LOCATION BREETON MT
Established Series
Rev. DES-JB-JAL
07/2012
BREETON SERIES
The Breeton series consists of very deep, well drained soils that formed in alluvium or colluvium derived from granite and other coarse grained igneous rocks. These soils are on alluvial fans, stream terraces and hills. Slopes are 1 to 50 percent. Mean annual precipitation is about 17 inches, and mean annual air temperature is about 40 degrees F.
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Pachic Haplustolls
TYPICAL PEDON: Breeton loam, in rangeland (colors are for dry soil unless otherwise noted).
A1--0 to 4 inches; very dark grayish brown (10YR 3/2) gravelly loam, black (10YR 2/1) moist; moderate medium granular structure; soft, very friable, slightly sticky and nonplastic; many very fine and fine roots; many very fine and fine interstitial pores; 15 percent gravel; neutral (pH 6.6); clear wavy boundary.
A2--4 to 12 inches; very dark gray (10YR 3/1) gravelly loam, black (10YR 2/1) moist; moderate coarse prismatic structure parting to moderate medium subangular blocky; soft, very friable, slightly sticky and nonplastic; many very fine and fine roots; many very fine and fine interstitial and tubular pores; 15 percent gravel; neutral (pH 7.0); gradual wavy boundary. (Combined thickness of A1 and A2 horizons is 10 to 24 inches)
Bw--12 to 26 inches; dark grayish brown (10YR 4/2) gravelly coarse sandy loam, dark brown (10YR 3/3) moist; moderate coarse prismatic structure parting to weak medium subangular blocky; slightly hard, very friable, nonsticky and nonplastic; many very fine and fine roots; many very fine and fine interstitial and tubular pores; 20 percent gravel; slightly alkaline (pH 7.4); gradual irregular boundary. (10 to 22 inches thick)
BC--26 to 60 inches; brown (10YR 5/3) gravelly coarse sandy loam, brown (10YR 5/3) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; 25 percent gravel; slightly alkaline (pH 7.6).
TYPE LOCATION: Jefferson County, Montana; 1,900 feet north and 2,500 feet east of the SW corner of sec. 28, T. 8 N., R. 4 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 38 to 45 degrees F.
Moisture control section - between 8 and 24 inches.
Mollic epipedon thickness - 16 to 40 inches.
Soil phases - bouldery, moist (for areas with Douglas fir or ponderosa pine canopy cover)
Rock fragments, surface cover: 0 to 0.1 percent boulders
A horizons
Hue: 10YR or 2.5Y
Value: 3 or 4 dry; 2 or 3 moist
Chroma: 1 or 2
Texture: loam, coarse sandy loam, or sandy loam
Clay content: 8 to 25 percent
Rock fragments: 0 to 15 percent gravel (mainly less than 7mm in diameter)
Reaction: pH 6.1 to 7.3
Bw horizon
Hue: 7.5YR, 10YR, or 2.5Y
Value: 4, 5, or 6 dry; 3, 4, or 5 moist
Chroma: 2 or 3
Texture: sandy loam, coarse sandy loam, or loam
Clay content: 8 to 18 percent, more than 35 percent fine sand and coarser
Rock fragments: 5 to 30 percent gravel (mainly less than 7mm in diameter)
Reaction: pH 6.1 to 7.8
BC horizon
Hue: 7.5YR, 10YR, or 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 or 3
Texture: sandy loam, coarse sandy loam, loamy coarse sand, or loamy fine sand
Clay content: 5 to 15 percent, more than 50 percent fine sand and coarser
Rock fragments: 10 to 30 percent gravel (mainly less than 10 mm in diameter)
Reaction: pH 6.1 to 7.8
COMPETING SERIES:
Breece (CO) - does not have a Bw horizon.
Chrishall (NM) - has a cambic horizon; does not have horizons of secondary carbonate accumulation; receives more than 20 inches of precipitation.
Coberly (CO) - has sandstone bedrock at depths of 20 to 40 inches.
Dotsero (CO) - has horizons of secondary carbonate accumulation; has a discontinuity of fine sandy loam below a depth of 40 inches.
Flathead (MT) - has horizons of secondary carbonate accumulation.
Hedoes (MT) - has horizons of secondary carbonate accumulation; has a discontinuity of loamy-skeletal material above a depth of 60 inches.
Klizhin (NM) - has an AB horizon; has buried argillic horizons below a depth of 40 inches.
Parshall (ND) - has horizons of secondary carbonate accumulation; has less than 10 percent rock fragments throughout.
Ruso (ND) - has sandy-skeletal materials above a depth of 40 inches.
Tuntsa (NM) - has 5 percent or less rock fragments throughout; base of mollic epipedon ranges to 50 inches; has BA horizons; has less than 35 percent fine sand and coarser.
GEOGRAPHIC SETTING:
Landform - alluvial fans; stream terraces; hills; mountains.
Elevation - 4,200 to 6,200 feet.
Slope - 1 to 50 percent.
Parent material - alluvium or colluvium derived from granite and other coarse grained igneous rocks.
Climate - long, cold winters; moist springs; warm summers.
Mean annual precipitation - 15 to 19 inches.
Mean annual air temperature - 36 to 43 degrees F.
Frost-free period - 70 to 115 days.
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; moderately rapid permeability.
USE AND VEGETATION: Breeton soils are primarily used for rangeland. The potential native vegetation is mainly Idaho fescue, rough fescue, Western wheatgrass, needleandthread, prairie junegrass, serviceberry, shrubby cinquefoil, big sagebrush, and Rocky Mountain juniper. Areas in woodland have an overstory of Douglas fir or ponderosa pine and an understory of Idaho fescue, rough fescue, and big sagebrush.
DISTRIBUTION AND EXTENT: Breeton soils are of small extent in southwestern Montana. MLRA 43B.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Gallatin County, Montana, 1997; proposed in Jefferson County, Montana, 1993.
REMARKS: Soil interpretation record: MT1546. Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - from the surface to 26 inches (A1, A2, and Bw horizons);
Particle-size control section - from 10 to 40 inches (A2, Bw, BC horizons).
Breeton soils have a frigid temperature regime and an ustic moisture regime.
National Cooperative Soil Survey
U.S.A.