LOCATION PLOME COEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Typic Haplustalfs
TYPICAL PEDON: Plome sandy loam- forest. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 1 inch; slightly decomposed organic materials, mainly needles, bark, twigs, and leaves.
Oe--1 to 2 inches; partially decomposed organic material like that of the horizon above.
A--2 to 5 inches; brown (7.5YR 5/2) sandy loam, dark brown (7.5YR 3/2) moist; strong fine granular structure; soft, very friable; neutral; clear smooth boundary. (0 to 4 inches thick)
E--5 to 18 inches; pinkish gray (7.5YR 6/2) coarse sandy loam, brown (7.5YR 4/2) moist; moderate thin platy structure parting to strong fine granular; soft, very friable; vesicular; slightly acid; clear smooth boundary. (6 to 15 inches thick)
E/B--18 to 23 inches; reddish brown (2.5YR 5/4) and pinkish gray (7.5YR 6/2) sandy loam, reddish brown (2.5YR 4/4) and brown (7.5YR 4/2) moist; weak medium subangular blocky structure; hard, very friable; this horizon contains nodules and seams of clayey material like that of the underlying horizon embedded in a lighter colored matrix like that of the overlying horizon; slightly acid; clear smooth boundary. (4 to 10 inches thick)
Bt1--23 to 37 inches; reddish brown (2.5YR 5/4) sandy clay loam, reddish brown (2.5YR 4/4) moist, strong medium subangular blocky structure; very hard, firm, very plastic; common continuous distinct clay films on faces of peds; slightly acid; gradual smooth boundary.
Bt2--37 to 44 inches; reddish brown (2.5YR 5/4) sandy loam, reddish brown (2.5YR 4/4) moist; weak medium subangular blocky structure; hard, very friable; few patchy distinct clay films on horizontal and vertical faces of peds; slightly acid; gradual smooth boundary. (combined thickness of the Bt horizons: 7 to 38 inches thick)
C--44 to 62 inches; reddish brown (2.5YR 5/4) sandy loam, reddish brown (2.5YR 4/4) moist; slightly hard, very friable; neutral. (Several feet thick)
TYPE LOCATION: Douglas County, Colorado; about 5 miles west of Larkspur; l50 feet north of the road to Perry Park Ranch and 0.6 mile west of highway 150 in Sec. 26, T. 9 S., R. 68 W.; Larkspur USGS quad.
RANGE IN CHARACTERISTICS:
Soil moisture: The soil moisture control section is usually dry in some part in early summer, moist in some or all parts in late July and August, and intermittently dry in fall; ustic regime, typic subclass.
Calcium carbonate equivalent: less than one percent
Exchangeable sodium percentage: less than 1 throughout
Base saturation: 60 to 100 percent in the argillic horizon (75 to 100 percent by sum of cations)
Thickness of argillic horizon: 14 to 20 inches
Rock fragments: 5 to 35 percent by volume; mainly gravel but includes cobble.
Solum thickness: 24 to 60 inches
Mean annual soil temperature: 44 to 46 degrees F.
Mean summer soil temperature: 59 to 66 degrees F.
A horizon:
Hue: 5YR through 10YR
Value: 5 or 6 dry, 2 through 4 moist
Chroma: 1 through 3, dry or moist
Reaction: slightly acid or neutral
E horizon:
Hue: 10YR through 2.5YR
Value: 6 through 8 dry, 4 through 6 moist
Chroma: 2 through 4
Reaction: moderately acid through neutral
E/B horizon:
E part has same properties as E horizon, and Bt part has same properties as Bt horizon
Bt horizon:
Hue: 5YR through 10R
Value: 5 or 6 dry, 3 through 5 moist
Chroma: 3 through 6
Texture, fine earth fraction: sandy clay loam, clay loam, coarse sandy loam; sandy loam occurs in the lower part of the Bt in some pedons
Clay content: 18 to 35 percent
Reaction: moderately acid through neutral
Some pedons have a BC horizon.
C horizon:
Hue: 5YR through 10R
Value: 5 or 6 dry, 3 through 5 moist
Chroma: 3 through 6, dry or moist
Texture: sandy loam, sandy clay loam, coarse sandy loam
Clay content: 16 to 35 percent
Reaction: slightly acid through slightly alkaline
COMPETING SERIES:
These are the
Alderon,
Allens Park,
Bayerton,
Belltower,
Elbeth,
Elbuck,
Elmark,
Haugan,
Heflin,
Hoyt,
Jemco,
Jemez,
Kunz,
Kwiavu,
Littlepine,
Losindios,
Lumpgulch,
Northrim,
Rule,
Shoemaker,
Sweetweed, and
Tunitcha series.
Alderon, Heflin, and Tunitcha soils are deep to a lithic or paralithic contact.
Allens Park, Bayerton, Belltower, Elmark, Jemco, Jemez, Lumpgulch, Rule, and Shoemaker soils are moderately deep to a lithic or paralithic contact.
Elbeth, Elbuck, Haugan, Hoyt, Kwiavu, Littlepine, Losindios, Northrim, and Sweetweed soils do not have hues in the Bt horizons that are 5YR or redder.
Kunz soils are dry in
May and June.
GEOGRAPHIC SETTING: Plome soils are on upland hills, hills on half grabens, fan remnants, and ridges. Slopes range from 0 to 20 percent. Elevations range from 6,500 to 8,600 feet. The soil formed in parent materials which have been locally transported from red and reddish brown sedimentary arkosic beds of the Fountain and Lyons formations or in red eolian material over sandstone. At the type location the average annual precipitation is 16 to 22 inches, approximately 2/3 of which falls during the months of April through August. Mean annual temperature ranges from 42 to 50 degrees F, and the mean summer temperature is 60 to 64 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Lonetree, Gove, and Redtom soils, all of which have mollic epipedons.
DRAINAGE AND PERMEABILITY: Well drained; low through high runoff; slow through moderate permeability (moderately high Ksat).
USE AND VEGETATION: These soils are used for forestry, pastureland, and recreation. Native vegetation is mainly ponderosa pine, Gambel's oak, and an understory of grasses.
DISTRIBUTION AND EXTENT: The foothill and mountain areas of east-central Colorado. MLRA 48A. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Douglas County, Colorado, Castle Rock Area soil survey, 1974.
REMARKS:
Diagnostic horizons and features recognized in this pedon:
Ochric epipedon: 2 to 18 inches (A and E horizons)
Albic horizon: 5 to 18 inches (E horizon)
Glossic horizon: 18 to 23 inches (E/B horizon)
Argillic horizon: 23 to 44 inches (Bt1, Bt2 horizons)
Particle-size control section: the zone from 23 to 43 inches (upper 20 inches of the argillic horizon)
The Inceptic and Ultic subgroups are possibilities for this series and need further study. The typical pedon used in the Castle Rock area, where this series was established, is in the Inceptic subgroup.
When established this series was classified as fine-loamy, mixed Typic Eutroboralfs.