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

56 Soil Survey
Bt horizons
Hue: 2.5YR, 5YR, 7.5YR, 10YR, or 2.5Y
Value: 5 to 7 dry; 4 or 5 moist
Chroma: 3, 4, or 6
Texture (less than 2 mm): Clay loam or clay
Clay content: 35 to 50 percent
Content of rock fragments: 0 to 35 percent—0 to
15 percent stones and cobbles; 0 to 25 percent
gravel
Reaction: pH 5.6 to 7.3
Danvers Series
Depth class: Very deep (greater than 60 inches)
Drainage class: Well drained
Permeability: Slow (0.06 to 0.20 inch/hour)
Landform: Fan and terrace
Parent material: Loamy alluvium
Slope range: 0 to 8 percent
Elevation range: 4,200 to 6,200 feet
Mean annual precipitation: 15 to 20 inches
Mean annual air temperature: 39 to 45 degrees F
Frost-free period: 70 to 115 days
Taxonomic Class: Fine, smectitic, frigid Vertic
Argiustolls
Typical Pedon
Danvers gravelly clay loam, in an area of Danvers
gravelly clay loam, 2 to 8 percent slopes, in an area
of hayland, 2,100 feet south and 450 feet west of the
northeast corner of sec. 26, T. 4 N., R. 14 E.; USGS
Melville topographic quadrangle (lat. 46 o 04'09" N.;
long. 109 o 56'13" W.)
Ap—0 to 7 inches; dark grayish brown (10YR 4/2)
gravelly clay loam, very dark grayish brown
(10YR 3/2) moist; strong fine granular structure;
moderately hard, friable, slightly sticky, slightly
plastic; few fine and many very fine roots;
common very fine pores; 15 percent gravel;
5 percent cobbles; neutral (pH 7.2); abrupt
smooth boundary.
Bt—7 to 16 inches; brown (10YR 5/3) clay, brown
(10YR 4/3) moist; moderate medium prismatic
structure parting to strong fine subangular blocky;
very hard, friable, moderately sticky, moderately
plastic; few fine and common very fine roots; few
fine and common very fine pores; many
discontinuous distinct dark brown (7.5YR 3/4)
moist; clay films on faces of peds and lining
pores; 10 percent gravel; slightly alkaline
(pH 7.6); clear smooth boundary.
Btk—16 to 22 inches; light brownish gray (10YR 6/2)
clay loam, dark grayish brown (2.5Y 4/2) moist;
moderate medium prismatic structure; moderately
hard, friable, moderately sticky, moderately
plastic; common very fine roots; few fine pores;
few patchy distinct dark brown (10YR 3/3) moist;
clay films on faces of peds; many fine soft
masses of lime; 10 percent gravel; strongly
effervescent; moderately alkaline (pH 8.4); clear
smooth boundary.
Bk1—22 to 31 inches; light brownish gray (10YR 6/2)
clay loam, grayish brown (10YR 5/2) moist; weak
coarse prismatic structure; moderately hard,
friable, moderately sticky, moderately plastic; few
very fine roots; few fine pores; many fine and
medium soft masses of lime; 10 percent gravel;
violently effervescent; strongly alkaline (pH 8.6);
gradual smooth boundary.
2Bk2—31 to 60 inches; light gray (10YR 7/2) gravelly
clay loam, grayish brown (2.5Y 5/2) moist; weak
coarse subangular blocky structure; moderately
hard, friable, slightly sticky, slightly plastic; few
very fine pores; carbonate coats on undersides
of rock fragments; many fine and medium soft
masses of lime; 20 percent gravel; violently
effervescent; strongly alkaline (pH 8.6).
Range in Characteristics
Soil temperature: 41 to 47 degrees F
Moisture control section: Between 4 and 12 inches
Thickness of the mollic epipedon: 7 to 12 inches
Depth to the calcic horizon: 14 to 25 inches
A horizon
Hue: 7.5YR or 10YR
Value: 4 or 5 dry; 2 or 3 moist
Chroma: 2 or 3
Texture (less than 2 mm): Clay loam or loam
Clay content: 18 to 35 percent
Content of rock fragments: 0 to 35 percent—0 to
15 percent stones and cobbles; 0 to 20 percent
gravel
Reaction: pH 6.1 to 7.8
Bt horizon
Hue: 7.5YR, 10YR, or 2.5Y
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 2 to 4
Texture (less than 2 mm): Clay loam, clay, silty
clay, or silty clay loam
Clay content: 35 to 50 percent
Content of rock fragments: 0 to 15 percent—0 to
5 percent stones and cobbles; 0 to 10 percent
gravel
Reaction: pH 6.6 to 8.4