LOCATION CATGULCH MT
Established Series
Rev. TJK-JB-EMM
07/2012
CATGULCH SERIES
The Catgulch series consists of shallow, well drained soils that formed in residuum derived from granite or other coarse grained igneous rocks, gneiss or schist. These soils are on bedrock-floored plains, mountains, and hills. Slopes are 2 to 75 percent. Mean annual precipitation is about 17 inches, and mean annual air temperature is about 40 degrees F.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Lithic Haplustolls
TYPICAL PEDON: Catgulch gravelly sandy clay loam, in rangeland (colors are for dry soil unless otherwise noted).
A--0 to 5 inches; dark grayish brown (10YR 4/2) gravelly sandy clay loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; common very fine and few fine roots; many very fine and common fine interstitial pores; 10 percent gravel; slightly acid (pH 6.5); clear smooth boundary. (4 to 9 inches thick)
Bw1--5 to 9 inches; brown (10YR 5/3) very gravelly sandy clay loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and few fine roots; common very fine and fine pores; 35 percent gravel; neutral (pH 6.6); clear smooth boundary.
Bw2--9 to 12 inches; brown (10YR 5/3) very gravelly sandy loam, brown (10YR 4/3) moist; weak fine subangular blocky structure; slightly hard, very friable, slightly sticky and nonplastic; few very fine and fine roots; common very fine and fine pores; 45 percent gravel; slightly acid (pH 6.5); abrupt smooth boundary. (Combined thickness of Bw1 and Bw2 horizons is 5 to 15 inches.)
Cr--12 to 15 inches; yellowish brown (10YR 5/4) decomposed granitic bedrock that crushes to very gravelly loamy coarse sand; neutral (pH 6.8). (2 to 8 inches thick)
R--15 inches; hard granite bedrock.
TYPE LOCATION: Jefferson County, Montana; 1,800 feet north and 600 feet west of the SE corner of sec. 33, T. 7 N., R. 4 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 38 to 44 degrees F.
Moisture control section - between 4 and 12 inches, or between 4 inches and lithic contact if bedrock is less than 12 inches deep.
Mollic epipedon thickness - 7 to 12 inches.
Depth to Cr horizon - 10 to 18.
Depth to bedrock - 12 to 20 inches.
Phases - moist (for areas with Douglas fir or ponderosa pine overstory), stony, very stony, and bouldery.
Rock fragments, surface cover: 0.01 to 15 percent stones, boulders.
A horizon
Hue: 10YR or 2.5Y
Value: 3 or 4 dry, 2 or 3 moist
Chroma: 1, 2 or 3
Texture: sandy loam, loam, sandy clay loam, or coarse sandy loam
Clay content: 12 to 24 percent
Rock fragments: 5 to 50 percent--0 to 20 percent cobbles and stones; 5 to 40 percent gravel
Reaction: pH 6.1 to 7.3
Bw horizons
Hue: 10YR or 2.5Y
Value: 4 or 5 dry; 3 or 4 moist
Chroma: 3, 4, or 6
Texture: sandy loam, loam, coarse sandy loam, or sandy clay loam
Clay content: 10 to 22 percent
Rock fragments: 35 to 60 percent--5 to 15 percent cobbles and stones; 30 to 55 percent gravel
Reaction: pH 6.1 to 7.3
COMPETING SERIES:
Castner (MT) - has a horizon of secondary carbonate accumulation; does not have a paralithic contact above a lithic contact of granite.
Celeste (CO) - has hue of 5YR and redder; does not have a paralithic contact above the lithic contact.
Duffymont (CO) - has dominant rock fragments greater than 10 inches; does not have a paralithic contact of grus above the lithic contact.
Firo (NM) - has dominant rock fragments greater than 10 inches; has O horizons; formed in acid-igneous rock at elevations above 6,800 feet.
Highpark (CO) - does not have a paralithic contact above a lithic contact.
Moonset (UT) - does not have a paralithic contact above a lithic contact.
Nivean (MT) - has vitrandic properties.
Paunsaugunt (UT) - calcareous throughout.
Vershal (MT) - has a lithic contact at depths of 5 to 10 inches.
Whitlash (MT) - does not have a paralithic contact of grus above a lithic contact of granite.
Wuby (UT) - does not have a paralithic contact above a lithic contact.
GEOGRAPHIC SETTING:
Landform - bedrock-floored plains; mountains; hills.
Elevation - 4,400 to 7,000 feet.
Slope - 2 to 75 percent.
Parent material - residuum derived from granite or other coarse grained igneous rocks, gneiss or schist.
Climate - long, cold winters; moist springs; warm summers.
Mean annual precipitation - 15 to 22 inches.
Mean annual air temperature - 36 to 43 degrees.
Frost-free period - 70 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Catgulch soils are used primarily for rangeland and woodland. The potential native vegetation is mainly Idaho fescue, bluebunch wheatgrass, rough fescue, Sandberg bluegrass, mountain big sagebrush, and rubber rabbitbrush. Areas with a forest canopy have an overstory of ponderosa pine, Douglas-fir, and limber pine and an understory of Idaho fescue, bluebunch wheatgrass, big sagebrush, and Rocky mountain juniper.
DISTRIBUTION AND EXTENT: Catgulch soils are of small extent in southwestern Montana. MLRA 43B.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Gallatin County, Montana, 1997; proposed in Jefferson County, Montana, 1993.
REMARKS: Soil interpretation record: MT1551, MT3044.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - from the soil surface to 9 inches (A, Bw1 horizons);
Cambic horizon - from 9 to 12 inches (Bw2 horizon);
Particle-size control section - from the soil surface to 12 inches (A, Bw1, Bw2 horizons);
Paralithic contact - layer of decomposed granite bedrock (grus) from 12 to 15 inches (Cr horizon);
Lithic contact - hard granite bedrock at 15 inches (R horizon).
Catgulch soils have a frigid temperature regime and an ustic moisture regime.
National Cooperative Soil Survey
U.S.A.