LOCATION YAMPATIKA COTentative Series
TAXONOMIC CLASS: Fine, smectitic, frigid Leptic Haplusterts
TYPICAL PEDON: Yampatika silty clay on a west facing, 22 percent slope in cultivated land at an elevation of 6,600 feet. (Colors are for dry soil unless otherwise noted.) Soil described on October 17, 1978.
Ap1--0 to 4 inches; brown (10YR 5/3) silty clay, brown (10YR 5/3) moist; weak fine granular structure; hard, friable, sticky and plastic; many fine and very fine roots; few fine tubular pores; moderately alkaline (pH 8.0); clear smooth boundary.
Ap2--4 to 10 inches; light brownish gray (10YR 6/2) silty clay, brown (10YR 5/3) moist; weak medium subangular blocky structure parting to weak fine subangular blocky; hard, friable, very sticky and very plastic; common fine, few medium roots; few fine tubular pores; moderately alkaline (pH 8.0); abrupt smooth boundary. (Combined thickness of A horizons is 2 to 12 inches)
Bw--10 to 20 inches; pale brown (10YR 6/3) silty clay, brown (10YR 5/3) moist; strong coarse angular blocky structure parting to strong moderate angular blocky; extremely hard, friable, very sticky and very plastic; few fine and medium roots; few fine tubular pores; moderately alkaline (pH 8.0); gradual smooth boundary. (8 to 28 inches thick)
Bky--20 to 28 inches; pale brown (10YR 6/3) silty clay, brown (10YR 5/3) moist; massive; hard, friable, sticky and plastic; 50 percent soft shale pararock fragments that slake in water; few fine seams of gypsum; common fine and medium irregular soft masses of calcium carbonate; 11 percent calcium carbonate equivalent; moderately alkaline (pH 8.0); gradual wavy boundary. (6 to 20 inches thick)
Cr--28 to 38 inches; moderately cemented shale bedrock.
TYPE LOCATION: Routt County, Colorado; about 7 miles southwest of Hayden; located about 100 feet south and 1,600 feet east of the northwest corner, sec. 36 T. 6 N., R. 89 W. 40 degrees 26 minutes 07 seconds N. Latitude and 107 degrees 19 minutes 22 seconds W Longitude, NAD 27
RANGE IN CHARACTERISTICS:
Soil moisture: The soil moisture regime is typic ustic
Mean annual soil temperature: 41 to 45 degrees F.
Mean annual summer soil temperature: 59 to 64 degrees F.
Depth to Bk or Bky horizon - 10 to 25 inches.
Depth to paralithic contact - 20 to 40 inches
These soils typically have cracks which extend to approximately 20 inches and are 1/4 inch to 1 inch wide at the surface.
Ap and A horizons
Hue: 10YR or 2.5Y
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 3 or 4, dry or moist
Texture: silty clay, clay
Clay content: 40 to 50 percent
Reaction: pH 7.4 to 8.4
Organic matter: 1 to 2 percent
Bw horizon
Hue: 10YR or 2.5Y
Value: 4 to 6 dry; 4 or 5 moist
Chroma: 3 or 4, dry or moist
Texture: silty clay, clay
Clay content: 40 to 55 percent
Fragments: 0 to 5 percent parachanners
0 to 5 percent paracobbles
Calcium carbonate equivalent: 0 to 2 percent
Reaction: pH 7.4 to 8.4
Organic matter: 0.5 to 1 percent
Bk and Bky horizons
Hue: 10YR, 2.5Y, or 5Y
Value: 5 to 7 dry; 4 or 5 moist
Chroma: 1 to 4 dry or moist
Texture: clay, silty clay, silty clay loam
Clay content: 38 to 55 percent
Fragments: 5 to 15 percent parachanners
0 to 5 percent paracobbles
Calcium carbonate equivalent: 5 to 15 percent
Gypsum: 1 to 5 percent
Reaction: pH 7.9 to 9.0
COMPETING SERIES:
There are no competing series. A closely similar series is the
Abor series. Abor soils have an ustic moisture regime bordering on aridic.
GEOGRAPHIC SETTING:
Parent Material: slope alluvium, colluvium and residuum
Landform: hills, mountains and structural benches.
Slope: 10 to 65 percent
Elevation: 6,300 feet to 7,200 feet
Mean annual air temperature: 40 to 45 degrees F.
Mean annual precipitation: 16 to 20 inches evenly distributed throughout the year.
Frost-free period: 80 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bulkley and Morapos series. Bulkley and Morapos soils are on the same landform but Bulkley soils are very deep Vertisols and Morapos soils have mollic epipedons.
DRAINAGE AND PERMEABILITY: Well drained, very slow permeability, moderate to very high runoff.
USE AND VEGETATION: Yampatika soils are used for crops, pastureland, rangeland and wildlife habitat. The potential native vegetation is mainly alkali sagebrush, Saskatoon service berry, Lettermans needlegrass, slender wheatgrass, bluebunch wheatgrass, and western wheatgrass. Mountain big sagebrush and Wyoming big sagebrush are also be present in some areas.
DISTRIBUTION AND EXTENT: Northwest Colorado, LRR D, MLRA 34A, small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Routt County, Colorado, 2004. The name is derived from the Yampatika Ute Indians who were early inhabitants of the Yampa River Valley.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: The zone from the surface of the soil to a depth of 10 inches (Ap horizons).
Paralithic contact at 28 inches. (Cr layer)
Vertic properties: Cracks 0.25 to 1 inch wide from the surface to 20 inches that are open from late June to Early September.
Particle-size control section - the zone from 10 to 38 inches, (Bw and Bky horizons)
Series control section - the zone from 0 38 inches, (all horizons and upper 10 inches of Cr layer)
Taxonomic Key Version: 9th edition, 2003.