LOCATION ABOR MT+SD
Established Series
Rev. JAL-CJH
03/2018
ABOR SERIES
The Abor series consists of moderately deep, well drained soils that formed in colluvium derived from semiconsolidated shale, residuum from semiconsolidated shale, or semiconsolidated shale interbedded with siltstone or thin layers of sandstone, or in alluvium that is 20 to 40 inches deep over the shale. These soils are on sedimentary plains, hills, alluvial fans, and lake plains. Slopes are 0 to 65 percent. Mean annual precipitation is about 12 inches, and mean annual air temperature is about 43 degrees F.
TAXONOMIC CLASS: Fine, smectitic, frigid Leptic Udic Haplusterts
TYPICAL PEDON: Abor silty clay, cultivated. (Colors are for dry soil unless otherwise noted)
Ap--0 to 6 inches; light brownish gray (2.5Y 6/2) silty clay, dark grayish brown (2.5YR 4/2) moist; moderate very fine granular structure; very hard, friable, sticky and very plastic; many very fine and fine roots; slightly effervescent; slightly alkaline (pH 7.8); abrupt smooth boundary. (3 to 7 inches thick)
Bss--6 to 16 inches; grayish brown (2.5Y 5/2) silty clay, dark grayish brown (2.5Y 4/2) moist; weak medium prismatic structure parting to strong fine and medium blocky; extremely hard, firm, sticky and very plastic; many fine and very fine roots; many fine and very fine pores; few slickensides; disseminated lime; strongly effervescent; moderately alkaline (pH 8.4); gradual wavy boundary. (5 to 12 inches thick)
Bssk--16 to 26 inches; light brownish gray (2.5Y 6/2) silty clay, dark grayish brown (2.5Y 4/2) moist; moderate medium and coarse blocky structure; extremely hard, firm, sticky and very plastic; many fine and very fine roots; many fine and very fine pores; few slickensides; few fine masses of carbonates; strongly effervescent; strongly alkaline (pH 8.5); gradual wavy boundary. (0 to 12 inches thick)
Bky--26 to 30 inches; light brownish gray (2.5Y 6/2) silty clay, dark grayish brown (2.5Y 4/2) moist; weak coarse blocky structure; extremely hard, firm, sticky and very plastic; many fine and very fine roots; many fine and very fine pores; few very dark gray (N 3/ ) shale chips; few fine masses and threads of carbonates and gypsum; strongly effervescent; strongly alkaline (pH 8.6); clear smooth boundary. (4 to 16 inches thick)
Cr--30 to 60 inches; semiconsolidated shale interbedded with thin discontinuous layers of sandstone. The shale has variegated dry colors of mainly light yellowish brown (10YR 6/4) and light brownish gray (10YR 6/2); nests of gypsum are common in the upper 10 inches.
TYPE LOCATION: Cascade County, Montana; 110 feet north and 1,640 feet east of the SW corner of sec. 19, T. 22 N., R. 2 E.
RANGE IN CHARACTERISTICS:
Soil Temperature - 42 to 47 degrees F with summer temperatures of 60 to 72 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 41 degrees or higher.
Depth to Bk horizon - 10 to 20 inches.
Depth to bedrock - 20 to 40 inches, but mainly 25 to 35 inches.
These soils have cracks which extend to the paralithic contact and are as wide as 1/4 inch to 3 inches at the surface and are open for 150 days or less.
Soil phases - saline, cobbly.
Ap horizon - Hue: 10YR, 2.5Y or 5Y
Value: 5, 6 or 7 dry; 4, 5 or 6 moist
Chroma: 1, 2, 3 or 4 (The 1 chromas are inherent from the parent material).
Texture: clay, silty clay, clay loam or silty clay loam
Clay content: 35 to 55 percent
Rock fragments: 0 to 35 percent--0 to 20 percent greater than 3 inches cobbles and stones; 0 to 25 percent less than 3 inches pebbles
Electrical conductivity: 0 to 8 mmhos/cm; saline phase is 4 to 8 mmhos/cm
Reaction: pH 7.4 to 9.0
Bss horizon - Hue: 10YR, 2.5Y or 5Y
Value: 5, 6 or 7 dry; 4, 5 or 6 moist
Chroma: 1, 2, 3 or 4
Texture: silty clay, silty clay loam or clay
Clay content: 35 to 60 percent
Rock fragments: 0 to 15 percent--0 to 3 percent greater than 3 inches cobbles and stones, 0 to 12 percent less than 3 inches pebbles
Electrical conductivity: 0 to 16 mmhos/cm; saline phase is 8 to 16 mmhos/cm
Reaction: pH 7.4 to 9.0
Slickensides: Few to common
Bssk horizon - Hue: 2.5Y, 5Y, 2.5YR or 10YR
Value: 5, 6 or 7 dry; 4 or 5 moist
Chroma: 1, 2, 3, or 4
Texture: silty clay, silty clay loam, clay loam or clay
Clay content: 35 to 60 percent
Slickensides: few to common
Structure: weak, moderate medium, or weak coarse blocky
Rock fragments: 0 to 20 percent--0 to 5 percent greater than 3 inches cobbles and stones; 0 to 15 percent less than 3 inches pebbles
Electrical conductivity: 0 to 16 mmhos/cm; saline phase is 8 to 16 mmhos/cm
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.4 to 9.0
Some pedons have a Bssky horizon.
Bky horizon - Hue: 2.5Y, 5Y, 10YR or 2.5YR
Value: 5, 6 or 7 dry; 4, 5 or 6 moist
Chroma: 1, 2, 3 or 4
Texture: silty clay, silty clay loam or clay
Clay content: 35 to 60 percent
Structure: weak medium or weak coarse blocky grading to massive
Rock fragments: 0 to 20 percent--0 to 5 percent greater than 3 inches cobbles and stones; 0 to 15 percent less than 3 inches pebbles
Electrical conductivity: 0 to 16 mmhos/cm; saline phase is 8 to 16 mmhos/cm
Gypsum: 1 to 5 percent
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.4 to 9.0
Some pedons have a By horizon.
COMPETING SERIES:
Barkof (MT) - has a mean annual precipitation greater than 15 inches; does not have a Bk horizon.
Bascovy (MT) - does not have a Bk horizon or a Bky horizon.
GEOGRAPHIC SETTING:
Landform - sedimentary plains; hills; alluvial fans; lake plains.
Elevation - 2,200 to 4,500 feet and ranges up to 6,800 feet in the southern latitudes. (In Colorado it ranges up to 7,200 feet.)
Slope - 0 to 65 percent.
Parent material - colluvium derived from semiconsolidated shale,, residuum from semiconsolidated shale, or semiconsolidated shale interbedded with siltstone or thin layers of sandstone, or in alluvium that is 20 to 40 inches deep over shale.
Climate - long, cold winters; moist springs; warm summers.
Mean annual precipitation - 10 to 14 inches. (In Colorado it ranges to 15 inches.)
Mean annual air temperature - 40 to 45 degrees F.
Frost-free period - 95 to 135 days. (In Colorado it is 75 to 95 days.)
DRAINAGE AND PERMEABILITY: Well drained; very slow permeability.
USE AND VEGETATION: Abor soils are used for nonirrigated crops and as pastureland and rangeland. The potential native vegetation is mainly green needlegrass, western wheatgrass, bluebunch wheatgrass, prairie junegrass, blue grama, forbs, and shrubs.
DISTRIBUTION AND EXTENT: This series is of moderate extent in eastern and central Montana and parts of Colorado and South Dakota.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: SALINA, KANSAS
SERIES ESTABLISHED: Broadwater County, Montana, 1971.
REMARKS: Soil interpretation records: MT0076, MT0721, MT1039
Diagnostic horizons and features recognized in this pedon are: ochric epipedon - the zone from the surface of the soil to a depth of 7 inches (Ap and Bss horizons); Vertisol criteria - slickensides from a depth of 6 inches to the paralithic contact (Bss, Bssk Bky horizons), cracks from the surface to the paralithic contact (Ap, Bss, Bssk, Bky horizons); particle-size control section - the zone from a depth of 10 to 40 inches, or to the paralithic contact (Bss, Bssk amd Bky horizons). Abor soils have a frigid temperature regime and an ustic moisture regime that borders on aridic.
National Cooperative Soil Survey
U.S.A.