LOCATION DONKEHILL IDTentative Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Lithic Argicryolls
TYPICAL PEDON: Donkehill very gravelly loam - on a 22 percent north-facing slope at 7,400 feet in rangeland. (Colors are for dry soil unless otherwise noted. This profile was described September 15, 1978.)
A--0 to 3 inches; brown (10YR 5/3) very gravelly loam, dark brown (7.5YR 3/2) moist; weak very fine granular structure; slightly hard, very friable; nonsticky and nonplastic; many very fine and fine roots; many very fine tubular pores; about 40 percent gravel; slightly alkaline (pH 7.5); clear wavy boundary. (3 to 6 inches thick)
Bt--3 to 11 inches; brown (10YR 5/3) very gravelly loam, dark brown (7.5YR 3/2) moist; weak very fine subangular blocky structure; slightly hard, very friable; nonsticky and nonplastic; many very fine and fine roots; many very fine tubular pores; few faint clay films on faces of peds; about 40 percent gravel; slightly alkaline (pH 7.6); clear wavy boundary. (3 to 9 inches thick)
Btk--11 to 13 inches; pale brown (10YR 6/3) very gravelly loam, dark brown (10YR 4/3) moist; weak very fine subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; common very fine and fine roots; many very fine tubular pores; few faint clay films on faces of peds; about 50 percent pebbles; lime coatings on undersides of gravel; slightly alkaline (pH 7.8); abrupt smooth boundary. (2 to 7 inches thick)
Bk--13 to 16 inches; pale brown (10YR 6/3) extremely gravelly sandy loam, dark brown (10YR 4/3) moist; massive; soft, very friable; nonsticky and nonplastic; few very fine and fine roots in cracks; about 85 percent gravel; lime coatings on undersides of gravel with lime pendants on some; slightly alkaline (pH 7.5); abrupt smooth boundary. (0 to 6 inches)
R--16 inches; bedrock; strongly effervescent in cracks.
TYPE LOCATION: Custer County, Idaho; about 21 miles southeast of Patterson, Idaho; 1,560 feet north and 100 feet west from the southeast corner, sec. 34, T. 11 N. R. 24 E.
Latitude - 44 degrees, 14 minutes, 08 seconds North; Longitude - 113 degrees, 34 minutes, 40 seconds West.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 36 to 40 degrees F.
Average summer soil temperature - 46 to 50 degrees F.
Xeric soil moisture regime
Mollic epipedon thickness - 7 to 12 inches
Control section - percent clay 16 to 24
Rock fragments - 35 to 60 percent
Depth to bedrock - 10 to 20 inches
Reaction of profile - slightly or moderately alkaline
A horizon
Hue - 7.5YR or 10YR
Value - 3 to 5 dry
Chroma - 2 or 3 dry and moist
Bt and Btk horizon
Hue - 7.5YR or 10YR
Value - 4 to 6 dry, 3 or 4 moist
Chroma - 2 to 4 dry, 3 or 4 moist
Bk horizon
Hue - 7.5YR or 10YR
Value - 3 or 4 moist
Chroma - 2 to 4 moist and dry
Texture - GRX-SL, or GRX-L
Coarse fragments - 60 to 85 percent
GEOGRAPHIC SETTING: Donkehill soils are on foothills, mountainsides and ridges and have slopes of 8 to 50 percent. Elevations are 6,500 to 9,000 feet. The soils formed in residuum and slope alluvium weathered from felsic volcanic rocks. The climate is cold and moist in winter and spring, and cool and dry to moist in summer. Average annual precipitation is 13 to 18 inches. Average annual temperature is 34 to 38 degrees F. Frost-free period is 30 to 60 days.
COMPETING SERIES: These are the Bushvalley, Copenhaver, Genoa, Hogmalat, Layview, Mosroc, Nieman and Nielsen series. Bushvalley soils have hues of 7.5YR or redder in the argillic horizon. Bushvalley and Nielsen are noncalcareous above lithic contact and have precipitation of 16 inches or more. Genoa soils are noncalcareous above lithic contact and have an average annual soil temperature of 44 to 47 degrees F. Hogmalat soils have 24 to 34 percent clay in the control section and average summer soil temperatures of 54 to 57 degrees F. Layview soils have an average soil temperature of 43 to 45 and lack carbonates above the bedrock. Mosroc soils are 18 to 35 percent clay and are noneffervescent above the bedrock. Copenhaver and Nieman soils have an ustic soil moisture regime. Maygal soils are slightly acid to neutral and have a mean summer soil temperature of 54 to 59 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the tentative Dacore, Goldhill, Meegero, Zeale, and Zeebar soils. Dacore, Goldhill, and Zeebar soils are on mountains and are very deep. Zeale and Meegero soils are on mountains and fan terraces and are very deep.
DRAINAGE AND PERMEABILITY: Well drained, medium runoff; moderate permeability to the bedrock, but very slow through the fractured bedrock.
USE AND VEGETATION: Rangeland. Vegetation is mainly low sagebrush and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: East central Idaho. These soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Custer County, Idaho, 1980.
REMARKS: Diagnostic horizons and features in this pedon are:
Mollic epipedon - The zone from the soil surface to a depth of 11 inches (A and Bt horizons).
Argillic horizon - The zone from 3 to 13 inches (Bt and Btk horizons).
Bedrock - At 16 inches.
Xeric soil moisture regime
Particle-size control section - from 3 to 13 inches