LOCATION MELVILLE MTEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive Ustic Argicryolls
TYPICAL PEDON: Melville cobbly loam, in rangeland (colors are for dry soil unless otherwise noted).
A--0 to 2 inches; dark grayish brown (10YR 4/2 ) cobbly loam, very dark brown (10YR 2/2) moist; weak fine platy structure parting to moderate very fine crumbs; soft, very friable, slightly sticky and nonplastic; very few clean quartz grains; 10 percent pebbles, 15 percent cobbles; neutral; clear smooth boundary. (2 to 3 inches thick)
Bt1--2 to 5 inches; dark grayish brown (10YR 4/2) gravelly clay loam, very dark brown (10YR 2/2) moist; weak medium and fine subangular blocky structure parting to moderate fine crumbs; soft very friable, slightly sticky and slightly plastic; faint continuous clay films on surface of peds, few unstained sand grains; 10 percent pebbles, 5 percent cobbles; neutral; clear wavy boundary.
Bt2--5 to 8 inches; dark brown (7.5YR 4/3) gravelly clay, dark brown (7.5YR 3/3) moist; moderate medium prismatic structure parting to strong fine and very fine subangular blocky; hard, friable, moderately sticky and moderately plastic; distinct continuous clay films on surface of peds; few unstained sand grains; 10 percent pebbles, 5 percent cobbles; neutral; clear smooth boundary.
Bt3--8 to 14 inches; dark brown (7.5YR 4/4) clay loam, dark brown (7.5YR 3/4) moist; strong fine and medium prismatic structure parting to strong fine and very fine subangular blocky; very hard, friable, very sticky and very plastic; prominant discontinuous clay films on surface of peds; 5 percent pebbles, 5 percent cobbles; neutral; gradual wavy boundary.
Bt4--14 to 18 inches; brown (10YR 5/3) clay loam, dark brown (10YR 3/3) moist; strong fine and medium prismatic structure parting to strong fine and very fine subangular blocky; very hard, friable, moderately sticky and very plastic; prominant continuous clay films on surface of peds; 5 percent pebbles, 5 percent cobbles; neutral; gradual wavy boundary.
Bt5--18 to 23 inches; yellowish brown (10YR 5/4) gravelly clay loam, dark yellowish brown (10YR 4/4) moist; moderate medium prismatic structure parting to strong fine subangular blocky; hard friable, slightly sticky and slightly plastic; faint continuous clay films on horizontal and moderately thick on vertical faces; 20 percent pebbles, 5 percent cobbles; neutral; abrupt wavy boundary. (combined thickness of Bt horizons is 15 to 30 inches)
Bk1--23 to 30 inches; light gray and white (2.5Y 7/2 and 8/2) very gravelly loam, light olive brown and pale yellow (2.5Y 5/3 and 7/3) moist; massive; very hard, friable, slightly sticky and slightly plastic; many lime coats on coarse fragments and soft masses of lime throughout; 30 percent pebbles, 5 percent cobbles; strongly effervescent; moderately alkaline; clear wavy boundary. (7 to 15 inches thick)
2Bk2--30 to 40 inches; light yellowish brown and white (2.5Y 6/3 and 8/3) very gravelly coarse sandy loam, olive brown and pale yellow (2.5Y 4/3 and 7/2) moist; massive; very hard, friable, slightly sticky and slightly plastic; many lime threads throughout and lime coats on coarse fragments; 40 percent pebbles, 10 percent cobbles; strongly effervescent; moderately alkaline; gradual wavy boundary.
2Bk3--40 to 60 inches; light yellowish brown and white (2.5Y 6/3 and 8/3) very cobbly coarse sandy loam, light olive brown and pale yellow (2.5Y 4/3 and 7/3) moist; massive; hard, friable, slightly sticky and slightly plastic; many lime threads throughout and lime coats on coarse fragments; 30 percent pebbles, 20 percent cobbles; strongly effervescent; moderately alkaline; gradual wavy boundary.
TYPE LOCATION: Sweet Grass County, Montana; 1,480 feet east and 120 feet south of the northwest corner of section 3, T. 5 N., R. 13 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 36 to 44 degrees F.
Moisture control section - between 4 and 12 inches.
Mollic epipedon thickness - 7 to 16 inches and includes part of the Bt horizon
Depth to the 2Bk horizon - 17 to 35 inches.
A horizon - Hue: 10YR or 2.5Y
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 1, 2, or 3
Clay content: 15 to 27 percent
Rock fragments: 0 to 35 percent--0 to 5 percent stones, 0 to 15 percent cobbles, 0 to 15 percent pebbles
Reaction: pH 6.1 to 7.8
Bt horizons - Hue: 7.5YR, 10YR or 2.5Y
Value: 4, 5, or 6 dry, 3 or 4 moist
Chroma: 2, 3, or 4
Texture: clay loam, silty clay, silty clay loam, or clay
Clay content: 35 to 50 percent
Rock fragments: 0 to 35 percent--0 to 10 percent cobbles, 0 to 25 percent pebbles
Reaction: pH 6.1 to 7.8
BC horizon (where present) - Hue: 10YR or 2.5Y
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 2, 3, or 4
Texture: clay loam or loam
Clay content: 15 to 35 percent
Rock fragments: 15 to 35 percent--5 to 15 percent cobbles, 10 to 20 percent pebbles
Reaction: pH 6.6 to 7.8
2Bk horizons - Hue: 10YR or 2.5Y
Value: 6, 7, or 8 dry; 4, 5, or 6 moist
Chroma: 2, 3, or 4
Texture: loam, clay loam or sandy loam
Clay content: 15 to 35 percent
Rock fragments: 35 to 60 percent--0 to 5 percent stones, 10 to 25 percent cobbles, 15 to 30 percent pebbles
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.4 to 8.4
COMPETING SERIES:
Bangtail (MT) - has a paralithic contact at a depth of 20 to 40 inches; does not have a horizon of secondary calcium carbonate accumulation.
Bridger (MT) - does not have a loamy skeletal discontinuity above a depth of 40 inches.
Duckcreek (T MT) - has a paralithic contact at a depth of 20 to 40 inches.
Echard (UT) - does not have a horizon of secondary calcium carbonate accumulation; does not have a loamy skeletal discontinuity above a depth of 40 inches; formed
in soft rhyolitic tuff or strongly cemented ash.
Mollet (MT) - does not have a loamy skeletal discontinuity above a depth of 40 inches; does not have a horizon of secondary calcium carbonate accumulation.
Rattler (MT) - has less than 35 percent coarse fragments in the lower part of the series control section.
Sevier (UT) - has a paralithic contact at a depth of 20 to 40 inches; is moderately well drained; does not have horizons of secondary calcium carbonate accumulation.
GEOGRAPHIC SETTING:
Landform - outwash plains; stream terraces, relict stream terraces.
Elevation - 5,500 to 8,000 feet.
Slope - 0 to 35 percent.
Parent material - alluvium or glaciofluvial deposits.
Climate - long, cold winters; moist springs; short summers.
Mean annual precipitation - 19 to 25 inches.
Mean annual air temperature - 34 to 45 degrees F.
Frost-free period - 50 to 70 days.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability through the Bt horizons to moderate permeability in the 2Bk horizon.
USE AND VEGETATION: Melville soils are used as rangeland. Potential native vegetation is mainly bluebunch wheatgrass, Idaho fescue, Columbia needlegrass,
lupine and big sagebrush.
DISTRIBUTION AND EXTENT: The Melville soils are of minor extent in south central Montana.
MLRA OFFICE RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Sweetgrass County, Montana 1999; proposed in Wheatland County, Montana, 1960.
REMARKS: Soil interpretation record: MT0439 and MT1539. Diagnostic horizons and features recognized in this pedon are: a mollic epipedon from the soil surface to 8 inches (A, Bt1 and Bt2 horizons); an argillic horizon from 2 to 23 inches (Bt1, Bt2, Bt3, Bt4 and Bt5 horizons); a particle size control section from 2 to 22 inches; an accumulation of calcium carbonate from 23 to more than 60 inches (Bk and 2Bk horizons); and lithilogic discontinuity at 30 inches. Melville soils have a cryic temperature regime and a ustic moisture regime.