LOCATION PLEASANTVALLEY MTTentative Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Vitrandic Eutrudepts
TYPICAL PEDON: Pleasantvalley gravelly ashy silt loam, in coniferous forest (colors are for dry soil unless otherwise noted).
Oi--0 to 1 inch; undecomposed and slightly decomposed needles and twigs. (1 to 3 inches thick)
E--1 to 4 inches; brown (10YR 5/3) gravelly ashy silt loam, brown (10YR 4/3) moist; weak fine subangular blocky structure parting to weak fine granular; soft, very friable, nonsticky and nonplastic; 15 percent gravel, 5 percent stones; neutral (pH 6.6); clear wavy boundary. (0 to 3 inches thick)
Bw--4 to 14 inches; yellowish brown (10YR 5/4) gravelly ashy silt loam, dark yellowish brown (10YR 4/4) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; 15 percent gravel, 5 percent stones; slightly acid (pH 6.4); clear wavy boundary. (7 to 14 inches thick)
2E--14 to 26 inches; pale brown (10YR 6/3) very cobbly silt loam, brown (10YR 5/3) moist; weak fine subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; 30 percent gravel, 20 percent cobbles, 5 percent stones; neutral (pH 6.8); gradual wavy boundary. (6 to 19 inches thick)
2E/Bw--26 to 34 inches; E part (85 percent) is pale yellow (2.5Y 7/3) very cobbly silt loam, light yellowish brown (2.5Y 6/3) moist that surrounds the B part; B part (15 percent) is light yellowish brown (10YR 6/4) very cobbly silt loam, yellowish brown (10YR 5/4) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; 30 percent gravel, 20 percent cobbles, 5 percent stones; neutral (pH 7.0); abrupt wavy boundary. (4 to 12 inches thick)
2E and Bt--34 to 60 inches; E part (85 percent) is pale olive (5Y 6/3) very cobbly silt loam, olive (5Y 5/3) moist; B part (15 percent) is light yellowish brown (2.5Y 6/3) silty clay loam discontinuous lamellae 1/8- to 1/4-inch thick, light olive brown (2.5Y 5/3) moist; texture mixed is very cobbly silt loam, weak fine and medium subangular blocky structure; hard, firm, slightly sticky and slightly plastic; 20 percent gravel, 15 percent cobbles; neutral (pH 7.2).
TYPE LOCATION: Flathead County, Montana; 2500 feet south and 500 feet east of the NW corner of sec. 14, T. 28 N., R. 26 W. Dahl Lake topographic quadrangle. UTM Zone 11: Northing 5339662, Easting 658331.
RANGE IN CHARACTERISTICS:
Soil temperature - 40 to 45 degrees F.
Moisture control section - approximately between the depths of 8 and 24 inches. An A horizon occurs in place of the E horizon in some profiles on southern aspects.
A 2E/Bt horizon occurs in place of the 2E and Bt horizon in some profiles.
E horizon
Hue: 7.5YR or 10YR
Value: 4 or 5 dry; 3 or 4 moist
Chroma: 2 or 3
Texture: ashy silt loam or ashy loam
Clay content: 7 to 15 percent
Rock fragments: 0 to 35 percent--0 to 25 percent gravel; 0 to 20 percent cobbles and stones
Volcanic Glass: 5 to 20 percent Bulk density: 1.0 to 1.3 g/cc
Acid oxalate Al + 1/2 Fe: 0.4 to 1 percent
Reaction: pH 5.6 to 6.6
Bw horizon
Hue: 7.5YR or 10YR
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 3 or 4
Texture: ashy silt loam or ashy loam
Clay content: 7 to 15 percent
Rock fragments: 0 to 35 percent--0 to 25 percent gravel; 0 to 20 percent cobbles and stones Volcanic Glass: 5 to 20 percent
Bulk density: 1.0 to 1.3 g/cc
Acid oxalate Al + 1/2 Fe: 0.4 to 1 percent
Reaction: pH 5.6 to 6.6
2E horizon
Hue: 2.5Y or 10YR
Value: 6, 7, or 8 dry; 4, 5, or 6 moist
Chroma: 2 or 3
Texture: silt loam, loam, fine sandy loam
Clay content: 5 to 18 percent
Rock fragments: 35 to 60 percent--20 to 40 percent gravel; 5 to 25 percent cobbles; 0 to 10 percent stones
Reaction: pH 5.6 to 7.3
2E/Bw horizon
Hue: 2.5Y or 10YR
Value: B part 5 or 6, E part 6, 7, or 8 dry; B part 4, 5 or 6, E part 5 or 6 moist
Chroma: E part 2 or 3; B part 3 or 4
Texture: silt loam, loam, fine sandy loam
Clay content: 5 to 18 percent
Rock fragments: 35 to 60 percent--20 to 40 percent gravel; 5 to 25 percent cobbles; 0 to 10 percent stones
Reaction: pH 5.6 to 7.3
2E and Bt horizon
Hue: 2.5Y or 10YR
Value: B part 5 or 6, E part 6, 7, or 8 dry; B part 4, 5 or 6, E part 5 or 6 moist
Chroma: E part 2 or 3; B part 3 or 4
Texture: silt loam, loam, fine sandy loam
Clay content: 5 to 18 percent, lamellae has less than 3 percent increase in clay
Rock fragments: 35 to 60 percent--20 to 40 percent gravel; 5 to 25 percent cobbles; 0 to 10 percent stones
Reaction: pH 5.6 to 7.3
COMPETING SERIES:
Lesier - has horizons of secondary carbonate accumulation.
GEOGRAPHIC SETTING:
Landform - foothills, moraines, and mountain slopes in glaciated valleys.
Elevation - 3,000 to 5,200 feet.
Slope - 2 to 60 percent.
Parent material - till.
Climate - long, cold winters, moist springs, warm summers.
Mean annual effective precipitation - 22 to 28 inches
Mean annual air temperature - 39 to 44 degrees F.
Frost-free period - 70 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Winfall, Courville, Rockhill, and Sharrott series. Winfall soils are on similar positions and do not have an ash-derived mantle. Courville soils are on similar positions on northern aspects and have a lower bulk density, ash-derived mantle. Rockhill soils are on glacially scoured ridges, are ash-derived, and are shallow to bedrock. Sharrott soils are on glacially scoured ridges, have an ustic moisture regime and are shallow to bedrock.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Pleasantvalley soils are used mainly for timber production, woodland grazing, and as wildlife habitat. The potential native vegetation is coniferous forest consisting mainly of Douglas-fir, western larch, lodgepole pine, and ponderosa pine with an understory of kinnikinnick, pinegrass, white spirea, rough fescue, elk sedge, dwarf huckleberry, and Oregon grape.
DISTRIBUTION AND EXTENT: Pleasantvalley soils are of limited extent in northwestern Montana. MLRA 43A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES PROPOSED: Flathead County, Montana, 2004. The name is taken from the name of a valley in the survey area.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ash influenced layer - 1 to 14 inches (E, Bw horizons);
Ochric epipedon - 0 to 14 inches (Oi, A, Bw horizons);
Albic horizon - 14 to 26 inches (2E horizon);
Cambic horizon - 26 to 60 inches (2E/Bw, 2E/Bt horizons); and
Particle-size control section - 10 to 40 inches (Bw, 2E, 2E/Bw, 2E/Bt horizons).
Pleasantvalley soils have a udic moisture regime bordering on ustic and a frigid temperature regime.