LOCATION LOBERG MT+CO
Established Series
Rev. JB-JJU-RJS
05/2011
LOBERG SERIES
The Loberg series consists of very deep, well drained soils that formed in till, alluvium, colluvium or slide deposits derived from mixed rock sources. These soils are on till plains, moraines, alluvial fans, mountains, hills or landslides. Slopes are 2 to 65 percent. Mean annual precipitation is about 22 inches, and mean annual air temperature is about 42 degrees F.
TAXONOMIC CLASS: Clayey-skeletal, mixed, superactive Ustic Glossocryalfs
TYPICAL PEDON: Loberg stony clay loam with .05 percent stones on the surface, forested (colors are for dry soil unless otherwise noted).
Oi--0 to 2 inches; forest litter and humus. (1 to 4 inches thick)
E--2 to 5 inches; light brownish gray (10YR 6/2) gravelly clay loam, dark brown (7.5YR 3/2) moist; weak thick platy structure parting to moderate fine granular; soft, friable, slightly sticky and slightly plastic; many very fine and fine roots; sand grains are clear and unstained; 15 percent gravel and 10 percent cobbles; strongly acid (pH 5.1); clear wavy boundary. (3 to 20 inches thick)
E/Bt--5 to 14 inches; E part (75 percent) light brownish gray (10YR 6/2) stony loam, dark brown (7.5YR 3/3) moist, tongues; Bt part (25 percent) pale brown (10YR 6/3) stony clay, dark brown (10YR 3/3) moist; moderate fine and medium subangular blocky structure parting to moderate fine granular; hard, friable, slightly sticky and slightly plastic; many fine roots; continuous distinct clay films on faces of peds which are coated with clear unstained sand grains; 15 percent gravel, 5 percent cobbles and 10 percent stones; strongly acid (pH 5.2); clear wavy boundary. (3 to 18 inches thick)
Bt1--14 to 29 inches; pale brown (10YR 6/3) very stony clay, dark brown (10YR 3/3) moist; strong fine and medium blocky structure; very hard, firm, very sticky and very plastic; continuous prominent clay films on faces of peds; continuous prominent clay films on gravel surfaces; common fine roots; stones and 20 percent gravel, 10 percent cobbles and 10 percent; moderately acid (pH 5.6); gradual boundary.
Bt2--29 to 51 inches; pale brown (10YR 6/3) very stony clay, dark brown (10YR 3/3) moist; strong fine and medium blocky structure parting to moderate medium blocky in lower part; very hard, firm, very sticky and very plastic; common fine roots; continuous prominent clay films on faces of peds; continuous prominent clay films of surface of gravel; 20 percent gravel, 10 percent cobbles and 10 percent stones; slightly acid (pH 6.4); gradual boundary. (combined thickness of Bt1, Bt2 horizons - 17 to 55 inches)
Bt3--51 to 68 inches; grayish brown (10YR 5/2) very stony clay, dark grayish brown (10YR 4/2) moist; very weak fine and medium blocky structure; very hard, firm, very sticky and very plastic; common fine roots; common faint clay film of faces of peds; common distinct clay films on surface of gravel; 25 percent gravel, 15 percent cobbles and 10 percent stones; slightly alkaline (pH 7.4); abrupt boundary. (0 to 18 inches thick)
BC--68 to 72 inches; grayish brown (10YR 5/2) stony clay, very dark grayish brown (10YR 3/2) moist; massive; very hard, firm, very sticky and very plastic; few fine pores; continuous faint clay film on surface of gravel; 25 percent gravel, 5 percent cobbles and 10 percent stones; slightly alkaline (pH 7.8).
TYPE LOCATION: Judith Basin County, Montana; Highwood Mountains; approximately 800 feet south and 200 feet west of the center of sec. 22, T. 19N, R. 9E.
RANGE IN CHARACTERISTICS:
Soil temperature - 36 to 47 degrees F.
Depth to top of argillic horizon - 8 to 25 inches
Particle-size control section - averages 35 to 50 percent clay
Note: Some pedons may have an A and/or Bt/E horizon.
E horizon
Hue: 10YR, 7.5YR, 5Y or 2.5Y; dry or moist
Value: 5 to 7 dry; 3 to 5 moist
Chroma: 2 to 4; dry or moist
Texture: clay loam, loam or sandy loam
Clay content: 15 to 35 percent
Rock fragments: 10 to 85 percent--10 to 45 percent gravel, 0 to 70 percent cobbles and stones
Reaction: pH 5.1 to 7.3
E/Bt horizon
Hue: 10YR, 7.5YR, 5Y or 2.5Y; dry or moist
Value: E part 5 to 7 dry; 3 to 5 moist
Bt part 4 to 6 dry; 3 to 5 moist
Chroma: 2 to 4; dry or moist
Texture: loam or clay loam
Clay content: 15 to 35 percent
Rock fragments: 20 to 60 percent--10 to 40 percent gravel, 0 to 45 percent cobbles and stones
Reaction: pH 5.1 to 7.3
Bt1, Bt2, Bt3 horizons:
Hue: 10YR, 7.5YR, 5Y or 2.5Y; dry or moist
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 2 to 6; dry or moist
Texture: sandy clay, clay or clay loam
Clay content: 35 to 50 percent
Rock fragments: 35 to 60 percent--20 to 40 percent gravel, 0 to 45 percent cobbles and stones
Reaction: pH 5.1 to 7.8
BC horizon
Hue: 10YR, 7.5YR, 5Y or 2.5Y; dry or moist
Value: 5 or 6 dry; 3 to 5 moist
Chroma: 2 or 3; dry or moist
Texture: sandy clay, clay or clay loam
Clay content: 35 to 45 percent
Rock fragments: 35 to 60 percent--20 to 40 percent gravel, 5 to 45 percent cobbles and stones
Reaction: pH 6.1 to 8.4
COMPETING SERIES:
Nopurg (CO) - have hues redder than 7.5YR in the Bt horizons
GEOGRAPHIC SETTING:
Landform - till plains, moraines, alluvial fans, mountains, hills or landslides
Elevation - 4,000 to 8,800 feet
Slope - 2 to 65 percent
Parent material - till, alluvium, colluvium or slide deposits derived from mixed rock sources
Climate - long, cold winters; moist springs; warm summers
Mean annual precipitation - 18 to 35 inches
Mean annual temperature - 34 to 45 degrees F.
Frost-free period - 30 to 70 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; slow permeability.
USE AND VEGETATION: Loberg soils are used mainly for woodland and some summer grazing. Potential native vegetation is mainly Douglas-fir, Engelmann spruce, and lodgepole pine with an understory of pinegrass, Oregon-grape, and snowberry.
DISTRIBUTION AND EXTENT: Loberg soils are extensive in the mountains and foothills of central and western Montana. MLRAs - 43B, 44B, 48A, 49.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES ESTABLISHED: Judith Basin Area, Montana, 1960.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Albic horizon - from 2 to 5 inches (E horizon)
Glossic horizon - from 5 to 14 inches (E/Bt horizon)
Argillic horizon - from 14 to 68 inches (Bt1, Bt2, Bt3 horizons)
Particle-size control section - from 14 to 34 inches (Bt1, part of Bt2 horizons)
Loberg soils have a cryic temperature regime and an ustic moisture regime that borders on udic.
ADDITIONAL DATA: Soil interpretations records - MT0111, MT0720, MT0719, MT0223.
National Cooperative Soil Survey
U.S.A.