LOCATION CARRACAS CO
Established Series
Rev. JPP/TWH/KLS
03/2018
CARRACAS SERIES
The Carracas series consists of shallow, well drained soils that formed in slope alluvium or colluvium derived from shale. Carracas soils are on hillslopes and mountain slopes. Slopes range from 3 to 60 percent. Mean annual precipitation is about 510 mm and the mean annual air temperature is approximately 6.1 degrees C.
TAXONOMIC CLASS: Clayey, mixed, superactive, frigid, shallow Typic Haplustepts
TYPICAL PEDON: Carracas clay loam, on a west facing, simple, 12 percent slope in ponderosa pine woodland at an elevation of 2,225 meters. (Colors are for dry soil unless otherwise noted.) When described on June 21, 1984 the soil was moist from 0 to 38 cm.
A--0 to 8 cm; grayish brown (10YR 5/2) clay loam, dark grayish brown (10YR 4/2) moist; weak thick platy structure parting to moderate medium granular structure; hard, firm, moderately sticky, moderately plastic; common very fine roots throughout; common fine and very fine tubular pores; 2 percent cobbles and 5 percent parachanners; slightly effervescent; 3 percent calcium carbonate equivalent; moderately alkaline (pH 8.0); clear smooth boundary. (5 to 13 cm thick)
Bk1--8 to 20 cm; grayish brown (10YR 5/2) clay, brown (10YR 4/3) moist; weak medium angular blocky structure; very hard, very firm, very sticky, very plastic; common fine and very fine roots; common very fine tubular pores; 10 percent parachanners; strongly effervescent; 8 percent calcium carbonate equivalent; moderately alkaline (pH 8.0); clear wavy boundary. (8 to 30 cm thick)
Bk2--20 to 38 cm; brown (10YR 5/3) clay, brown (10YR 4/3) moist; weak medium angular blocky structure; very hard, very firm, very sticky, very plastic; common fine and very fine roots; common very fine tubular pores; 14 percent parachanners; strongly effervescent; 10 percent calcium carbonate equivalent; moderately alkaline (pH 8.0); clear wavy boundary. (0 to 20 cm thick)
Cr--38 to 64 cm; weakly cemented shale bedrock, moderately alkaline.
TYPE LOCATION: Archuleta County, Colorado; about 19 kilometers west of Pagosa Springs; located about 290 meters east and 1,158 meters north of the southwest corner of Sec. 4, T. 35 N., R. 3 W.; Lonetree Canyon USGS quad; Lat. 37 degrees 14 minutes 22 seconds N., Long. 107 degrees 13 minutes 0 seconds W., NAD 27.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 6.7 to 8.3 degrees C.
Mean summer soil temperature: 15.6 to 17.2 degrees C.
Depth to paralithic contact: 25 to 51 cm to shale
Depth to calcium carbonate: 0 to 13 cm
Thickness of cambic horizon: 18 to 43 cm
Particle-size control section (weighted average):
Clay content: 35 to 45 percent
Rock fragments: 0 to 2 percent
A horizon
Hue: 10YR or 2.5Y
Value: 5 or 6 dry, 3 to 5 moist
Chroma: 1 to 3, dry or moist
Clay content: 40 to 45 percent
Rock fragments: 0 to 5 percent
Rock fragments: 0 to 15 percent total; 0 to 10 percent parachanners, 0 to 5 percent cobbles
Reaction (pH): 7.4 to 8.4
Bk1 horizon
Hue: 10YR or 2.5Y
Value: 5 to 7 dry, 4 or 5 moist
Chroma: 1 to 3
Texture: clay, clay loam, silty clay loam
Clay content: 35 to 45 percent
Rock fragments: 0 to 15 percent parachanners
Calcium carbonate equivalent: 5 to 15 percent
Reaction (pH): 7.9 to 8.4
Bk2 horizon
Hue: 10YR or 2.5Y
Value: 5 to 7 dry, 4 or 5 moist
Chroma: 1 to 3
Texture: clay, clay loam, silty clay loam, parachannery clay loam
Clay content: 35 to 45 percent
Rock fragments: 0 to 35 percent parachanners
Calcium carbonate equivalent: 5 to 15 percent
Reaction (pH): 7.9 to 8.4
COMPETING SERIES:
Saruche (CO) - do not have free carbonates in the control section
GEOGRAPHIC SETTING:
Landform - hillslopes, mountain slopes
Elevation - 1,830 to 2,530 meters
Slopes - 3 to 60 percent
Parent material - slope alluvium or colluvium derived from shale
Mean annual air temperature - 5.6 to 7.2 degrees C.
Mean annual precipitation - 460 to 560 mm
Precipitation pattern - Wettest months are May and June, July and August are the driest months.
Frost-free period - 80 to 100 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained, high runoff, slow permeability.
USE AND VEGETATION: Major use is for livestock grazing, timber production, and wildlife habitat. Native vegetation is ponderosa pine, Rocky mountain juniper, Gambel oak, antelope bitterbrush, big sagebrush, mountain mahogany, western wheatgrass, Arizona fescue, and Indian ricegrass.
DISTRIBUTION AND EXTENT: Southwestern Colorado. LRR D, MLRA 36. This series is of moderate extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: La Plata County (Piedra Area), Colorado, 1974. The current type location is in the Archuleta soil survey area. The name is from a small community in Archuleta County.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Cambic horizon: 8 to 38 cm (Bk1 and Bk2 horizons)
Paralithic contact: 38 cm to unconsolidated shale bedrock (Cr layer)
Particle-size control section: 25 to 38 cm (part of the Bk2 horizon to bedrock)
Series control section: 0 to 25 inches (all horizons and upper 25 cm of the paralithic layer)
Carracas soils are in a frigid temperature regime with an ustic soil moisture class and a typic subclass.
National Cooperative Soil Survey
U.S.A.