LOCATION SEBUD MT+ID WY
Established Series
Rev. DES-JJU-EMM
06/2014
SEBUD SERIES
The Sebud series consists of very deep, well drained soils that formed in till, outwash, alluvium, slope alluvium and colluvium derived from igneous, metamorphic or sedimentary rock. These soils are on alluvial fans, fan remnants, till plains, moraines, hills and mountains. Slopes are 2 to 60 percent. Mean annual precipitation is about 22 inches, and mean annual air temperature is about 40 degrees F.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Ustic Haplocryolls
TYPICAL PEDON: Sebud loam, with 3 percent surface stones and boulders, in rangeland (colors are for dry soil unless otherwise noted).
A1--0 to 4 inches; very dark grayish brown (10YR 3/2) loam, very dark brown (10YR 2/2) moist; weak granular structure; soft, friable, nonsticky and nonplastic; many very fine and fine roots; 10 percent gravel; neutral (pH 7.2); clear boundary.
A2--4 to 10 inches; dark grayish brown (10YR 4/2) very stony clay loam, very dark grayish brown (10YR 3/2) moist; very dark brown (10YR 2/2) moist coatings; moderate fine and medium blocky structure; slightly hard, friable, moderately sticky and moderately plastic; many very fine roots; many very fine pores; 10 percent gravel and cobbles, 40 percent stones and 1 percent boulders; slightly alkaline (pH 7.5); clear wavy boundary. (combined thickness of A1, A2 horizons - 10 to 16 inches)
Bw1--10 to 22 inches; yellowish brown (10YR 5/4) very stony clay loam, dark brown (10YR 3/3) moist; dark yellowish brown (10YR 3/4) moist coatings; moderate fine and medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few very fine roots; few very fine pores; 10 percent gravel and cobbles, 40 percent stones and 1 percent boulders; slightly alkaline (pH 7.4); clear smooth boundary. (8 to 14 inches thick)
Bw2--22 to 28 inches; light yellowish brown (10YR 6/4) very stony coarse sandy clay loam, yellowish brown (10YR 5/4) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly moderately sticky and slightly plastic; few very fine roots; few very fine pores; 5 percent gravel and cobbles, 40 percent stones and 1 percent boulders; slightly alkaline (pH 7.6); gradual boundary.
Bw3--28 to 49 inches; very pale brown (10YR 7/3) very stony coarse sandy clay loam, yellowish brown (10YR 5/4) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and moderately plastic; few very fine roots; many clear quartz sand grains, 5 percent gravel and cobbles, 40 percent stones and 1 percent boulders; slightly alkaline (pH 7.8); gradual boundary.
Bw4--49 to 62 inches; very pale brown (10YR 7/3) very stony clay loam, yellowish brown (10YR 5/4) moist; moderate coarse subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine tubular pores; 5 percent gravel and cobbles, 40 percent stones and 1 percent boulders; slightly alkaline (pH 7.8).
TYPE LOCATION: Carbon County, Montana; 2,900 feet west and 1,000 feet south of the northeast corner of sec. 16, T. 6S, R. 18E.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 36 to 46 degrees F.
Mollic epipedon thickness - 10 to 16 inches
Particle-size control section (weighted average) - 18 to 35 percent clay
Note: Some pedons may have a BC and/or C horizons.
A1, A2 horizons
Hue: 2.5Y or 10YR; dry or moist
Value: 3 or 4 dry; 2 or 3 moist
Chroma: 1 to 3; dry or moist
Texture: loam or sandy loam
Clay content: 12 to 27 percent
Rock fragments: 10 to 60 percent--5 to 25 percent gravel, 0 to 45 percent cobbles or stones
Reaction: pH 6.1 to 7.8
Bw1, Bw2, Bw3, Bw4 horizons
Hue: 2.5Y or 10YR; dry or moist
Value: 5 to 7 dry; 3 to 6 moist
Chroma: 2 to 4; dry or moist
Texture: loam, clay loam, sandy clay loam, coarse sandy loam or sandy loam
Clay content: 15 to 35 percent
Rock fragments: 35 to 60 percent--5 to 40 percent gravel, 5 to 45 percent cobbles, stones or boulders
Reaction: pH 5.6 to 7.8
BC, C horizons (where present)
Hue: 2.5Y or 10YR; dry or moist
Value: 5 to 7 dry; 3 to 6 moist
Chroma: 2 to 4; dry or moist
Texture: loam, clay loam, sandy clay loam, coarse sandy loam or sandy loam
Clay content: 15 to 30 percent
Rock fragments: 45 to 70 percent--30 to 55 percent gravel, 5 to 30 percent cobbles, stones or boulders
Reaction: pH 5.6 to 7.2
COMPETING SERIES:
Antrobus (CO) - do not have a cambic horizon
Grafen (CO) - are moderately deep to a paralithic contact
Greyback (WY) - have secondary calcium carbonate accumulation
Handran (CO) - do not have a cambic horizon
Maurice (MT) - average less than 18 percent clay in the particle-size control section
Mccort (WY) - average less than 18 percent clay in the particle-size control section
Midelight (WY) - are deep to a lithic contact
Parachute (CO) - are moderately deep to a lithic contact
Supervisor (NM) - are moderately deep to a lithic contact
Surdal (MT) - are moderately deep to a lithic contact
Teemat (WY) - have secondary calcium carbonate accumulation
Thornburgh (CO) - average less than 18 percent clay in the particle-size control section
Tiban (MT) - have secondary calcium carbonate accumulation
Tineman (WY) - have a lithologic discontinuity
Vanwirt (CO) - have Bt horizons
GEOGRAPHIC SETTING:
Landform - alluvial fans, fan remnants, till plains, outwash fans, moraines, hills, and mountains
Elevation - 4,500 to 8,450 feet
Slope - 2 to 60 percent
Parent material - till, alluvium, slope alluvium and colluvium derived from igneous, metamorphic or sedimentary rock
Climate - long, cold winters; moist springs; early, cool summers; and late falls
Mean annual air temperature - 34 to 44 degrees F.
Mean annual precipitation - 14 to 35 inches
Frost-free period - 30 to 70 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Sebud soils are used mainly for rangeland. Potential native vegetation is mainly western wheatgrass, rough fescue, bluebunch wheatgrass, green needlegrass, Idaho fescue, annual forbs, and woody plants.
DISTRIBUTION AND EXTENT: Sebud soils are of small extent in Montana and Wyoming. MLRAs - 43B, 44B, 46.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES ESTABLISHED: Carbon County (Bridger Area), Montana, 1971.
REMARKS: Diagnostic horizons and features recognized in this soil are:
Mollic epipedon - from 0 to 10 inches (A1, A2 horizons)
Cambic horizon - from 10 to 60 inches (Bw1, Bw2, Bw3, Bw4 horizons)
Particle-size control section - from 10 to 40 inches (Bw1, Bw2, part of Bw3 horizons)
Sebud soils have a cryic temperature regime and an ustic moisture regime that borders on udic.
ADDITIONAL DATA: Soil interpretations records - MT0190, MT0669, MT1108, MT0247.
National Cooperative Soil Survey
U.S.A.