LOCATION WEINGART MTEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Torrertic Natrustalfs
TYPICAL PEDON: Weingart clay loam, in grassland (colors are for dry soil unless otherwise noted).
E--0 to 2 inches; light gray (2.5Y 7/2) clay loam, dark grayish brown (2.5Y 4/2) moist; moderate very thin platy structure with vesicular pores; slightly hard, very friable, sticky and plastic; many medium, fine, and very fine roots; many fine and very fine pores; 5 percent soft shale fragments; moderately acid (pH 5.9); abrupt wavy boundary. (1 to 5 inches thick)
Btn1--2 to 7 inches; grayish brown (2.5Y 5/2) clay, dark grayish brown (2.5Y 4/2) moist; strong medium columnar structure parting to strong fine and very fine angular blocky; extremely hard, firm, sticky and very plastic; many medium, fine, and very fine roots; many fine and very fine pores; continuous faint clay films on faces of peds; few soft shale fragments; slightly alkaline (pH 7.5); clear irregular boundary.
Btn2--7 to 13 inches; light yellowish brown (2.5Y 6/4) clay, olive brown (2.5Y 4/4) moist; strong medium and fine angular blocky structure; very hard, firm, sticky and very plastic; common medium, fine, and very fine roots; many fine and very fine pores; continuous faint clay films on faces of peds; few soft shale fragments; moderately alkaline (pH 8.1); clear irregular boundary. (Combined thickness of the Btn horizons is 6 to 19 inches)
Bkn--13 to 21 inches; light brownish gray (2.5Y 6/2) clay, dark grayish brown (2.5Y 4/2) moist; moderate medium and fine subangular blocky structure; very hard, firm, sticky and very plastic; common fine and very fine roots and few medium roots; many fine and very fine pores; few soft shale fragments with continuous faint lime coating undersides; common medium and fine masses of lime; strongly effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (0 to 10 inches thick)
Bknyz--21 to 29 inches; light brownish gray (2.5Y 6/2) clay, dark grayish brown (2.5Y 4/2) moist; weak medium and fine subangular blocky structure; very hard, firm, sticky and very plastic; few to common medium, fine, and very fine roots; common fine and very fine pores; few fine distinct olive brown (2.5Y 4/4) mottles; few soft shale fragments; many medium prominent masses of gypsum and other salts; common faint lime coatings on fragments; slightly effervescent; moderately alkaline (pH 7.9); clear irregular boundary. (5 to 15 inches thick)
Bnyz--29 to 35 inches; light olive gray (5Y 6/2) channery clay, dark gray (5Y 4/1) moist; massive; extremely hard, firm, sticky and very plastic; few fine and very fine roots; common fine and very fine pores; 45 percent soft shale fragments; 25 percent hard shale fragments; many fine distinct light yellowish brown (10YR 6/4) mottles, yellowish brown (10YR 5/6) moist; common fine and medium distinct masses of gypsum and other salts; mildly alkaline (pH 7.5); gradual wavy boundary. (0 to 12 inches)
Cr-35 to 60 inches; semiconsolidated shale, few fine and medium distinct masses and streaks of gypsum in cracks; slightly alkaline (pH 7.6).
TYPE LOCATION: Fergus County, Montana; about 165 feet east and 920 feet north of the SW corner of sec. 33, T. 19 N., R. 22 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 is 41 degrees F or above.
Depth to Bk horizon - 7 to 16 inches.
Depth to gypsum and other salts - 10 to 24 inches.
Depth to bedrock - 20 to 40 inches.
Some pedons are calcareous above 10 inches.
Btnk and Bnyz horizons are allowed.
Soil phases - stony.
E horizon - Hue: 10YR or 2.5Y
Value: 5, 6, or 7 dry; 3, 4, 5, or 6 moist
Chroma: 2 or 3
Texture: clay, clay loam, or silty clay mixed to 7 inches (some uncultivated areas have a thin A horizon that is a loam or silt loam)
Clay content: 27 to 40 percent
Rock fragments: 0 to 10 percent--0 to 10 percent stones and cobbles, 0 to 5 percent hard shale, 0 to 5 percent soft shale
Reaction: pH 5.6 to 7.8
Btn horizons - Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2, 3, or 4
Texture: clay, silty clay, silty clay loam or sandy clay
Clay content: 35 to 60 percent
Rock fragments: 0 to 10 percent--0 to 5 percent hard shale, 0 to 5 percent soft shale
EC: 0 to 8 mmhos/cm
SAR: 10 to 30
Reaction: pH 6.6 to 9.6
When the SAR is less than 13, there is more exchangeable magnesium plus sodium then calcium plus exchange acidity.
Bkn horizon - Hue: 10YR, 2.5Y, or 5Y
Value: 5, 6, or 7 dry; 4 or 5 moist
Chroma: 2 or 3
Texture: clay loam, silty clay, clay, sandy clay, or silty clay loam
Clay content: 35 to 55 percent
Rock fragments: 0 to 10 percent--0 to 5 percent hard shale, 0 to 5 percent soft shale
EC: 4 to 16 mmhos/cm
SAR: 13 to 30
Lime: few to common masses
Gypsum: none to common seams, 0 to 2 percent
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.9 to 9.6
Bknyz horizon - Hue: 10YR, 2.5Y or 5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 1, 2, 3, or 4
Texture: clay, silty clay, clay loam, or silty clay loam
Clay content: 35 to 55 percent
Rock fragments: 0 to 10 percent--0 to 5 percent hard shale, 0 to 5 percent soft shale
EC: 4 to 16 mmhos/cm
SAR: 13 to 30
Gypsum: 1 to 5 percent
Reaction: pH 7.9 to 9.6
Calcium carbonate equivalent: 2 to 12 percent
Bnyz horizon - Hue: 10YR, 2.5Y, or 5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 1 to 4
Texture: clay, silty clay, clay loam, or silty clay loam
Clay content: 35 to 55 percent
Rock fragments: 0 to 75 percent--0 to 30 percent hard shale, 0 to 55 percent soft shale
EC: 4 to 16 mmhos/cm
SAR: 13 to 30
Gypsum: 1 to 5 percent
Reaction: pH 7.9 to 9.6
Cr horizon - semiconsolidated shale or interbedded shale and siltstone with thin layers of sandstone
Reaction: greater than 7.8
COMPETING SERIES:
Absher (MT) - does not have shale bedrock at depths of 20 to 40 inches.
Creed (MT) - does not have shale bedrock at depths of 20 to 40 inches.
Elloam (MT) - does not have shale bedrock at depths of 20 to 40 inches.
Gerdrum (MT) - does not have shale bedrock at depths of 20 to 40 inches.
Oburn (MT) - does not have shale bedrock at depths of 20 to 40 inches.
Thoeny (MT) - does not have shale bedrock at depths of 20 to 40 inches.
Waltham (MT) - does not have shale bedrock at depths of 20 to 40 inches.
GEOGRAPHIC SETTING:
Landform - sedimentary plains; hills.
Elevation - 1,900 to 4,500 feet.
Slope- 0 to 35 percent.
Parent material - alluvium, colluvium, or residuum derived from semiconsolidated shale or interbedded shale and sandstone.
Climate - long, cold winters; moist springs; hot, dry summers.
Mean annual air temperature - 40 to 45 degrees F.
Mean annual precipitation - 10 to 16 inches.
Frost-free period - 100 to 135 days.
DRAINAGE AND PERMEABILITY: Well drained; very slow permeability.
USE AND VEGETATION: Weingart soils are used mainly for rangeland and pastureland. Some areas are used for nonirrigated cropland. The potential native vegetation is mainly western wheatgrass, green needlegrass, thickspike wheatgrass, prairie junegrass, Nuttall saltbush, forbs, and shrubs.
DISTRIBUTION AND EXTENT: Central and eastern Montana. Weingart soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Fergus County, Montana, 1979.
REMARKS: Soil interpretation records: MT0318, MT0363.
Diagnostic horizons and features recognized in this pedon are: albic horizon - from the soil surface to 2 inches which is also the ochric epipedon (E horizon); argillic horizon - from 2 to 13 inches which is also the particle size control section (Btn1, Btn2 horizons); accumulation of lime - from 13 to 21 inches (Bkn horizon); accumulation of gypsum and other salts - from 21 to 35 inches (Bknyz, Bnyz horizons); paralithic contact - at a depth of 35 inches (Cr horizon). Weingart soils have a frigid temperature regime and an ustic moisture regime that borders on aridic.