LOCATION PHILLIPS MTEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Aridic Haplustalfs
TYPICAL PEDON: Phillips loam, grassland (colors are for dry soil unless otherwise noted).
A--0 to 2 inches; brown (10YR 5/3) loam, very dark grayish brown (10YR 3/2) moist; weak thin and very thin platy structure parting to moderate very fine granular; soft, very friable, nonsticky and nonplastic; upper surface of plates are light gray (10YR 7.2) many fine and very fine roots; many fine pores; slightly acid (pH 6.4); clear smooth boundary. (1 to 4 inches thick)
E1--2 to 4 inches; pale brown (10YR 6.3) loam, brown (10YR 4/3) moist; weak medium prismatic structure parting to weak thin platy; soft, very friable, slightly sticky and nonplastic; upper surface of plates have skeletans of light gray (10YR 7.2) unstained sand and silt grains; many fine roots; many fine pores; slightly acid (pH 6.3); clear wavy boundary.
E2--4 to 7 inches; light brownish gray (10YR 6/2) loam, dark grayish brown (10YR 4/2) moist; moderate medium prismatic structure parting to moderate very thin platy; hard, very friable, slightly sticky and slightly plastic; upper surface of plates have skeletans of light gray (10YR 7/2) unstained sand grains; many fine roots; many fine pores; slightly acid (pH 6.3); abrupt wavy boundary. (Combined E horizons 4 to 6 inches thick)
Bt1--7 to 10 inches; brown (10YR 5.3) clay, dark brown (10YR 4/3) moist; strong fine and medium prismatic structure parting to strong fine and very fine subangular blocky; very hard, friable, sticky and plastic; continuous faint dark grayish brown (10YR 4/2) clay films on faces of peds and in pores; light gray (10YR 7/2) skeletans on vertical surfaces of peds; many fine roots; many fine and very fine pores; neutral (pH 7.0); clear wavy boundary.
Bt2--10 to 15 inches; pale brown (10YR 6/3) clay loam, dark brown (10YR 4/3) moist; strong fine and medium prismatic structure parting to strong fine and very fine subangular blocky; very hard, friable, sticky and plastic; continuous faint dark grayish brown (10YR 4/2) clay films on faces of peds and as lining in some pores; common unstained sand grains on faces of prisms; many fine roots mainly along faces of peds; many very fine pores; moderately alkaline (pH 8.0); clear wavy boundary. (Combinded Bt horizons 7 to 15 inches thick)
Bk1--15 to 22 inches; grayish brown (2.5Y 5/2) clay loam, dark grayish brown (2.5Y 4/2) moist; strong medium prismatic structure parting to strong medium and coarse subangular blocky; extremely hard, firm, sticky and plastic; few faint clay films on faces of peds; common fine roots; many fine pores; few fine masses of lime; slightly effervescent; moderately alkaline (pH 8.4); clear wavy boundary.
Bk2--22 to 36 inches; grayish brown (2.5Y 5/2) clay loam, dark grayish brown (2.5Y 4/2) moist; moderate coarse and very coarse prismatic structure parting to moderate medium and coarse subangular blocky; very hard, firm, sticky and plastic; common to few fine roots; many fine pores; 5 percent pebbles; few lignite and shale chips; common fine masses of lime; strongly effervescent; moderately alkaline (pH 8.4); gradual wavy boundary. (Combined Bk horizons 18 to 35 inches thick)
By--36 to 60 inches; grayish brown (2.5Y 5/2) clay loam, dark grayish brown (2.5Y 4.2) moist; weak very coarse prismatic structure parting to weak very thick platy; very hard, firm, sticky and plastic; few fine roots; common fine pores; common fine and medium masses of gypsum; 5 percent cobbles, 5 percent pebbles and common lignite chips; slightly effervescent; slightly alkaline (pH 7.7). (0 to 24 inches thick)
TYPE LOCATION: Blaine County, Montana; 1,840 feet south and 300 feet east of the SW corner of sec. 3, T. 35 N., R. 19 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 47 degrees F.
Moisture control section - between 4 and 12 inches; dry in all parts between four-tenths and five-tenths of the cumulative days per year when the soil temperature at a depth of 20 inches is higher than 41 degrees F.
Depth to Bk horizon - 12 to 25 inches.
Depth to By horizon - 30 to 40 inches.
E/B and Bky horizons are allowed.
A horizon - Hue: 10YR or 2.5Y
Value: 3 or 4 moist
Chroma: 2 or 3
Texture: loam (when mixed to a depth of about 7 inches the Ap horizon is loam, sandy loam, or clay loam with 10 to 35 percent clay).
Clay content: 15 to 27 percent
Rock fragments: 0 to 15 percent--0 to 5 percent cobbles, 0 to 10 percent pebbles
Reaction: pH 6.1 to 7.3
E horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 or 3
Texture: loam or sandy loam
Clay content: 10 to 27 percent
Rock fragments: 0 to 15 percent--0 to 5 percent cobbles, 0 to 10 percent pebbles
Reaction: pH 6.1 to 7.3
Bt1 and Bt2 horizons - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 or 3
Texture: clay loam or clay
Clay content: 35 to 45 percent
Rock fragments: 0 to 15 percent--0 to 5 percent cobbles, 0 to 10 percent pebbles
EC: 0 to 2 mmhos/cm
Reaction: pH 6.6 to 8.4
Bk1 and Bk2 horizons - Hue: 10YR or 2.5Y
Value: 5, 6, or 7 dry; 4 or 5 moist
Chroma: 2, 3, or 4
Texture: loam or clay loam
Clay content: 25 to 40 percent
Rock fragments: 0 to 15 percent--0 to 5 percent cobbles, 0 to 10 percent pebbles
EC: 2 to 4 mmhos/cm
Calcium carbonate equivalent: 5 to 15 percent
SAR: 0 to 13
Reaction: pH 7.4 to 9.0
By horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2, 3, or 4
Texture: loam or clay loam
Clay content: 20 to 35 percent
Rock fragments: 0 to 15 percent--0 to 5 percent cobbles, 0 to 10 percent pebbles
EC: 4 to 8 mmhos/cm
Gypsum: 1 to 3 percent
SAR: 0 to 13
Reaction: pH 7.4 to 9.0
Moist bulk density: 1.55 to 1.75 g/cc
COMPETING SERIES:
Campspass (MT) - has an O horizon; lithic bedrock at depths of 40 to 60 inches.
Citadel (SD) - does not have a horizon of secondary carbonate accumulation; is strongly acid above a depth of 23 inches.
Fortwingate (NM) - has a lithic contact at depths of 20 to 40 inches.
Goldvale (CO) - does not have a horizon of secondary carbonate accumulation.
Kelvin (ND) - does not have a horizon of secondary carbonate accumulation.
Larkson (CO) - does not have a horizon of secondary carbonate accumulation.
McVickers (AZ) - does not have a horizon of secondary carbonate accumulation.
Osoridge (NM) - has a lithic contact at depths above 20 inches.
Pinehill (MT) - did not form in till; does not have a moist bulk density of 1.55 to 1.75 g/cc; does not have a horizon of gypsum accumulation; does not have an EC of 4 mmhos/cm or greater.
Pylon (MT) - has a paralithic contact at depths of 20 to 40 inches.
Sonnett (MT) - does not have a moist bulk density of 1.55 to 1.75 g/cc below a depth of 30 inches; has EC of 4 mmhos/cm or less below a depth of 20 inches.
Zuni (NM) - does not have a horizon of secondary carbonate accumulation.
GEOGRAPHIC SETTING:
Landform - till plains.
Elevation - 2,300 to 3,600 feet.
Slope- 0 to 15 percent.
Parent material - till.
Climate - long, cold winters; moist springs; warm summers.
Mean annual precipitation - 10 to 14 inches.
Mean annual air temperature - 40 to 45 degrees F.
Frost-free period - 100 to 130 days.
DRAINAGE AND PERMEABILITY: Well drained; slow permeability.
USE AND VEGETATION: Phillips soils are used for dryland crops and as rangeland. Potential native vegetation is mainly western wheatgrass, needleandthread, bluebunch wheatgrass, green needlegrass, and perennial forbs.
DISTRIBUTION AND EXTENT: Phillips soils are extensive on the glaciated uplands in northern Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Milk River area, Montana, 1928.
REMARKS: Soil interpretations record: MT0848.
Diagnostic horizons and features recognized in this pedon are: ochric epipedon - from the soil surface to 7 inches (A, E1, E2 horizons); argillic horizon and particle-size control section - from 7 to 15 inches (Bt1, Bt2 horizons); horizons of secondary carbonate accumulation - from 15 to 36 inches (Bk1, Bk2 horizons); high bulk density glacial till at a depth of 36 inches. Phillips soils have a frigid temperature regime and an aridic moisture regime that borders on ustic.
ADDITIONAL DATA: Laboratory sample S62-MT-3-7.