LOCATION SEITZ COEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic Ustic Glossocryalfs
TYPICAL PEDON: Seitz very stony loam - on a steep slope at 10,000 feet elevation in woodland. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 2 inches; slightly decomposed organic material, mainly bark, twigs, and needles.
Oe--2 inches to 4; partially decomposed organic material like that of the horizon above.
A--4 to 6 inches; dark gray (10YR 4/1) very stony loam, black (10YR 2/1) moist; strong fine granular structure; soft, very friable; 40 percent stones, mostly on the surface; neutral (pH 7.0); abrupt smooth boundary. (0 to 3 inches thick)
E--6 to 13 inches; pinkish gray (7.5YR 7/2) very stony very fine sandy loam, brown (7.5YR 5/2) moist; weak thick platy structure parting to strong fine granular; soft, very friable; 40 percent stones; neutral (pH 6.8); diffuse wavy boundary. (4 to 8 inches thick)
E/B--13 to 18 inches; mixed pinkish gray (7.5YR 7/2) very stony loam (E), brown (7.5YR 5/2) moist; brown (7.5YR 5/3) very stony loam (Bt), brown (7.5YR 4/3) moist; weak fine subangular blocky structure; slightly hard, very friable; the more clayey peds are hard; few faint clay films on faces of peds; 40 percent stones; this horizon consists of clayey material like that of the underlying horizon embedded in a light colored matrix like that of the overlying horizon, and occurs as blotches rather than tongues about the rock fragments; neutral (pH 6.8); gradual wavy boundary. (4 to 8 inches thick)
Bt1--18 to 32 inches; brown (7.5YR 5/3) very stony clay, brown (7.5YR 4/3) moist; moderate fine subangular blocky structure; extremely hard, firm, very plastic; common faint clay films on faces of peds and in root channels; few faint clay films on rock fragments; 40 percent stones; neutral (pH 6.8); gradual wavy boundary. (9 to 29 inches thick)
Bt2--32 to 36 inches; brown (7.5YR 5/3) very stony clay loam, brown (7.5YR 4/3) moist; weak medium subangular blocky structure; very hard, plastic; common faint clay films on faces of peds; few faint clay films in root channels; 40 percent stones; neutral (pH 6.8); gradual wavy boundary. (3 to 6 inches thick)
C--36 to 64 inches; brown (7.5YR 5/4) extremely stony clay loam, brown (7.5YR 4/4) moist; massive; very hard, friable; 60 percent stones; neutral (pH 7.0).
TYPE LOCATION: Rio Grande County, Colorado; about 11 miles southwest of Monte Vista; near the center of section 30, T.37 N., R.7 E.
RANGE IN CHARACTERISTICS:
Soil moisture regime: udic bordering on ustic
Mean annual soil temperature: 34 to 46 degrees F.
Mean annual summer soil temperature: 42 to 48 degrees F.
Depth to the base of the argillic horizon: 17 to 45 inches or more
A horizon: (not present in all pedons):
Hue: 5Y to 7.5YR
Value: 4 or 5 dry, 2 or 3 moist; where moist value is 4 or less, horizon thickness is less than 4 inches.
Chroma: 1 or 2
Rock fragments: 35 to 60 percent total rock fragments (very gravelly, very cobbly, and very stony modifiers allowed)
Reaction: slightly acid or neutral
E horizon:
Hue: 5Y to 7.5YR
Value: 5 or 7 dry, 4 or 5 moist
Chroma: 2 or 3
Texture: loam, clay loam, sandy clay loam and sandy loam
Rock fragments: 35 to 60 percent total rock fragments (very gravelly, very cobbly and very stony modifiers allowed)
Reaction: slightly acid or neutral
E/B horizon:
E part (albic materials):
Pattern: interfingering, not tonguing
Hue: 5Y to 7.5YR
Value: 3 to 7 dry, 2 to 5 moist
Chroma: 2 or 3
Reaction: slightly acid or neutral
Bt part:
Hue: 2.5Y to 7.5YR
Value: 3 to 7 dry, 2 to 5 moist
Chroma: 2 to 6, dry or moist
Rock fragments: 35 to 60 percent total rock fragments (very gravelly, very cobbly, and very stony modifiers allowed)
Bt horizons:
Hue: 2.5Y to 7.5YR
Value: 3 to 7 dry, 2 to 5 moist
Chroma: 2 to 6
Texture: clay loam or clay with gravelly, cobbly and stony modifiers.
Clay content: 27 to 55 percent
Silt content: 10 to 40 percent
Sand content: 20 to 45 percent
Rock fragments: 35 to 85 percent
Reaction: slightly acid or neutral
BC and C horizons (not present in all pedons):
Hue: 2.5Y to 7.5YR
Value: 3 to 7 dry, 3 to 5 moist
Chroma: 2 to 5, dry or moist
Texture: clay, sandy clay loam, clay loam, loam, or sandy loam
Clay content: 10 to 50 percent
Content of fine or coarser sand: 15 to 55 percent
Rock fragments: 35 to 85 percent total rock fragments (very and extremely gravelly, cobbly and stony modifiers allowed)
Some pedons have BCt horizons
COMPETING SERIES:
Vulcan (CO) soils have fragmental layers at depths of 20 to 40 inches (51 to 102 centimeters).
GEOGRAPHIC SETTING:
Parent material: formed in noncalcareous colluvium or slope alluvium derived from granite, gneiss, mica schist, rhyolite, andesite, trachyte, interbedded sandstone/shale and basalt.
Landform: hills, ridges, valley sides, and mountain slopes.
Slopes: 2 to 65 percent.
Elevation: 7,500 to 12,000 feet (2,286 to 3,658 meters).
Mean annual air temperature: 32 to 44 degrees F (0.0 to 6.7 degrees C).
Mean annual precipitation: 14 to 32 inches (36 to 81 centimeters).
Precipitation pattern: The soil moisture control section is affected by snow melt in early spring and peak precipitation occurring in the form of thunderstorms from June to September.
Frost-free period: 40 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Tolman and Empedrado soils. Both of these soils have a mollic epipedon and a frigid temperature regime; Tolman is shallow, and Empedrado has secondary carbonates. Both of these soils are at lower elevations than Seitz and have pinyon-juniper vegetation.
DRAINAGE AND PERMEABILITY: Well drained; high and very high runoff; slow permeability.
USE AND VEGETATION: These soils are used principally as native pastureland or for forestry and recreational purposes. Native vegetation is Engelmanns spruce, Rocky Mountain Douglas-fir, subalpine fir, and a sparse understory of grasses and shrubs.
DISTRIBUTION AND EXTENT: Mountainous areas bordering the San Luis Valley in south-central Colorado and in western Colorado. MLRA 48A, Land Resource Region E. The series is of large extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Rio Grande County Area, Colorado, 1972. The name is taken from a stream in Rio Grande County.
REMARKS: 1999 revision changes the classification from clayey-skeletal, montmorillonitic Typic Cryoboralfs to clayey-skeletal, smectitic Ustic Glossocryalfs.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: from 4 to 6 inches (10 to 15 centimeters) (A horizon)
Albic horizon: from 6 to 13 inches (15 to 33 centimeters) (E horizon)
Glossic horizon: from 13 to 18 inches (33 to 46 centimeters) (E/B horizon)
Argillic horizon: from 18 to 36 inches (46 to 91 centimeters) (Bt1 and Bt2 horizons)
Particle-size control section: the zone from 18 to 36 inches (46 to 91 centimeters) the entire argillic horizon.
Keys to Soil Taxonomy: Classified according to 10th Edition, 2006
ADDITIONAL DATA: National Soil Survey Lab data is available. Sample number S84CO-105-002, S91CO-037-003.