LOCATION WATNE MTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Typic Argiustolls
TYPICAL PEDON: Watne silt loam, in rangeland (colors are for dry soil unless otherwise noted).
A1--0 to 3 inches; very dark grayish brown (10YR 3/2) silt loam, black (10YR 2/1) moist; moderate very fine and fine granular structure; soft, very friable, slightly sticky and nonplastic; many very fine and fine roots; many very fine and fine interstitial pores; 5 percent pebbles; neutral (pH 6.8); clear wavy boundary.
A2--3 to 10 inches; very dark grayish brown (10YR 3/2) silt loam, black (10YR 2/1) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; slightly hard, very friable, slightly sticky and nonplastic; many very fine and fine roots; many very fine and fine interstitial and tubular pores; 5 percent pebbles; neutral (pH 7.0); clear wavy boundary. (Combined thickness of A horizons is 10 to 15 inches)
Bt1--10 to 14 inches; grayish brown (10YR 5/2) silty clay loam, dark brown (10YR 3/3) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine interstitial and tubular pores; common distinct dark grayish brown (10YR 4/2) clay films on faces of peds; 5 percent pebbles; neutral (pH 7.0); clear wavy boundary.
Bt2--14 to 20 inches; brown (10YR 5/3) silt loam, brown (10YR 4/3) moist; moderate medium and coarse prismatic structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine roots; many very fine and fine interstitial and tubular pores; few faint dark grayish brown (10YR 4/2) clay films on faces of peds; 5 percent pebbles; moderately alkaline (pH 8.0); gradual wavy boundary. (Combined thickness of Bt horizons is 6 to 13 inches)
Bk1--20 to 31 inches; light gray (10YR 7/2) gravelly loam, light brownish gray (10YR 6/2) moist; moderate coarse prismatic structure; slightly hard, very friable, slightly sticky and nonplastic; few very fine and fine roots; common very fine and fine interstitial and tubular pores; 25 percent pebbles; disseminated lime; common fine masses and threads of lime; common distinct lime coatings around pebbles; violently effervescent; moderately alkaline (pH 8.2); gradual wavy boundary. (8 to 20 inches thick)
Bk2--31 to 60 inches; very pale brown (10YR 7/3) gravelly loam, pale brown (10YR 6/3) moist; weak coarse prismatic structure; slightly hard, very friable, slightly sticky and nonplastic; few very fine roots; few very fine and fine interstitial and tubular pores; 20 percent pebbles; disseminated lime; common fine masses and threads of lime; common distinct lime coatings around pebbles; violently effervescent; moderately alkaline (pH 8.4).
TYPE LOCATION: Jefferson County, Montana; 1,450 feet north and 350 feet west of the southeast corner of sec. 2, T. 1 N., R. 2 W.
RANGE IN CHARACTERISTICS:
Annual soil temperature - 38 to 44 degrees F.
Moisture control section - between 4 and 12 inches.
Mollic epipedon thickness - 10 to 15 inches.
Depth to argillic horizon - 10 to 15 inches.
Depth to the Bk horizon - 16 to 28 inches.
A horizons - Hue: 7.5YR, 10YR, or 2.5Y
Value: 3 or 4 dry; 2 or 3 moist
Chroma: 1 or 2
Texture: loam or silt loam
Clay content: 15 to 27 percent
Rock fragments: 0 to 15 percent pebbles
Reaction: pH 6.6 to 7.8
Bt horizons - Hue: 7.5YR, 10YR, or 2.5Y
Value: 4, 5, or 6 dry; 3, 4, or 5 moist
Chroma: 2 or 3
Texture: silt loam or silty clay loam
Clay content: 25 to 35 percent
Rock fragments: 0 to 15 percent pebbles
Reaction: pH 6.6 to 8.4
Bk1 horizon - Hue: 10YR or 2.5Y
Value: 5, 6, or 7 dry; 4, 5, or 6 moist
Chroma: 2, 3, or 4
Texture: loam, silt loam, or silty clay loam
Clay content: 18 to 30 percent
Rock fragments: 10 to 30 percent pebbles
Calcium carbonate equivalent: 15 to 25 percent
Reaction: pH 7.4 to 8.4
Bk2 horizon - Hue: 10YR or 2.5Y
Value: 5, 6, or 7 dry; 4, 5, or 6 moist
Chroma: 2, 3, or 4
Texture: loam, silt loam, or fine sandy loam
Clay content: 15 to 27 percent
Rock fragments: 10 to 30 percent pebbles
Calcium carbonate equivalent: 10 to 20 percent
Reaction: pH 7.4 to 8.4
COMPETING SERIES:
Absarook (MT) - has a lithic contact at 20 to 40 inches.
Beartooth (MT) - has loamy-skeletal Bk horizons.
Beeno (WY) - has a paralithic contact at 20 to 40 inches.
Bielenberg (MT) - has paralithic and lithic contacts at 40 to 60 inches; does not have horizon of secondary carbonate accumulation.
Bookcliff (UT) - has a lithic contact at 40 to 60 inches.
Bullflat (SD) - has a lithologic discontinuity.
Burtoner (MT) - has a paralithic contact at 20 to 38 inches.
Clancy (MT) - has a paralithic contact at 20 to 40 inches.
Clasoil (MT) - does not have horizons of secondary carbonate accumulation.
Cortyzack (CO) - has less than 10 percent coarse fragments in the Bk horizons.
Dooley (MT) - does not have a calcic horizon.
Empedrado (CO) - does not have a calcic horizon.
Fairfield (MT) - has a calcic horizon at 7 to 10 inches.
Farnuf (MT) - does not have a calcic horizon.
Felor (SD) - has a discontinuity of clayey sediments at 20 to 35 inches.
Greenway (SD) - has horizons of glacial till at 15 to 25 inches.
Gurney (SD) - has a lithic contact at 20 to 40 inches.
Hangdo (UT) - has hues redder than 10YR throughout the profile; does not have a calcic horizon.
Hoppers (MT) - has a lithic contact at 20 to 40 inches.
Hyalite (MT) - does not have horizons of secondary carbonate accumulation.
Jeffcity (MT) - has a paralithic contact at 20 to 38 inches.
Lefor (ND) - has a paralithic contact at 20 to 40 inches.
Lininger (CO) - has a paralithic contact at 20 to 40 inches.
Livona (ND) - does not have a calcic horizon; has horizons of glacial till below 20 inches.
Martinsdale (MT) - has more sand in the argillic horizon.
Maudlin (CO) - has a lithic contact at 20 to 40 inches.
Meagher (MT) - has a loamy-skeletal discontinuity at 20 to 35 inches.
Moen (CO) - has a lithic contact at 20 to 40 inches.
Pianohill (MT) - has a lithic contact at 20 to 40 inches.
Placerton (MT) - has a paralithic contact at 20 to 40 inches.
Reeder (ND) - has a paralithic contact at 20 to 40 inches.
Reedwest (MT) - has a paralithic contact at 20 to 40 inches.
Snakejohn (UT) - has a lithic contact at 40 to 60 inches.
Sponseller (AZ) - does not have horizons of secondary carbonate accumulation.
Trag (CO) - does not have horizons of secondary carbonate accumulation.
Trazuni (NM) - does not have horizons of secondary carbonate accumulation.
Tschicoma (NM) - does not have horizons of secondary carbonate accumulation.
Ulrant (WY) - has a lithic contact at 40 to 60 inches.
Vida (MT) - does not have a calcic horizon; formed in till.
Watrous (ND) - has a lithic contact at 20 to 40 inches.
Wemple (MT) - has a paralithic contact at 20 to 40 inches.
Williams (ND) - does not have a calcic horizon; formed in till.
Yegen (MT) - does not have a calcic horizon.
GEOGRAPHIC SETTING:
Landform - alluvial fans, interfluves, knolls and sideslopes of hills.
Elevation - 4,400 to 6,000 feet.
Slope- 2 to 15 percent.
Parent material - alluvium or colluvium derived from limestone or argillite.
Climate - long, cold winters; moist springs; warm summers.
Mean annual precipitation - 15 to 19 inches.
Mean annual air temperature - 36 to 42 degrees F.
Frost-free period - 70 to 105 days.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.
USE AND VEGETATION: Watne soils are primarily used for rangeland and cropland. The potential native vegetation is mainly Western wheatgrass, bluebunch wheatgrass, green needlegrass, Idaho fescue, rough fescue, sandberg bluegrass, prairie junegrass, timber danthonia, lupine, stoneseed, Western yarrow, serviceberry, big sagebrush, and rose.
DISTRIBUTION AND EXTENT: Watne soils are of small extent in southwestern Montana.
MLRA OFFICE RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Jefferson County, Montana, 1998.
REMARKS: Soil interpretation record: MT1587. Diagnostic horizons and features recognized in this pedon are: a mollic epipedon from the surface to 14 inches (A1, A2, Bt1 horizons); an argillic horizon from 10 to 20 inches (Bt1, Bt2 horizons); a calcic horizon from 20 to 31 inches (Bk1 horizon); a particle-size control section from 10 to 20 inches (Bt1, Bt2 horizons). Watne soils have a frigid temperature regime and an ustic moisture regime.