LOCATION PYLON MTEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Torrertic Haplustalfs
TYPICAL PEDON: Pylon silty clay loam, cultivated. (Colors are for dry soil unless otherwise noted)
Ap--0 to 6 inches; light brownish gray (2.5Y 6/2) silty clay loam, dark grayish brown (2.5Y 4/2) moist; massive; many vesicular pores; very hard, friable, sticky and plastic; neutral (pH 7.0); abrupt wavy boundary. (2 to 8 inches thick)
Bt1--6 to 10 inches; brown (10YR 5/3) heavy silty clay, brown (10YR 4/3) moist; strong fine and medium columnar structure parting to weak fine blocky structure; extremely hard, firm, sticky and very plastic; common fine and very fine pores; thin continuous clay film on peds; neutral (pH 7.2); clear wavy boundary.
Bt2--10 to 17 inches; brown (10YR 5/3) heavy silty clay, brown (10YR 4/3) moist; strong medium prismatic structure parting to strong fine and medium blocky structure; extremely hard, firm, sticky and very plastic; few fine ant very fine roots; common fine and very fine pores; thin continuous clay film on peds; slightly alkaline (pH 7.6); clear irregular boundary. (Combined Bt horizons 7 to 20 inches thick)
Btk--17 to 24 inches; grayish brown (2.5Y 5/2) silty clay, dark grayish brown (2.5Y 4/2) moist; strong medium prismatic structure parting to strong fine and medium blocky structure; extremely hard, friable, sticky and very plastic; few fine and very fine roots; common fine and very fine pores; few fine and medium masses of segregated lime; strongly effervescent; strongly alkaline (pH 8.6); gradual wavy boundary. (0 to 10 inches thick)
Bky--24 to 34 inches; light brownish gray (2.5Y 6/2) silty clay, dark grayish brown (2.5Y 4/2) moist; moderate medium and coarse subangular blocky structure; extremely hard, friable, sticky and very plastic; few fine and very fine roots; common fine and very fine pores; few masses of gypsum; few shale chips; few fine masses of segregated lime; strongly effervescent; strongly alkaline (pH 8.6); gradual wavy boundary. (3 to 14 inches thick)
Cr--34 to 50 inches; gray (N 6/0) platy shale of clay texture, gray (N 5/0) moist; clay shale with very thin hard sandstone layers; strongly effervescent.
TYPE LOCATION: Cascade County, Montana; 1,440 feet north and 50 feet west of the SE corner of sec. 20, T.22N., R.2E.
RANGE IN CHARACTERISTICS:
Soil Temperature - 41 to 47 degrees F.
Particle-size control section - 35 to 55 percent clay
Rock fragments - less than 5 percent throughout
Depth to bedrock - 20 to 40 inches
Depth to carbonates - 12 to 18 inches
A horizon - Hue: 10YR or 2.5Y
Value: 5 or 6 dry, 3 or 4 moist
Chroma: 1 to 3
Texture: silty clay loam or clay loam
Clay content: 30 to 40 percent
Reaction: 6.1 to 7.3
Bt horizon - Hue: 10YR or 2.5Y
Value: 4 to 6 dry, 3 to 5 moist
Chroma: 2 to 4
Texture: silty clay loam, clay or clay loam
Clay content: 35 to 55 percent
Reaction: 6.6 to 7.8
Bk horizon - Hue: 10YR or 2.5Y
Value: 5 to 7 dry, 4 to 6 moist
Chroma: 2 to 4
Texture: silty clay loam, clay or clay loam
Clay content: 35 to 50 percent
Reaction: 7.9 to 9.0
Notes: It does not have gypsum in some pedons.
Cr horizon - This horizon consists of platy clay shale that typically has thin sandstone layers. Some pedons do not have sandstone layers.
COMPETING SERIES: These are the Acel and Bew soils. These soils are deeper than 40 inches to a paralithic contact.
GEOGRAPHIC SETTING: The Pylon soils are sedimentary uplands, hills and ridges. Elevations are 2,700 to 5,200 feet. Slopes are 0 to 15 percent. They formed in residuum from interbedded shale and sandstone or alluvium over shale. The climate is cool, semiarid, continental. It is characterized by long, cold winters; moist springs; and warm summers. The mean annual air temperature is 40 to 46 degrees F., with a mean summer temperature of 60 to 70 degrees F. The mean annual precipitation is 10 to 16 inches, most of which falls during spring and early summer. The (32 degree F.) growing season is 105 to 135 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Abor, Cargill and Dutton soils. Abor and Cargill soils do not have an argillic horizon. Dutton soils have a mollic epipedon. In addition, Abor and Dutton soils lack paralithic contact at depths of less than 40 inches.
DRAINAGE AND PERMEABILITY: Well drained; low or medium runoff; slow or very slow permeability.
USE AND VEGETATION: Pylon soils are used mainly for dryland crops and rangeland. Potential native vegetation is mainly green needlegrass, western wheatgrass, bluebunch wheatgrass, Canby bluegrass, Prairie junegrass and perennial forbs and shrubs.
DISTRIBUTION AND EXTENT: Mainly on the sedimentary plains in central Montana and extreme northeastern Wyoming. They are of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Cascade County, Montana, 1975.