LOCATION WIMPER MT
Established Series
Rev. PEM-DES-RJS
04/2013
WIMPER SERIES
The Wimper series consists of very deep, well drained soils that formed in alluvium or colluvium. These soils are on stream terraces, alluvial fans, fan remnants, eroded fan remnants, escarpments, hillslopes and mountain slopes. Slopes are 2 to 60 percent. Mean annual precipitation is about 425 mm, and mean annual air temperature is about 4.5 degrees C.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Typic Haplustolls
TYPICAL PEDON: Wimper gravelly loam, stony, in rangeland (colors are for dry soil unless otherwise noted).
A--0 to 18 cm; very dark grayish brown (10YR 3/2) gravelly loam, very dark brown (10YR 2/2) moist; moderate medium granular structure; slightly hard, very friable, slightly sticky and nonplastic; many very fine and fine and few medium roots; many very fine and fine pores; 20 percent gravel; neutral (pH 7.3); clear wavy boundary. (12 to 20 cm thick)
Bw--18 to 33 cm; dark grayish brown (10YR 4/2) gravelly loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; slightly hard, very friable, slightly sticky and nonplastic; many very fine and few fine and medium roots; many very fine and fine interstitial and tubular pores; 20 percent gravel; slightly alkaline (pH 7.6); clear wavy boundary. (10 to 25 cm thick)
Bk1--33 to 43 cm; brown (10YR 5/3) very gravelly loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; slightly hard, very friable, slightly sticky and nonplastic; common fine and few fine and medium roots; many very fine and fine interstitial and tubular pores; 35 percent gravel; many faint calcium carbonate coatings on undersides of fragments; strongly effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (0 to 28 cm thick)
Bk2--43 to 79 cm; very pale brown (10YR 8/2) very gravelly loam, grayish brown (10YR 5/2) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and few fine and medium roots; many very fine and fine interstitial and tubular pores; 40 percent gravel; few very fine and fine masses and threads of calcium carbonate, continuous distinct calcium carbonate casts on undersides of fragments; violently effervescent; moderately alkaline (pH 8.3); gradual wavy boundary. (18 to 50 cm thick)
Bk3--79 to 152 cm; light gray (10YR 7/2) very gravelly loam, light brownish gray (10YR 6/2) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; common very fine and fine interstitial and tubular pores; 55 percent gravel; few very fine and fine masses and threads of calcium carbonate, continuous faint calcium carbonate coatings on undersides of fragments; violently effervescent; moderately alkaline (pH 8.3).
TYPE LOCATION: Jefferson County, Montana; 135 meters north and 90 meters east of the SW corner of sec. 6, T. 1 N., R. 2 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 3.5 to 8.0 degrees C.
Mollic epipedon thickness - 18 to 38 cm
Depth to secondary calcium carbonate accumulation - 25 to 38 inches
Note: Some pedons may have a C horizon below a depth of 100 cm.
A horizon
Hue: 7.5YR or 10YR; dry or moist
Value: 3 to 5 dry; 2 or 3 moist
Chroma: 1 to 3; dry or moist
Texture: sandy loam, loam or silt loam
Clay content: 10 to 27 percent
Rock fragments: 0 to 40 percent--0 to 35 percent gravel, 0 to 20 percent cobbles and stones
Reaction: pH 6.6 to 7.8
Bw horizon
Hue: 7.5YR or 10YR; dry or moist
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 2 to 4; dry or moist
Texture: loam or silt loam
Clay content: 10 to 27 percent
Rock fragments: 15 to 50 percent--15 to 40 percent gravel, 0 to 10 percent cobbles and stones
Reaction: pH 6.6 to 7.8
Bk1 horizon
Hue: 7.5YR, 10YR or 2.5Y; dry or moist
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 2 or 3; dry or moist
Texture: sandy loam, loam or silt loam
Clay content: 10 to 27 percent
Rock fragments: 35 to 60 percent--25 to 50 percent gravel, 0 to 15 percent cobbles and stones
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.9 to 8.4
Bk2 horizon
Hue: 7.5YR, 10YR or 2.5Y; dry or moist
Value: 6 to 8 dry; 5 or 6 moist
Chroma: 2 or 3; dry or moist
Texture: sandy loam, loam or silt loam
Clay content: 15 to 27 percent
Rock fragments: 35 to 60 percent--25 to 45 percent gravel, 0 to 15 percent cobbles and stones
Calcium carbonate equivalent: 15 to 25 percent
Reaction: pH 7.9 to 9.0
Bk3 horizon
Hue: 7.5YR, 10YR or 2.5Y; dry or moist
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 2 or 3; dry or moist
Texture: sandy loam, loam or silt loam
Clay content: 15 to 27 percent
Rock fragments: 35 to 70 percent--25 to 55 percent gravel, 0 to 15 percent cobbles
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.9 to 9.0
C horizon (where present)
Hue: 7.5YR, 10YR or 2.5Y; dry or moist
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 2 or 3; dry or moist
Texture: loam, sandy loam or loamy sand
Clay content: 5 to 15 percent
Rock fragments: 35 to 70 percent--25 to 55 percent gravel, 0 to 15 percent cobbles
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.9 to 8.4
COMPETING SERIES:
Aguja (NM) - do not have a calcic horizon
Finleypoint (MT) - does not have secondary calcium carbonate accumulation
Flott (MT) - depths to secondary calcium carbonate accumulation is greater than 38 cm
Kutler (CO) - are moderately deep to a paralithic contact
Labre (MT) - have scoria rock fragments (baked sandstone and shale)
Perma (MT) - do not have a calcic horizon
Peso (NM) - are moderately deep to a lithic contact
Pesowyo (WY) - are moderately deep to a lithic contact
Renegade (UT) - are deep to a paralithic contact
Sandia (NM) - have greater than 50 percent cobbles and stones in the control section; chroma of 1 in the mollic epipedon
Slimbutte (SD) - are fragmental below a depth of 100 cm
Subwell (MT) - have a discontinuity of very gravelly sandy loam at depths of 25 to 50 cm; nonskeletal above the discontinuity
Towave (UT) - do not have a calcic horizon
Veatch (CO) - are moderately deep to a lithic contact
Vigilante (MT) - are deep to a lithic contact
Walstead (MT) - depths to secondary calcium carbonate accumulation is greater than 58 cm
Wanagan (ND) - have a lithological discontinuity at 30 to 50 cm
GEOGRAPHIC SETTING:
Landform - stream terraces, alluvial fans, fan remnants, eroded fan remnants, escarpments, hillslopes, and mountain slopes
Elevation - 875 to 2,025 meters
Slope - 2 to 60 percent
Parent material - alluvium or colluvium
Climate - long, cold winters; moist springs; warm summers
Mean annual precipitation - 365 to 575 mm
Mean annual air temperature - 2.5 to 7.5 degrees C.
Frost-free period - 70 to 110 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained, moderate permeability.
USE AND VEGETATION: Wimper soils are primarily used for rangeland, woodland, and wildlife habitat. The potential native vegetation is mainly rough fescue, Idaho fescue, bluebunch wheatgrass, prairie junegrass, parry danthonia, yellow stonecrop, salsify, American vetch, milkvetch, fringed sagewort, goldenrod, and big sagebrush. Areas in woodland have an overstory of Douglas-fir, ponderosa pine, and limber pine with an understory of rough fescue, Idaho fescue, bluebunch wheatgrass, Rocky Mountain juniper, and big sagebrush.
DISTRIBUTION AND EXTENT: Wimper soils are of small extent in southwestern Montana. MLRAs - 43A, 43B, 44A and 44B.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Granite County, Montana, 1997; proposed in Jefferson County, Montana, 1993.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - from 0 to 33 cm (A, Bw horizons)
Secondary calcium carbonate accumulation - from 33 to 152 cm (Bk1, Bk2, Bk3 horizons)
Calcic horizon - from 43 to 79 cm (Bk2 horizon)
Particle-size control section - 25 to 100 cm (part of Bw, Bk1, Bk2, part of Bk3 horizons).
Wimper soils have a frigid temperature regime and an ustic moisture regime.
ADDITIONAL DATA: Soil interpretation records - MT1532 and MT3013.
National Cooperative Soil Survey
U.S.A.