LOCATION SAWBUCK MT
Established Series
Rev. DES/JAL/KLS
11/2022
SAWBUCK SERIES
The Sawbuck series consists of deep and very deep, well drained soils that formed in colluvium derived from igneous, argillite, metamorphic, and sedimentary rock. These soils are on alluvial fans, escarpments and sideslopes of hills and mountains. Slopes are 15 to 60 percent. Mean annual precipitation is about 460 mm, and mean annual air temperature is about 5 degrees C.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Typic Argiustolls
TYPICAL PEDON: Sawbuck loam, forested (colors are for dry soil unless otherwise noted).
Oi--0 to 3 cm; forest litter of partially decomposed twigs and needles.
A1--3 to 18 cm; gray (10YR 5/1) loam, very dark gray (10YR 3/1) moist; moderate fine and very fine granular structure; soft, very friable, slightly sticky and slightly plastic; many fine and very fine roots, few medium and coarse roots; 5 percent angular pebbles; slightly acid (pH 6.2); gradual smooth boundary.
A2--18 to 26 cm; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; moderate very fine granular structure; soft, very friable, slightly sticky and slightly plastic; many fine and very fine roots, few medium and coarse roots; many faint gray silt and sand skeletans on faces of peds; 5 percent angular pebbles; moderately acid (pH 5.6); gradual smooth boundary. (The combined A horizons are 13 to 23 cm thick.)
Bt1--26 to 41 cm; brown (10YR 5/3) gravelly clay loam, dark brown (10YR 3/3) moist; moderate medium and fine subangular blocky structure; hard, friable, moderately sticky and moderately plastic; common fine and very fine roots, few medium roots; many very fine tubular and interstitial pores; common distinct dark brown (10YR 3/3) moist clay films on faces of peds; many faint gray silt and sand skeletans on faces of peds; 25 percent angular pebbles; moderately acid (pH 5.6); clear smooth boundary. (5 to 20 cm thick)
Bt2--41 to 105 cm; brown (10YR 5/3) very gravelly clay loam, brown (10YR 4/3) moist; strong medium and fine subangular blocky structure; hard, friable, moderately sticky and moderately plastic; common fine and very fine tubular and interstitial pores; many distinct dark brown (10YR 3/3) moist clay films on faces of peds and lining pores; 45 percent angular pebbles and 5 percent angular cobbles; moderately acid (pH 5.6); gradual smooth boundary. (13 to 76 cm thick)
Bt3--105 to 125 cm; light gray (2.5Y 7/2) very gravelly silty clay loam, grayish brown (2.5Y 5/2) moist; moderate medium and fine subangular blocky structure; hard, friable, moderately sticky and slightly plastic; common fine and very fine roots, few medium roots; many very fine tubular and interstitial pores; many distinct clay films on faces of peds; many faint silt and sand skeletans on faces of peds; common distinct pale yellow (2.5Y 7/4) stains on faces of peds and on coarse fragments; 40 percent angular pebbles; moderately acid (pH 6.0); gradual smooth boundary. (13 to 25 cm thick)
Bt4--125 to 155 cm; light brownish gray (2.5Y 6/2) gravelly silty clay loam, dark grayish brown (2.5Y 4/2) moist; moderate medium and fine subangular blocky structure; hard, friable, moderately sticky and slightly plastic; few very fine roots; many very fine tubular and interstitial pores; common distinct clay films on faces of peds; common distinct pale yellow (2.5Y 7/4) stains on peds and coarse fragments; 15 percent pebble size angular sandstone and shale fragments; moderately acid (pH 5.9).
TYPE LOCATION: Lewis & Clark County, Montana; about 425 meters north and 400 meters east of the SW corner of sec. 4, T. 14 N., R. 2 W.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--3 to 7 degrees C
Moisture control section--between 10 and 30 cm
Mollic epipedon thickness--25 to 38 cm
Depth to argillic horizon--13 to 40 cm
Surface stones or boulders--0 to 3 percent
Soil phases--shale substratum
A horizon
Value--3, 4 or 5 dry; 2 or 3 moist
Chroma--1 or 2
Texture--loam, sandy clay loam or sandy loam
Clay content--10 to 30 percent
Rock fragment content--0 to 30 percent total; 0 to 5 percent stones, 0 to 5 percent angular cobbles, 0 to 20 percent angular pebbles
Reaction--pH 5.6 to 7.3
Bt1 horizon
Hue--10YR or 2.5Y
Value--4, 5 or 6 dry; 3 or 4 moist
Chroma--2 or 3
Texture--sandy clay loam, clay loam or loam
Clay content--22 to 30 percent
Rock fragment content--15 to 60 percent total; 5 to 10 percent angular cobbles, 10 to 50 percent angular pebbles
Reaction--pH 5.6 to 7.3
Bt2 and Bt3 horizons
Hue--10YR or 2.5Y
Value--5, 6, or 7 dry; 4 or 5 moist
Chroma--2, 3, or 4
Texture--clay loam, silty clay loam, loam or sandy clay loam
Clay content--25 to 35 percent
Rock fragment content--35 to 60 percent; 5 to 10 percent angular cobbles, 30 to 50 percent angular pebbles
Reaction--pH 5.6 to 7.3
Bt4 horizon
Hue--10YR or 2.5Y
Value--5, 6, or 7 dry; 4 or 5 moist
Chroma--2, 3, or 4
Texture--silty clay loam or clay loam
Clay content--27 to 35 percent
Rock fragment content--15 to 60 percent; 5 to 10 percent angular cobbles, 10 to 50 percent angular pebbles
Reaction--pH 5.6 to 7.3
COMPETING SERIES:
Bendire (CO) - has a lithic contact at 50 to 100 cm
Blainecreek (MT) - has a lithic contact at 50 to 100 cm
Borpark (CO) - has a calcareous Bt horizon
Crackerville (MT) - has a paralithic and lithic contact above 100 cm
Crampton (MT) - has a paralithic contact at 50 to 100 cm
Curecanti (CO) - has more than 60 percent rock fragments; hues redder than 10YR; 15 to 75 percent sand in the argillic horizon
Harol (UT) - has a lithological discontinuity above a depth of 100 cm
Harpole (UT) - has hue redder than 10YR in the argillic and to a depth of 150 cm; very cobbly or extremely gravelly loamy sand or sandy loam discontinuity above a depth of 100 cm
Hilger (MT) - has calcic horizons
Holter (MT) - has a lithological discontinuity above a depth of 100 cm; has carbonates above a depth of 150 cm
Quincreek (MT) - has a lithic contact at 50 to 100 cm
Sawicki (MT) - depth to the base of the argillic horizon is less than 100 cm
Shawmut (MT) - has calcic horizons
Shirttail (SD) - has the base of the argillic horizon at a depth of 30 cm or less
Wickes (MT) - has a lithic contact at 50 to 100 cm
Widstoe (UT) - has hues redder than 10YR and a strongly cemented calcic horizon
GEOGRAPHIC SETTING:
Landform--alluvial fans, escarpments and sideslopes of hills and mountains
Elevation--1225 to 1825 meters
Slope--2 to 60 percent
Parent material--colluvium or residuum derived from igneous, argillite, metamorphic, and sedimentary rock
Climate--long, cold winters; moist springs; warm summers
Mean annual precipitation--380 to 610 mm
Mean annual air temperature--2 to 6 degrees C
Frost-free period--80 to 105 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability
USE AND VEGETATION: These soils are used mainly for woodland and range. Potential native vegetation is mainly Douglas fir, ponderosa pine, ninebark, pinegrass, rough fescue, elk sedge, snowberry, arnica, spirea, forbs, and low shrubs.
DISTRIBUTION AND EXTENT: Sawbuck soils are moderately extensive in central and southwestern Montana and northwestern Wyoming; MLRA 43B.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Lewis & Clark County Area, Montana, 1991; proposed in Lewis & Clark County Area, Montana, 1979
REMARKS: Soil interpretation records: MT0427, MT8148
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon--3 to 41 cm (A1, A2, and Bt1 horizons)
Argillic horizon--26 to 155 cm (Bt1, Bt2, Bt3, Bt4 horizons)
Particle-size control section--26 to 76 cm (Bt1 and part of Bt2 horizons)
Sawbuck soils have a frigid soil temperature regime and an ustic soil moisture regime with a typic subclass.
Converted to metric, updated formatting, and O horizons were updated to start at zero. Competing series section was not updated. 11/2022
National Cooperative Soil Survey
U.S.A.