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

Sweet Grass County Area, Montana—Part I 121
granular structure; soft, very friable, nonsticky,
nonplastic; common medium and coarse and
many very fine and fine roots; many very fine and
fine pores; 13 percent gravel; 7 percent cobbles;
3 percent stones; moderately acid (pH 6.0); clear
smooth boundary.
E—7 to 11 inches; grayish brown (2.5Y 5/2) cobbly
loam, dark grayish brown (2.5Y 4/2) moist;
moderate very fine and fine granular structure;
slightly hard, friable, slightly sticky, slightly plastic;
common medium and coarse and many very fine
and fine roots; many very fine and fine pores;
13 percent gravel; 13 percent cobbles;
moderately acid (pH 6.0); gradual smooth
boundary.
Bt1—11 to 26 inches; light yellowish brown (2.5Y 6/3)
very cobbly sandy clay loam, olive brown (2.5Y
4/3) moist; moderate fine and medium
subangular blocky structure; moderately hard,
friable, slightly sticky, slightly plastic; few very fine
to coarse roots; few distinct discontinuous dark
yellowish brown (10YR 3/4) moist; clay films on
rock fragments; 17 percent gravel; 13 percent
cobbles; 7 percent stones; slightly acid (pH 6.2);
gradual smooth boundary.
Bt2—26 to 35 inches; light yellowish brown (2.5Y 6/3)
very cobbly clay loam, olive brown (2.5Y 4/3)
moist; moderate fine and medium subangular
blocky structure; moderately hard, friable, slightly
sticky, slightly plastic; few very fine to coarse
roots; common distinct discontinuous dark
yellowish brown (10YR 3/4) moist; clay films on
faces of peds and rock fragments; 23 percent
gravel; 17 percent cobbles; 7 percent stones;
slightly acid (pH 6.4); gradual wavy boundary.
Bt3—35 to 41 inches; light yellowish brown (2.5Y 6/4)
very cobbly sandy clay loam, olive brown (2.5Y
4/3) moist; moderate fine and medium
subangular blocky structure; moderately hard,
friable, slightly sticky, slightly plastic; few medium
and coarse roots; few distinct discontinuous dark
yellowish brown (10YR 3/4) moist; clay films on
rock fragments; 23 percent gravel; 20 percent
cobbles; 4 percent stones; neutral (pH 6.6);
gradual wavy boundary.
BC—41 to 62 inches; light yellowish brown (2.5Y 6/4)
very gravelly sandy clay loam, light olive brown
(2.5Y 5/3) moist; massive; slightly hard, friable,
slightly sticky, slightly plastic; few medium roots;
33 percent gravel; 10 percent cobbles; 13 percent
stones; neutral (pH 6.6).
Range in Characteristics
Soil temperature: 36 to 40 degrees F
Moisture control section: Between 4 and 12 inches
A horizon
Hue: 10YR or 2.5Y
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 35 percent—
10 to 20 percent stones and cobbles; 5 to
15 percent gravel
Reaction: pH 5.6 to 7.3
E horizon
Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 1 or 2
Texture (less than 2 mm): Loam
Clay content: 18 to 27 percent
Content of rock fragments: 15 to 40 percent—
10 to 20 percent stones and cobbles; 5 to
20 percent gravel
Reaction: pH 5.6 to 7.3
Bt horizons
Hue: 10YR or 2.5Y
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 2 to 4
Texture (less than 2 mm): Sandy clay loam, clay
loam, or loam
Clay content: 25 to 35 percent
Content of rock fragments: 35 to 60 percent—
20 to 30 percent stones and cobbles; 15 to
30 percent gravel
Reaction: pH 6.1 to 7.8
BC horizon
Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 3 or 4
Texture (less than 2 mm): Sandy clay loam,
sandy loam, or loam
Clay content: 18 to 27 percent
Content of rock fragments: 35 to 70 percent—
20 to 35 percent stones and cobbles; 15 to
35 percent gravel
Reaction: pH 6.6 to 7.8
Roy Series
Depth class: Very deep (greater than 60 inches)
Drainage class: Well drained
Permeability: Moderately slow (0.2 to 0.6 inch/hour)
Landform: Escarpment, fan, landslide, stream terrace,
terrace
Parent material: Gravelly alluvium or gravelly
glaciofluvial deposits
Slope range: 0 to 60 percent