LOCATION DAWTONIA IDEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Xeric Calciargids
TYPICAL PEDON: Dawtonia very gravelly loam on a north facing smooth slope of 21 percent in rangeland at 6,600 feet elevation. The profile was moist throughout when described on July 5, 1977. (Colors are for air-dry soil unless otherwise stated)
A--0 to 4 inches; brown (10YR 5/3) very gravelly loam, dark brown (10YR 3/3) moist; weak fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine, fine and medium roots; 40 percent pebbles; neutral (pH 7.2); clear wavy boundary. (2 to 7 inches thick)
Bt--4 to 12 inches; yellowish brown (10YR 5/4) very gravelly loam, dark brown (10YR 4/3) moist; moderate fine and very fine subangular blocky structure; hard, friable, moderately sticky and moderately plastic; many very fine, fine and medium roots; many very fine tubular pores; few faint clay films on faces of peds and in pores; 40 percent pebbles, 10 percent cobbles; slightly alkaline (pH 7.4); clear wavy boundary. (6 to 12 inches thick)
Bk--12 to 24 inches; pale brown (10YR 6/3) very gravelly loam, brown (10YR 5/3) moist; weak fine and very fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; few very fine and medium roots; many very fine tubular pores; violently effervescent (20 percent calcium carbonate); 40 percent pebbles, 10 percent cobbles; slightly alkaline (pH 7.8); clear wavy boundary. (8 to 14 inches thick)
Bkq1--24 to 37 inches; pale brown (10YR 6/3) extremely gravelly loam, brown (10YR 5/3) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; few very fine and fine roots; many very fine tubular pores; strongly effervescent (12 percent calcium carbonate); common thin lime and silica coatings and pendants on the underside of rock fragments; 50 percent pebbles, 10 percent cobbles; slightly alkaline (pH 7.8); clear wavy boundary. (8 to 22 inches thick)
Bkq2--37 to 60 inches; light yellowish brown (10YR 6/4) extremely gravelly loam, yellowish brown (10YR 5/4) moist; massive; slightly hard, very friable; nonsticky and nonplastic; few very fine and fine roots; many very fine interstitial pores; slightly effervescent (2 percent calcium carbonate); common thin lime and silica coatings and pendants on the underside of rock fragments; 50 percent pebbles, 10 percent cobbles; moderately alkaline (pH 8.0).
TYPE LOCATION: Custer County, Idaho; about 1.9 miles south southwest of the Spar Canyon turnoff from Highway 93; 1,920 feet north, 1,375 feet west from the southeast corner of sec. 15, T. 11 N., R. 20 E.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 38 to 44 degrees F.
Depth to secondary carbonates - 10 to 18 inches
Clay content averages - 18 to 33 percent in the control section
Rock fragment content averages - 35 to 60 percent in the control section
A horizon
Color, hue - 7.5YR or 10YR
Value, dry - 5 or 6
Value, moist - 3 or 4
Chroma, moist or dry - 2 to 4
Bt horizon
Color, hue - 7.5YR or 10YR
Value, dry - 4 to 6
Value, moist - 3 to 5
Chroma, moist or dry - 3 to 6
Texture - Very gravelly loam or very gravelly clay loam
Clay percentage - 25 to 33 percent
Bk and Bkq horizon
Color, hue - 2.5Y, 10YR or 7.5YR
Value, dry - 5 to 7
Value, moist - 4 to 6
Chroma, moist or dry - 2 to 4
Calcium carbonate content - 1 to 30 percent
Reaction - slightly or moderately alkaline
Rock fragments - 50 to 75 percent
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Dawtonia soils are on nearly level to steep fan terraces, foothills and mountain sides. Slopes range from 1 to 50 percent. Elevation ranges from 4,000 to 7,200 feet. The soil formed in slope alluvium. The climate is semiarid with cold moist winters and cool dry summers. The average annual precipitation is 8 to 11 inches, the average annual air temperature is 37 to 43 degrees F. The frost-free period is about 65 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bregar, Dacont, and Parkay. Bregar soils are less than 20 inches deep to bedrock. Dacont and Parkay soils have mollic epipedons.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderately slow permeability.
USE AND VEGETATION: Used for range. Vegetation is Wyoming big sagebrush, bluebunch wheatgrass, salmon wildrye and Sanberg bluegrass.
DISTRIBUTION AND EXTENT: East central Idaho. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Custer County, Idaho, 1999.
REMARKS: Diagnostic horizons and other features:
Ochric epipedon
Argillic horizon - 4 to 12 inches
Calcic horizon - 12 to 24 inches