LOCATION LOBERG MT+COEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, mixed, superactive Ustic Glossocryalfs
TYPICAL PEDON: Loberg stony clay loam, 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) stony 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 fine and very fine roots; sand grains are clear and unstained; .05 percent stones on surface; 10 percent cobbles, and 15 percent pebbles; 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 medium and fine 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; 10 percent stones, 5 percent cobbles, and 15 percent pebbles; 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 medium and fine blocky structure; very hard, firm, very sticky and very plastic; continuous prominent clay films on faces of peds; continuous prominent clay films on pebble surfaces; common fine roots; 10 percent stones, 10 percent cobbles, and 20 percent pebbles; 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 medium and fine 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 pebbles; 10 percent stones, 10 percent cobbles, and 20 percent pebbles; slightly acid (pH 6.4); gradual boundary. (The combined thickness of the Bt1 and Bt2 horizons is 17 to 55 inches thick.)
Bt3--51 to 68 inches; grayish brown (10YR 5/2) stony clay, dark grayish brown (10YR 4/2) moist; very weak medium and fine 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 pebbles; 10 percent stones, 15 percent cobbles, and 25 percent pebbles; slightly alkaline (pH 7.4); abrupt boundary. (0 to 18 inches thick)
BC--68 to 72 inches; dark grayish brown (10YR 5/2) stony clay, very dark grayish brown (10YR 3/2) moist; massive; very hard, firm, very sticky and very plastic; continuous faint clay film on surface of pebbles; 10 percent stones, 5 percent cobbles, and 25 percent pebbles; few fine pores; 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. 19 N., R. 9 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 36 to 47 degrees F.
Moisture control section - between 4 and 12 inches.
Control section - 35 to 50 percent clay.
A thin 1 to 4 inch A horizon is allowed.
Some pedons have a Bt/E horizon.
Surface cover, stones: 0 to 3 percent
E horizon - Hue: 10YR, 7.5YR, 5Y, or 2.5Y
Value: 5, 6, or 7 dry; 3, 4, or 5 moist
Chroma: 2, 3 or 4
Texture: clay loam, loam, or sandy loam
Clay content: 15 to 35 percent
Rock fragments: 10 to 75 percent--0 to 70 percent stones and cobbles, 10 to 45 percent pebbles
Reaction: pH 5.1 to 7.3
E/Bt horizon - Hue: 10YR, 7.5YR, 5Y, or 2.5Y
Value: E part 5, 6, or 7, Bt part 4, 5, or 6 dry; E part 3, 4, or 5, Bt part 3, 4, or 5 moist
Chroma: 2, 3 or 4
Texture: loam or clay loam
Clay content: 15 to 35 percent
Rock fragments: 20 to 60 percent--15 to 45 percent stones and cobbles, 10 to 40 percent pebbles
Reaction: pH 5.1 to 7.3
Bt1, Bt2, Bt3 horizons: Hue: 10YR, 7.5YR, 5Y, or 2.5Y
Value: 4, 5, or 6 dry; 3, 4, or 5 moist
Chroma: 2, 3, 4 or 6
Texture: sandy clay, clay, or clay loam
Clay content: 35 to 50 percent
Rock fragments: 35 to 60 percent--0 to 45 percent stones and cobbles, 20 to 40 percent pebbles
Reaction: pH 5.1 to 7.8
BC horizon - Hue: 10YR, 7.5YR, 5Y, or 2.5Y
Value: 5 or 6 dry; 3, 4, or 5 moist
Chroma: 2 or 3
Texture: sandy clay, clay, or clay loam
Clay content: 35 to 45 percent
Rock fragments: 35 to 60 percent--5 to 45 percent stones and cobbles, 20 to 40 percent pebbles
Reaction: pH 6.1 to 8.4
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform - till plains, moraines, mountains, alluvial fans, and hills in the northern Rocky Mountains.
Elevation - 4,000 to 8,800 feet.
Slope - 2 to 65 percent.
Parent material - till, alluvium, and colluvium derived from igneous, sedimentary, and metamorphosed rocks.
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.
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.
MLRA OFFICE RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Judith Basin Area, Montana, 1960.
REMARKS: Soil interpretations records: MT0111, MT0720, MT0719, MT0223. Diagnostic horizons and features recognized in this pedon are: an albic horizon from 2 to 5 inches (E horizon); a glossic horizon from 5 to 14 inches (E/Bt horizon); an argillic horizon from 14 to 68 inches (Bt1, Bt2, Bt3 horizons); a particle-size control section from 14 to 34 inches (Bt1, part of Bt2 horizon). Loberg soils have a cryic temperature regime and an ustic moisture regime that borders on udic.