LOCATION DOLCAN COEstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, calcareous, mesic, shallow Aridic Ustorthents
TYPICAL PEDON: Dolcan extremely cobbly fine sandy loam, on a south facing, 37 percent slope in Pinyon-Juniper woodland at an elevation of 6,800 feet. (Colors are for dry soil unless otherwise noted. When described on April 15, 1993, the soil profile was at field capacity.) The surface is covered by 30 percent gravel, 20 percent cobbles, 10 percent stones, and 1 percent boulders.
A--0 to 2 inches; brown (10YR 5/3) extremely cobbly fine sandy loam, brown (10YR 4/3) moist; weak fine granular structure; soft, loose, nonsticky and nonplastic; slightly effervescent; 30 percent gravel, 20 percent cobbles, 10 percent stones, and 1 percent boulders; slightly alkaline (pH 7.6); abrupt smooth boundary.
C1--2 to 8 inches; brown (7.5YR 4/2) cobbly clay loam, dark brown (7.5YR 3/2) moist; massive; slightly hard, friable, moderately sticky and moderately plastic; common medium and common very fine roots throughout; common fine tubular pores; strongly effervescent; 15 percent gravel, 10 percent cobbles, 5 percent stones, and 1 percent boulders; slightly alkaline (pH 7.8); abrupt smooth boundary.
C2--8 to 11 inches; reddish brown (5YR 4/4) clay loam, dark reddish brown (5YR 3/4) moist; massive; slightly hard, firm, moderately sticky and moderately plastic; common very fine roots throughout; strongly effervescent; 10 percent gravel and 3 percent cobbles; slightly alkaline (pH 7.8); abrupt smooth boundary.
Cr--11 inches; strongly effervescent soft Morrison shale
TYPE LOCATION: Montezuma County, CO.; Williams Draw, about 3/4 mile west of Bradfield Bridge; located about 1,900 feet east and 800 feet south of the northwest corner of sec. 17, T. 39 N., R. 17 W.; Doe Canyon USGS quad; lat. 37 degrees 38 minutes 36 seconds N. and long. 108 degrees 44 minutes 53 seconds W., NAD
RANGE IN CHARACTERISTICS:
Soil moisture regime: ustic bordering on aridic.
Soil temperature regime: mesic
Mean annual soil temperature: 50 to 52 degrees F
Depth to paralithic contact: 6 to 20 inches
Particle-size control section:
Clay content: 18 to 35 percent
A horizon:
Hue: 7.5YR or 10YR
Value: 4 to 6 (3 or 4 moist)
Chroma: 1 to 3
Texture: fine sandy loam or clay loam
Rock fragments: 20 percent or more
Calcium carbonate equivalent: 0 to 2 percent
C horizon:
Hue: 5YR to 10YR
Value: 3 to 7 dry (3 to 6 moist)
Chroma: 2 to 4
Texture: clay loam or loam
Rock fragments: 5 to 35 percent
Calcium carbonate equivalent: 0 to 5 percent
Reaction: slightly or moderately alkaline
COMPETING SERIES: These are the Fairburn, Mittenbutte, Sipapu, and Spearfish series. Fairburn soils receive most of their moisture in the late spring and early summer. Menefee soils have less than 15 percent coarse fragments below the A horizon and hues yellower than 7.5YR. Mittenbutte soils have less than 18 percent clay. Sipapu soils receive about half their precipitation from July to September and have pararock fragments. Spearfish soils have accumulations of gypsum in the C and Cr horizons.
GEOGRAPHIC SETTING:
Parent material: colluvium and residuum derived from sandstone and shale
Landform: canyons and hills
Slopes: 6 to 80 percent
Elevation: 6,000 to 8,200 feet
Mean annual temperature: 46 to 50 degrees F
Mean annual precipitation: 13 to 19 inches
Precipitation is fairly evenly distributed throughout the year with July and August being slightly wetter and June being slightly dryer.
Frost-free period: 100 to 150 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Prater and Wauquie series. Prater and Wauquie soils are very deep and have argillic horizons.
DRAINAGE AND PERMEABILITY: well drained, high and very high runoff, and moderately slow permeability
USE AND VEGETATION: These soils are used for wildlife habitat and rangeland. Native vegetation is pinyon, juniper, serviceberry, Indian ricegrass, and forbs.
DISTRIBUTION AND EXTENT: Southwest Colorado. LRR D, MLRA 36. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Cortez Area, Colorado, Parts of Dolores and Montezuma Counties 1997.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: The zone from 0 to 2 inches. (A horizon)
Paralithic contact: The zone at 11 inches. (Cr horizon)
Particle size control section: The zone from 0 to 11 inches. (A, C1, C2 )
This series replaces Cragola in the 13 to 16 inch precipitation zone as a result of the Four Corners Climate Conference 10/92.
Soil Taxonomy Second Edition, 1999