LOCATION CRESPIN COEstablished Series
TAXONOMIC CLASS: Fine, smectitic Chromic Haplocryerts
TYPICAL PEDON: Crespin Clay - grassland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 4 inches; brown (10YR 5/3) clay, dark brown (10YR 4/3) moist; strong fine granular structure; slightly hard, very friable; sticky; plastic; mildly alkaline (pH 7.6); clear smooth boundary. (3 to 6 inches thick)
AC--4 to 9 inches; brown (10YR 5/3) clay, dark brown (10YR 4/3) moist; weak coarse angular blocky structure; hard, firm, very sticky, very plastic; peds are extremely hard, very firm; cracks 1 to 3 cm. in width when dry; mildly alkaline (pH 7.6); gradual wavy boundary. (4 to 6 inches thick)
C--9 to 60 inches; brown (10YR 5/3) clay, dark brown (10YR 4/3) moist; very weak, very coarse angular blocky structure; extremely hard, very firm, very sticky, very plastic; many slickensides and pressure faces on peds; cracks 1 to 3 cm. in width when dry; mildly alkaline (pH 7.6).
TYPE LOCATION: Jackson County, Colorado; approximately 1/4 mile west and 1/8 mile south of NE corner of Sec. 23, T. 9 N., R. 79 W.
RANGE IN CHARACTERISTICS: Mean annual soil temperature is about 42 degrees F and mean summer soil temperature is about 54 degrees F. Depth to uniformly calcareous material ranges from 40 to more than 60 inches. The control section is usually heavy clay loam or clay but averages 35 to 60 percent clay, 10 to 50 percent silt, and 10 to 45 percent sand. COLE ranges from .05 to .15 and total extensibility exceeds 2.4 inches. Rock fragments range from 0 to 35 percent and are mainly 1/4 to 10 inches in diameter.
The A horizon has hue of 5Y through 7.5YR, value of 5 through 7 dry, 3 through 6 moist, and chroma of 1 through 4. It ranges from slightly acid to mildly alkaline.
The C horizon has hue of 5Y through 7.5YR but subhorizons redder than 7.5YR occur in some pedons. It ranges from slightly acid to mildly alkaline.
COMPETING SERIES: These are the Aaberg, Bundyman, and Carlstrom series. These soils have a paralithic contact above a depth of 40 inches.
GEOGRAPHIC SETTING: Crespin soils are on gently to moderately sloping alluvial fans and valley filling side slopes. Slopes typically range from 2 to about 15 percent. The soils formed in thick, noncalcareous, fine textured deposits derived principally from noncalcareous shales. At the type location the average annual precipitation is 10 inches with peak periods of precipitation during the spring and early summer. The average annual temperature is 38 degrees F and the average summer temperature is 57 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Aaberg, Bundyman, and Carlstrom soils.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderately slow permeability.
USE AND VEGETATION: These soils are used principally as native pastureland. Native vegetation is junegrass, western wheatgrass, squirreltail, and big sage.
DISTRIBUTION AND EXTENT: High mountain valleys of north-central Colorado. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Jackson County, Colorado, 1973.
REMARKS: Last updated by the state 10/73.