LOCATION PAGODA CO+UTEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Vertic Argiustolls
TYPICAL PEDON: Pagoda clay loam, on a southwest facing, simple, 25 percent slope in ponderosa pine woodland at an elevation of 7,880 feet. (Colors are for dry soil unless otherwise noted.)
A--0 to 4 inches; dark grayish brown (10YR 4/2) clay loam, black (10YR 2/1) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and slightly plastic; neutral (pH 7.2); clear smooth boundary. (2 to 6 inches thick)
Bt1--4 to 14 inches; brown (10YR 4/3) clay, very dark gray (10YR 3/1) moist; moderate medium subangular blocky structure; very hard, friable, moderately sticky and moderately plastic; common distinct clay films on faces of peds; neutral (pH 7.2); clear smooth boundary.
Bt2--14 to 26 inches; grayish brown (10YR 5/2) clay loam, very dark grayish brown (10YR 3/2) moist; strong medium angular blocky structure; very hard, very firm, moderately sticky and moderately plastic; common prominent clay films on faces of peds; slightly alkaline (pH 7.8); clear smooth boundary. (combined thickness of the Bt is 16 to 36 inches)
Btk--26 to 36 inches; brown (10YR 5/3) clay loam, dark grayish brown (10YR 4/2) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few distinct clay films on faces of peds; strongly effervescent; calcium carbonate disseminated; moderately alkaline (pH 8.0); clear smooth boundary. (0 to 12 inches thick)
Bk1--36 to 45 inches; pale brown (10YR 6/3) clay loam, dark grayish brown (10YR 4/2) moist; massive; very hard, friable, slightly sticky and slightly plastic; violently effervescent; calcium carbonate disseminated; moderately alkaline (pH 8.0); clear wavy boundary. (8 to 20 inches thick)
Bk2--45 to 60 inches; brown (10YR 5/3) clay loam, very dark grayish brown (10YR 3/2) moist; massive; extremely hard, firm, slightly sticky and moderately plastic; violently effervescent; few fine calcium carbonate mycelium; moderately alkaline (pH 8.0).
TYPE LOCATION: Dolores County, Colorado; about 30 miles north of Dolores, Colorado; located about 2,800 feet west and 1,200 feet south of the northeast corner of Sec. 12, T. 41 N., R. 14 W.; Groundhog Reservoir USGS quad; lat. 37 degrees 50 minutes 04 seconds N. and long. 108 degrees 22 minutes 02 seconds W., NAD 27
RANGE IN CHARACTERISTICS:
Soil moisture regime: Ustic moisture regime (typic ustic subclass). The moisture control section is usually dry for 15 consecutive days from May 30 to July 15 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 this period.
Mean annual soil temperature: 43 to 47 degrees F.
Mean annual summer soil temperature: 59 to 68 degrees F.
Depth to secondary calcium carbonate: 20 to 40 inches or more
Thickness of the mollic epipedon: 16 to 36 inches
Linear extensibility: 6.0 to 8.0 between the surface and 40 inches.
Particle-size control section: averages 35 to 50 percent clay, although individual horizons are as high as 60 percent clay, 0 to 5 percent rock fragments, mainly gravel.
A horizon:
Hue: 7.5YR to 5Y
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 1 to 3 dry or moist
Texture: Clay loam, Loam
Rock fragments: 0 to 5 percent
Reaction: slightly acid to slightly alkaline
Bt horizon:
Hue: 10YR to 5Y
Value: 4 to 7 dry, 3 to 6 moist
Chroma: 1 to 6 dry or moist
Texture: Clay loam, Silty clay loam, Clay
Rock fragments: 0 to 5 percent
Reaction: neutral to moderately alkaline
Bk horizon:
Hue: 10YR to 5Y
Value: 5 or 6 dry, 3 to 5 moist
Chroma: 2 to 4 dry or moist
Texture: Clay loam, Silty clay, Clay, Silty clay loam
Rock fragments: 0 to 10 percent
Calcium carbonate equivalent: 1 to 10 percent
Reaction: slightly alkaline or moderately alkaline
COMPETING SERIES: These are the Burnel and Grail series. Burnel soils have ustic bordering on udic soil moisture regimes. The Grail have soil moisture control sections that are affected by peak periods of precipitation in the spring and early summer (May through July).
GEOGRAPHIC SETTING:
Parent material: clayey slope alluvium derived dominantly from shale.
Landform: mesas and hills.
Slopes: 0 to 60 percent
Elevation: 6,200 to 9,000 feet
Mean annual air temperature: 40 to 45 degrees F.; in the Cortez Area, temperature ranges to 47 degrees F.
Mean annual precipitation: 15 to 22 inches.
Wettest months: July and August.
Driest months: May and June
Frost-free period: 65 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Coulterg, Dapoin, Narraguinnep, and Sagedale soils.
Coulterg soils have mollic epipedon less than 16 inches thick and are fine-loamy and are on hillslopes.
Dapoin soils do not have an argillic horizon are on alluvial fans.
Narraguinnep soils do not have an argillic horizon and are on toeslopes and footslopes.
Sagedale soils do not have a mollic epipedon and are on toeslopes.
DRAINAGE AND PERMEABILITY: Well drained; medium to very high runoff; slow or very slow permeability.
USE AND VEGETATION: These soils are used for livestock grazing, woodland, and wildlife habitat. Native vegetation is ponderosa pine, Gambel's oak, snowberry, elk sedge, western wheatgrass, Arizona fescue, and Kentucky bluegrass.
DISTRIBUTION AND EXTENT: Southwestern Colorado. LRR E, MLRA 48A. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Dolores County (San Miguel Area), Colorado, 1987.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: The zone from 0 to 26 inches. (A, Bt1 and Bt2 horizons)
Pachic feature: the mollic epipedon is more than 16 inches thick.
Argillic horizon: The zone from 4 to 36 inches. (Bt1, Bt2, and Btk horizons)
Vertic feature: linear extensibility is estimated to range from 6.0 to 8.0 between the mineral surface and 100 cm depth.
Keys to Soil Taxonomy: Series classified according to Eighth Edition, 1998.
ADDITIONAL DATA: Sampled at another location by the NSSL, sample No. S86CO-033-003. Classification changed to a vertic subgroup based on this sample.