LOCATION DUBAY MTEstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, frigid Lamellic Haploxerepts
TYPICAL PEDON: Dubay silt loam, forest (colors are for dry soil unless otherwise noted).
Oi--0 to 1 inch; undecomposed and slightly decomposed forest litter.
A--1 to 6 inches; grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; slightly hard, very friable, nonsticky and nonplastic; many fine and medium roots; many fine and medium pores; neutral (pH 6.8); clear irregular boundary. (3 to 8 inches thick)
E1--6 to 13 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; weak coarse subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; many fine roots; many fine and medium pores; neutral (pH 7.0); gradual irregular boundary.
E2--13 to 31 inches; very pale brown (10YR 7/3) silt loam, brown (10YR5/3) moist; weak coarse subangular blocky structure; hard, very friable, nonsticky and nonplastic; many fine roots; many fine pores; neutral (pH 7.0); gradual irregular boundary. (Combined thickness of the E horizons is 5 to 35 inches)
E and Bw--31 to 60 inches; E part (70 percent) very pale brown (10YR 7/3) silt loam, pale brown (10YR 6/3) moist; Bw part (30 percent) yellowish brown (10YR 5/4) very fine sandy loam, dark yellowish brown (10YR 4/4) moist, lamellae 1/4- to 1/2-inch thick and total less than 3 inches thick; massive; slightly hard, very friable, nonsticky and nonplastic; common fine roots; common fine pores; neutral (pH 7.0).
TYPE LOCATION: Lake County, Montana; 1,000 feet south and 200 feet west of the NE corner of sec. 18, T. 22 N., R. 19 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 47 degrees F.
Moisture control section - between 4 and 12 inches; moist during December through March and dry for more than 45 consecutive days during July, August, and early September.
Control section - 5 to 15 percent clay and less than 15 percent fine sand or coarser, and 0 to 10 percent pebbles.
The dark colored surface of this soil does not meet the thickness requirements for a mollic epipedon. Some pedons have free lime below a depth of 40 inches.
A horizon - Value: 4 or 5 dry; 2 or 3 moist
Chroma: 1 or 2
Clay content: 10 to 18 percent
Rock fragments: 0 to 10 percent pebbles
Reaction: pH 5.6 to 7.3
E1 and E2 horizons - Value: 5, 6, or 7 dry; 4 or 5 moist
Chroma: 2 or 3
Texture: silt loam or very fine sandy loam
Clay content: 5 to 15 percent
Rock fragments: 0 to 10 percent pebbles
Reaction: pH 5.1 to 7.3
E and Bw horizon - Value: E part 6 or 7, B part 5 or 6 dry; E part 4, 5, or 6, B part 4 or 5 moist
Chroma: E part 2 or 3; B part 2, 3, or 4
Texture: silt loam or very fine sandy loam
Clay content: 5 to 15 percent
Rock fragments: 0 to 10 percent pebbles
Reaction: pH 5.6 to 7.8
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform - stream terraces and dissected alluvial fans.
Elevation - 2,300 to 3,500 feet.
Slope- 0 to 30 percent.
Parent material - alluvium and glaciofluvial deposits.
Climate - long, cold winters; moist falls and springs; warm, dry summers.
Mean annual precipitation - 16 to 22 inches.
Mean annual temperature - 40 to 45 degrees F.
Frost-free period - 105 to 125 days.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderate permeability through the E2 horizon and moderately slow permeability in the E and Bw horizon.
USE AND VEGETATION: Dubay soils are used mainly for irrigated and nonirrigated crops, pasture, and for timber production. Potential native vegetation is mainly ponderosa pine and Douglas fir with an understory of common snowberry, pinegrass, and Oregon-grape.
DISTRIBUTION AND EXTENT: Dubay soils are of small extent in northwestern Montana valleys.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Lake County, Montana, 1991; proposed in Lake County, Montana, 1982.
REMARKS: Soil interpretation record: MT0746. Diagnostic horizons and features recognized in this pedon are: an ochric epipedon from the mineral soil surface to 7 inches (A and E1 horizons); an albic horizon from 6 to 31 inches (E1 and E2 horizons); and a particle-size control section from 10 to 40 inches below the mineral soil surface (E1, E2, E and Bw horizons). Dubay soils have a frigid temperature regime and a xeric moisture regime.