LOCATION PATOUZA            MT
Established Series
Rev. GAR-JAL
01/2000

PATOUZA SERIES


The Patouza series consists of very deep, well drained soils that formed in clayey alluvium. These soils are on alluvial fans. Slopes are 0 to 8 percent. Mean annual precipitation is about 12 inches, and the mean annual temperature is about 43 degrees F.

TAXONOMIC CLASS: Fine, smectitic, frigid Torrertic Argiustolls

TYPICAL PEDON: Patouza clay, in hayland (Colors are for dry soil unless otherwise noted).

Ap--0 to 4 inches; dark grayish brown (10YR 5/2) clay, very dark grayish brown (10YR 3/2) moist; strong fine granular structure; slightly hard, friable, moderately sticky and moderately plastic; many very fine and fine and common medium roots; neutral (pH 7.2); clear wavy boundary. (4 to 7 inches thick)

Bt1--4 to 11 inches; dark grayish brown (10YR 5/2) clay, very dark grayish brown (10YR 3/2) moist; moderate medium prismatic structure parting to moderate fine subangular blocky; slightly hard, friable, moderately sticky and moderately plastic; common very fine and fine and few medium roots; common distinct clay films on faces of peds and lining pores; few slickensides; neutral (pH 7.2); clear wavy boundary. (3 to 9 inches thick)

Bt2--11 to 16 inches; pale brown (10YR 6/3) clay, grayish brown (10YR 5/2) moist; moderate medium prismatic structure parting to moderate fine subangular blocky; slightly hard, friable, moderately sticky and moderately plastic; few very fine, fine and medium roots; common distinct clay films on faces of peds and lining pores; few slickensides; slightly effervescent; moderately alkaline (pH 8.3); clear wavy boundary. (3 to 14 inches thick)

Btk--16 to 24 inches; pale brown (10YR 6/3) clay loam, brown (10YR 5/3) moist; moderate medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few very fine, fine and medium roots; few distinct clay films on faces of peds and lining pores; common fine masses and seams of lime; strongly effervescent; moderately alkaline (pH 8.3); clear wavy boundary. ( 0 to 10 inches thick)

Bk--24 to 60 inches; pale brown (10YR 6/3) stratified silty clay loam and fine sandy loam, brown (10YR 5/3) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; few very fine roots; few fine masses and seams of lime; strongly effervescent; moderately alkaline (pH 8.3).

TYPE LOCATION: Gallatin County, Montana; 2000 feet north and 900 feet east of the southwest corner of section 11, T.1N, R.1E.

RANGE IN CHARACTERISTICS:

Mean annual soil temperature - 43 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 41 degrees F. or higher.
Mollic epipedon thickness - 7 to 12 inches and includes all or part of the Bt horizon.
Depth to Bk horizon - 21 to 30 inches.
Note: Uncultivated areas of this soil contains cracks 5mm or more wide which extend to the Bk horizons.

Ap horizon - Hue: 10YR or 2.5Y
Value: 4 or 5 dry
Clay content: 40 to 50 percent
Rock fragments: 0 to 5 percent pebbles
Reaction: pH 6.6 to 7.8

Bt horizons - Hue: 10YR or 2.5Y
Value: 4, 5 or 6 dry; 3, 4 or 5 moist
Chroma: 2, 3 or 4
Texture: clay or silty clay
Clay content: 40 to 50 percent
Rock fragments: 0 to 10 percent pebbles
Reaction: pH 6.6 to 8.4

Btk horizon - Hue: 10YR or 2.5Y
Chroma: 2 or 3
Texture: clay loam or clay
Clay content: 35 to 45 percent
Rock fragments: 0 to 10 percent pebbles
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.9 to 9.0

Bk horizon - Hue: 10YR or 2.5Y
Chroma: 2 or 3
Texture: stratified fine sandy loam, sandy clay loam, silty clay loam, or sandy loam
Clay content: 18 to 35 percent
Rock fragments: 0 to 15 percent pebbles
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.9 to 9.0

COMPETING SERIES:

Dutton (MT) - has a paralithic contact at 20 to 40 inches.

Ethridge (MT) - has a Bky horizon with 1 to 3 percent gypsum.

Linnet (MT) - has a BCy horizon with 2 to 5 percent gypsum; has 35 to 50 percent clay in the Bk horizon.

Sofia (MT) - has a lithologic discontinuity at 40 to 80 inches.

GEOGRAPHIC SETTING:

Landform - alluvial fans.
Elevation - 4,000 to 4,400 feet.
Slope - 0 to 8 percent.
Parent material - alluvium.
Climate - long, cold winters; moist springs; warm summers.
Mean annual precipitation - 10 to 14 inches.
Mean annual air temperature - 41 to 45 degrees F.
Frost-free period - 95 to 115 days.

DRAINAGE AND PERMEABILITY: Well drained; slow permeability.

USE AND VEGETATION: Patouza soils are used mainly for
cropland, hayland and rangeland. Potential native vegetation may include western wheatgrass, bluebunch wheatgrass, Sandberg bluegrass, big sagebrush and other perennial grasses and forbs.

DISTRIBUTION AND EXTENT: Patouza soils are of small extent in southwestern Montana.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Gallatin County, Montana, 1997.

REMARKS: Soil interpretation record: MT1449. Diagnostic horizons and features recognized in this pedon are: a mollic epipedon from the surface to 11 inches (A, Bt1 horizon); an argillic horizon which is also the particle-size control section from 4 to 24 inches (Bt1, Bt2, Btk horizons); horizons of secondary carbonate accumulation from 16 to 60 inches (Btk, Bk horizons). Patouza soils have a frigid temperature regime and an ustic moisture regime bordering on aridic.


National Cooperative Soil Survey
U.S.A.