LOCATION SPECIE COEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Typic Haplustepts
TYPICAL PEDON: Specie gravelly loam - ponderosa pine. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 1 inch; slightly decomposed pine needles and twigs.
A--1 to 4 inches; dark reddish brown (5YR 3/4) gravelly loam, dark reddish brown (5YR 3/2) moist; moderate medium granular structure; slightly hard, friable, nonsticky and nonplastic; 15 percent gravel, 5 percent cobbles; slightly effervescent (5 percent calcium carbonate equivalent); neutral (pH 7.2); clear smooth boundary. (2 to 10 inches thick)
Bw--4 to 17 inches; reddish brown (2.5YR 5/4) very stony loam, dark reddish brown (2.5YR 3/4) moist; weak medium subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; 15 percent gravel, 10 percent cobbles, 30 percent stones; strongly effervescent (9 percent calcium carbonate equivalent); moderately alkaline (pH 8.0); clear smooth boundary. (10 to 24 inches thick)
C--17 to 61 inches; reddish brown (2.5YR 5/4) extremely gravelly loam, dark reddish brown (2.5YR 3/4) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; 45 percent gravel, 10 percent cobbles, and 10 percent stones; strongly effervescent (14 percent calcium carbonate equivalent); moderately alkaline (pH 8.2).
TYPE LOCATION: San Miguel County, Colorado; 1,100 feet west and 100 feet north of the southeast corner, sec. 23, T. 44 N., R. 11 W.
RANGE IN CHARACTERISTICS: (Depths are measured from the mineral surface.)
Soil moisture regime: ustic; the moisture control section is dry for 15 consecutive days from May 15 to June 30 when the soil temperature at 20 inches is greater than 41 degrees F. It is not dry in all parts of the moisture control section for as long as 45 consecutive days following the summer solstice to October 20, and for as long as 90 cumulative days during that period.
Mean annual soil temperature: 44 to 47 degrees F
Mean summer soil temperature: 59 to 64 degrees F.
Depth to calcareous material: 0 to 25 inches
Particle-size control section:
Clay content: 18 to 25 percent
Rock fragment content: 35 to 70 percent
A horizon:
Hue: 2.5YR or 5YR
Value: 3 or 4 dry, 2 or 3 moist
Chroma: 2 to 6, dry or moist
Rock fragment content: 0 to 35 percent, dominantly gravel and cobble
Calcium carbonate equivalent: 5 to 14 percent
Reaction: neutral to moderately alkaline.
Bw and C horizons:
Hue: 2.5YR or 5YR
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 3 to 8, dry or moist
Texture: loam or sandy loam; with extremely gravelly, very cobbly, very stony, and extremely stony modifiers
Calcium carbonate equivalent: 5 to 14 percent
COMPETING SERIES:
Kadygulch soils - are noncalcareous throughout
Kingspoint - have hue yellower than 5YR
Lamedeer - are deeper than 25 inches to carbonates
Mowbray - have hue yellower than 5YR
Redfist - have a lithic contact
Repkie have less than 18 percent clay throughout
Repp - have albic horizons
Vanet - have a paralithic contact
Wilde - have a lithic contact
Wildgen - have lamellae in the B horizons
Wilspring - have a lithic contact
Winkler - are noncalcareous and have lamellae in the B horizons
GEOGRAPHIC SETTING: Specie soils are on mesa slopes, terraces, and alluvial fans. Slopes are 5 to 60 percent. These soils formed in alluvium and colluvium from sandstone. Elevation is 7,000 to 9,000 feet. Mean annual precipitation is 16 to 22 inches and is evenly distributed throughout the year, but with a slight maximum during late summer. Over 50 percent of the precipitation falls as snow. Mean annual temperature is 41 to 43 degrees F. The frost free period is 70 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ceek and Winz soils. Ceek soils are clayey-skeletal and have an argillic horizon. Winz soils are clayey-skeletal and have an argillic horizon.
DRAINAGE AND PERMEABILITY: Well drained; medium to very rapid runoff; moderately rapid permeability.
USE AND VEGETATION: These soils are used mainly for wildlife habitat, livestock grazing, and recreation. Principal native vegetation is Rocky Mountain Douglas fir and scattered ponderosa pine with an understory of slender wheatgrass, elk sedge, boxleaf myrtle, and Oregon grape. Some areas have shrub and grass vegetation consisting of antelope bitterbrush, true mountainmahogany, mountain big sagebrush, Indian ricegrass, prairie junegrass, and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: Southwestern Colorado. MLRA 48A. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES ESTABLISHED: San Miguel County (San Miguel Area), Colorado, 1987.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: from 1 to 4 inches (A horizon).
Cambic horizon: from 4 to 17 inches (Bw horizon).
Particle-size control section: the zone from 11 to 41 inches (part of the Bw and C horizons).
Keys to Soil Taxonomy: Series classified according to Seventh Edition, 1996
This revision changes the classification from loamy-skeletal, mixed (calcareous), frigid Typic Ustorthents to loamy-skeletal, mixed, superactive, frigid Typic Ustochrepts. The 4 to 17-inch horizon was judged to be a cambic horizon because of the blocky structure and apparent loss of carbonates.
The superactive CEC activity class is presumed for this series based on the general trend indicated by lab data throughout this region.