LOCATION WEMINUCHE COEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive Ustic Haplocryalfs
TYPICAL PEDON: Weminuche loam, on a southwest facing, simple, 55 percent slope in coniferous forest at an elevation of 8,800 feet. When described on July 10, 1980, the soil was moist throughout. (Colors are for dry soil unless otherwise noted.)
0i--0 to 2 inches; partially decomposed, organic material consisting mainly of needles, twigs, and bark. (1 to 4 inches thick)
A--2 to 4 inches; reddish brown (5YR 4/3) loam, dark reddish brown (5YR 3/3) moist; weak very thin platy structure parting to moderate very fine granular; soft, very friable, nonsticky and nonplastic; 3 percent gravel, 3 percent cobble; neutral (pH 7.2); clear wavy boundary. (0 to 3 inches thick)
E--4 to 11 inches; reddish brown (5YR 4/4) loam, dark reddish brown (5YR 3/4) moist; weak fine subangular blocky structure parting to weak very fine granular; soft, very friable, nonsticky and nonplastic; 3 percent gravel, 3 percent cobble; neutral (pH 7.0); clear wavy boundary. (6 to 14 inches thick)
E/B--11 to 21 inches; (65 percent E), reddish brown (5YR 5/4) loam, reddish brown (5YR 4/4) moist, and (35 percent B), reddish brown (5YR 5/4) clay loam, dark red (2.5YR 3/6) moist; weak medium subangular blocky structure parting to weak fine granular; soft, very friable, slightly sticky and moderately plastic; 5 percent gravel, 3 percent cobble, 1 percent stones; neutral (pH 6.8); clear wavy boundary. (6 to 12 inches thick)
Bt1--21 to 34 inches; reddish brown (5YR 5/4) clay loam, dark red (2.5YR 3/6) moist; weak medium prismatic structure parting to moderate medium subangular blocky; slightly hard, very friable, slightly sticky and moderately plastic; many distinct clay films on faces of peds and in pores; 8 percent gravel, 4 percent cobbles, 2 percent stones; neutral (pH 6.8); clear wavy boundary.
Bt2--34 to 44 inches; red (2.5YR 5/6) gravelly clay loam, red (2.5YR 4/6) moist; weak medium prismatic structure parting to moderate medium subangular blocky; slightly hard, very friable, slightly sticky and moderately plastic; many distinct clay films on faces of peds and in pores; 15 percent gravel, 3 percent cobble, 3 percent stones; neutral (pH 6.6); gradual wavy boundary. (combined thickness of the Bt horizons is 16 to 35 inches)
BC--44 to 62 inches; red (2.5YR 4/6) clay loam, red (2.5YR 4/6) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and moderately plastic; 10 percent gravel, 3 percent cobble, 1 percent stones; neutral (pH 6.6).
TYPE LOCATION: La Plata County, Colorado; about 16 miles northeast of Durango, Colorado; located about 1,000 feet east and 800 feet north of the southwest corner of sec. 9, T. 36 N., R. 7 W.; Lemon Reservoir USGS quad; lat. 37 degrees 23 minutes 54 seconds N. and long. 107 degrees 38 minutes 51 seconds W., NAD 27
RANGE IN CHARACTERISTICS: (depths given are measured from the mineral soil surface
Soil moisture regime: udic; dry in some part of the moisture control section for 45 to 90 cumulative days (ustic udic subclass)
Mean annual soil temperature: 37 to 42 degrees F.
Mean summer soil temperature: 54 to 58 degrees F. without an O horizon, 44 to 47 degrees F. with an O horizon.
Lithology of rock fragments: mostly sandstone
Particle-size control section:
Clay content: 23 to 35 percent
Rock fragment content: 5 to 25 percent.
A horizon: (not in all pedons)
Hue: 2.5YR to 5YR
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 2 to 4, dry and moist
Rock fragment content: 5 to 15 percent
Base saturation: estimated at 70 to 80 percent
E horizon:
Hue: 2.5YR to 5YR
Value: 4 to 6 dry, 3 or 4 moist
Chroma: 3 or 4, dry and moist
Texture: L, FSL
Rock fragment content: 5 to 15 percent
Base saturation: estimated at 70 to 80 percent
Reaction: slightly acid or neutral
E/B horizon:
Hue: 2.5YR or 5YR
E Part:
Value: 4 to 6 dry, 3 or 4 moist
chroma: 3 or 4, dry and moist
Texture, fine earth fraction: L, FSL
B Part:
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 4 to 6, dry and moist
Texture, fine earth fraction: L, SCL, CL
Rock fragment content: 5 to 25 percent
Base saturation: estimated at 70 to 80 percent
Reaction: slightly acid or neutral
Bt horizon:
Hue: 2.5YR or 5YR
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 4 to 6, dry and moist
Texture, fine earth fraction: L, SCL, CL
Rock fragment content: 5 to 25 percent
Base saturation: estimated at 70 to 80 percent
Reaction: slightly acid or neutral
BC horizon:
Hue: 2.5YR to 7.5YR
Value: 4 to 6 dry or moist
Chroma: 2 to 6, dry and moist
Texture, fine earth fraction: L, CL, SCL
Rock fragment content: 5 to 25 percent
Base saturation: estimated at 70 to 90 percent
Reaction: slightly acid or neutral
COMPETING SERIES: These are the
Ansel,
Edloe,
Howlett, an
Wix series.
Ansel soils: have hues of 7.5YR or yellower
Edloe soils: have a lithic contact at depths of 20 to 40 inches
Howlet soils: have an albic horizon and do not have combination E/B horizons.
Wix sois: have a paralithic contact at depths of 20 to 40 inches
GEOGRAPHIC SETTING:
Parent material: slope alluvium derived mostly from redbed sandstone.
Landform: backslopes and toeslopes of mountain slopes.
Slopes: 5 to 75 percent
Elevation: 8,200 to 9,600 feet
Mean annual air temperature: 35 to 40 degrees F.
Mean annual precipitation: 25 to 32 inches.
Wettest months: July, August, September, October, and December.
Driest months: May and June receive the least precipitation, however the soils are still wet from snowmelt.
Frost-free period: 60 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Anvik,
Tuckerville, and
Sponsor soils. All are on mountain slopes.
Anvik and Sponsor soils have mollic epipedons.
Tuckerville soils have loamy-skeletal particle size control sections.
DRAINAGE AND PERMEABILITY: Well drained; medium to high runoff; moderately slow permeability.
USE AND VEGETATION: These soils are used for timber production, livestock grazing, recreation, and wildlife habitat. The native vegetation is white fir, Rocky Mountain Douglas fir, quaking aspen, Arizona fescue, elk sedge, snowberry, serviceberry, and Oregon grape.
DISTRIBUTION AND EXTENT: Mountainous areas of Southwestern Colorado. LRR E, MLRA 48A. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES ESTABLISHED: La Plata County, Animas-Dolores Soil Survey Area, Colorado, 2002. Series proposed in 1997.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: The zone from 2 to 11 inches. (A and E horizons)
Argillic horizon: The zone from 21 to 44 inches. (Bt1 and Bt2 horizon)
Particle size control section: The zone from 21 to 41 inches. (Bt1 and part of Bt2 horizons)
Keys to Soil Taxonomy, classified according to the Eighth Edition, 1998.
Activity class is presumed based on general trend of other soils in the area.