LOCATION MCMANUS MT
Established Series
Rev. HAL/BDD/SJJ
02/2018
MCMANUS SERIES
The Mcmanus series consists of very deep, somewhat poorly drained soils that formed in alluvium. These soils are on flood plains, stream terraces, and glacial outwash plains. Slopes are 0 to 4 percent. Mean annual precipitation is about 14 inches and mean annual air temperature is about 42 degrees F.
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Oxyaquic Haplustolls
TYPICAL PEDON: Mcmanus silty clay loam, in hayland, (colors are for moist soil unless otherwise noted).
A1--0 to 7 inches; very dark gray (10YR 3/1) silty clay loam, gray (10YR 5/1) dry; moderate medium subangular blocky structure; slightly hard, friable, moderately sticky and slightly plastic; many fine and very fine roots, many very fine and fine discontinuous pores; moderately alkaline (pH 8.2); gradual smooth boundary. (2 to 7 inches thick)
A2--7 to 14 inches; very dark gray (10YR 3/1) silt loam, gray (10YR 5/1) dry; moderate medium subangular blocky structure; slightly hard, friable, moderately sticky and slightly plastic; many very fine and common medium roots; many very fine irregular pores; slightly effervescent; moderately alkaline (ph 8.0); clear smooth boundary. (5 to 7 inches thick)
Bk1--14 to 27 inches; dark grayish brown (10YR 4/2) loam, light brownish gray (10YR 6/2) dry; few fine faint brownish yellow (10YR 6/6) redox concentrations; moderate medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine and fine roots; many very fine irregular pores; disseminated lime, few fine masses of lime; strongly effervescent; moderately alkaline (pH 8.2); gradual wavy boundary. (4 to 13 inches thick )
Bk2--27 to 34 inches; grayish brown (10YR 5/2) loam, light brownish gray (10YR 6/2) dry; few fine faint brownish yellow (10YR 6/6) redox concentrations; weak medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots; few very fine irregular pores; disseminated lime, few fine masses of lime; violently effervescent; moderately alkaline (pH 8.2); gradual wavy boundary. (3 to 7 inches thick)
Bk3--34 to 42 inches; brown (10YR 5/3) sandy loam, pale brown (10YR 6/3) dry; few fine faint brownish yellow (10YR 6/6) redox concentrations; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; few very fine and fine roots; few fine irregular tubular pores; disseminated lime, few fine masses of lime; violently effervescent; moderately alkaline (ph 8.4); gradual wavy boundary. (3 to 8 inches thick)
Bk4--42 to 60 inches; brown (10YR 5/3) very gravelly sandy clay loam, pale brown (10YR 6/3) dry; many faint brownish yellow (10YR 6/6) redox concentrations; massive; slightly hard, very friable, slightly sticky and slightly plastic; few very fine and fine roots; 5 percent cobbles, 40 percent pebbles; few fine irregular pores; disseminated lime, few fine masses of lime; strongly effervescent; moderately alkaline (ph 8.4).
TYPE LOCATION: Granite County, Montana; 400 feet west and 700 feet north of the SE corner of sec. 24, T. 10 N., R. 13 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 41 to 47 degrees F.
Moisture control section - between 4 and 12 inches.
Mollic epipedon thickness - 7 to 15 inches.
Depth to seasonal high water table - 24 to 42 inches.
Depth to the Bk horizon - 7 to 14 inches.
A horizons - Value: 3, 4, or 5 dry; 2 or 3 moist
Chroma: 1, 2, or 3
Texture: loam, clay loam, silt loam, silty clay loam
Clay content: 18 to 40 percent
Rock fragments: 0 to 15 percent--0 to 5 percent cobbles; 0 to 10 percent pebbles
Reaction: pH 7.4 to 8.4
Bk1 horizon - Value: 5 or 6 dry; 2, 3, 4, or 5 moist
Chroma: 2, 3, or 4
Redox concentrations: 10YR 6/6, 10YR 6/8
Texture: loam, sandy loam, silty clay loam, clay loam
Clay content: 18 to 35 percent
Rock fragments: 0 to 15 percent--0 to 10 percent cobbles; 0 to 5 percent pebbles
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.4 to 8.4
Bk2 horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 2, 3, 4, or 5 moist
Chroma: 2, 3, or 4
Redox concentrations: 10YR 6/6, 10YR 6/8
Texture: loam, clay loam, fine sandy loam, silty clay loam
Clay content: 18 to 35 percent
Rock fragments: 0 to 15 percent--0 to 5 percent cobbles; 0 to 10 percent pebbles
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.4 to 8.4
Bk3 horizon - Hue: 2.5Y or 10YR
Value: 5 or 6 dry; 3, 4, or 5 moist
Chroma: 2, 3, or 4
Redox concentrations: 10YR 6/6, 10YR 6/8
Texture: loam, clay loam, sandy loam
Clay content: 15 to 35 percent
Rock fragments: 0 to 15 percent--0 to 5 percent cobbles; 0 to 10 percent pebbles
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.4 to 8.4
Bk4 horizon - Hue: 2.5Y, 10YR
Value: 5 or 6 dry; 3, 4,or 5 moist
Chroma: 2, 3, or 4
Redox concentrations: 10YR 6/6, 10YR 6/8
Texture: sandy clay loam, sandy loam, loam
Clay content: 15 to 30 percent
Rock fragments: 10 to 60 percent--5 to 20 percent cobbles, 5 to 40 percent pebbles
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.4 to 8.4
COMPETING SERIES:
This is the
Peatross series. The Peatross series does not have visible secondary carbonates.
GEOGRAPHIC SETTING:
Landform - flood plains; stream terraces; glacial outwash plains.
Elevation - 3,600 to 6,200 feet
Slope - 0 to 4 percent
Parent material - alluvium
Climate - long, cold winters; cool, moist springs; warm summers.
Mean annual precipitation - 10 to 19 inches.
Mean annual air temperature - 39 to 44 degrees F.
Frost-free period - 70 to 105 days.
GEOGRAPHICALLY ASSOCIATED SOILS:
None recognized at this time.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained, moderate permeability.
USE AND VEGETATION: Mcmanus soils are primarily used for pasture, rangeland, and hayland. The potential native vegetation is mainly tall reedgrass, tufted hairgrass, and willows.
DISTRIBUTION AND EXTENT: Mcmanus soils are of small extent in southwestern Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Granite County, Montana, 1997.
REMARKS: Soil interpretation record: MT1479. Diagnostic horizons and features recognized in this pedon are: a mollic epipedon from the surface to 14 inches (A1, A2 horizons); accumulation of secondary calcium carbonate from 14 to 60 inches (Bk1, Bk2, Bk3, Bk4 horizons); particle- size control section from 10 to 40 inches (A2, Bk1, Bk2, Bk3 horizons). Mcmanus soils have a frigid temperature regime and an ustic moisture regime bordering on aquic.
National Cooperative Soil Survey
U.S.A.