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

28 Soil Survey
very friable, slightly sticky, slightly plastic; many
very fine and fine roots; many very fine and fine
pores; neutral (pH 7.0); clear smooth boundary.
A2—4 to 7 inches; grayish brown (10YR 5/2) loam,
dark brown (10YR 3/3) moist; weak fine
subangular blocky structure parting to weak very
fine granular; soft, very friable, slightly sticky,
slightly plastic; few medium and common very
fine and fine roots; many very fine and fine pores;
neutral (pH 7.2); clear smooth boundary.
Bw—7 to 12 inches; brown (10YR 5/3) loam, dark
brown (10YR 3/3) moist; moderate fine and
medium subangular blocky structure; slightly
hard, friable, slightly sticky, slightly plastic; few
very fine and fine roots; common very fine
pores; very slightly effervescent; slightly alkaline
(pH 7.4); abrupt smooth boundary.
Bk1—12 to 22 inches; light brownish gray (10YR 6/2)
loam, dark grayish brown (10YR 4/2) moist; weak
fine and medium subangular blocky structure;
moderately hard, friable, slightly sticky, slightly
plastic; few very fine roots; common very fine
pores; common fine soft masses of lime; strongly
effervescent; slightly alkaline (pH 7.8); clear
smooth boundary.
Bk2—22 to 30 inches; light brownish gray (2.5Y 6/2)
loam, grayish brown (2.5Y 5/2) moist; weak fine
and medium subangular blocky structure;
moderately hard, friable, slightly sticky, slightly
plastic; few very fine roots; common very fine
pores; common fine and medium soft masses of
lime; 5 percent channers; violently effervescent;
moderately alkaline (pH 8.2); clear smooth
boundary.
BCk—30 to 34 inches; light gray (2.5Y 7/2) loam,
grayish brown (2.5Y 5/2) moist; weak fine and
medium subangular blocky structure; moderately
hard, friable, slightly sticky, slightly plastic; few
very fine roots; common very fine pores; common
fine and medium soft masses of lime; 5 percent
soft siltstone chips; 10 percent channers; violently
effervescent; moderately alkaline (pH 8.2); abrupt
smooth boundary.
Cr—34 to 60 inches; soft interbedded sandstone and
siltstone bedrock; few very fine roots in cracks;
strongly effervescent.
Range in Characteristics
Soil temperature: 42 to 47 degrees F
Moisture control section: Between 4 and 12 inches
Thickness of the mollic epipedon: 7 to 15 inches
Depth to the Bk horizon: 10 to 20 inches
Depth to the Cr horizon: 20 to 40 inches
A horizons
Hue: 10YR
Value: 3 to 5 dry; 2 or 3 moist
Chroma: 2 or 3
Texture (less than 2 mm): Loam
Clay content: 15 to 27 percent
Content of rock fragments: 0 to 15 percent gravel
or channers
Reaction: pH 6.6 to 7.3
Bw horizon
Hue: 10YR or 2.5Y
Value: 4 to 7 dry; 3 to 6 moist
Chroma: 2 to 4
Texture (less than 2 mm): Loam, clay loam, sandy
clay loam, or fine sandy loam
Clay content: 18 to 35 percent
Content of rock fragments: 0 to 15 percent gravel
or channers
Reaction: pH 6.6 to 8.4
Bk horizons
Hue: 10YR or 2.5Y
Value: 5 to 8 dry; 4 to 6 moist
Chroma: 2 to 4
Texture (less than 2 mm): Loam, clay loam, fine
sandy loam, or silt loam
Clay content: 18 to 35 percent
Content of rock fragments: 0 to 15 percent gravel
or channers
Calcium carbonate equivalent: 5 to 10 percent
Reaction: pH 7.4 to 8.4
BCk horizon
Hue: 10YR or 2.5Y
Value: 5 to 8 dry; 4 to 6 moist
Chroma: 2 to 4
Texture (less than 2 mm): Loam, clay loam, fine
sandy loam, or silt loam
Clay content: 18 to 35 percent
Content of rock fragments: 5 to 35 percent gravel
or channers
Calcium carbonate equivalent: 5 to 10 percent
Reaction: pH 7.4 to 8.4
Arrowpeak Series
Depth class: Shallow (10 to 20 inches)
Drainage class: Well drained
Permeability: Moderately rapid (2 to 6 inches/hour)
Landform: Mountain
Parent material: Residuum weathered from
sandstone or gabbro
Slope range: 2 to 60 percent