Soil Survey of Sweet Grass County Area, Montana - Soil Data Mart

Sweet Grass County Area, Montana—Part I 103
Texture (less than 2 mm): Sandy loam or loam
Clay content: 12 to 20 percent
Content of rock fragments: 35 to 80 percent—0 to
10 percent stones and cobbles; 35 to
70 percent gravel
Reaction: pH 5.6 to 6.5
Millerlake Series
Depth class: Very deep (greater than 60 inches)
Drainage class: Well drained
Permeability: Moderate (0.6 to 2.0 inches/hour)
Landform: Fan, mountain, terrace, and fan on
mountain
Parent material: Loamy alluvium or colluvium
Slope range: 4 to 35 percent
Elevation range: 5,500 to 7,500 feet
Mean annual precipitation: 20 to 25 inches
Mean annual air temperature: 36 to 38 degrees F
Frost-free period: 50 to 70 days
Taxonomic Class: Fine-loamy, mixed, superactive
Pachic Argicryolls
Typical Pedon
Millerlake loam, in an area of Millerlake-Arrowpeak-
Adel complex, 8 to 35 percent slopes, in an area of
rangeland, 1,300 feet south and 1,400 feet west of
the northeast corner of sec. 21, T. 2 N., R. 12 E.;
USGS Raspberry Butte topographic quadrangle
(lat. 45 o 54'40" N.; long. 110 o 14'08" W.)
A—0 to 7 inches; brown (10YR 5/3) loam, dark brown
(10YR 3/3) moist; weak fine subangular blocky
structure parting to moderate fine granular; soft,
very friable, slightly sticky, slightly plastic; few
medium, common fine, and many very fine roots;
many very fine and fine pores; 5 percent gravel;
neutral (pH 7.0); clear smooth boundary.
Bt1—7 to 16 inches; brown (10YR 5/3) clay loam,
dark grayish brown (10YR 4/2) moist; moderate
medium subangular blocky structure; slightly
hard, friable, moderately sticky, moderately
plastic; common very fine and fine roots; common
very fine and fine pores; common faint
discontinuous dark brown (10YR 3/3) moist; clay
films on faces of peds; 5 percent gravel; neutral
(pH 7.2); clear wavy boundary.
Bt2—16 to 24 inches; light yellowish brown (2.5Y 6/4)
clay loam, grayish brown (2.5Y 5/2) moist;
moderate fine subangular blocky structure;
slightly hard, friable, moderately sticky,
moderately plastic; common very fine and fine
roots; common very fine and fine pores; few
distinct discontinuous dark brown (10YR 3/3)
moist; clay films on faces of peds; 5 percent
gravel; neutral (pH 7.2); clear smooth boundary.
Bk—24 to 60 inches; light brownish gray (10YR 6/2)
gravelly clay loam, grayish brown (10YR 5/2)
moist; weak coarse prismatic structure; slightly
hard, friable, moderately sticky, moderately
plastic; few very fine roots; common very fine
and fine pores; common fine threads and soft
masses of lime; 10 percent gravel; 5 percent
cobbles; strongly effervescent; moderately
alkaline (pH 8.2).
Range in Characteristics
Soil temperature: 36 to 42 degrees F
Moisture control section: Between 4 and 12 inches
Thickness of the mollic epipedon: 16 to 20 inches
Depth to the Bk horizon: 20 to 39 inches
A horizon
Hue: 7.5YR or 10YR
Value: 3 to 5 dry; 2 or 3 moist
Chroma: 1 to 3
Texture (less than 2 mm): Loam
Clay content: 20 to 27 percent
Content of rock fragments: 0 to 30 percent—0 to
5 percent cobbles; 0 to 25 percent gravel
Reaction: pH 6.1 to 7.3
Bt horizons
Hue: 7.5YR, 10YR, or 2.5Y
Value: 5 or 6 dry; 3 to 5 moist
Chroma: 2 to 4
Texture (less than 2 mm): Clay loam or loam
Clay content: 25 to 35 percent
Content of rock fragments: 0 to 35 percent—0 to
10 percent cobbles; 0 to 25 percent gravel
Reaction: pH 6.1 to 8.4
Bk horizon
Hue: 10YR or 2.5Y
Value: 6 or 7 dry; 5 or 6 moist
Chroma: 2 to 4
Texture (less than 2 mm): Clay loam or loam
Clay content: 20 to 30 percent
Content of rock fragments: 10 to 35 percent—0 to
15 percent cobbles; 10 to 20 percent gravel
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.9 to 9.0
Monaberg Taxadjunct
Depth class: Very deep (greater than 60 inches)
Drainage class: Well drained
Permeability: Moderate (0.6 to 2.0 inches/hour)