LOCATION FELAN MTEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Andic Haplocryalfs
TYPICAL PEDON: Felan gravelly ashy silt loam, forested (colors are for dry soil unless otherwise noted).
Oi--0 to 2 inches; undecomposed and slightly decomposed forest litter.
E--2 to 5 inches; light gray (10YR 7/2) gravelly ashy silt loam, grayish brown (10YR 5/2) moist; strong fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine, fine, medium, and coarse roots; many very fine and fine pores; 15 percent angular pebbles; moderately acid (pH 5.6); clear wavy boundary. (0 to 4 inches thick)
Bw--5 to 10 inches; light yellowish brown (10YR 6/4) gravelly ashy silt loam, dark yellowish brown (10YR 4/4) moist; moderate fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine, fine, medium, and coarse roots; many very fine and fine pores; 25 percent angular pebbles; moderately acid (pH 5.6); clear wavy boundary. (7 to 10 inches thick)
2E--10 to 25 inches; light gray (2.5Y 7/2) very gravelly silt loam, light brownish gray (2.5Y 6/2) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine, medium, and coarse roots; many very fine and fine pores; 45 percent angular pebbles; moderately acid (pH 5.6); clear smooth boundary. (10 to 20 inches thick)
2Bt1--25 to 35 inches; pale yellow (2.5Y 7/4) very gravelly silt loam, light yellowish brown (2.5Y 6/4) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine, medium, and coarse roots; many very fine and fine pores; common faint clay bridging and coatings on sand grains; 40 percent angular pebbles; neutral (pH 7.2); clear smooth boundary.
2Bt2--35 to 51 inches; light yellowish brown (2.5Y 6/4) very gravelly loam, light olive brown (2.5Y 5/4) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine, and medium roots; many very fine and fine pores; common faint clay bridging and coatings on sand grains; 40 percent angular pebbles; slightly alkaline (pH 7.8); gradual smooth boundary. (Combined thickness of 2Bt1 and 2Bt2 horizons is 18 to 32 inches.)
2Bt3--51 to 60 inches; pale yellow (2.5Y 7/4) very gravelly loam, light olive brown (2.5Y 5/4) moist; weak coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; many very fine and fine pores; common faint clay bridging and coatings on sand grains; 40 percent angular pebbles; 5 percent cobbles; moderately alkaline (pH 8.0).
TYPE LOCATION: Missoula County, Montana; 1,500 feet north and 1,500 feet west of the SE corner of sec. 18, T. 15 N., R. 16 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 39 to 44 degrees F.
Moisture control section - between 8 and 24 inches.
Control section - 8 to 18 percent clay, 40 to 60 percent silt, and less than 45 percent total sand, and less than 35 percent sand coarser than very fine sand.
Depth to carbonates - commonly below 60 inches, but as shallow as 40 inches in some pedons.
E horizon - Hue: 2.5Y or 10YR
Value: 6 or 7 dry; 5 or 6 moist
Chroma: 2 or 3
Clay content: 5 to 15 percent
Rock fragments: 15 to 35 percent--0 to 5 percent angular cobbles and stones; 15 to 30 percent angular pebbles
Moist bulk density: 1.0 g/cc or less
Acid oxalate Al + 1/2 Fe: 1.0 percent or more
Reaction: pH 5.1 to 6.0
Bw horizon - Hue: 10YR or 7.5YR
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 4 or 6
Texture: ashy silt loam or ashy loam
Clay content: 5 to 20 percent
Rock fragments: 15 to 35 percent--0 to 5 percent angular cobbles and stones; 15 to 30 percent angular pebbles
Moist bulk density: 1.0 g/cc or less
Acid oxalate Al + 1/2 Fe: 1.0 percent or more
Reaction: pH 5.1 to 6.5
2E horizon - Hue: 2.5Y or 10YR
Value: 6 or 7 dry; 5 or 6 moist
Chroma: 2 or 3
Texture: silt loam or loam
Clay content: 5 to 20 percent
Rock fragments: 35 to 70 percent--0 to 10 percent angular cobbles and stones; 35 to 60 percent angular pebbles
Reaction: pH 5.1 to 7.3
2Bt horizons - Hue: 2.5Y or 10YR
Value: 5, 6, or 7 dry; 4 or 5 moist
Chroma: 3, 4, 5, or 6
Texture: loam or silt loam
Clay content: 8 to 20 percent
Rock fragments: 40 to 75 percent--0 to 10 percent angular cobbles and stones; 40 to 65 percent angular pebbles
Reaction: pH 6.6 to 8.4
COMPETING SERIES:
Jimlake (MT) - has mixed 2Bt/E horizons.
Ortellcreek (WA) - has compact till below 35 inches; has 20 to 34 percent clay in the argillic horizon; has a xeric moisture regime.
Pileup (WA) - has a xeric moisture regime.
Sherlock (WA) - has an argillic horizon with 25 to 35 percent clay.
GEOGRAPHIC SETTING:
Landform - mountains.
Elevation - 3,600 to 8,000 feet.
Slope - 8 to 60 percent.
Parent material - colluvium derived from limestone or argillite.
Climate - cool with cold winters and moist springs.
Mean annual precipitation - 30 to 60 inches, much of which falls as snow and spring rain.
Mean annual temperature - 37 to 42 degrees F.
Frost-free period - 30 to 70 days.
DRAINAGE AND PERMEABILITY: Well drained, moderate permeability.
USE AND VEGETATION: Felan soils are used for timber production, watersheds and wildlife habitat. The potential native vegetation is subalpine fir, Douglas-fir, Engelmann spruce, western larch, and lodgepole pine with an understory of twinflower, blue huckleberry, rusty menziesia, grouse whortleberry, and common beargrass.
DISTRIBUTION AND EXTENT: Felan soils are moderately extensive in western Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Missoula County, Montana, 1985
REMARKS: Soil Interpretation Record: MT0534. Diagnostic horizons and features recognized in this pedon are: an ochric epipedon from the mineral soil surface to 25 inches (E, Bw and 2E horizons); an albic horizon from 10 to 25 inches (2E horizon); an argillic horizon from 25 to 60 inches (2Bt1, 2Bt2 and 2Bt3 horizons); a particle-size control section from 25 to 45 inches (2Bt1 and part of the 2Bt2 horizons). Felan soils have a cryic temperature regime and a udic moisture regime.
ADDITIONAL DATA: Laboratory data-S70MT-63-2; Riverside Lab. S70MT-32-2.