LOCATION STAPLETON COEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Aridic Haplustolls
TYPICAL PEDON: Stapleton coarse sandy loam - grassland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 10 inches; grayish brown (10YR 5/2) coarse sandy loam, dark grayish brown (10YR 3/2) moist; moderate very fine granular structure; slightly hard, very friable; 5 percent fine and very fine angular granitic gravel; neutral; gradual smooth boundary.
(6 to 20 inches thick)
B2--10 to 20 inches; brown (10YR 5/3) coarse sandy loam, dark brown (10YR 4/3) moist; moderate medium subangular blocky structure; hard, very friable; peds are extremely hard, very friable; few thin clay films on some peds and in some root channels and pores; 5 percent fine and very fine angular granitic gravel; neutral; gradual smooth boundary. (9 to 20 inches thick)
C--20 to 60 inches; light brownish gray (10YR 6/2) coarse sandy loam, grayish brown (10YR 5/2) moist; massive; extremely hard, very friable; 5 percent fine and very fine angular granitic gravel; neutral.
TYPE LOCATION: Douglas County, Colorado; 1,900 feet north and 500 feet east of the SW corner of Sec. 26, T. 6 S., R. 66 W.
RANGE IN CHARACTERISTICS: Stapleton soils typically are noncalcareous to depths of more than 60 inches but depth to uniformly calcareous material ranges from 40 to more than 60 inches. Base saturation typically is more than 80 percent and ranges from 60 to 100 percent. The control section is usually coarse sandy loam, and has 5 to 18 percent clay, 5 to 35 percent silt, and 50 to 80 percent sand with more than 35 percent being fine or coarser sand. A large proportion is medium, coarse, and very coarse angular sand which has a high percentage of flat bearing surfaces between sand grains. Rock fragments range from O to 15 percent and are mainly less than 3 inches in diameter but range from 1/8 to 10 inches in diameter. The solum and C horizon range from slightly acid through mildly alkaline. The mean annual soil temperature is 49 degrees F. and the mean summer soil temperature is 64 degrees F.
The A horizon has hue of 5Y through 7.5YR, value of 4 or 5 dry, 2 or 3 moist, and chroma of 1 through 3.
The B2 horizon has hue of 5Y through 7.5YR, value of 5 through 7 dry, 4 through 6 moist, and chroma of 1 through 6.
The C horizon has hue of 5Y through 7.5YR.
COMPETING SERIES: These are the Alice, Creighton, Jayem, Phiferson, and Unaweep series. Alice, Creighton and Phiferson soils are calcareous in the lower part of the solum and in the C horizon and have continuous horizons of secondary calcium carbonate accumulation. Jayem soils have only small amounts of medium, coarse, and very coarse angular sand and lack hard setting properties. Unaweep soils have hue of 5YR or redder.
GEOGRAPHIC SETTING: Stapleton soils are on gently to moderately steeply sloping alluvial fans and valley side slopes. Slope gradients range from 1 to 30 or more percent. The soil formed in alluvial materials derived principally from arkose beds of the Dawson and Arapahoe formations. At the type location the average annual precipitation is 17 inches, with peak periods of precipitation in the spring and summer.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bresser and Truckton soils. Bresser soils have sandy clay loam argillic horizons. Truckton soils have sandy loam argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; rapid permeability.
USE AND VEGETATION: These soils are used as dry and irrigated cropland, and as native pastureland. Native vegetation is mainly big and little bluestem, sandreed grass, needleandthread, and blue grama.
DISTRIBUTION AND EXTENT: Foothill and Black Forest areas of east-central Colorado. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Douglas County, Colorado, 1974.
REMARKS: OSED scanned by NSSQA and cleaned up by Colorado. Last revised by state on 8/74.
The superactive cation exchange activity class was added in 03/2003 to the taxonomic classification by the National Soil Survey Center on request of the Lakewood MLRA office, without review of the soil series property data. The remainder of this document has not been updated.