LOCATION PIANOHILL MT
Established Series
Rev. DRS-WDB-RJS
11/2012
PIANOHILL SERIES
The Pianohill series consists of moderately deep, well drained soils that formed in colluvium over residuum derived from volcanic mudflow breccia. These soils are on structural benches, lahars and hills. Slopes are 0 to 35 percent. Mean annual precipitation is about 400 mm, and mean annual air temperature is about 4.5 degrees C.
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Typic Argiustolls
TYPICAL PEDON: Pianohill loam, in rangeland (colors are for dry soil unless otherwise noted).
A1--0 to 15 cm; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots many very fine and fine interstitial pores; 5 percent angular cobbles; slightly acid (pH 6.4); abrupt smooth boundary.
A2--15 to 25 cm; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; weak medium subangular blocky structure parting to weak fine and medium granular; soft, very friable, slightly sticky and slightly plastic, many very fine and fine roots; many very fine and fine pores; slightly acid (pH 6.2); clear smooth boundary. (combined thickness of A horizons - 18 to 30 cm)
Bw--25 to 40 cm; pale brown (10YR 6/3) loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine pores; neutral (ph 6.6); clear smooth boundary. (0 to 18 cm thick)
Bt1--40 to 53 cm; 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; many very fine and fine roots; many very fine and fine pores; common faint dark yellowish brown (10YR 4/4) moist clay films on faces of peds and in pores; 5 percent angular gravel; neutral (ph 6.6); clear smooth boundary. (10 to 25 cm thick)
Bt2--53 to 74 cm; very pale brown (10YR 7/4) loam, light yellowish brown (10YR 6/4) moist; moderate medium subangular blocky structure; soft, friable, moderately sticky and moderately plastic; common very fine and fine roots; common very fine and fine pores; few faint dark yellowish brown (10YR 4/4) moist clay films on faces of peds and in pores; 12 percent angular gravel; neutral (ph 6.8); clear smooth boundary. (12 to 40 cm thick)
R--74 to 152 cm; volcanic mudflow breccia.
TYPE LOCATION: Sweet Grass County, Montana; 640 meters east and 245 meters north of the SW corner of sec. 23, T.2S, R.15E.
RANGE IN CHARACTERISTICS:
Soil temperature - 5.5 to 8.0 degrees C.
Mollic epipedon thickness - 18 to 38 cm
Rock fragments - angular gravel and cobbles of lahar breccia
Depth to a lithic contact - 50 to 100 cm
Note: Some pedons may have a BC horizon.
A horizons
Hue: 10YR or 2.5Y; dry or moist
Value: 3 to 5 dry; 2 or 3 moist
Chroma: 2 or 3; dry or moist
Clay content: 15 to 27 percent
Rock fragments: 0 to 15 percent--0 to 10 percent gravel, 0 to 5 percent cobbles
Reaction: pH 6.1 to 7.3
Bw horizon
Hue: 10YR or 2.5Y; dry or moist
Value: 5 or 6 dry; 3 to 5 moist
Chroma: 2 to 4; dry or moist
Clay content: 15 to 27 percent
Rock fragments: 0 to 15 percent--0 to 10 percent gravel, 0 to 5 percent cobbles
Reaction: pH 6.1 to 7.3
Bt1 horizon
Hue: 10YR or 2.5Y; dry or moist
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 3 or 4; dry or moist
Texture: loam, clay loam
Clay content: 20 to 35 percent
Rock fragments: 0 to 15 percent--0 to 10 percent gravel, 0 to 5 percent cobbles
Reaction: pH 6.1 to 7.4
Bt2 horizon
Hue: 10YR or 2.5Y; dry or moist
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 3 or 4; dry or moist
Texture: loam, clay loam or sandy clay loam
Clay content: 20 to 35 percent
Rock fragments: 0 to 35 percent--0 to 25 percent gravel, 0 to 10 percent cobbles
Reaction: pH 6.1 to 7.6
COMPETING SERIES:
Absarook (MT) - have secondary calcium carbonate accumulation
Archmesa (CO) - have late summer and fall precipitation peaks
Beartooth (MT) - are very deep
Bielenberg (MT) - are deep to a paralithic contact
Bitterroot (MT) - are moderately deep to a paralithic contact
Bookcliff (UT) - are deep to a lithic contact
Burtoner (MT) - are moderately deep to a paralithic contact
Clancy (MT) - are deep to a lithic contact
Clasoil (MT) - are very deep
Dooley (MT) - are very deep
Doughty (MT) - are very deep
Empedrado (CO) - have secondary calcium carbonate accumulation
Fairfield (MT) - are very deep
Farnuf (MT) - are very deep
Farside (MT) - are very deep
Felor (SD) - are very deep
Greenway (SD) - are very deep
Gurney (SD) - secondary calcium carbonate accumulation
Hangdo (UT) - are very deep
Hoppers (MT) - are moderately deep to a paralithic contact
Howbert (CO) - are very deep
Hyalite (MT) - are very deep
Jeffcity (MT) - are moderately deep to a paralithic contact
Kokoruda (MT) - are very deep
Livona (ND) - are very deep
Martinsdale (MT) - are very deep
Maudlin (CO) - dry in all parts for 45 or more consecutive days after July 15
Meagher (MT) - are very deep
Moen (CO) - has hue of 7.5YR in the lower part of the argillic horizon
Moento (CO) - have late summer and fall precipitation peaks
Perrypark (CO) - are very deep
Placerton (MT) - are moderately deep to a paralithic contact
Reeder (ND) - are moderately deep to a paralithic contact
Reedwest (MT) - are moderately deep to a paralithic contact
Snakejohn (UT) - are deep to a lithic contact
Sponseller (AZ) - are not moderately deep to a lithic contact
Trag (CO) - are very deep
Tragmon (CO) - are very deep
Trazuni (NM) - are very deep
Ulrant (WY) - are deep to a lithic contact
Vida (MT) - are very deep
Watne (MT) - are very deep
Watrous (ND) - have secondary calcium carbonate accumulation
Wemple (MT) - are deep to a lithic contact
Williams (ND) - are very deep
Yegen (MT) - are very deep
GEOGRAPHIC SETTING:
Landform - structural benches, lahars and hills
Elevation - 1,280 to 1,830 meters
Parent material - colluvium over residuum derived from volcanic mudflow breccia
Slope - 0 to 35 percent
Climate - long, cold winters; moist springs; warm summers
Mean annual precipitation - 380 to 500 cm, most of which falls during spring and early summer
Mean annual air temperature - 3.5 to 7.5 degrees C.
Frost-free period - 80 to 120 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Pianohill soils are used mainly for rangeland. Potential native vegetation is mainly Idaho fescue, Columbia needlegrass, prairie junegrass, bluebunch wheatgrass, big sagebrush, and fringed sagewort.
DISTRIBUTION AND EXTENT: Pianohill soils are of moderate extent in south central Montana. MLRAs - 43B, 46.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES ESTABLISHED: Sweet Grass County Area, Montana, 2000.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 25 cm (A1, A2 horizons)
Cambic horizon - 25 to 40 cm (Bw horizon)
Argillic horizon - 40 to 74 cm (Bt1, Bt2 horizons)
Lithic contact - 74 cm (R horizon).
Pianohill soils have a frigid temperature regime and an ustic moisture regime.
ADDITIONAL DATA: Soil interpretations record - MT1489.
National Cooperative Soil Survey
U.S.A.