LOCATION RITTEL MT
Established Series
Rev. JAL-KLS
03/2023
RITTEL SERIES
The Rittel series consists of moderately deep, well drained soils that formed in slope alluvium over residuum derived from semiconsolidated shale. These soils are on hills and sides of mountains. Slopes are 15 to 35 percent. Mean annual precipitation is about 430 mm, and mean annual air temperature is about 6 degrees C.
TAXONOMIC CLASS: Fine, mixed, superactive, frigid Typic Haplustalfs
TYPICAL PEDON: Rittel loam, forested (colors are for dry soil unless otherwise noted).
Oe--0 to 5 cm; forest litter of partially decomposed needles and twigs; abrupt smooth boundary.
A--5 to 8 cm; dark gray (10YR 4/1) loam, very dark gray (10YR 3/1) moist; moderate thin platy structure parting to moderate very fine granular; soft, very friable, slightly sticky and slightly plastic; many very fine roots and common medium roots; 5 percent angular gravel, 5 percent cobbles; moderately acid (pH 6.0); clear smooth boundary. (0 to 13 cm thick)
E--8 to 16 cm; light gray (10YR 7/2) loam, brown (10YR 5/3) moist; moderate thin and very thin platy structure parting to moderate very fine granular; soft, very friable, slightly sticky and slightly plastic; many very fine roots, common medium roots, and few coarse roots; many light gray silt and sand skeletons on faces of peds; 10 percent angular gravel; moderately acid (pH 6.0); clear smooth boundary. (5 to 33 cm thick)
Bt/E--16 to 26 cm; Bt part (90 percent) pale brown (10YR 6/3) silty clay, brown (10YR 4/3); E part (10 percent) light gray (10YR 7/2) loam, brown (10YR 5/3) moist; strong fine and medium subangular blocky structure; hard, firm, sticky and plastic; common very fine roots and few medium and coarse roots; many very fine tubular and interstitial pores; many distinct clay films on faces of peds; 5 percent angular gravel; slightly acid (pH 6.2); abrupt smooth boundary. (0 to 15 cm thick)
Bt1--26 to 44 cm; pale brown (10YR 6/3) silty clay, dark grayish brown (10YR 4/2) moist; strong medium prismatic structure parting to strong medium and coarse subangular blocky; very hard, firm, sticky and plastic; common very fine roots and few medium roots; many very fine tubular and interstitial pores; continuous prominent clay films on faces of peds; 5 percent angular gravel; moderately acid (pH 5.6); gradual smooth boundary. (13 to 25 cm thick)
Bt2--44 to 67 cm; light yellowish brown (2.5Y 6/4) silty clay, olive brown (2.5Y 4/4) moist; strong medium prismatic structure parting to strong medium and coarse subangular blocky; very hard, firm, sticky and plastic; common very fine roots and few medium roots; many very fine tubular and interstitial pores; continuous prominent clay films on faces of peds; moderately acid (pH 5.6); gradual smooth boundary. (Combined thickness of Bt1 and Bt2 horizons--25 to 50 cm)
Bt3--67 to 87 cm; light yellowish brown (2.5Y 6/4) silty clay, olive brown (2.5Y 4/4) moist; moderate medium prismatic structure parting to strong medium and coarse subangular blocky; very hard, firm, sticky and plastic; common very fine roots and few medium roots; many very fine tubular and interstitial pores; many distinct clay films on faces of peds; moderately acid (pH 5.6); gradual smooth boundary. (13 to 25 cm thick)
Cr--87 to 158 cm; light yellowish brown (2.5Y 6/4) and light brownish gray (2.5Y 6/2) semiconsolidated shale; slightly acid (pH 6.2).
TYPE LOCATION: Lewis and Clark County, Montana; about 410 meters north and 790 meters west of the southeast corner of sec. 9, T. 18 N., R. 7 W.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--6 to 8 degrees C
Soil moisture control section--10 to 30 cm
Depth to paralithic contact--50 to 100 cm
Particle-size control section:
Clay content--35 to 50 percent
Rock fragment content--0 to 15 percent
A horizon
Hue--10YR or 2.5Y
Value--4 or 5 dry; 2 or 3 moist
Chroma--1 or 2
Clay content--15 to 27 percent
Rock fragment content--0 to 20 percent total; 0 to 10 percent cobbles, 0 to 10 percent angular gravel
Reaction--pH 5.6 to 7.3
E horizon
Hue--10YR or 2.5Y
Value--5 through 7 dry; 4 or 5 moist
Chroma--2 or 3
Clay content--15 to 27 percent
Rock fragment content--0 to 20 percent total; 0 to 10 percent cobbles, 0 to 15 percent gravel or channers
Reaction--pH 5.6 to 7.3
Bt/E or E/Bt horizons
Hue--2.5Y, 10YR, 7.5YR, or 2.5YR
Value--Bt part 5 or 6, E part 6 or 7 dry; Bt part 4 or 5 moist, E part 3 through 5 moist
Chroma--2 through 4
Texture--clay loam, clay, or silty clay
Clay content--27 to 45 percent
Rock fragment content--0 to 20 percent gravel or channers
Reaction--pH 5.6 to 7.8
Bt horizons
Hue--10YR, 7.5YR, or 2.5Y
Value--5 or 6 dry; 4 or 5 moist
Chroma--2 through 4
Texture--clay loam, clay, or silty clay
Clay content--35 to 50 percent
Rock fragment content--0 to 15 percent gravel of channers
Reaction--pH 5.6 to 7.8
COMPETING SERIES:
Crow (MT) - are very deep.
Heckly (NM) - have lithic contact at 50 to 100 cm.
Ligocki (NM) - are very deep.
Loosegate (NM) - have lithic contact at 50 to 100 cm.
Silverchief (MT) - are very deep.
GEOGRAPHIC SETTING:
Landform--hills and mountain slopes
Elevation--1340 to 1980 meters
Slope--15 to 35 percent
Parent material--slope alluvium over residuum derived from semiconsolidated shale
Climate--long, cold winters; moist springs; warm summers
Mean annual precipitation--380 to 640 mm
Mean annual air temperature--3 to 6 degrees C
Frost free period--70 to 105 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; slow permeability.
USE AND VEGETATION: Rittel soils are used mainly for grazeable understory and wildlife habitat. Potential native vegetation is mainly Douglas-fir and limber pine with an understory of rough fescue, bluebunch wheatgrass, Idaho fescue, common snowberry, elk sedge, and arrowleaf balsamroot.
DISTRIBUTION AND EXTENT: Rittel soils are of small extent in west-central Montana; MLRA 43B.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Lewis and Clark County Area, Montana, 1991; proposed in Lewis and Clark County, Montana, 1987.
REMARKS: Soil interpretation record: MT1177
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon--5 to 16 cm (A and E horizons)
Albic horizon--8 to 16 cm (E horizon)
Argillic horizon--16 to 87 cm (Bt/E and Bt horizons)
Paralithic contact--87 cm (Cr horizon)
Particle-size control section--16 to 66 cm (Bt/E, Bt1, and Bt2 horizons)
Rittel soils have a frigid temperature regime and an ustic soil moisture regime with a typic subclass.
Converted to metric and O horizons were updated to start at zero. Competing series section was not updated. 02/2023
National Cooperative Soil Survey
U.S.A.