LOCATION VANDA MT+ND WYEstablished Series
TAXONOMIC CLASS: Fine, smectitic, calcareous, frigid Torrertic Ustorthents
TYPICAL PEDON: Vanda clay, cultivated (colors are for dry soil unless otherwise noted).
Ap--0 to 4 inches, light brownish gray (2.5Y 6/2) clay, dark grayish brown (2.5Y 4/2) moist; a massive 1/8 to 1/4 inch thick crust over weak very fine granular structure; very hard, friable, very sticky and very plastic; common fine and very fine roots; many fine and very fine vesicular pores; slightly effervescent; strongly alkaline (pH 8.6); abrupt wavy boundary. (4 to 6 inches thick)
Bz--4 to 12 inches, light brownish gray (2.5Y 6/2) clay, dark grayish brown (2.5Y 4/2) moist; massive; extremely hard, firm, very sticky and very plastic; common fine and very fine roots; common fine and very fine pores; few fine masses of salts; slightly effervescent; strongly alkaline (pH 8.8); clear wavy boundary. (0 to 24 inches thick)
Byz--12 to 60 inches, light brownish gray (2.5Y 6/2) clay, dark grayish brown (2.5Y 4/2) moist; massive; extremely hard, firm, very sticky and very plastic; few fine and very fine roots; common fine and very fine pores; many fine and medium masses of gypsum and other salts; slightly effervescent; moderately alkaline (pH 8.4).
TYPE LOCATION: Cascade County, Montana; 800 feet north and 50 feet west of the SE corner of sec. 8, T. 21 N., R. 2 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 when the soil temperature at a depth of 20 inches is 41 degrees F.
Depth to Byz horizon - 4 to 24 inches.
A Bw horizon is allowed above a depth of 7 inches that has characteristics similar to the A horizon.
Soil phases - wet.
Ap or E horizons - Hue: 10YR, 2.5Y or 5Y
Value: 5, 6, or 7 dry; 4 or 5 moist
Chroma: 1, 2, or 3
Texture: clay, silty clay, or silty clay loam
Clay content: 30 to 60 percent
Hardness: very hard or extremely hard, massive crusts
EC: 2 to 8 mmhos/cm; wet phase greater than 16 mmhos/cm
Reaction: pH 7.8 to 9.6; wet phase greater than pH 8.4
SAR: 1 to 30
In some pedons the upper 6 inches of soil is noncalcareous unless mixed.
Bz horizon - Hue: 10YR, 2.5Y or 5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 or 3
Texture: clay, silty clay, or silty clay loam
Clay content: 35 to 60 percent
Hardness: very hard or extremely hard
EC: 2 to 8 mmhos/cm; wet phase greater than 16 mmhos/cm
Reaction: pH 7.9 to 9.6; wet phase greater than pH 8.4
SAR: 13 to 30
Byz horizon - Hue: 10YR, 2.5Y or 5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 or 3
Texture: clay, silty clay, or silty clay loam
Clay content: 35 to 60 percent
Hardness: very hard or extremely hard
Gypsum: 1 to 5 percent with total gypsum less than 150
EC: 8 to 25 mmhos/cm; wet phase greater than 16 mmhos/cm
SAR: 13 to 30
Gypsum: 1 to 5 percent
Reaction: pH 7.9 to 9.6
COMPETING SERIES:
Orinoco (MT) - has a Bky horizon; has a paralithic contact at depths of 20 to 40 inches.
Sunburst (MT) - has Bk and Bky horizons; has electrical conductivity of less than 8 mmhos/cm; does not have a vesicular surface crust.
GEOGRAPHIC SETTING:
Landform - alluvial fans; stream terraces; lake plains; sedimentary plains; drainageways.
Elevation - 1,900 to 4,500 feet.
Slope- 0 to 15 percent slopes.
Parent material - alluvium derived mainly from semiconsolidated sedimentary bedrock or from glaciolacustrine or glaciofluvial deposits.
Climate - long, cold winters; moist springs; hot, dry summers.
Mean annual precipitation - 10 to 16 inches, most of which falls in the spring and in the early part of summer.
Mean annual air temperature - 40 to 45 degrees F.
Frost-free period - 90 to 135 days.
DRAINAGE AND PERMEABILITY: Well drained; very slow permeability.
USE AND VEGETATION: Vanda soils are used mainly for range. The potential native vegetation is mainly western wheatgrass, Nuttall alkaligrass, big sagebrush, blue grama, alkali sacaton, forbs, and shrubs.
DISTRIBUTION AND EXTENT: Vanda soils are extensive and occur in the eastern plains of Montana and in the states of North Dakota, South Dakota, and Wyoming.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Blaine County, Montana, 1969.
REMARKS: Soil interpretation records: MT0023, MT0157.
Diagnostic horizons and features recognized in this pedon are: ochric epipedon - from the soil surface to 7 inches (Ap, Bz horizons); massive material that is extremely hard - from 4 to 60 inches (Bz, Byz horizons); particle size control section - from 10 to 40 inches (Bz, Byz horizons). The Vanda soils have a frigid temperature regime and an ustic moisture regime bordering on aridic.
Series will be reclassified to proposed Torrertic subgroup as soon as it is approved.
ADDITIONAL INFORMATION: Laboratory data S71MT-013-004; S50MT-085-006.