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

66 Soil Survey
Bk3 horizon
Hue: 7.5YR, 10YR, or 2.5Y
Value: 6 to 8 dry; 5 to 7 moist
Chroma: 2 to 4
Texture (less than 2 mm): Very fine sandy loam,
loam, clay loam, or silty clay loam
Clay content: 18 to 35 percent
Content of rock fragments: 0 to 35 percent—0 to
15 percent cobbles; 0 to 20 percent gravel
Calcium carbonate equivalent: 10 to 30 percent
Reaction: pH 7.9 to 9.0
Fairway Series
Depth class: Very deep (greater than 60 inches)
Drainage class: Somewhat poorly drained
Permeability: Moderate (0.6 to 2.0 inches/hour)
Landform: Flood plain, flood-plain step, and stream
terrace
Parent material: Loamy alluvium
Slope range: 0 to 4 percent
Elevation range: 3,750 to 6,200 feet
Mean annual precipitation: 10 to 20 inches
Mean annual air temperature: 39 to 46 degrees F
Frost-free period: 70 to 130 days
Taxonomic Class: Fine-loamy, mixed, superactive,
frigid Fluvaquentic Haplustolls
Typical Pedon
Fairway loam, in an area of Fairway loam, 0 to
2 percent slopes, in an area of hayland, 1,800 feet
south and 2,150 feet east of the northwest corner
of sec. 34, T. 1 N., R. 12 E.; USGS Kelly Hills
topographic quadrangle (lat. 45 o 47'41" N.; long.
110 o 13'12" W.)
Ap—0 to 5 inches; grayish brown (2.5Y 5/2) loam,
very dark grayish brown (2.5Y 3/2) moist; weak
medium granular structure; slightly hard, friable,
slightly sticky, slightly plastic; few medium and
common very fine and fine roots; common very
fine and fine pores; slightly effervescent; slightly
alkaline (pH 7.6); clear smooth boundary.
A2—5 to 10 inches; grayish brown (2.5Y 5/2) loam,
very dark grayish brown (2.5Y 3/2) moist;
moderate medium subangular blocky structure;
slightly hard, friable, slightly sticky, slightly plastic;
few fine, medium, and coarse and common very
fine roots; common very fine and fine pores;
slightly effervescent; moderately alkaline (pH
8.0); gradual smooth boundary.
Bk1—10 to 18 inches; light brownish gray (2.5Y 6/2)
clay loam, dark grayish brown (2.5Y 4/2) moist;
moderate medium prismatic structure parting to
moderate medium angular blocky; moderately
hard, friable, moderately sticky, moderately
plastic; few medium and coarse and common
very fine and fine roots; common fine soft masses
of lime; strongly effervescent; moderately alkaline
(pH 8.4); clear wavy boundary.
Bk2—18 to 25 inches; light brownish gray (2.5Y 6/2)
clay loam, dark grayish brown (2.5Y 4/2) moist;
few fine faint olive brown (2.5Y 4/4) moist, redox
concentrations; weak coarse subangular blocky
structure; moderately hard, friable, moderately
sticky, moderately plastic; few fine and common
very fine roots; common very fine and fine pores;
common fine soft masses of lime; strongly
effervescent; moderately alkaline (pH 8.4); clear
wavy boundary.
Bg—25 to 44 inches; light brownish gray (2.5Y 6/2)
loam, dark grayish brown (2.5Y 4/2) moist;
common medium prominent strong brown (7.5YR
4/6) moist, redox concentrations; massive; slightly
hard, very friable, slightly sticky, slightly plastic;
few very fine and fine roots; few thin strata of
coarser textured material; strongly effervescent;
moderately alkaline (pH 8.0); clear smooth
boundary.
2Cg—44 to 60 inches; gray (10YR 6/1) sandy loam,
dark gray (10YR 4/1) moist; common medium
prominent strong brown (7.5YR 4/6) moist, redox
concentrations; few fine faint dark greenish gray
(5BG 4/1) moist, redox depletions; massive; soft,
very friable, slightly sticky, nonplastic; thin strata
of gravelly loamy sand and very fine sandy
loam; few very fine and fine roots; 5 percent
gravel; slightly effervescent; moderately alkaline
(pH 8.0).
Range in Characteristics
Soil temperature: 42 to 47 degrees F
Moisture control section: Between 4 and 12 inches
Thickness of the mollic epipedon: 10 to 15 inches
Depth to the seasonal high water table: 24 to
42 inches
Depth to the 2Cg horizon: Greater than 40 inches
A or Ap horizon
Hue: 10YR or 2.5Y
Value: 4 or 5 dry; 2 or 3 moist
Chroma: 1 or 2
Texture (less than 2 mm): Loam
Clay content: 15 to 35 percent
Content of rock fragments: 0 to 15 percent gravel
Calcium carbonate equivalent: 2 to 5 percent
Reaction: pH 6.6 to 7.8