LOCATION CULEBRA COEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Lithic Calciustepts
TYPICAL PEDON: Culebra very gravelly coarse sandy loam, 5 to 65 percent slope in forestland at an elevation of 8,885 feet (colors are for dry soil unless otherwise noted).
A--0 to 8 centimeters; brown (7.5YR 4/3) very gravelly coarse sandy loam, dark brown (7.5YR 3/2) moist; 12 percent clay; weak fine granular structure; friable, soft, nonsticky, nonplastic; common very fine and medium roots throughout; calcium carbonate coatings (relict) on rock fragments; 35 percent gravel and 5 percent cobbles; noneffervescent; slightly alkaline (pH 7.4); clear smooth boundary.
Bk--8 to 28 centimeters; light brown (7.5YR 6/3) very gravelly coarse sandy loam, brown (7.5YR 4/3) moist; 12 percent clay; weak fine granular structure; friable, soft, nonsticky, nonplastic; common very fine and medium roots throughout; common calcium carbonate coatings on bottom surface of rock fragments and few fine threadlike carbonate masses; 45 percent gravel and 10 percent cobbles; strongly effervescent; 15 percent calcium carbonate equivalent; slightly alkaline (pH 7.8); abrupt irregular boundary.
R--28 centimeters; fractured sandstone bedrock; calcium carbonate coatings on bedrock.
TYPE LOCATION: Culebra very gravelly coarse sandy loam; in an area of
Uracca-Culebra complex, 5 to 65 percent slopes; Trinchera Ranch USGS
Topographic quadrangle, NAD83; 37 degrees 24 minutes 20.61 seconds north
Latitude and 105 degrees 18 minutes 44.89 seconds west longitude; UTM 472,346
Meters E, 4,139,928 meters N, zone 13.
RANGE IN CHARACTERISTICS:
Soil moisture:
Soil moisture regime subclass: aridic (torric)
Soil moisture regime class: ustic
Mean annual soil temperature: 41 to 46 degrees F (5 to 7.8 degrees C)
Mean summer soil temperature: 63 to 66 degrees F (17.2 to 18.9 degrees C)
Depth to restrictive feature: 10 to 20 inches (25 to 51 centimeters) to bedrock, lithic
Depth to diagnostic feature: 2 to 8 inches (5 to 20 centimeters) to calcic horizon
Thickness of Calcic horizon: 5 to 16 inches (13 to 41 centimeters)
Particle-size control section (weighted average):
Clay content:<p> 5 to 18 percent
Sand content:<p> 65 to 90 percent
Rock fragment content:<p> 35 to 90 percent indurated gravel and cobbles
A horizon(s)
Hue: 7.5YR to 10YR
Value: 4 or 5 dry; 3 or 4 moist
Chroma: 2 or 3
Texture: very gravelly coarse sandy loam
Clay content: 8 to 18 percent
Carbonate clay content: 0 to 2 percent
Sand content: 52 to 75 percent
Silt content: 10 to 30 percent
Fragment content, total: 35 to 60 percent
Fragment size and content: 35 to 50 percent indurated gravel
0 to 10 percent indurated cobbles
Calcium carbonate equivalent: 0 to 5 percent
Electrical conductivity: 0 to 2 mmhos/cm
Reaction: pH 6.6 to 7.8
Organic matter content: 0.5 to 1.0 percent
Bk horizon(s)
Hue: 7.5YR to 10YR
Value: 5 or 6 dry; 3 to 5 moist
Chroma: 2 or 3
Texture: very gravelly coarse sandy loam, extremely gravelly loamy coarse sand, very cobbly coarse sandy loam
Clay content: 5 to 18 percent
Carbonate clay content: 3 to 8 percent
Sand content: 65 to 90 percent
Silt content: 5 to 30 percent
Fragment content, total: 35 to 90 percent
Fragment size and content: 35 to 70 percent indurated gravel
0 to 20 percent indurated cobbles
Calcium carbonate equivalent: 5 to 20 percent
Electrical conductivity: 0 to 2 mmhos/cm
Reaction: pH 7.4 to 8.4
Organic matter content: 0.0 to 0.5 percent
R-horizon - sandstone bedrock with calcium carbonate coatings on bedrock
COMPETING SERIES: These are the
Cedarknoll,
Hackling,
Rencot,
Rentsac and
Schoonover series.
Cedarknoll soils have a cambic horizon and depth to calcic horizon is 20 to 28 centimeters.
Hackling soils have hues of 2.5 YR or 5YR throughout.
Rencot and Schoonover soils have greater than 18 percent clay (weighted average) in the particle-size control section.
Rentsac soils are dry in all parts of the moisture control between four-tenths and five-tenths of the cumulative days per year that the soil temperature at a depth of 51 centimeters is 5 degrees C. or higher.
GEOGRAPHIC SETTING:
Parent material: gravelly colluvium derived from igneous, metamorphic and sedimentary rock
Landform: mountain slopes
Slope: 5 to 65 percent
Elevation: 8,000 to 10,000 feet (2,438 to 3,048 meters)
Mean annual air temperature: 37 to 41 degrees F. (3.0 to 5.0 degrees C)
Mean annual precipitation: 12 to 16 inches (305 to 406 millimeters)
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: 75 to 90 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Morval soils have mollic epipedons and are very deep.
Shawa soils are pachic and are very deep.
Uracca soils have mollic epipedons and are very deep.
DRAINAGE AND PERMEABILITY: Well drained and have moderately rapid permeability.
USE AND VEGETATION: Culebra soils are used mainly as woodland and wildlife habitat. Potential native vegetation is mainly pinyon pine, Rocky Mountain juniper, blue grama and Wyoming big sagebrush.
DISTRIBUTION AND EXTENT: High intermountain valleys of south central Colorado, LLR E, MLRA 51. The series is of is minor extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Costilla County, Colorado, 2008.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Calcic horizon: 3 to 11 inches
Taxonomic version: Tenth Edition, 2006.