LOCATION TOLVAR COEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Ustollic Glossocryalfs
TYPICAL PEDON: Tolvar gravelly sandy loam, forested. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 3 inches; slightly decomposed organic material, principally needles, bark, and twigs.
Oe--3 to 4 inches; moderately decomposed organic material, principally needles, bark, and twigs.
A--4 to 6 inches; dark grayish brown (10YR 4/2) gravelly sandy loam, very dark brown (10YR 2/2) moist; strong medium granular structure; soft, very friable; 15 percent fine granite gravel; slightly acid; clear smooth boundary. (0 to 4 inches thick)
E--6 to 18 inches; light gray (10YR 7/2) gravelly sandy loam, grayish brown (10YR 5/2) moist; moderate medium platy structure that parts to strong medium granular; soft, very friable; 30 percent fine granitic gravel; moderately acid; gradual irregular boundary. (4 to 16 inches thick)
E/B--18 to 25 inches; mixed light gray (10YR 7/2) and reddish brown (5YR 5/4) very gravelly sandy clay loam, grayish brown (10YR 5/2) and reddish brown (5YR 4/4) moist; weak fine subangular blocky structure; hard, very friable; few faint clay films on faces of peds; this horizon consists of clayey material like that of the underlying horizon embedded in a lighter colored matrix like that of the overlying horizon; 40 percent fine granite gravel; slightly acid; gradual irregular boundary. (4 to 10 inches thick)
Bt1--25 to 44 inches; reddish brown (5YR 5/4) very gravelly sandy clay loam, reddish brown (5YR 4/4) moist; moderate medium subangular blocky structure; extremely hard, very friable; common distinct clay films on vertical faces of peds; 50 percent angular granitic gravel; slightly acid; gradual wavy boundary. (8 to 25 inches thick)
Bt2--44 to 50 inches; brown (7.5YR 5/4) very gravelly sandy loam, brown (7.5YR 4/4) moist; weak medium subangular blocky structure; extremely hard, very friable; common distinct clay films on vertical faces of peds; 50 percent granite gravel; slightly acid; gradual wavy boundary. (4 to 1025 inches thick)
C--50 to 64 inches; light yellowish brown (10YR 6/4) very gravelly sandy loam, yellowish brown (10YR 5/4) moist; massive; extremely hard, very friable; 50 percent angular granitic gravel and 5 percent stones; slightly acid.
TYPE LOCATION: Gunnison County, SW1/4 Sec. 4, T. 46 N., R. 1 W.
RANGE IN CHARACTERISTICS:
Soil moisture: Udic moisture regime bordering on ustic.
Mean annual soil temperature: 34 to 44 degrees F (1.1 to 6.7 degrees C)
Mean summer soil temperature: 42 to 48 degrees F (5.6 to 8.9 degrees C)
Depth to albic materials: 1 to 10 inches (3 to 25 centimeters)
Depth to argillic horizon: 12 to 40 inches (30 to 102 centimeters)
Particle-size control section (weighted average):
Clay content: 18 to 35 percent
Sand content: 40 to 70 percent
Rock fragments: 35 to 80 percent
Base saturation: 80 to 100 percent
A horizon (if present):
Hue: 7.5YR or 10YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 1 through 3
Texture: gravelly sandy loam
Reaction: moderately acid to neutral
Organic matter: 1 to 3 percent
E horizon:
Hue: 10YR or 7.5YR
Value: 5 to 7 dry, 4 to 6 moist
Chroma: 1 to 4
Texture: gravelly sandy loam and very gravelly sandy loam
Reaction: moderately acid to slightly acid
E/B, B/E, E/Bt or Bt/E horizon:
Hue: 5YR or 7.5YR
Value: 5 to 7 dry, 4 to 6 moist
Chroma: 1 to 6
Texture: very gravelly sandy loam, very gravelly sandy clay loam, sandy clay loam, loam and sandy loam
Clay content: 12 to 35 percent
Reaction: moderately acid to slightly acid
Bt horizon(s):
Hue: 5YR or 7.5YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 to 6
Texture: very gravelly sandy clay loam, very gravelly sandy loam, very gravelly clay loam and extremely gravelly sandy clay loam
Clay content: 18 to 35 percent
Rock fragments: 35 to 80 percent
Reaction: moderately acid to slightly acid
C horizon(s):
Hue: 5YR through 10YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 to 5
Texture: very gravelly sandy loam, extremely gravelly sandy loam, sandy clay loam, clay loam
Clay content: 12 to 35 percent
Rock fragments: 35 to 80 percent
Reaction: moderately acid to neutral
COMPETING SERIES: There are no competing series in this family.
GEOGRAPHIC SETTING:
Parent materials: formed in slope alluvium derived mainly from granitic rocks and slope alluvium over colluvium derived from granite, gneiss, and mica schist.
Landforms: mountain slopes and alluvial fans at relatively high elevations
Slope: 3 to 70 percent.
Elevation: 8,500 to 12,000 feet (2,591 to 3,658 meters).
Mean annual air temperature: 33 to 41 degrees F (to degrees C).
Mean annual precipitation: 16 to 30 inches (406 to 762 millimeters).
Precipitation pattern: The soil moisture control section is affected by snow melt in early spring and peak precipitation occurring as thunderstorms from June to September.
Frost-free period: 40 to 70 days.
GEOGRAPHICALLY ASSOCIATED SOILS: There are the Uinta soils and they are fine-loamy in the particle control section.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderate permeability.
USE AND VEGETATION: These soils are used principally for forestry, recreation, wildlife and watershed. Native over story vegetation is mainly Rocky Mountain Douglas fir, quaking aspen. The understory is chiefly mountain ash, common juniper, box leaf myrtle, elk sedge bearberry.
DISTRIBUTION AND EXTENT: High mountainous area of central Colorado; LLR E, MLRA 48A. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Gunnison County, Colorado, 1975.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Albic horizon: 6 to 18 inches (15 to 46 centimeters) (E)
Glossic horizon: 18 to 25 inches (46 to 64 centimeters) (E/B)
Argillic horizon: 18 to 50 inches (46 to 127 centimeters) (E/B, Bt1, Bt2)
Particle-size control section: The zone from 18 to 50 inches (46 to centimeters)
Based upon lab samples from Gunnison County, Colorado the NH4Oac base saturation ranges from 60 to 88 percent below the surface layer to the 60 inch depth.
Last updated by the state 01/02
Taxonomic Version: Tenth edition, 2006