LOCATION YOURAME MTEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Typic Haplustalfs
TYPICAL PEDON: Yourame gravelly loam, forested (colors are for dry soil unless otherwise noted).
Oi--0 to 2 inches; slightly decomposed forest litter.
E1--2 to 6 inches; light brownish gray (10YR 6/2) gravelly loam, very dark grayish brown (10YR 3/2) moist; moderate medium granular structure; soft, very friable, nonsticky and nonplastic; many very fine, fine, medium, and coarse roots; 15 percent pebbles; slightly acid (pH 6.4); abrupt wavy boundary.
E2--6 to 11 inches; very pale brown (10YR 7/3) gravelly loam, brown (10YR 5/3) moist; strong medium and coarse granular structure; slightly hard, very friable, nonsticky and nonplastic; many very fine, fine, medium, and coarse roots; 15 percent pebbles; neutral (pH 6.6); clear smooth boundary. (Combined thickness of the E horizons is 8 to 16 inches.)
E/Bt--11 to 21 inches; E part (about 80 percent) is very pale brown (10YR 7/3) gravelly loam, brown (10YR 5/3) moist; which interfingers into B part; B part (about 20 percent) is light yellowish brown (10YR 6/4) gravelly loam, yellowish brown (10YR 5/4) moist; mixed texture is gravelly loam, moderate medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; many very fine, fine, medium, and coarse roots; few faint clay films on faces of peds; 20 percent pebbles; neutral (pH 6.8); clear smooth boundary. (0 to 15 inches thick)
Bt--21 to 48 inches; light yellowish brown (10YR 6/4) very gravelly clay loam, yellowish brown (10YR 5/4) moist; moderate medium subangular blocky structure; very hard, friable, sticky, and plastic, common very fine, and medium roots; common distinct thick clay films on faces of peds; 10 percent cobbles, 40 percent pebbles, neutral (pH 7.0); abrupt smooth boundary. (17 to 40 inches thick)
Bk--48 to 60 inches; very pale brown (10YR 7/3) very gravelly clay loam, brown (10YR 5/3) moist; massive; hard, very friable, slightly sticky, and slightly plastic; few very fine and fine roots; 15 percent cobbles; 40 percent pebbles; disseminated lime; strongly effervescent; moderately alkaline (pH 8.4).
TYPE LOCATION: Missoula County, Montana; 360 feet south of the E 1/4 corner of sec. 1, T. 15 N., R. 14 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 46 degrees F.
Depth to Bk horizon - 30 to 60 inches.
E1 horizon - Value: 6 or 7 dry; 3, 4, or 5 moist
Chroma: 2 or 3
Clay content: 7 to 20 percent
Rock fragments: 15 to 35 percent--5 to 15 percent cobbles and stones; 15 to 35 percent pebbles
Reaction: pH 5.6 to 7.3
E2 horizon - Value: 6 or 7 dry; 5 or 6 moist
Chroma: 2 or 3
Texture: loam or sandy loam
Clay content: 7 to 20 percent
Rock fragments: 15 to 35 percent--0 to 10 percent cobbles and stones; 15 to 25 percent pebbles
Reaction: pH 5.6 to 7.3
E/Bt horizon - Hue: E part 10YR or 7.5YR; B part 10YR or 7.5YR
Value: E part 6 or 7, B part 5, 6 or 7 dry; E part 5 or 6, B part 4 or 5 moist
Chroma: E part 2 or 3; B part 2, 3, or 4
Texture: loam or sandy loam
Clay content: 7 to 25 percent (mixed)
Rock fragments: 15 to 35 percent--0 to 10 percent cobbles and stones; 15 to 25 percent pebbles
Reaction: pH 5.6 to 7.3
Bt horizon - Hue: 10YR or 7.5YR
Value: 5, 6 or 7 dry; 4 or 5 moist
Chroma: 2, 3, or 4
Texture: clay loam or sandy clay loam
Clay content: 20 to 35 percent
Rock fragments: 35 to 60 percent--5 to 20 percent cobbles and stones; 30 to 40 percent pebbles
Reaction: pH 5.6 to 7.3
Bk horizon - Value: 6, 7, or 8 dry; 5, 6, or 7 moist
Chroma: 2 or 3
Texture: clay loam or loam
Clay content: 18 to 30 percent
Rock fragments: 35 to 60 percent--5 to 20 percent cobbles and stones; 30 to 40 percent pebbles
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.9 to 8.4
COMPETING SERIES:
Macmeal (MT) - does not have an E/Bt horizon.
Mocmont (MT) - does not have horizon of secondary carbonate accumulation; has a glossic horizon.
Yreka (MT) - does not have horizon of secondary carbonate accumulation.
Macmeal (MT) - has a firm argillic horizon with channers and flagstone rock fragments.
GEOGRAPHIC SETTING:
Landform - stream terraces, alluvial fans, moraines, till plains, hills, mountains.
Elevation - 3,000 to 6,500 feet.
Slope- 4 to 60 percent.
Parent material - till and colluvium.
Climate - long, cold winters; moist springs.
Mean annual precipitation - 17 to 25 inches, much of which falls as snow or as spring rain.
Mean annual temperature - 38 to 44 degrees F.
Frost-free period - 70 to 90 days.
DRAINAGE AND PERMEABILITY: Well drained, moderately slow permeability.
USE AND VEGETATION: Yourame soils are used for timber production, understory grazing, and watersheds and as wildlife habitat. The native vegetation is Douglas-fir and ponderosa pine with an understory of common snowberry, pinegrass, and white spiraea.
DISTRIBUTION AND EXTENT: Yourame soils are of small extent in western Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Granite County, Montana, 1966.
REMARKS: Soil interpretation record: MT0620. Diagnostic horizons and features recognized in this pedon are: an ochric epipedon from the soil surface to 21 inches (E1, E2, E/Bt horizons); an albic horizon from 2 to 6 inches (E1 horizon); an argillic horizon from 21 to 48 inches (Bt horizon); a particle-size control section from 21 to 41 inches or the upper 20 inches of the argillic horizon (Bt horizon). Yourame soils have a frigid temperature regime and an ustic moisture regime.