LOCATION HELLROARING MT
Established Series
REV. KTS-RJS
01/2012
HELLROARING SERIES
The Hellroaring series consists of very deep, somewhat poorly drained soils that formed in lacustrine deposits. These sodium affected soils occur on lakebeds. Slopes are 0 to 4 percent. Mean annual precipitation is about 400 mm, and the mean annual air temperature is about 3 degrees C.
TAXONOMIC CLASS: Fine, smectitic Oxyaquic Haplocryalfs
TYPICAL PEDON: Hellroaring loam, in rangeland on a 1 percent slope at an elevation of 2021 meters (colors are for dry soil unless otherwise noted).
A1--0 to 9 cm; dark grayish brown (10YR 4/2) loam, very dark brown (10YR 2/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine, fine and medium roots; many very fine and fine irregular pores; moderately alkaline (pH 8.0); clear smooth boundary. (0 to 15 cm thick)
A2--9 to 15 cm; grayish brown (10YR 5/2) fine sandy loam, very dark grayish brown (10YR 3/2) moist; moderate medium and thick platy structure; slightly hard, very friable, nonsticky and nonplastic; common very fine and fine roots; many very fine and fine irregular pores; strongly alkaline (pH 8.6); abrupt smooth boundary. (4 to 15 cm thick)
Btn1--15 to 28 cm; grayish brown (10YR 5/2) clay loam, dark brown (10YR 3/3) moist; strong fine and medium columnar structure; extremely hard, extremely firm, very sticky and very plastic; few very fine and fine roots; common fine tubular pores; 70 percent prominent continuous clay films on all faces of peds; very strongly alkaline (pH 9.4); clear smooth boundary.
Btn2--28 to 45 cm; light brownish gray (10YR 6/2) clay loam, dark grayish brown (10YR 4/2) moist; strong fine and medium subangular blocky structure; very hard, very firm, very sticky and very plastic; few very fine roots; common fine tubular pores; 35 percent distinct continuous clay films on all faces of peds; finely disseminated calcium carbonate; slightly effervescent; very strongly alkaline (pH 9.6); clear wavy boundary. (combined thickness of Btn horizons - 30 to 65 cm)
Btkn--45 to 67 cm; light gray (10YR 7/2) clay loam, light brownish gray (10YR 6/2) moist; moderate fine and medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few fine tubular pores; 5 percent faint patchy clay films on all faces of peds; finely disseminated calcium carbonate and 2 percent fine, faint, irregular soft masses of calcium carbonate; strongly effervescent; very strongly alkaline (pH 9.6); gradual wavy boundary. (0 to 25 cm thick)
C--67 to 152 cm; light yellowish brown (2.5Y 6/3) clay loam, olive brown (2.5Y 4/3) moist; 25 percent medium prominent brownish yellow (10YR 6/6) redox concentrations; massive; very hard, very firm, very sticky and very plastic; few fine tubular pores; finely disseminated calcium carbonate; slightly effervescent; strongly alkaline (pH 9.0).
TYPE LOCATION: Beaverhead County, Montana; located about 500 meters east and 375 meters south of the northwest corner of sec. 13, T. 14 S., R 5 W; Corral Creek topographic quadrangle; UTM 12T, 407893e., 4941563n. NAD 83.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 2 to 6 degrees C.
Depth to natric horizon - 5 to 20 cm
Depth to secondary calcium carbonates - 25 to 50 cm
Depth to redoximorphic features - 60 to 100 cm
A1 horizon
Value: 3 or 4 dry; 2 or 3 moist
Chroma: 2 or 3; dry or moist
Clay content: 15 to 25 percent
Rock fragments: 0 to 15 percent gravel
Calcium carbonate equivalent: 0 to 1 percent
Electrical conductivity: 0 to 1 mmhos/cm
Sodium adsorption ratio: 3 to 8
Reaction: pH 7.9 to 8.4
A2 horizon
Value: 5 or 6 dry; 3 or 4 moist
Chroma: 2 or 3 dry or moist
Texture: fine sandy loam or loam
Clay content: 12 to 25 percent
Rock fragments: 0 to 15 percent gravel
Calcium carbonate equivalent: 0 to 1 percent
Electrical conductivity: 0 to 1 mmhos/cm
Sodium adsorption ratio: 8 to 20
Reaction: pH 8.0 to 9.0
Btn horizons
Hue: 10YR or 2.5Y; dry or moist
Value: 5 or 6 dry; 3 to 5 moist
Chroma: 2 to 4; dry or moist
Texture: clay loam, silty clay loam, silty clay or clay
Clay content: 35 to 50 percent
Rock fragments: 0 to 15 percent gravel
Calcium carbonate equivalent: 0 to 1 percent
Electrical conductivity: 0 to 4 mmhos/cm
Sodium adsorption ratio: 25 to 75
Reaction: pH greater than or equal to 9.0
Btkn horizon
Hue: 10YR or 2.5Y
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 2 to 4; dry or moist
Texture: clay loam, silty clay loam, silty clay or clay
Clay content: 27 to 50 percent
Rock fragments: 0 to 15 percent gravel
Calcium carbonate equivalent: 3 to 15 percent
Electrical conductivity: 0 to 4 mmhos/cm
Sodium adsorption ratio: 25 to 75
Reaction: pH greater than or equal to 9.0
C horizons
Hue: 10YR or 2.5Y; dry or moist
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 2 to 4; dry or moist
Texture: clay loam, silty clay loam, silty clay or clay
Clay content: 27 to 45 percent
Rock fragments: 0 to 15 percent gravel
Calcium carbonate equivalent: 1 to 5 percent
Electrical conductivity: 0 to 4 mmhos/cm
Sodium adsorption ratio: 13 to 25
Reaction: pH greater than or equal to 8.5
COMPETING SERIES:
Elkwalow (CO) - does not have a natric horizon
GEOGRAPHIC SETTING:
Landform - lakebeds
Elevation - 1980 to 2140 meters
Slope - 0 to 4 percent
Parent material - lacustrine deposits
Climate - long, cold winters; moist springs; short warm summers
Mean annual precipitation - 380 to 485 mm
Mean annual air temperature - 1 to 4 degrees C.
Frost-free period - 50 to 70 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow permeability.
USE AND VEGETATION: Hellroaring soils are used mainly for rangeland. The vegetation is mainly greasewood, rubber rabbitbrush, inland saltgrass, mat muhly, squirreltail, basin wildrye, thickspike wheatgrass, POA (species), and miscellaneous forbs.
DISTRIBUTION AND EXTENT: Hellroaring soils are of small extent in southwestern Montana. MLRA - 44B.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES ESTABLISHED: Horse Prairie-South Valley Area - Part of Beaverhead County, Montana, 2011; proposed in Beaverhead County, Montana, 2010.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - from 0 to 15 cm (A1, A2 horizons)
Natric horizon - from 15 to 67 cm (Btn1, Btn2, Btkn horizons)
Particle-size control section - from 15 to 65 cm (Btn1, Btn2, part of Btkn horizons)
Note: The Btn1 horizon has mollic colors, but does not meet the rupture resistance requirement for a mollic epipedon
Hellroaring soils have a cryic temperature regime, an ustic moisture regime and an oxyaquic subclass.
Taxonomic version: Eleventh Edition, 2010.
National Cooperative Soil Survey
U.S.A.