to 25 percent CaCO3 equivalent in the calcic horizon. Wayup series have 15 to 40 percent CaCO3 equivalent in the calcic horizon.
GEOGRAPHIC SETTING: Bluegulch soils are on dipslopes and ridgetops. The slope ranges from 2 to 30 percent. The soils formed in colluvium from welded tuff. Elevations are 3,500 to 4,000 feet. The mean annual precipitation is 8 to 10 inches. The mean annual temperature is 49 to 51 degrees F. The frost-free season is 120 to 140 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Chuska, Elijah, Pigtail, and Roseworth soils. Chuska and Roseworth soils are shallow to a duripan and occur on terraces. Elijah and Pigtail soils are moderately deep to a duripan and occur on terraces.
DRAINAGE AND PERMEABILITY: Well drained, slow or medium runoff; moderate permeability.
USE AND VEGETATION: Bluegulch soils are used for livestock grazing. Native vegetation is Thurber needlegrass, Sandberg bluegrass and Wyoming big sagebrush.
DISTRIBUTION AND EXTENT: Bluegulch soils are of small extent in south-central Idaho.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Twin Falls County, Idaho, l992.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 4 inches (A horizon)
Cambic horizon - the zone from 4 to 20 inches (Bw1 and Bw2 horizons)
Calcic horizon - the zone from 20 to 44 inches (Bk horizon)