LOCATION LUMPGULCH MT
Established Series
Rev. PEM-JAL-RJS
11/2012
LUMPGULCH SERIES
The Lumpgulch series consists of moderately deep, well drained soils that formed in colluvium over residuum derived from granitic bedrock. These soils are on bedrock-floored plains, hillslopes, mountains and escarpments. Slopes are 4 to 60 percent. Mean annual precipitation is about 430 mm, and mean annual air temperature is about 4.5 degrees C.
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Typic Haplustalfs
TYPICAL PEDON: Lumpgulch gravelly sandy clay loam, bouldery, in forest (colors are for dry soil unless otherwise noted).
Oi--0 to 2 cm; partially decomposed needles, twigs and leaves.
A--2 to 7 cm; brown (10YR 4/3) gravelly sandy clay loam, very dark grayish brown (10YR 3/2) moist; weak fine and medium granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine, common fine, and few medium and coarse roots; many very fine and fine, and few medium pores; 15 percent gravel; neutral (pH 7.0); clear smooth boundary. (5 to 14 cm thick)
E--7 to 18 cm; light brownish gray (10YR 6/2) gravelly sandy clay loam, brown (10YR 5/3) moist; weak fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine, common fine, and few medium and coarse roots; many very fine and few fine tubular and interstitial pores; 25 percent gravel; neutral (pH 6.6); clear smooth boundary. (10 to 25 cm thick)
Bt--18 to 56 cm; light olive brown (2.5Y 5/4) gravelly sandy clay loam, olive brown (2.5Y 4/4) moist; moderate medium and coarse prismatic structure parting to moderate medium subangular blocky; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine, and few medium and coarse roots; many very fine and few fine tubular and interstitial pores; many faint clay films bridging sand grains and on faces of peds; 30 percent gravel; neutral (pH 6.8); clear wavy boundary. (36 to 64 cm thick)
Cr--56 to 69 cm; light olive gray decomposed granite bedrock (grus) that crushes to very gravelly loamy coarse sand; neutral (pH 6.7). (3 to 12 cm thick)
R--69 inches; hard granite bedrock.
TYPE LOCATION: Jefferson County, Montana; 205 meters north and 265 meters west of the SE corner of sec. 17, T.5N, R.2W.
RANGE IN CHARACTERISTICS:
Soil temperature - 3.5 to 7.0 degrees C.
Depth to the argillic horizon - 18 to 40 cm
Depth to a paralithic contact - 50 to 96 cm
Depth to a lithic contact - 58 to 100 cm
Note: Some pedons may have a thin BC or C horizon between the Bt and Cr horizons.
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: sandy clay loam, sandy loam, coarse sandy loam or loam
Clay content: 10 to 25 percent
Rock fragments: 0 to 25 percent gravel
Reaction: pH 6.1 to 7.3
E horizon
Hue: 10YR or 2.5Y; dry or moist
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 or 3; dry or moist
Texture: coarse sandy loam, sandy loam or sandy clay loam
Clay content: 10 to 25 percent
Rock fragments: 5 to 25 percent gravel (mostly less than 7mm in diameter)
Reaction: pH 6.1 to 7.3
Bt horizon
Hue: 10YR or 2.5Y; dry or moist
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 3 or 4; dry or moist
Texture: sandy clay loam or clay loam
Clay content: 20 to 30 percent
Rock fragments: 10 to 35 percent gravel (mostly less than 7mm in diameter)
Reaction: pH 6.1 to 7.3
COMPETING SERIES:
Alderon (WY) - do not have a lithic contact within 100 cm
Allens Park (CO) - do not have a paralithic contact
Bayerton (WY) - do not have a paralithic contact
Belltower (MT) - have secondary calcium carbonate accumulation
Elbeth (CO) - are very deep
Elbuck (NM) - are very deep
Elmark (MT) - have a lithic contact at a depth of 100 to 150 cm
Haugan (MT) - are very deep
Heflin (CO) - are deep to a paralithic contact
Hoyt (MT) - are very deep
Jemco (CO) - do not have a lithic contact
Jemez (NM) - do not have a paralithic contact
Kunz (UT) - are very deep
Kwiavu (CO) - are very deep
Lakoa (SD) - have secondary calcium carbonate accumulation
Lick (MT) - are very deep
Littlepine (CO) - are very deep
Losindios (NM) - are very deep
Maitland (SD) - are very deep
Northrim (CO) - are very deep
Plome (CO) - are very deep
Rule (CO) - do not have a lithic contact within 100 cm
Shoemaker (NM) - do not have a paralithic contact
Sweetweed (MT) - are very deep
Tunitcha (NM) - are deep to a paralithic contact
GEOGRAPHIC SETTING:
Landform - bedrock-floored plains, hillslopes, mountains and escarpments
Elevation - 1,370 to 1,900 meters
Slope - 4 to 60 percent
Parent material - colluvium over residuum derived from granitic bedrock
Climate - long, cold winters; moist springs; warm summers
Mean annual precipitation - 380 to 500 mm
Mean annual air temperature - 2.5 to 6.0 degrees C.
Frost-free period - 70 to 105 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained, moderate permeability.
USE AND VEGETATION: Lumpgulch soils are primarily used for woodland. The potential native vegetation is mainly Douglas-fir, ponderosa pine, pinegrass, common snowberry, raceme pussytoes, currant, Rocky Mountain juniper, big sagebrush, rough fescue, Idaho fescue, and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: Lumpgulch soils are of small extent in southwestern Montana. MLRA - 43B.
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 - 0 to 18 cm (Oi, A, E horizons)
argillic horizon - 18 to 56 cm (Bt horizon)
particle-size control section - 18 to 56 cm (Bt horizon)
paralithic layer - 56 to 69 cm (Cr horizon)
lithic contact - at 69 cm (R horizon).
Lumpgulch soils have a frigid temperature regime and an ustic moisture regime.
Additional Information: Classification changed from Typic Eutroboralfs in 1997. Soil interpretation record - MT3066
National Cooperative Soil Survey
U.S.A.