LOCATION LUBRECHT MTEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, frigid Typic Haplustalfs
TYPICAL PEDON: Lubrecht silt loam, in coniferous forest (colors are for dry soil unless otherwise noted).
Oi--0 to 2 inches; undecomposed and slightly decomposed forest litter.
E--2 to 6 inches; light brownish gray (10YR 6/2) silt loam, dark grayish brown (10YR 4/2) moist; weak very fine platy structure parting to moderate very fine granular; soft, very friable, slightly sticky and slightly plastic; many very fine, fine, medium, and coarse roots; many very fine pores; 5 percent pebbles; strongly acid (pH 5.5); abrupt smooth boundary. (3 to 6 inches thick)
E/Bt--6 to 10 inches; E part (75 percent) is light gray (10YR 7/2) silt loam, grayish brown (10YR 5/2) moist which interfingers into the B part; B part (25 percent) is brown (10YR 5/3) silty clay loam, brown (10YR 4/3) moist; texture mixed is silt loam; moderate fine subangular blocky structure; slightly hard, very friable, slightly sticky and moderately plastic; many very fine, fine, medium, and coarse roots; many very fine pores; common distinct clay films on faces of peds; 5 percent pebbles; slightly acid (pH 6.5); clear smooth boundary. (0 to 8 inches thick)
Bt/E--10 to 13 inches; B part (80 percent) is brown (10YR 5/3) silty clay loam, dark yellowish brown (10YR 4/4); E part (20 percent) is very pale brown (10YR 7/4) silt loam, brown (10YR 4/3) moist which interfingers into the B part; texture mixed is silty clay loam; strong fine blocky structure; very hard, firm, moderately sticky and moderately plastic; many very fine, fine, medium, and coarse roots; many fine pores; common distinct clay films on faces of peds; moderately acid (pH 6.0); abrupt wavy boundary. (0 to 4 inches thick)
Bt1--13 to 21 inches; brown (10YR 5/3) silty clay, dark yellowish brown (10YR 4/4) moist; strong medium and coarse blocky structure; very hard, firm, moderately sticky and moderately plastic; common very fine, fine, medium, and coarse roots; common very fine pores; common distinct clay films on faces of peds; common very dark grayish brown (10YR 3/2) organic stains; moderately acid (pH 6.0); clear smooth boundary.
Bt2--21 to 32 inches; brown (10YR 5/3) silty clay, brown (10YR 5/3) moist; moderate medium blocky structure; hard, friable, moderately sticky and moderately plastic; common very fine and fine roots and few medium and coarse roots; common very fine pores; many distinct clay films on faces of peds; moderately acid (pH 6.0); clear smooth boundary. (Combined thickness of the Bt1 and Bt2 horizons is 8 to 22 inches.)
Bt3--32 to 38 inches; pale brown (10YR 6/3) gravelly silty clay loam, brown (10YR 5/3) moist; weak fine blocky structure; slightly hard, friable, slightly sticky and moderately plastic; common very fine and fine roots; common very fine pores; few faint clay films on faces of peds; 20 percent pebbles; moderately acid (pH 6.0); clear smooth boundary. (7 to 12 inches thick)
Cr--38 to 60 inches; semiconsolidated siltstone.
TYPE LOCATION: Missoula County, Montana; about 2,300 feet west of the SE corner of sec. 20, T. 13 N., R. 15 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 46 degrees F.
Moisture control section - between 4 and 12 inches.
Depth to sedimentary beds - 20 to 40 inches.
Base saturation - 60 to 100 percent.
A thin 2 to 4 inch thick, dark colored A horizon occurs intermittently.
E horizon - Value: 5 or 6 dry; 4 or 5 moist
Clay content: 10 to 27 percent
Texture: loam or silt loam
Rock fragments: 0 to 15 percent pebbles
Reaction: pH 5.1 to 7.3
E/Bt horizon - Value: E part 6 or 7, B part 5 or 6 dry; E part 4, 5, or 6, B part 3 or 4 moist
Chroma: E part 2 or 3; B part 2, 3 or 4
Clay content, mixed: 10 to 27 percent
Texture: loam or silt loam
Rock fragments: 0 to 15 percent pebbles
Reaction: pH 6.1 to 7.3
Bt/E horizon - Value: B part 5 or 6, E part 6 or 7 dry; B part 4 or 5, E part 4, 5, or 6 moist
Chroma: B part 2, 3, or 4; E part 2, 3, or 4
Texture: silty clay loam or clay loam
Clay content, mixed: 27 to 40 percent
Reaction: pH 5.6 to 7.3
Bt1 and Bt2 horizons - Hue: 10YR or 7.5YR
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2, 3, or 4
Texture: silty clay or clay
Clay content: 40 to 60 percent
Reaction: pH 5.1 to 7.3
Bt3 horizon - Value: 5 or 6 dry; 4, 5, or 6 moist
Chroma: 2, 3, or 4
Clay content: 27 to 40 percent
Texture: silty clay or clay
Rock fragments: 15 to 35 percent--0 to 5 percent angular cobbles, 15 to 30 percent angular pebbles
Reaction: pH 5.1 to 7.3
COMPETING SERIES:
Crow - are very deep.
Dargol - have a lithic contact at 20 to 40 inches.
Heckly - have a lithic contact at 20 to 40 inches.
Ligocki - are very deep.
Rittel - have less than 15 percent rock fragments in the lower argillic horizon.
Valnor - does not have a glossic horizon.
Zuni - have a lithic contact at 20 to 40 inches.
GEOGRAPHIC SETTING:
Landform - stream terraces and hills in mountain valleys.
Elevation - 3,500 to 4,500 feet.
Slope - 4 to 35 percent.
Parent material - colluvium or residuum derived mainly from semiconsolidated Tertiary Age siltstone.
Climate - long, cold winters and moist springs.
Mean annual precipitation - 16 to 22 inches, much of which falls as snow or as spring rain.
Mean annual air temperature - 40 to 44 degrees F.
Frost-free period - 70 to 105 days.
DRAINAGE AND PERMEABILITY: Well drained, slow permeability.
USE AND VEGETATION: Lubrecht soils are used for timber production, watersheds, and as wildlife habitat. The native vegetation is ponderosa pine and Douglas fir with an understory of pinegrass, common snowberry, and dwarf huckleberry.
DISTRIBUTION AND EXTENT: Lubrecht soils are inextensive in western Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Missoula County, Montana, 1972.
REMARKS: Soil interpretation record: MT0048. Diagnostic horizons and features recognized in this pedon are: an ochric epipedon from 2 to 10 inches (E, E/Bt horizons); an albic horizon from 2 to 6 inches (E horizon); a glossic horizon from 6 to 13 inches (E/Bt, Bt/E horizons); bedrock at moderate depths; a particle-size control section from 10 to 30 inches (from the top of the argillic horizon to a depth of 20 inches (Bt/E, Bt1, Bt2 horizons). Lubrecht soils have a frigid temperature regime and an ustic moisture regime.