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

Sweet Grass County Area, Montana—Part I 141
Calcium carbonate equivalent: 1 to 5 percent
Electrical conductivity: 8 to 16 mmhos/cm
Sodium adsorption ratio: 0 to 20
Reaction: pH 7.4 to 9.0
Cyz horizon
Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 3 or 4
Texture (less than 2 mm): Clay loam, loam, or
silty clay loam with or without thin strata of fine
sandy loam, loam, clay loam, silty clay loam, or
silt loam
Clay content: 18 to 35 percent
Calcium carbonate equivalent: 1 to 5 percent
Electrical conductivity: 8 to 16 mmhos/cm
Sodium adsorption ratio: 0 to 30
Gypsum content: 2 to 5 percent
Reaction: pH 7.4 to 9.0
Tiban Series
Depth class: Very deep (greater than 60 inches)
Drainage class: Well drained
Permeability: Moderate (0.6 to 2.0 inches/hour)
Landform: Stream terrace
Parent material: Gravelly colluvium
Slope range: 0 to 8 percent
Elevation range: 6,000 to 7,500 feet
Mean annual precipitation: 20 to 25 inches
Mean annual air temperature: 36 to 43 degrees F
Frost-free period: 50 to 70 days
Taxonomic Class: Loamy-skeletal, mixed,
superactive Ustic Haplocryolls
Typical Pedon
Tiban gravelly loam, in an area of Bearmouth-Tiban-
Beehive complex, 0 to 8 percent slopes, in an area of
coniferous forest, 1,700 feet south and 900 feet west
of the northeast corner of sec. 25, T. 3 S., R. 13 E.;
USGS Squaw Peak topographic quadrangle (lat.
45 o 32'56" N.; long. 110 o 03'24" W.)
A—0 to 3 inches; dark grayish brown (10YR 4/2)
gravelly loam, black (10YR 2/1) moist; weak very
fine and fine granular structure; soft, very friable,
nonsticky, slightly plastic; common medium and
many very fine and fine roots; many very fine and
fine pores; 15 percent gravel; neutral (pH 7.2);
abrupt smooth boundary.
Bw—3 to 10 inches; grayish brown (10YR 5/2)
gravelly loam, very dark grayish brown (10YR 3/
2) moist; weak fine and medium subangular
blocky structure; soft, very friable, nonsticky,
slightly plastic; few medium and many very fine
and fine roots; many very fine and fine pores;
25 percent gravel; 5 percent cobbles; slightly
alkaline (pH 7.4); clear wavy boundary.
Bk—10 to 60 inches; light brownish gray (10YR 6/2)
very gravelly loam, dark grayish brown (10YR
4/2) moist; weak medium subangular blocky
structure; soft, very friable, slightly sticky, slightly
plastic; few very fine and fine roots; common very
fine and fine pores; 35 percent gravel; 10 percent
cobbles; carbonate coats on undersides of rock
fragments; many fine and medium soft masses of
lime; strongly effervescent; moderately alkaline
(pH 8.2).
Range in Characteristics
Soil temperature: 36 to 45 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 24 inches
Note: Some pedons have a C horizon.
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: 18 to 27 percent
Content of rock fragments: 15 to 70 percent—0 to
30 percent stones and cobbles; 15 to
40 percent gravel or channers
Reaction: pH 6.6 to 7.3
Bw horizon
Hue: 7.5YR or 10YR
Value: 4 to 6 dry; 3 or 4 moist
Chroma: 2 to 4
Texture (less than 2 mm): Loam or clay loam
Clay content: 18 to 35 percent
Content of rock fragments: 15 to 60 percent—0 to
20 percent stones and cobbles; 15 to
40 percent gravel or channers
Reaction: pH 7.4 to 8.4
Bk horizon
Hue: 7.5YR or 10YR
Value: 5 to 8 dry; 4 to 6 moist
Chroma: 2 to 4
Texture (less than 2 mm): Loam or clay loam
Clay content: 18 to 35 percent
Content of rock fragments: 35 to 80 percent—5 to
20 percent stones and cobbles; 30 to
60 percent gravel
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.4 to 8.4