LOCATION ROEGULCH                MT

Established Series
Rev. PEM-JAL-RJS
04/2013

ROEGULCH SERIES

The Roegulch series consists of shallow, well drained soils that formed in colluvium, slope alluvium or residuum derived from granite and other coarse grained igneous rocks. These soils are on escarpments, ridges and hillslopes. Slopes are 8 to 60 percent. Mean annual precipitation is about 430 mm, and mean annual air temperature is about 4.5 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Lithic Haplustepts

TYPICAL PEDON: Roegulch cobbly sandy clay loam, very bouldery, forested (colors are for dry soil unless otherwise noted).

Oi--0 to 5 cm; partially decomposed needles, twigs, and leaves. (0 to 6 cm thick)

A--5 to 13 cm; dark grayish brown (10YR 4/2) cobbly sandy clay loam, very dark grayish brown (10YR 3/2) moist; weak medium and fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine and few fine roots; many very fine and fine, and few medium pores; 20 percent cobbles, 10 percent gravel; neutral (pH 7.0); clear smooth boundary. (8 to 12 cm thick)

Bw--13 to 40 cm; pale brown (10YR 6/3) very cobbly sandy clay loam, brown (10YR 5/3) moist; moderate medium and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine, common fine and medium and few coarse roots; many very fine and few fine tubular and interstitial pores; 10 percent stones, 20 percent cobbles, 20 percent gravel; slightly acid (pH 6.2); clear smooth boundary. (16 to 36 cm thick)

Cr--40 to 48 cm; light brownish gray (2.5Y 6/2) decomposed granite bedrock (grus) that crushes to very gravelly coarse sand; gradual wavy boundary. (5 to 15 cm thick)

R--48 cm; hard granite bedrock.

TYPE LOCATION: Jefferson County, Montana; 640 meters south and 150 meters west of the NE corner of sec. 28, T. 9 N., R. 2 W.

RANGE IN CHARACTERISTICS:
Soil temperature - 4.5 to 6.5 degrees C.
Depth to a paralithic contact - 25 to 46 cm
Depth to a lithic contact - 30 to 50 cm

A horizon
Hue: 10YR or 2.5Y; dry or moist
Value: 4 or 5 dry; 3 or 4 moist
Chroma: 2 or 3; dry or moist
Texture: loam or sandy clay loam
Clay content: 10 to 25 percent
Rock fragments: 20 to 60 percent--10 to 40 percent gravel, 10 to 20 percent cobbles and stones
Reaction: pH 6.1 to 7.3

Bw horizon
Hue: 10YR or 2.5; dry or moist
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 to 4; dry or moist
Texture: coarse sandy loam, sandy loam or sandy clay loam
Clay content: 10 to 25 percent
Rock fragments: 35 to 70 percent--20 to 35 percent gravel, 15 to 25 percent cobbles, 0 to 10 percent stones
Reaction: pH 6.1 to 7.3

COMPETING SERIES:
Cinnadale (NM) - does not have a paralithic layer
Cypher (NM) - does not have a paralithic layer
Devilfence (MT) - have secondary calcium carbonate accumulation
Deville (MT) - does not have a paralithic layer
Kounter (MT) - have secondary calcium carbonate accumulation
Quaint (MT) - have secondary calcium carbonate accumulation
Shaboom (MT) - does not have a paralithic layer
Sharrott (MT) - does not have a paralithic layer
Valto (CO) - does not have a paralithic layer
Villareal (CO) - does not have a paralithic layer

GEOGRAPHIC SETTING:
Landform - escarpments, ridges and hillslopes
Elevation - 1,250 to 1,850 meters
Slope - 8 to 60 percent
Parent material - colluvium, slope alluvium or residuum derived from granite and other coarse grained igneous rocks
Climate - long, cold winters; moist springs; warm summers
Mean annual precipitation - 375 to 485 mm
Mean annual air temperature - 2.5 to 5.5 degrees C.
Frost-free period - 70 to 105 days.

GEOGRAPHICALLY ASSOCIATED SOILS: None listed.

DRAINAGE AND PERMEABILITY: Well drained, moderate permeability.

USE AND VEGETATION: Roegulch soils are primarily used for timber production, wildlife habitat, and understory grazing. The potential native vegetation is mainly Douglas fir, ponderosa pine, common snowberry, heartleaf arnica, Kinnikinnick, Oregongrape, rough fescue, Idaho fescue, and bluebunch wheatgrass.

DISTRIBUTION AND EXTENT: Roegulch soils are of small extent in southwestern Montana. MLRAs - 43B, 44A.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.

SERIES ESTABLISHED: Jefferson County, Montana, 1998.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - from 0 to 13 cm (Oi, A horizons);
Cambic horizon - from 13 to 40 cm (Bw horizon);
Paralithic layer - from 40 to 48 cm (Cr horizon);
Lithic contact - at 48 cm (R horizon); and
Particle-size control section - from 25 to 40 cm (part of Bw horizon).

Roegulch soils have a frigid temperature regime and an ustic moisture regime.

ADDITIONAL DATA: Soil interpretation records - MT3081, MT3082.

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National Cooperative Soil Survey
U.S.A.