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

54 Soil Survey
prismatic structure parting to moderate medium
and coarse angular blocky; very hard, firm, very
sticky, very plastic; common very fine and fine
roots; common very fine and fine pores; many
distinct discontinuous dark olive brown (2.5Y
3/3), moist; clay films on faces of peds and lining
pores; slightly alkaline (pH 7.4); abrupt smooth
boundary.
Btnk—14 to 22 inches; light brownish gray (2.5Y 6/2)
clay loam, grayish brown (2.5Y 5/2) moist;
moderate coarse prismatic structure parting to
weak coarse angular blocky; very hard, friable,
moderately sticky, moderately plastic; common
very fine and fine roots; common very fine and
fine pores; few distinct patchy olive brown (2.5Y
4/3) moist; clay films on faces of peds; few fine
soft masses of lime; strongly effervescent;
moderately alkaline (pH 8.0); gradual smooth
boundary.
Bky—22 to 32 inches; light brownish gray (2.5Y 6/2)
clay loam, grayish brown (2.5Y 5/2) moist; weak
coarse prismatic structure; very hard, friable,
moderately sticky, moderately plastic; few fine
and medium roots; few very fine and fine pores;
few fine and medium masses of gypsum;
common fine and medium soft masses of lime;
strongly effervescent moderately alkaline
(pH 8.4); gradual smooth boundary.
Byz—32 to 60 inches; light gray (2.5Y 7/2) clay loam,
light brownish gray (2.5Y 6/2) moist; weak coarse
prismatic structure; very hard, friable, moderately
sticky, moderately plastic; many medium and
coarse masses of gypsum; common medium
and coarse masses of salt; few fine soft masses
of lime; strongly effervescent; strongly alkaline
(pH 8.6).
Range in Characteristics
Soil temperature: 42 to 47 degrees F
Moisture control section: Between 4 and 12 inches
Depth to the Btnk horizon: 10 to 20 inches
Depth to the Bky horizon: 22 to 30 inches
A horizon
Hue: 10YR, 2.5Y, or 5Y
Value: 5 or 6 dry; 3 to 5 moist
Chroma: 2 or 3
Texture (less than 2 mm): Loam
Clay content: 20 to 27 percent
Content of rock fragments: 0 to 15 percent gravel
Reaction: pH 6.1 to 8.4
E horizon
Hue: 10YR, 2.5Y, or 5Y
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 2 or 3
Texture (less than 2 mm): Loam
Clay content: 20 to 27 percent
Content of rock fragments: 0 to 15 percent gravel
Reaction: pH 6.1 to 8.4
Btn horizons
Hue: 10YR, 2.5Y, or 5Y
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 2 or 3
Texture (less than 2 mm): Clay loam, clay, silty
clay, or silty clay loam
Clay content: 35 to 55 percent
Content of rock fragments: 0 to 15 percent gravel
Electrical conductivity: 2 to 4 mmhos/cm
Sodium adsorption ratio: 8 to 13
Reaction: pH 6.6 to 9.0
Btnk and Bky horizons
Hue: 10YR, 2.5Y, or 5Y
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 2 to 4
Texture (less than 2 mm): Clay loam, silty clay,
silty clay loam, loam, or clay
Clay content: 25 to 45 percent
Content of rock fragments: 0 to 15 percent gravel
Calcium carbonate equivalent: 5 to 15 percent
Electrical conductivity: 4 to 8 mmhos/cm
Sodium adsorption ratio: 13 to 20
Gypsum content: 0 to 2 percent
Reaction: pH 7.9 to 9.0
Byz horizon
Hue: 10YR, 2.5Y, or 5Y
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 2 to 4
Texture (less than 2 mm): Clay loam, silty clay
loam, sandy clay loam, or loam
Clay content: 25 to 35 percent
Content of rock fragments: 0 to 15 percent gravel
Calcium carbonate equivalent: 5 to 10 percent
Electrical conductivity: 4 to 16 mmhos/cm
Sodium adsorption ratio: 13 to 25
Gypsum content: 1 to 5 percent
Reaction: pH 7.9 to 9.0
Danaher Series
Depth class: Very deep (greater than 60 inches)
Drainage class: Well drained
Permeability: Slow (0.06 to 0.20 inches/hour)
Landform: Mountain
Parent material: Silty and clayey alluvium or colluvium
Slope range: 15 to 60 percent
Elevation range: 5,500 to 7,500 feet