LOCATION DEEPONE MT
Established Series
REV. GFB-KTS-RJS
01/2012
DEEPONE SERIES
The Deepone series consists of very deep, well drained soils that formed in alluvium. These soils occur on fan remnants, stream terraces and hills. Slopes are 0 to 15 percent. Mean annual precipitation is about 300 mm, and the mean annual air temperature is about 5 degrees C.
TAXONOMIC CLASS: Fine, smectitic, frigid Aridic Paleustalfs
TYPICAL PEDON: Deepone loam, in rangeland (colors are for dry soil unless otherwise noted).
E--0 to 10 cm; pale brown (10YR 6/3) loam, brown (10YR 4/3) moist; moderate medium and fine platy structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine roots throughout; many very fine and fine vesicular pores; slightly alkaline (pH 7.6); abrupt smooth boundary. (5 to 15 cm thick)
Bt--10 to 28 cm; yellowish brown (10YR 5/4) clay, dark yellowish brown (10YR 4/4) moist; strong medium and coarse prismatic structure; extremely hard, very firm, very sticky and very plastic; common very fine and fine roots throughout; common very fine and fine dendritic tubular pores; 60 percent prominent clay films on faces of peds; slightly alkaline (pH 7.8); gradual wavy boundary. (15 to 40 cm thick)
Btk--28 to 41 cm; light yellowish brown (10YR 6/4) clay loam, yellowish brown (10YR 5/4) moist; moderate medium subangular blocky structure; very hard, very firm, very sticky and very plastic; common very fine and fine roots throughout; common very fine and fine dendritic tubular pores; 30 percent distinct clay films on faces of peds; finely disseminated calcium carbonate and 5 percent fine and medium irregular soft masses of calcium carbonate throughout; strongly effervescent; moderately alkaline (pH 8.2); gradual wavy boundary. (0 to 25 cm thick)
Bk--41 to 71 cm; very pale brown (10YR 7/3) loam, pale brown (10YR 6/3) moist; weak medium subangular blocky structure; hard, very friable, moderately sticky and moderately plastic; few very fine and fine roots throughout; common very fine and fine dendritic tubular pores; 5 percent gravel; finely disseminated calcium carbonate and 30 percent fine and medium soft masses and threads of calcium carbonate throughout; violently effervescent; moderately alkaline (pH 8.4); gradual wavy boundary. (25 to 51 cm thick)
C--71 to 152 cm; light very pale brown (10YR 7/3) loam, light yellowish brown (10YR 6/4) moist; massive; slightly hard, very friable, moderately sticky and moderately plastic; few very fine and fine roots in the upper part; common very fine and fine dendritic tubular pores; 5 percent gravel; finely disseminated calcium carbonate throughout; strongly effervescent; moderately alkaline (pH 8.2).
TYPE LOCATION: Beaverhead County, Montana; Jeff Davis Peak topographic quadrangle. UTM 12T, 325947e, 4983610n; 1200 feet south and 1200 feet east of the northwest corner of sec. 9, T. 10 S., R 13 W.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 5 to 7 degrees C.
Ochric epipedon thickness - 5 to 15 cm
Depth to argillic horizon - 5 to 20 cm
Depth to secondary calcium carbonate accumulation - 20 to 50 cm
Linear extensibility percentage - averages less than 6.0 cm between the mineral soil surface and 100 cm
Note: Some pedons may have an A horizon (5 to 8 cm thick) above the E horizon.
E horizon
Hue: 10YR or 2.5Y; dry or moist
Value: 5 or 6 dry; 3 or 4 moist
Chroma: 2 or 3; dry or moist
Clay content: 15 to 24 percent
Rock fragments: 0 to 15 percent gravel
Reaction: pH 6.6 to 7.8
Bt horizon
Hue: 10YR or 2.5Y; dry or moist
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 to 4; dry or moist
Texture: silty clay loam, clay loam or clay
Clay content: 35 to 55 percent
Rock fragments: 0 to 15 percent gravel
Reaction: pH 7.2 to 7.8
Btk horizon
Hue: 10YR or 2.5Y; dry or moist
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 3 or 4; dry or moist
Texture: clay, clay loam or silty clay loam
Clay content: 30 to 45
Rock fragments: 0 to 15 percent gravel
Calcium carbonate equivalent: 1 to 5 percent
Reaction: pH 7.8 to 8.4
Bk horizon
Hue: 7.5YR, 10YR or 2.5Y; dry or moist
Value: 5 to 7 dry; 5 or 6 moist
Chroma: 2 to 4; dry or moist
Texture: loam, silty clay loam or clay loam
Clay content: 20 to 40 percent
Rock Fragments: 0 to 35 percent gravel
Electrical conductivity: 0 to 4 mmhos/cm
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 8.0 to 8.4
C horizon
Hue: 7.5 YR, 10YR or 2.5Y; dry or moist
Value: 5 to 7 dry; 5 or 6 moist
Chroma: 2 to 4; dry or moist
Texture: loam, silty clay loam or clay loam
Clay content: 20 to 40 percent
Rock Fragments: 0 to 35 percent gravel
Electrical conductivity: 0 to 4 mmhos/cm
Calcium carbonate equivalent: 1 to 10 percent
Reaction: pH 7.9 to 8.4
COMPETING SERIES:
Dyce (MT) - moderately deep to a paralithic contact
GEOGRAPHIC SETTING:
Landform - fan remnants, stream terraces and hills
Elevation - 1,800 to 1,980 meters
Slope - 0 to 15 percent.
Parent material - alluvium
Climate - long, cold winters; moist springs; warm short summers
Mean annual precipitation - 250 to 360 mm
Mean annual air temperature - 4 to 7 degrees C.
Frost-free period - 70 to 90 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; slow permeability.
USE AND VEGETATION: Deepone soils are used mainly for rangeland and wildlife habitat. Potential native vegetation is mainly bluebunch wheatgrass, western wheatgrass, prairie junegrass, poa (species), opuntia (species), Wyoming big sagebrush, and other grasses and forbs.
DISTRIBUTION AND EXTENT: Deepone soils are of small extent in southwestern Montana. MLRA - 44B.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES ESTABLISHED: Horse Prairie-South Valley Area - Part of Beaverhead County, Montana, 2011; proposed in Beaverhead County, Montana, 2008.
REMARKS: Diagnostic horizons and features recognized in this pedon are: Ochric epipedon - from 0 to 10 cm (E horizon)
Argillic horizon - from 10 to 41 cm (Bt and Btk horizons)
Pale great group feature - an increase in clay of more than 20 percent (absolute) within a vertical distance of 7.5 cm at the upper boundary of the Bt horizon
Particle-size control section - from 10 to 41 cm (Bt and Btk horizons)
Deepone soils have a frigid temperature regime and an ustic moisture regime bordering on aridic.
National Cooperative Soil Survey
U.S.A.