LOCATION VITROFF MTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive Vitrandic Haplocryalfs
TYPICAL PEDON: Vitroff ashy loam, forested (colors are for dry soil unless otherwise noted).
Oi--0 to 1 inch; forest litter of slightly decomposed needles, twigs and roots. (1 to 3 inches thick)
E1--1 to 3 inches; light brownish gray (10YR 6/2) ashy loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; common coarse, medium, fine and very fine roots; common very fine tubular pores; 2 percent angular pebbles; slightly acid (pH 6.2); clear smooth boundary.
E2--3 to 8 inches; very pale brown (10YR 7/3) ashy loam, very dark grayish brown (10YR 3/2) moist; moderate very fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; common coarse, medium, fine and very fine roots; common very fine tubular pores; 10 percent angular pebbles; neutral (pH 6.6); clear smooth boundary. (Combined thickness of E horizons is 6 to 20 inches)
Bt and E--8 to 15 inches; Bt part (65 percent) is brown (10YR 4/3) gravelly ashy clay loam lamellae 1/2 to 5/8 inches thick, very dark grayish brown (2.5Y 3/2) moist; E part (35 percent) is very pale brown (10YR 7/3) ashy sandy clay loam, dark grayish brown (2.5Y 4/2) moist; weak medium subangular blocky structure; Bt part is hard, firm, moderately sticky and moderately plastic; E part is slightly hard, friable, slightly sticky and slightly plastic, few coarse and common medium, fine and very fine roots; few fine and common very fine tubular pores; 20 percent pebbles and 5 percent angular cobbles; neutral (pH 6.8); gradual wavy boundary. (6 to 18 inches thick)
Bt--15 to 33 inches; pale brown (10YR 6/3) gravelly ashy clay loam, dark grayish brown (2.5Y 4/2) moist; weak medium subangular blocky structure; very hard, firm, moderately sticky and moderately plastic; few medium and fine and common very fine roots; few, fine and common very fine tubular pores; common faint clay films on faces of peds; 20 percent pebbles and 10 percent angular cobbles; neutral (pH 7.2); diffuse wavy boundary. (8 to 18 inches thick)
BC--33 to 60 inches; light gray (10YR 7/2) extremely gravelly ashy coarse sandy loam, olive brown (2.5Y 4/3) moist; massive; loose, nonsticky and nonplastic; few fine and very fine roots in the upper 2 feet; 50 percent pebbles and 20 percent angular cobbles; slightly alkaline (pH 7.4).
TYPE LOCATION: Jefferson County, Montana; 800 feet east and 450 feet north of the SW corner of sec. 22, T. 6 N., R. 6 W.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 38 to 42 degrees F.
Mean summer soil temperature - 42 to 46 degrees F.
Moisture control section - between 4 and 12 inches.
Depth to lamellae - 6 to 20 inches.
Volcanic glass - 20 to 50 percent in the coarse silt and sand fraction.
Acid oxalate Al + 1/2 Fe - .12 to .20 percent
E horizons - Hue: 10YR or 2.5Y
Value: 6 or 7 dry, 3 or 4 moist
Chroma: 2 or 3
Texture: ashy loam or ashy sandy loam
Clay content: 15 to 27 percent
Rock fragments: 0 to 60 percent--0 to 20 percent angular cobbles, 0 to 40 percent pebbles
Reaction: pH 5.6 to 7.3
Bt and E horizon - Hue: 10YR or 2.5Y
Value: B part - 4 or 5 dry, 3 or 4 moist; E part - 5, 6 or 7 dry, 4 or 5 moist
Chroma: 2 or 3
Texture: B part - ashy clay loam or ashy sandy clay loam; E part - ashy sandy clay loam or ashy sandy loam
Clay content: B part - 20 to 35 percent; E part - 15 to 24 percent
Rock fragments: 5 to 35 percent--0 to 5 percent angular cobbles, 5 to 30 percent pebbles
Reaction: pH 6.1 to 7.3
Bt horizon - Hue: 10YR or 2.5Y
Value: 5, 6 or 7 dry, 4 or 5 moist
Chroma: 2 or 3
Texture: ashy clay loam or ashy sandy clay loam
Clay content: 25 to 35 percent
Rock fragments: 10 to 35 percent--0 to 10 percent angular cobbles, 10 to 25 percent pebbles
Reaction: pH 6.1 to 7.3
BC horizon - Hue: 10YR or 2.5Y
Value: 6 or 7 dry, 4 or 5 moist
Chroma: 2, 3 or 4
Texture: ashy coarse sandy loam or ashy sandy clay loam
Clay content: 5 to 22 percent
Rock fragments: 35 to 85 percent--5 to 20 percent angular cobbles, 30 to 65 percent pebbles
Reaction: pH 6.6 to 7.8
COMPETING SERIES:
Culdecole (ID) - has a udic moisture regime; does not have horizons containing lamellae.
Hopburn (ID) - has a udic moisture regime; does not have horizons containing lamellae.
GEOGRAPHIC SETTING:
Landform - alluvial fans, saddles and sideslopes of mountains.
Elevation - 5,500 to 7,700 feet.
Slope - 4 to 60 percent.
Parent material - colluvium from tuffaceous volcanic bedrock.
Climate - long, cold winters; cool, moist springs; short, cool summers.
Mean annual precipitation - 15 to 24 inches.
Mean annual temperature - 36 to 40 degrees F.
Frost free period - 30 to 70 days.
GEOGRAPHICALLY ASSOCIATED SOILS: This is the Torpy series. Torpy soils do not have an argillic horizon and are loamy-skeletal. They are on similar landform postitions.
DRAINAGE AND PERMEABILITY: Well drained, moderate permeability.
USE AND VEGETATION: Vitroff soils are used mainly for timber production and understory grazing. Native vegetation is mainly lodgepole pine and Douglas-fir with an understory of grouse whortleberry, pinegrass, kinnikinnick, Oregongrape, woods pussytoes and common juniper.
DISTRIBUTION AND EXTENT: Vitroff soils are of small extent in southwestern Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Jefferson County, Montana, 1998.
REMARKS: Soil Interpretation Record: MT1732. Diagnostic horizons and features recognized in this pedon are: an ochric epipedon from the mineral soil surface to 8 inches (E1, E2 horizons); an argillic horizon from 8 to 33 inches (Bt and E, Bt horizons); a particle size control section from 8 to 28 inches (Bt and E and Bt horizons). Vitroff soils have a cryic temperature regime and an ustic moisture regime.