LOCATION BOBOWIC MT+WY
Established Series
Rev. PEM-EMM-KLS
03/2023
BOBOWIC SERIES
The Bobowic series consists of moderately deep, well drained soils that formed in slope alluvium, colluvium or residuum derived from granite bedrock. These soils are on dissected hills and mountains. Slopes are 4 to 70 percent. Mean annual precipitation is about 460 mm and mean annual air temperature is about 3 degrees C.
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive Ustic Haplocryepts
TYPICAL PEDON: Bobowic gravelly coarse sandy loam, very bouldery, forested (colors are for dry soil unless otherwise noted).
Oe--0 to 3 cm; partially decomposed needles, twigs, and leaves. (1 to 8 cm thick)
A--3 to 11 cm; dark grayish brown (10YR 4/2) gravelly coarse sandy loam, very dark brown (10YR 2/2) moist; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine and few fine roots; many very fine and fine and few medium pores; 20 percent gravel; neutral (pH 7.0); clear smooth boundary. (8 to 13 cm thick)
E--11 to 31 cm; light brownish gray (10YR 6/2) gravelly coarse sandy loam, dark grayish brown (10YR 4/2) moist; moderate coarse platy structure parting to weak fine angular blocky; soft, very friable, slightly sticky and nonplastic; many very fine and few fine and medium roots; many very fine and few fine interstitial and tubular pores; 25 percent gravel; neutral (pH 7.0); clear wavy boundary. (18 to 30 cm thick)
Bw--31 to 56 cm; brown (10YR 5/3) gravelly coarse sandy loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; many very fine and few fine and medium roots; many very fine and few fine interstitial and tubular pores; 25 percent gravel; neutral (pH 7.0); clear wavy boundary. (25 to 64 cm thick)
Cr--56 to 89 cm; light brownish gray (10YR 6/2) decomposed granite bedrock (grus) that crushes to gravelly loamy coarse sand; neutral (pH 7.2); gradual wavy boundary.
R--89 cm; hard granite bedrock.
TYPE LOCATION: Jefferson County, Montana; about 750 meters north and 100 meters west of the SE corner of sec. 4, T. 1 N., R. 6 W.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--3 to 6 degrees C
Soil moisture control section--20 to 60 cm, or between 20 cm and bedrock if less than 60 cm
Depth to paralithic contact--50 to 99 cm
Depth to lithic contact--58 to 100 cm
Surface stones or boulders--0 to 3 percent
A horizon
Hue--10YR or 2.5Y
Value--4 or 5 dry; 2 through 4 moist
Chroma--1 through 3
Texture--coarse sandy loam or sandy loam
Clay content--10 to 20 percent
Rock fragment content--10 to 35 percent total; 10 to 30 percent gravel and 0 to 5 percent cobbles
Reaction--pH 6.1 to 7.3
E horizon
Hue--10YR or 2.5Y
Value--6 or 7 dry; 4 or 5 moist
Chroma--2 or 3
Texture--coarse sandy loam or sandy loam
Clay content--10 to 18 percent
Rock fragment content--5 to 35 percent total; 15 to 35 percent gravel (mostly less than 7mm in diameter) and 0 to 15 percent cobbles
Reaction--pH 6.1 to 7.3
Bw horizon
Hue--10YR or 2.5Y
Value--5 or 6 dry; 4 or 5 moist
Chroma--2, 3, or 4
Texture--coarse sandy loam or sandy loam
Clay content--10 to 18 percent
Rock fragment content--10 to 35 percent gravel (mostly less than 7mm in diameter)
Reaction--pH 6.1 to 7.3
COMPETING SERIES:
Bobtail (CO) - the surface and cambic horizons are medium or very strongly acid; does not have a paralithic contact above the lithic contact of gneiss and schist
Progress (AK) - has a subarctic climate
Ganhona (AK) - does not have a lithic contact above 150 cm
Jenkins (CO) - is very strongly or medium acid in the surface and cambic horizons; does not have a paralithic contact above the lithic contact of sandstone and shale
Kalambach (AK) - has a subarctic climate
Mccloud (AK) - has a subarctic climate
Ryorp (MT) - does not have an albic horizon
Steese (AK) - has a mantle of micaeous loess 50 to 100 cm thick; has a horizon with lamellae; does not have a lithic contact above a depth of 150 cm
Tebay (AK) - does not have a lithic contact above a depth of 150 cm; has a discontinuity above a depth of 25 cm
Tsana (AK) - does not have a lithic contact above 150 cm; has a subarctic climate
GEOGRAPHIC SETTING:
Landform--dissected hills and mountains
Elevation--1675 to 2125 meters
Slope--4 to 70 percent
Parent material--slope alluvium, colluvium or residuum derived from granite bedrock
Climate--long, cold winters; cool, moist springs; short, cool summers
Mean annual precipitation--380 to 610 mm
Mean annual air temperature--2 to 4 degrees C
Frost-free period--40 to 70 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed
DRAINAGE AND PERMEABILITY: Well drained, moderately rapid permeability
USE AND VEGETATION: Bobowic soils are primarily used for timber production and wildlife habitat. The potential native vegetation is mainly Douglas-fir, lodgepole pine, pinegrass, common snowberry, white spiraea, Oregongrape, heartleaf arnica, common juniper, and Rocky Mountain juniper.
DISTRIBUTION AND EXTENT: Bobowic soils are of small extent in southwestern Montana and southwestern Wyoming; MLRAs 43B and 46.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Jefferson County, Montana, 1998
REMARKS: Soil interpretation records: MT1595, MT3074
Diagnostic horizons and features recognized in this pedon are:
A layer of partially decomposed needles, twigs, and leaves--0 to 3 cm (Oe horizon)
Ochric epipedon--3 to 18 cm, mixed (A horizon and part of the E horizon)
Albic horizon--11 to 31 cm (E horizon)
Depth to paralithic contact--56 to 89 cm to decomposed granite or grus (Cr horizon)
Depth to lithic contact--89 cm to hard granite bedrock (R horizon)
Cambic horizon--31 to 56 cm (Bw horizon)
Particle-size control section--25 to 56 cm (part of the E horizon and all of the Bw horizon)
Bobowic soils have a cryic soil temperature regime and an ustic soil moisture regime.
Classification changed from Coarse-loamy, mixed, superactive Ustic Eutrocryepts to Coarse-loamy, mixed, superactive Ustic Haplocryepts due to revision of the cryepts great groups and subgroups. The competing series section was not updated and should be reviewed after all the cryepts have been re-classified. 3/2008
Converted to metric and O horizons were updated to start at zero. Competing series section was not updated. 01/2023
National Cooperative Soil Survey
U.S.A.