LOCATION MOOSEJAW MTEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive Cumulic Cryaquolls
TYPICAL PEDON: Moosejaw mucky peat in wetlands (colors are for moist soil unless otherwise noted).
Oe--0 to 5 inches; dark brown (10YR 3/3) mucky peat, brown (10YR 4/3) dry; moderately decomposed herbaceous material and trapped sediment; soft, very friable, non-sticky and non-plastic; many very fine and fine and common medium roots; moderately acid (pH 5.8); clear, smooth boundary. (2 to 6 inches thick)
Ag--5 to 24 inches; black (N 2.5/ ) silt loam, very dark gray (10YR 3/1) dry; moderate, medium and coarse granular structure; slightly hard, friable, moderately sticky and slightly plastic; many very fine and fine, common medium, and few coarse roots; few very fine and fine tubular pores; 2 percent subrounded gravel; slightly acid (pH 6.3); clear, smooth boundary. (16 to 30 inches thick)
Cg--24 to 43 inches; black (5Y 2.5/1) stratified loam, silt loam and sandy loam, olive gray (5Y 5/2) dry; weak coarse subangular blocky structure; soft, very friable; slightly sticky and slightly plastic; common fine and very fine and few medium and coarse roots; 2 percent subrounded gravel; neutral (pH 6.6); abrupt smooth boundary. (14 to 42 inches thick)
2C--43 to 72 inches; olive (5Y 4/4) gravelly loamy coarse sand, light yellowish brown (2.5Y 6/4) dry; single grain; loose, non-sticky and non-plastic; few very fine roots; abundant interstitial pores; 30 percent subangular fine gravel; few medium distinct dark gray (5Y 4/1) redoximorphic depletions; neutral (pH 7.2).
TYPE LOCATION: Silver Bow County, Montana; 100 feet north and 1,600 feet west of the SE corner of sec. 15, T. 2 N., R. 8 W. Butte South topographic quadrangle, UTM zone 12T, 0377816E, 5085816N, NAD 27.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 36 to 42 degrees F., cryic temperature regime.
Soil moisture control section - 8 to 24 inches; wet in all or most parts throughout the year due to shallow groundwater. Aquic soil moisture regime.
Thickness of organic surface - 2 to 6 inches
Mollic epipedon thickness - 20 to 54 inches
Depth to persistent high water table - 0 to 16 inches
Depth to sand and gravel substratum - 36 to 72 inches
Weighted average of clay in the particle size control section - 8 to 18 percent
Weighted average of rock fragments in the particle size control section less than 35 percent
Oe Horizon - Value: 2 or 3 moist; 3 or 4 dry
Chroma: 2 or 3
Organic carbon: 15 to 30 percent
Reaction: pH 5.2 to 6.8
A or Ag Horizon - Hue: 10YR or N
Value: 2 or 3 moist; 3 or 4 dry
Chroma: 0, 1, or 2
Texture: loam, silt loam, or sandy loam
Clay content: 0 to 24 percent
Rock fragments: 0 to 35 percent--0 to 20 percent cobbles, stones and boulders, 0 to 20 percent, mainly fine, gravel
Reaction: pH 5.8 to 7.2
Cg Horizon - Hue: 10YR, 2.5Y, 5Y, or N
Value: 2 or 3 moist; 4, 5, or 6 dry
Chroma: 0, 1, or 2
Texture: stratified loam, sandy loam, silt loam, or coarse sandy loam
Clay content: 10 to 22 percent
Rock fragments: 0 to 35 percent--0 to 20 percent cobbles, stones and boulders, 0 to 20 percent, mainly fine, gravel
Reaction: pH 6.0 to 7.2
2C Horizon - Hue: 2.5Y, 10YR, or 5Y
Value: 3, 4 or 5 moist; 4, 5, or 6 dry
Chroma: 1, 2, 3, or 4
Texture: coarse sand, sand, or loamy coarse sand
Clay content: 0 to 8 percent
Rock fragments: 25 to 70 percent0 to 20 percent cobbles, stones and boulders, 25 to 50 percent mainly fine, gravel
Reaction: pH 6.6 to 7.8
COMPETING SERIES: These are the Dobrow and Hopeval series. Dobrow soils contain rock fragments that are mainly to 10 inches in diameter with limited amounts of fine pea gravel and receive 10 inches of precipitation. Hopeval soils have a xeric soil moisture regime.
GEOGRAPHIC SETTING:
Landform- floodplains and drainageways in foothills and mountains
Elevation - 5,360 to 7,860 feet
Slope - 0 to 15 percent
Parent material - moderately coarse alluvium from mixed sources over coarse grained alluvium from granite or other coarse grained, igneous or metamorphic rocks
Climate - long cold winters; moist cool springs; short, cool summers
Mean annual precipitation - 15 to 24 inches
Mean annual air temperature - 34 to 40 degrees F.
Frost-free period - 30 to 70 days
GEOGRAPHICALLY ASSOCIATED SOILS:
These are the Shewag, Mooseflat, and Pappascreek series. Shewag soils are shallow to coarse sand and gravel and generally occur adjacent to creeks, on old gravel bars. Mooseflat soils are 14 to 26 inches to coarse sand and gravel substrates and occur on similar landform positions as the Moosejaw series. Pappascreek soils are somewhat poorly drained and occur on slightly higher positions on floodplains, low terraces and along mountain drainages.
DRAINAGE AND PERMEABILITY: Very poorly drained; moderately rapid over rapid permeability.
USE AND VEGETATION: Moosejaw soils are primarily used for wetlands and wildlife habitat. The native vegetation is mainly water sedge, Northwest Territory sedge, Drummond willow or geyer and Booths willow, bluejoint reedgrass, horsetails, and mountain alder.
DISTRIBUTION AND EXTENT: Moosejaw soils are of limited extent in foothills and mountains of southwestern Montana. MLRA 43.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Silver Bow County, Montana, 2006.
REMARKS: Diagnostic horizons and features recognized in this pedon are: a surface layer of moderately decomposed plant material from 0 to 5 inches (Oe horizon); a mollic epipedon from 5 to 43 inches (Ag, Bg horizons); coarse sand and gravel substrates below 43 inches (2C horizon); a particle-size control section from 15 to 45 inches (Ag, Cg, and 2C horizons). Moosejaw soils have a cryic temperature regime and an aquic moisture regime. Gravels throughout the profile are primarily fine pea gravel less than 7 mm in diameter.