LOCATION RITTEL MTEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, frigid Typic Haplustalfs
TYPICAL PEDON: Rittel loam, forested (colors are for dry soil unless otherwise noted).
O--2 inches to 0; forest litter of partially decomposed needles and twigs; abrupt smooth boundary.
A--0 to 1 inch; 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 pebbles, 5 percent cobbles; moderately acid (pH 6.0); clear smooth boundary. (0 to 5 inches thick)
E--1 to 4 inches; 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 pebbles; moderately acid (pH 6.0); clear smooth boundary. (2 to 13 inches thick)
Bt/E--4 to 8 inches; Bt part (90 percent) pale brown (10YR 6/3) silty clay, dark 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 pebbles; slightly acid (pH 6.2); abrupt smooth boundary. (0 to 6 inches thick)
Bt1--8 to 15 inches; 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 pebbles; moderately acid (pH 5.6); gradual smooth boundary. (5 to 10 inches thick)
Bt2--15 to 24 inches; 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. (5 to 10 inches thick)
Bt3--24 to 32 inches; 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. (5 to 10 inches thick)
Cr--32 to 60 inches; 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; 1,350 feet north and 2,600 feet west of the SE corner of sec. 9, T. 18 N., R. 7 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 47 degrees F.
Moisture control section - between 4 and 12 inches.
Control section - 35 to 50 percent clay and 0 to 15 percent rock fragments.
Depth to Cr material - 20 to 40 inches.
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 fragments: 0 to 20 percent--0 to 10 percent cobbles, 0 to 10 percent angular pebbles
Reaction: pH 5.6 to 7.3
E horizon - Hue: 10YR or 2.5Y
Value: 5, 6 or 7 dry; 4 or 5 moist
Chroma: 2 or 3
Clay content: 15 to 27 percent
Rock fragments: 0 to 20 percent--0 to 10 percent cobbles, 0 to 15 percent pebbles 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, 4 or 5 moist
Chroma: 2, 3, or 4
Texture: clay loam, clay, or silty clay
Clay content: 27 to 45 percent
Rock fragments: 0 to 20 percent pebbles 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, 3, or 4
Texture: clay loam, clay, or silty clay
Clay content: 35 to 50 percent
Rock fragments: 0 to 15 percent pebbles of channers
Reaction: pH 5.6 to 7.8
COMPETING SERIES:
Crow (MT) - is very deep.
Heckly (NM) - has a lithic contact at 20 to 40 inches.
Ligocki (NM) - is very deep.
Loosegate (NM) - has a lithic contact at 20 to 40 inches.
Silverchief (MT) - is very deep.
GEOGRAPHIC SETTING:
Landform - hills and mountains.
Elevation - 4,400 to 6,500 feet.
Slope- 15 to 35 percent.
Parent material - material derived from semiconsolidated shale.
Climate - long, cold winters; moist springs; warm summers.
Mean annual precipitation - 15 to 25 inches.
Mean annual temperature - 38 to 42 inches degrees F.
Frost free period - 70 to 105 days.
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 inextensive in west central Montana.
MLRA OFFICE 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: an ochric epipedon from the surface to 4 inches (A and E horizons); an albic horizon from 1 to 4 inches (E horizon); an argillic horizon from 4 to 32 inches (Bt/E and Bt horizons); a particle-size control section from 4 to 24 inches (Bt/E, Bt1, and Bt2 horizons); and a paralithic contact at a depth of 32 inches (Cr horizon). The Rittel soils have a frigid temperature regime and an ustic moisture regime.
Classification changed to Typic Haplustalfs in 1997.