LOCATION BOWDOIN MTEstablished Series
TAXONOMIC CLASS: Very-fine, smectitic, frigid Sodic Haplusterts
TYPICAL PEDON: Bowdoin clay, in native hayland (colors are for dry soil unless otherwise noted).
Ap--0 to 6 inches; gray (5Y 5/1) clay, olive gray (5Y 4/2) moist; weak fine subangular blocky structure; extremely hard, firm, very sticky and very plastic; common fine roots; many very fine pores; slightly effervescent; moderately alkaline (pH 7.9); abrupt wavy boundary. (2 to 7 inches thick)
Bnss--6 to 34 inches; gray (5Y 5/1) clay, olive gray (5Y 4/2) moist; massive; extremely hard, very firm, very sticky and very plastic; few fine roots; few very fine pores; cracks 1/2- to 1-inch wide that extend to 20 inches; few intersecting slickensides; few fine threads of gypsum in lower part; slightly effervescent; moderately alkaline (pH 7.9); clear wavy boundary. (20 to 50 inches thick)
Bny--34 to 60 inches; grayish brown (2.5Y 5/2) clay, dark grayish brown (2.5Y 4/2) moist; massive; extremely hard, very firm, very sticky and very plastic; few to common fine threads and medium masses of gypsum; slightly effervescent; moderately alkaline (pH 8.1).
TYPE LOCATION: Blaine County, Montana; 900 feet west and 500 feet south of NE corner of sec. 36, T. 31 N., R. 25 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 40 to 47 degrees.
Moisture control section - between 4 and 12 inches.
Soil Moisture Regime - Ustic moisture regime that borders on Aridic (Aridic-Ustic).
A horizon - Hue: 2.5Y or 5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 1 or 2
Clay content: 50 to 70 percent
Electrical conductivity: 8 to 16 mmhos/cm
Sodium adsorption ratio: 5 to 13
Reaction: pH 7.4 to 9.0
Bnss horizon - Hue: 2.5Y or 5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 1 or 2
Clay content: 60 to 80 percent
Electrical conductivity: 8 to 16 mmhos/cm
Sodium adsorption ratio: 13 to 30
Reaction: pH 7.4 to 9.0
Bny horizon - Hue: 2.5Y or 5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 1 or 2
Clay content: 50 to 70 percent
Electrical conductivity: 8 to 16 mmhos/cm
Sodium adsorption ratio: 13 to 30
Reaction: pH 7.9 to 9.0
Some pedons have stratified silt loam, silty clay loam, and clay below 40 inches.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform - flood plains.
Elevation - 1,800 to 3,000 feet.
Slope- 0 to 2 percent.
Parent material - alluvium; glaciolacustrine deposits.
Climate - long, cold winters; warm summers.
Mean annual precipitation - 10 to 14 inches.
Mean annual temperature - 38 to 45 degrees F.
Frost-free period - 100 to 135 days.
DRAINAGE AND PERMEABILITY: Well drained; very slow permeability.
USE AND VEGETATION: Bowdoin soils are used mainly for native haylands of western wheatgrass; only a few small areas are used for irrigated cropland. Potential native vegetation is mainly western wheatgrass, alkaligrass, squirreltail, greasewood, and big sagebrush.
DISTRIBUTION AND EXTENT: Bowdoin soils are extensive mainly in the Milk River and Missouri River valleys and their tributaries in northern Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Milk River Area, Montana, 1928.
REMARKS: Soil interpretations records: MT0005, MT0677. Diagnostic features recognized in this pedon are: open cracks and intersecting slickensides (Bnss horizon); a sodium adsorption ratio greater than 13 (Bnss, Bny horizons); an accumulation of gypsum (Bny horizon); and a particle-size control section from 10 to 40 inches (Bnss, Bny horizons). Bowdoin soils have a frigid temperature regime and an ustic moisture regime bordering on aridic.
ADDITIONAL DATA: Lincoln Laboratory S67MONT-3-3, S67MONT-5-3 and reference samples S73MONT-3-3-1 and S73MONT-3-4-1.