LOCATION SELWAY MTEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Lamellic Eutrudepts
TYPICAL PEDON: Selway gravelly sandy loam, in coniferous forest. (Colors are for dry soil unless otherwise noted.)
0i--1 to 3 inches; undecomposed and slightly decomposed forest litter. (1 to 3 inches thick)
E1--3 to 11 inches; pale brown (10YR 6/3) gravelly sandy loam, brown (10YR 4/3) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine, fine, medium, and coarse roots; many very fine and fine pores; 20 percent angular pebbles; slightly acid (pH 6.2); clear wavy boundary.
E2--11 to 21 inches; light gray (10YR 7/2) gravelly sandy loam, brown (10YR 4/3) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine, fine, and moderate roots; many very fine and fine pores; 30 percent pebbles; slightly acid (pH 6.2); clear wavy boundary. (Combined thickness of the E horizon is 6 to 24 inches.)
E and Bt1--21 to 38 inches; E part (75 percent) is very pale brown (10YR 7/3) very gravelly coarse sandy loam, yellowish brown (10YR 5/4) moist; B part (25 percent) is few thin lamellae of yellowish brown (10YR 5/4) very gravelly fine sandy loam, dark yellowish brown (10YR 4/4) moist; texture mixed is very gravelly coarse sandy loam; weak fine and moderate subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; common very fine, fine, and medium roots; many very fine and fine pores; 55 percent pebbles; moderately acid (pH 6.0); abrupt wavy boundary.
E and Bt2--38 to 54 inches; E part (75 percent) is brownish yellow (10YR 6/6) very gravelly coarse sandy loam, yellowish brown (10YR 5/6) moist; B part (25 percent) is few thin lamellae of yellowish brown (10YR 5/4) very gravelly fine sandy loam, dark yellowish brown (10YR 4/4) moist; texture mixed is very gravelly coarse sandy loam; weak fine and medium subangular blocky structure; slightly hard, firm, nonsticky and nonplastic; common very fine, fine, and medium roots; many very fine and fine pores; 60 percent pebbles; moderately acid (pH 6.0); diffuse irregular boundary. (Combined thickness of E and Bt horizons is 20 to 40 inches)
BC--54 to 60 inches; brownish yellow (10YR 6/6) very gravelly loamy coarse sand, yellowish brown (10YR 5/6); single grain; loose, nonsticky and nonplastic; common very fine, fine, and medium roots; common very fine pores; 40 percent pebbles; slightly acid (pH 6.4); clear wavy boundary.
TYPE LOCATION: Missoula County, Montana; 2,000 feet west and 1,500 feet south of the NE corner of sec. 17, T. 11 N., R. 23 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 46 degrees F.
Moisture control section - between 8 and 24 inches
Control section - 5 to 15 percent clay and more than 50 percent coarse or very coarse sand
Base saturation - more than 60 percent in one or more horizons between 10 and 30 inches
E horizons: In some pedons the upper 3 to 5 inches of the E horizon is dark-colored, but does not meet the requirements for a mollic epipedon where mixed to a depth of 7 inches.
Value: 6 or 7 dry; 4 or 5 moist
Chroma: 2, 3, or 4
Clay content: 5 to 15 percent
Rock fragments: 15 to 35 percent--0 to 5 percent cobbles, stones and boulders; 15 to 30 percent angular pebbles
Reaction: pH 6.1 to 7.3
E and Bt horizons - Value: E part 6 or 7, B part 4, 5, or 6 dry; E part 5 or 6, B part 3 or 4 moist
Chroma: E part 3 or 4; B part 4 or 6
Clay content, mixed: 5 to 15 percent
Rock fragments: 35 to 75 percent pebbles
Reaction: pH 5.6 to 6.5
BC horizon - Value: 5, 6, or 7 dry; 4, 5, or 6 moist
Chroma: 3, 4, or 6
Clay content: 5 to 10 percent
Rock fragments: 35 to 80 percent--0 to 10 percent cobbles and stones; 35 to 70 percent pebbles
Reaction: pH 5.6 to 6.5
COMPETING SERIES:
Lantern (MT) - has 15 to 40 percent mica in the particle-size control section.
Winfall (MT) - has less than 50 percent coarse or very coarse sand in the particle-size control section.
GEOGRAPHIC SETTING:
Landform - mountain slopes.
Elevation - 4,200 to 5,500 feet.
Slope - 8 to 60 percent.
Parent material - material derived from granite and gneiss.
Climate - cool with long, cold winters and moist springs.
Mean annual precipitation - 25 to 35 inches, much of which falls as snow or as rain in spring or early in summer.
Mean annual temperature - 40 to 44 degrees F.
Frost-free period - 70 to 90 days.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; moderately rapid permeability.
USE AND VEGETATION: Selway soils are used for timber production and watersheds and as wildlife habitat. The native vegetation is ponderosa pine, Douglas-fir, lodgepole pine, and western larch with an understory of pinegrass, elk sedge, dwarf huckleberry, blue huckleberry, and common beargrass.
DISTRIBUTION AND EXTENT: Selway soils are not extensive in western Montana and northern Idaho.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Missoula County, Montana, 1985.
REMARKS: Diagnostic horizons and features recognized in this pedon are: an ochric epipedon from 3 to 10 inches (E1 horizon); an albic horizon from 3 to 21 inches (E1, E2 horizons); a cambic horizon from 21 to 54 inches (E and Bt1, E and Bt2 horizons); a particle-size control section from 13 to 43 inches (E2, E and Bt1, E and Bt2 horizons). Selway soils have a frigid temperature regime and a udic moisture regime.