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

Sweet Grass County Area, Montana—Part I 69
plastic; common very fine and fine roots; common
very fine and fine pores; few patchy carbonate
coats on undersides of rock fragments; few fine
soft masses of lime; 15 percent gravel; strongly
effervescent; slightly alkaline (pH 7.8); clear
smooth boundary.
Cr—16 to 60 inches; calcareous soft sandstone;
strongly effervescent; slightly alkaline (pH 7.8).
Range in Characteristics
Soil temperature: 39 to 46 degrees F
Moisture control section: Between 4 and 12 inches
Thickness of the mollic epipedon: 7 to 12 inches
Depth to the Cr horizon: 10 to 20 inches
A horizons
Hue: 10YR or 2.5Y
Value: 3 to 5 dry; 2 or 3 moist
Chroma: 1 or 2
Texture (less than 2 mm): Loam
Clay content: 18 to 27 percent
Content of rock fragments: 0 to 35 percent—0 to
5 percent cobbles; 0 to 30 percent gravel
Reaction: pH 6.6 to 7.8
Bk horizon
Hue: 10YR, 2.5Y, or 5Y
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 1 to 3
Texture (less than 2 mm): Loam, clay loam, or
silty clay loam
Clay content: 18 to 35 percent
Content of rock fragments: 0 to 35 percent—0 to
5 percent cobbles; 0 to 30 percent gravel
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.4 to 8.4
Foolhen Series
Depth class: Very deep (greater than 60 inches)
Drainage class: Very poorly drained
Permeability: Moderate (0.6 to 2.0 inches/hour)
Landform: Depression on flood plain
Parent material: Alluvium
Slope range: 0 to 2 percent
Elevation range: 6,000 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
Typic Cryaquolls
Typical Pedon
Foolhen mucky loam in an area of Foolhen, stony-
Tibkey, bouldery complex, 0 to 8 percent slopes, in an
area of wet meadow, 2,225 feet south and 1,100 feet
west of the northeast corner of sec. 6, T. 3 N., R. 3 W.;
Jefferson County, Montana.
Oe—0 to 1 inch; mat of partially decomposed organic
matter and roots.
A1—1 to 5 inches; black (5Y 2.5/2) mucky loam,
black (10YR 2/1) moist; weak fine granular
structure; soft, very friable, slightly sticky,
nonplastic; common medium and many very
fine and fine roots; 4 percent rounded cobbles;
10 percent rounded gravel; neutral (pH 6.8); clear
wavy boundary.
A2—5 to 14 inches; black (5Y 2.5/2) mucky silt loam,
black (10YR 2/1) moist; few distinct reddish
brown (5YR 5/4) redox concentrations; moderate
medium prismatic structure parting to moderate
fine subangular blocky; hard, very friable, slightly
sticky, nonplastic; many very fine and fine roots;
many very fine pores; 5 percent rounded cobbles;
20 percent rounded gravel; neutral (pH 6.8);
gradual wavy boundary.
Bw—14 to 22 inches; pale brown (10YR 6/3) gravelly
sandy clay loam, dark brown (10YR 3/3) moist;
many distinct yellowish red (5YR 5/6) redox
concentrations; common faint very dark gray
(5Y 3/1) redox depletions; moderate medium
subangular blocky structure; hard, friable,
moderately sticky, slightly plastic; many very fine
and fine roots; few very fine pores; 5 percent
rounded cobbles; 20 percent rounded gravel;
neutral (pH 7.0); gradual wavy boundary.
Cg1—22 to 33 inches; brown (10YR 5/3) gravelly
sandy clay loam, brown (10YR 4/3) moist; many
distinct yellowish red (5YR 5/6) redox
concentrations; common faint very dark gray
(5Y 3/1) redox depletions; weak medium
subangular blocky structure; hard, friable,
moderately sticky, slightly plastic; many very
fine and fine roots; few very fine pores; 5 percent
rounded cobbles; 20 percent rounded gravel;
neutral (pH 7.2); gradual wavy boundary.
Cg2—33 to 45 inches; yellowish brown (10YR 5/4)
cobbly sandy clay loam, brown (10YR 4/3) moist;
many distinct yellowish red (5YR 5/6) redox
concentrations; few faint very dark gray (5Y 3/1)
redox depletions; weak coarse subangular blocky
structure; slightly hard, friable, moderately sticky,