LOCATION BITTERROOT MT
Established Series
Rev. EMR/JMS/JCK
06/2012
BITTERROOT SERIES
The Bitterroot series consists of moderately deep, well drained soils that formed in alluvium, colluvium, or residuum from lithified earthflow deposits. These soils are on eroded fan remnants, earthflows and escarpments. Slopes are 2 to 60 percent. Mean annual precipitation is about 380 mm, and mean annual air temperature is about 6 degrees C.
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Typic Argiustolls
TYPICAL PEDON: Bitterroot gravelly loam, in rangeland on a 6 percent slope at 1,126 meters elevation. (Colors are for dry soil unless otherwise noted.)
A--0 to 32 cm; grayish brown (10YR 5/2) gravelly loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; many fine tubular pores; 15 percent gravel; slightly alkaline (pH 7.6); abrupt smooth boundary. (18 to 38 cm thick)
Bt--32 to 47 cm; light yellowish brown (10YR 6/4) gravelly loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; moderately hard, friable, slightly sticky and slightly plastic; common fine roots; common fine tubular pores; 10 percent distinct clay films on all faces of peds; 15 percent gravel; slightly alkaline (pH 7.8); clear smooth boundary. (15 to 52 cm thick)
Bk--47 to 79 cm; very pale brown (10YR 7/4) gravelly loam, dark yellowish brown (10YR 4/4) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine roots; common fine irregular pores; 15 percent gravel; finely disseminated carbonates and 10 percent prominent carbonate coats on rock fragments; violently effervescent; moderately alkaline (pH 8.1); clear smooth boundary. (17 to 64 cm thick)
Cr--79 to 152 cm; moderately cemented lithified earthflow deposit.
TYPE LOCATION: Corvallis topographic quadrangle, Ravalli County, Montana; 630 meters west and 40 meters south of the NE corner of section 2, T6N, R20W, UTM zone 11, 726456e, 5132939n, NAD 83.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 5 to 8 degrees C
Mollic epipedon thickness - 18 to 38 cm
Depth to argillic horizon - 18 to 38 cm
Depth to calcic horizon - 33 to 70 cm
Depth to paralithic contact - 50 to 102 cm
The paralithic material varies in origin and is typically rich in volcanic ash. In some pedons the upper part of the paralithic contact is calcareous.
A horizon:
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 2 or 3 dry or moist
Texture: loam or sandy loam
Clay content: 12 to 22 percent
Rock fragments: 0 to 25 percent; 0 to 25 percent gravel; 0 to 5 percent cobbles
Reaction: pH 6.2 to 7.8
Bt horizon:
Value: 5 or 6 dry
Chroma: 2, 3, or 4 dry or moist
Texture: loam, clay loam, or sandy clay loam
Clay content: 18 to 30 percent
Rock fragments: 0 to 30 percent; 0 to 30 percent gravel; 0 to 5 percent cobbles
Reaction: pH 6.0 to 7.9
Bk horizon:
Value: 6, 7, or 8 dry; 4 or 5 moist
Chroma: 2, 3, or 4
Texture: loam, fine sandy loam, or sandy loam
Clay content: 12 to 18 percent
Rock fragments: 0 to 25 percent; 0 to 25 percent gravel; 0 to 5 percent cobbles
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 8.0 to 8.4
COMPETING SERIES:
Absarook (MT) - have a lithic contact at depths of 50 to 102 cm
Archmesa (CO+NM) - do not have a horizon of secondary calcium carbonate accumulation; have a lithic contact at depths of 50 to 102 cm
Beartooth (MT) - do not have a paralithic contact above 102 cm
Beeno (WY) - do not have a calcic horizon
Bielenberg (MT) - do not have a horizon of secondary calcium carbonate accumulation; do not have a paralithic contact above 102 cm
Bookcliff (UT+WY) - do not have a calcic horizon; do not have more than 15 percent rock fragments in the upper part of the subsoil
Burtoner (MT) - do not have a horizon of secondary calcium carbonate accumulation; have a lithic contact at depths of 58 to 102 cm
Clancy (MT) - do not have a horizon of secondary calcium carbonate accumulation; have a lithic contact at depths of 102 to 152 cm
Clasoil (MT) - do not have a horizon of secondary calcium carbonate accumulation; do not have a paralithic contact above 102 cm
Dooley (MT,ND,UT) - do not have a paralithic contact above 102 cm
Doughty (MT) - do not have a paralithic contact above 102 cm
Empedrado (CO) - do not have a paralithic contact above 102 cm
Fairfield (MT+WY) - do not have a calcic horizon; do not have a paralithic contact above 102 cm
Farnuf (MT,ND,SD,WY) - do not have a calcic horizon; do not have a paralithic contact above 102 cm
Farside (MT) - do not have a horizon of secondary calcium carbonate accumulation; do not have a paralithic contact above 102 cm
Felor (SD+ND) - do not have a calcic horizon; do not have a paralithic contact above 102 cm
Greenway (SD) - do not have a calcic horizon; do not have a paralithic contact above 102 cm
Gurney (SD) - do not have a calcic horizon; have a lithic contact at depths of 50 to 102 cm
Hangdo (UT) - do not have a horizon of secondary calcium carbonate accumulation; do not have a paralithic contact above 102 cm
Hoppers (MT) - do not have a horizon of secondary calcium carbonate accumulation; have a lithic contact above 102 cm
Howbert (CO) - do not have a paralithic contact above 102 cm
Hyalite (MT) - do not have a horizon of secondary calcium carbonate accumulation; do not have a paralithic contact above 102 cm
Jeffcity (MT) - do not have a calcic horizon; have a lithic contact above 102 cm
Kokoruda (MT) - do not have a horizon of secondary calcium carbonate accumulation; do not have a paralithic contact above 102 cm
Livona (ND) - do not have a calcic horizon; do not have a paralithic contact above 102 cm
Martinsdale (MT+CO) - do not have a paralithic contact above 102 cm
Maudlin (CO) - do not have a horizon of secondary calcium carbonate accumulation; have a lithic contact at depths of 50 to 102 cm
Meagher (MT) - do not have a paralithic contact above 102 cm
Moen (CO) - do not have a horizon of secondary calcium carbonate accumulation; have a lithic contact at depths of 50 to 102 cm
Moento (CO) - do not have a horizon of secondary calcium carbonate accumulation; have a lithic contact at depths of 50 to 102 cm
Perrypark (CO) - do not have a horizon of secondary calcium carbonate accumulation; do not have a paralithic contact above 102 cm
Pianohill (MT) - do not have a horizon of secondary calcium carbonate accumulation; have a lithic contact at depths of 50 to 102 cm
Placerton (MT) - do not have a calcic horizon; have a lithic contact at depths of 102 to 152 cm
Reeder (ND) - do not have a calcic horizon; do not have rock fragments
Reedwest (MT) - do not have a calcic horizon; do not have more than 15 percent rock fragments
Snakejohn (UT) - do not have a paralithic contact above 102 cm; have a lithic contact at depths of 102 to 152 cm
Sponseller (AZ) - do not have a horizon of secondary calcium carbonate accumulation; do not have a paralithic contact above 102 cm
Trag (CO,NM,UT) - do not have a horizon of secondary calcium carbonate accumulation; do not have a paralithic contact above 102 cm
Tragmon (CO) - do not have a horizon of secondary calcium carbonate accumulation; do not have a paralithic contact above 102 cm
Trazuni (NM) - do not have a horizon of secondary calcium carbonate accumulation; do not have a paralithic contact above 102 cm
Trujillo (CO) - do not have a calcic horizon; do not have a paralithic contact above 102 cm
Ulrant (WY) - have a calcium carbonate equivalent greater than 40 percent in the calcic horizon; do not have a paralithic contact above 102 cm; have a lithic contact at depths of 102 to 152 cm
Vida (MT,SD) - do not have a calcic horizon; do not have a paralithic contact above 102 cm
Watne (MT) - do not have a paralithic contact above 102 cm
Watrous (ND,SD,UT) - do not have a calcic horizon; have a lithic contact at depths of 50 to 102 cm
Wemple (MT) - do not have a calcic horizon; do not have a paralithic contact above 102 cm; have a lithic contact at depths of 102 to 152 cm
Williams (ND,MT,SD) - do not have a calcic horizon; do not have a paralithic contact above 102 cm
Yegen (MT,ND,SD) - do not have a calcic horizon; do not have a lithic contact above 102 cm
GEOGRAPHIC SETTING:
Landform - fan remnants, earthflows, and escarpments
Elevation - 970 to 1,500 meters
Slope - 2 to 60 percent
Parent material - alluvium, colluviuum, or residuum from lithified earthflow deposits
Climate - long, cold winters; moist springs; warm summers
Mean annual air temperature - 4 to 7 degrees C
Mean annual precipitation - 330 to 559 mm
Frost-free period - 70 to 120 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Bitterroot soils are used mainly for rangeland, non-irrigated hayland and grain crops.
DISTRIBUTION AND EXTENT: Bitterroot soils are of small extent in intermountain valleys and foothills of western Montana. MLRA 43B, 44A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Ravalli County (Bitterroot Valley Area), Montana, 1952.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - from the soil surface to 32 cm (A horizon)
Argillic horizon - from 32 to 47 cm (Bt horizon)
Calcic horizon - from 47 to 79 cm (Bk horizon)
Paralithic contact - at 79 cm (Cr horizon)
Particle-size control section - from 32 to 47 cm (Bt horizon)
Bitterroot soils have a frigid temperature regime and an ustic moisture regime.
This description reflects an update in classification from Coarse-loamy, mixed, frigid Typic Haplustolls to Fine-loamy, mixed, frigid Typic Argiustolls. The type location has been moved and redescribed to current description standards.
National Cooperative Soil Survey
U.S.A.