LOCATION COWDREY CO+ID WYEstablished Series
TAXONOMIC CLASS: Fine, smectitic Eutric Glossocryalfs
TYPICAL PEDON: Cowdrey clay loam - woodland. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 3 inches; slightly decomposed organic material, mainly needles, bark, and twigs.
Oe--3 to 4 inches; partially decomposed organic material like that of the horizon above.
A--4 to 7 inches; very dark gray (10YR 3/1) light clay loam, black (10YR 2/1) moist; strong fine granular structure; soft, very friable, 5 percent pebbles and cobble; neutral (pH 6.6); abrupt wavy boundary. (0 to 4 inches thick)
E--7 to 12 inches; light gray (10YR 7/2) light clay loam, grayish brown (10YR 5/2) moist; moderate medium platy structure parting to strong fine granular; soft, very friable; 10 percent pebbles and cobbles; slightly acid (pH 6.2); gradual wavy boundary. (3 to 8 inches thick)
E/B--12 to 16 inches; mixed light gray (10YR 7/2) and brown (10YR 5/3) light clay loam, mixed grayish brown (10YR 5/2) and brown (10YR 4/3) moist; strong fine angular blocky structure; very hard, very friable; few continuous distinct clay films on the more clayey peds; this horizon consists of nodules and fragments of material like that of the underlying horizon embedded in a lighter colored matrix like that of the overlying horizon; slightly acid (pH 6.4); clear smooth boundary. (3 to 8 inches thick)
Bt1--16 to 28 inches; brown (10YR 5/3) light clay, brown (10YR 4/3) strrong medium and fine angular blocky structure; extremely hard, friable, very plastic; thin continuous wax-like coatings on rock fragments; 14 percent gravel; neutral (pH 6.6); gradual wavy boundary. (10 to 30 inches thick)
Bt2--28 to 34 inches; light olive brown (2.5Y 5/4) gravelly clay, olive brown (2.5Y 4/4) moist; weak medium angular blocky structure; very hard, firm, very plastic; extremely hard; many patchy distinct clay filmson faces of peds; few discontinuous faint clay films on surfaces along root channels; few discontinuous faint clay films on rock fragments; 25 percent gravel; neutral (pH 6.8); diffuse wavy boundary. (0 to 8 inches thick)
C--34 to 64 inches; light olive gray (5Y 6/2) clay, olive gray (5Y 5/2) moist; massive; extremely hard, very plastic; 14 percent gravel and cobble; neutral (ph 7.0).
TYPE LOCATION: Jackson County, Colorado; 740 feet south of the center of Sec. 24, T. 7 N., R. 77 W.
RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 32 to 46 degrees F., and mean summer soil temperature ranges from 38 to 46 degrees F. with an O horizon at least 4 inches thick and in areas of timber with a good crown cover. Typically these soils are noncalcareous to a depth of more than 60 inches but are calcareous between 40 and 60 inches in some pedons. The solum to the base of the Bt is 20 to 50 inches thick. Organic carbon content ranges from .8 to 2 percent in the surface horizons and decreases uniformly with depth. Exchangeable sodium percentage is usually less than 1 but in some pedons it is up to 15 percent in some subhorizon of the solum less than 4 inches thick. The soil is 80 to 100 percent base saturated. Cation exchange capabity ranges from about 70 to 90 milliequivalents per 100 grams of clay. The major part of the solum has 10 to 35 percent coarse fragments, mainly gravel and cobble, while the C horizon has 35 to 60 percent gravel and channers with some cobble below 40 inches.
The E horizon has hue of 5Y through 7.5YR, value of 6 through 8 dry, 4 through 6 moist, and chroma of 2 or 3. It typically has platy structure but has subangular blocky structure in some pedons. It is soft or slightly hard and slightly acid or neutral.
The Bt horizon has hue of 5Y through 7.5YR, value of 5 or 6 dry, 4 or 5 moist, and chroma of 2 through 6. It typically has angular blocky structure but has subangular blocky structure in some pedons. It is light clay or heavy clay loam with 35 to 50 percent clay, 15 to 40 percent silt, and 15 to 45 percent sand, with more than 15 percent fine or coarser sand. Oriented clay films occur in some part of this horizon. It is slightly acid or neutral. Gravelly modifiers are common.
The C horizon, when present, has hue of 5Y through 7.5YR, 6 or 7 dry, 4 or 5 moist, and chroma of 2 through 4. It is clay loam or light clay but the horizon contains more than 35 percent clay to depths of 40 inches. Sandy clay loams may occur below depths of 40 inches. Reaction is slightly acid to neutral.
COMPETING SERIES:
Gateway: Moderately deep to paralithic contact
Muggins: 5YR or redder hues in Bt horizon
GEOGRAPHIC SETTING: Cowdrey soils are on hillsides and ridge crests in mountainous areas. Slopes range from 2 to 65 percent. The soil formed in thick, fine textured noncalcareous glacial till or slope alluvium derived principally from clay shale. They are also formed in colluvial material derived from volcanic rocks. Average annual precipitation is 20 to 30 inches with peak periods of precipitation during the spring and summer months. Mean annual temperature ranges from 32 to 44 degrees F. Elevation ranges from 7,800 to 9,300 feet at the type location and ranges to 11,800 feet in southern latitudes in the state. Frost-free period is 20 to 30 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dell and the Gothic soils. Gothic soils have a mollic epipedon and lack an albic horizon.
DRAINAGE AND PERMEABILITY: Well drained; rapid runoff; slow permeability.
USE AND VEGETATION: These soils are used principally for native pastureland, for forestry purposes, and for recreational purposes. Native vegetation consists of lodgepole pine, Engelmanns spruce, subalpine fir, and a moderate understory of grasses and shrubs.
DISTRIBUTION AND EXTENT: Present known distribution is limited to the high mountainous areas of Colorado, Idaho, and Wyoming. The series is of large extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Star Valley Area, Idaho and Wyoming; 1971.
REMARKS:
2/2004 The concept of the series was narrowed to typic-udic moisture to match the type location and most areas where this series is mapped. Therefore, the classification was changed from Ustic to Eutric Glossocryalf.
Taxonomic Version: Ninth Edition, 2003