LOCATION FIRADA MTEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Calcic Haplocryepts
TYPICAL PEDON: Firada cobbly clay loam, woodland (colors are for dry soil unless otherwise noted).
Oi--0 to 1 inch; undecomposed and slightly decomposed forest litter.
E--1 to 4 inches; light gray (10YR 7/2) cobbly clay loam, brown (10YR 4/3) moist; moderate fine and very fine granular structure; slightly hard, very friable, slightly sticky and moderately plastic; many fine, medium, and coarse roots; many very fine and fine pores; 25 percent angular cobbles, 5 percent angular gravel; slightly acid (pH 6.5); clear wavy boundary. (1 to 4 inches thick)
Bw1--4 to 14 inches; brown (10YR 5/3) very cobbly clay loam, dark brown (10YR 4/3) moist; strong fine and very fine subangular blocky structure; hard, friable, moderately sticky and moderately plastic; many fine, medium, and coarse roots; many very fine and fine pores; 25 percent angular cobbles, 15 percent angular gravel; neutral (pH 7.3); clear wavy boundary.
Bw2--14 to 18 inches; pale brown (10YR 6/3) very cobbly light clay loam, brown (10YR 4/3) moist; moderate fine and very fine subangular blocky structure; hard, friable, moderately sticky and moderately plastic; many fine, medium, and coarse roots; many very fine and fine pores; 30 percent angular cobbles, 20 percent angular gravel; slightly effervescent; slightly alkaline (pH 7.6); gradual wavy boundary. (Combined thickness of Bw horizons is 5 to 25 inches)
Bk--18 to 26 inches; light brownish gray 910YR 6/2) extremely flaggy light clay loam, dark grayish brown (10YR 4/2) moist; moderate fine and very fine subangular blocky structure; hard, friable, moderately sticky and moderately plastic; common fine, medium, and coarse roots; many very fine and fine pores; 45 percent flagstones, 30 percent angular gravel; strongly effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (7 to 27 inches thick)
R--26 inches; extremely hard fractured limestone.
TYPE LOCATION: Fergus County, Montana; 2,540 feet north and 1,209 feet west of the SE corner of sec. 7, T. 12 N., R. 18 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 40 to 44 degrees F.
Moisture control section - between 4 and 12 inches.
Depth to bedrock - 20 to 40 inches.
Depth to Bk horizon - 7 to 25 inches.
E horizon - Hue: 10YR or 2.5Y
Value: 6 or 7 dry; 4 or 5 moist
Chroma: 2 or 3
Texture: loam or clay loam
Clay content: 15 to 35 percent
Rock fragments: 15 to 50 percent--0 to 25 percent angular cobbles; 5 to 35 percent angular gravel
Reaction: pH 6.1 to 7.3
Bw1 horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 or 3
Texture: loam or clay loam
Clay content: 15 to 35 percent
Rock fragments: 30 to 60 percent--15 to 30 percent angular cobbles; 15 to 30 percent angular gravel
Reaction: pH 6.1 to 7.8
Bw2 horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 or 3
Texture: loam or clay loam
Clay content: 20 to 35 percent
Rock fragments: 30 to 60 percent--15 to 30 percent angular cobbles; 15 to 30 percent angular gravel
Reaction: pH 7.4 to 7.8
Bk horizon - Hue: 10YR or 2.5Y
Value: 5, 6, or 7 dry; 4, 5 or 6 moist
Chroma: 2 or 3
Texture: loam or clay loam
Clay content: 15 to 35 percent
Rock fragments: 35 to 80 percent--20 to 50 percent angular cobbles; 20 to 30 percent angular gravel
Calcium Carbonate Equivalent: 5 to 15 percent
Reaction: pH 7.9 to 8.4
COMPETING SERIES:
Cuberant (UT) - does not have horizon of secondary calcium carbonate accumulation.
Garlet (MT) - is very deep; has transitional Bw/E horizon.
Gromes (NM) - is very deep; does not have horizon of secondary calcium carbonate accumulation.
Storm (CO) - is very deep; does not have horizon of secondary calcium carbonate accumulation.
Targhee (ID) - does not have horizon of secondary calcium carbonate accumulation; has a lithologic discontinuity.
Telay (AK) - is very deep; does not have horizon of secondary calcium carbonate accumulation; has a subarctic climate.
GEOGRAPHIC SETTING:
Landform- uplands and sideslopes of mountains
Elevation - 4,500 to 8,600 feet.
Slope - 4 to 60 percent.
Parent material - colluvium, alluvium, and residuum derived mainly from limestone.
Climate - long, cold winters; cool, moist springs; cool, moist summers; and cool, moist falls.
Mean annual precipitation - 20 to 30 inches.
Mean annual temperature - 36 to 42 degrees F.
Frost-free period - 50 to 70 days.
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Firada soils are used mainly for woodland, watershed, and recreation. Potential native vegetation is mainly Douglas-fir, white spruce, and lodgepole pine with an understory of white spiraea, blue huckleberry, Oregon-grape, twinflower, common pipsissewa, clematis, heartleaf arnica, feather solomon-seal, and northern bedstraw.
DISTRIBUTION AND EXTENT: Firada soils are of moderate extent in the mountains of central Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Fergus County, Montana, 1979.
REMARKS: Soil Interpretations Record: MT0310. Diagnostic horizons and features recognized in this pedon are: an ochric epipedon from the mineral soil surface to 4 inches (E horizon); a cambic horizon from 4 to 18 inches (Bw1 and Bw2 horizons); a particle-size control section from 10 inches to the lithic contact; a horizon of carbonate accumulation from 18 to 26 inches (Bk horizon); and a lithic contact at 26 inches (R horizon). Firada soils have a udic moisture regime and a cryic temperature regime.
The 3/2008 description reflects a change in classification from Loamy-skeletal, mixed, superactive Typic Eutrocryepts to Loamy-skeletal, mixed, superactive Calcic Haplocryepts due to revision of the cryepts great groups and subgroups. The competing series section was not updated and should be reviewed after all the cryepts have been re-classified.