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

Sweet Grass County Area, Montana—Part I 133
Bg horizon
Hue: 2.5Y or 5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 1 or 2
Redox concentrations: Few to many; chroma of 6
or 8
Redox depletions: None to common; chroma of 0
or 1
Texture (less than 2 mm): Clay loam, silty clay, or
clay
Clay content: 25 to 45 percent
Content of rock fragments: 0 to 15 percent gravel
Calcium carbonate equivalent: 1 to 15 percent
Electrical conductivity: 0 to 4 mmhos/cm
Reaction: pH 7.4 to 8.4
2Cg horizon:
Hue: 2.5Y or 5Y
Value: 5 to 7 dry; 4 or 5 moist
Chroma: 1 or 2
Redox concentrations: Few to many; chroma of 6
or 8
Redox depletions: None to common; chroma of 0
or 1
Texture (less than 2 mm): Sandy clay loam, clay
loam, or clay
Clay content: 25 to 45 percent
Content of rock fragments: 15 to 60 percent—0 to
10 percent cobbles; 15 to 50 percent gravel
Calcium carbonate equivalent: 1 to 15 percent
Electrical conductivity: 0 to 4 mmhos/cm
Reaction: pH 7.4 to 8.4
Stemple Series
Depth class: Very deep (greater than 60 inches)
Drainage class: Well drained
Permeability: Moderate (0.6 to 2.0 inches/hour)
Landform: Mountain
Parent material: Gravelly colluvium or gravelly till
Slope range: 25 to 70 percent
Elevation range: 5,500 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: Loamy-skeletal, mixed,
superactive Typic Palecryalfs
Typical Pedon
Stemple very cobbly loam, in an area of Stemple-
Worock complex, 35 to 70 percent slopes, very stony,
in an area of coniferous forest, 700 feet north and
2,000 feet east of the southwest corner of sec. 19,
T. 3 S., R. 13 E.; USGS McLeod Basin topographic
quadrangle (lat. 45 o 33'18" N.; long. 110 o 10'07" W.)
Oi—0 to 2 inches; partially decayed needles and
twigs.
E1—2 to 8 inches; brown (10YR 5/3) very cobbly
loam, brown (10YR 4/3) moist; weak medium
platy structure parting to weak fine and medium
granular; soft, very friable, nonsticky, nonplastic;
common medium and many very fine and
fine roots; common very fine and fine pores;
15 percent gravel; 15 percent cobbles; 5 percent
stones; moderately acid (pH 6.0); clear wavy
boundary.
E2—8 to 28 inches; light gray (10YR 7/2) very cobbly
loam, light brownish gray (10YR 6/2) moist; weak
fine and medium granular structure; soft, very
friable, nonsticky, nonplastic; common very fine to
medium roots; many very fine and fine pores;
20 percent gravel; 25 percent cobbles; 5 percent
stones; slightly acid (pH 6.4); clear wavy
boundary.
E/Bt—28 to 37 inches; E part (70 percent) light gray
(10YR 7/2) very cobbly loam, light brownish gray
(10YR 6/2) moist tongues; Bt part (30 percent)
yellowish brown (10YR 5/6) very cobbly sandy
clay loam, dark yellowish brown (10YR 4/6)
moist; weak fine and medium prismatic structure
parting to moderate medium subangular blocky;
slightly hard, friable, slightly sticky, slightly plastic;
few very fine roots; common very fine and fine
pores; 20 percent gravel; 25 percent cobbles;
5 percent stones; neutral (pH 6.6); gradual
smooth boundary.
Bt—37 to 62 inches; yellowish brown (10YR 5/6) very
cobbly sandy clay loam, dark yellowish brown
(10YR 4/6) moist; moderate medium and coarse
subangular blocky structure; very hard, firm,
moderately sticky, moderately plastic; few very
fine roots; common very fine pores; common
distinct discontinuous brown (7.5YR 4/4) moist;
clay films on faces of peds and rock fragments;
20 percent gravel; 20 percent cobbles; 5 percent
stones; neutral (pH 6.6).
Range in Characteristics
Soil temperature: 36 to 42 degrees F
Moisture control section: Between 4 and 12 inches
Depth to the Bt horizon: 25 to 50 inches
E1 horizon
Hue: 7.5YR, 10YR, or 2.5Y
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 2 or 3
Texture (less than 2 mm): Loam or sandy loam