LOCATION FERN CLIFF COEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Lamellic Haplustalfs
TYPICAL PEDON: Fine Cliff stony sandy loam - woodland. (Colors are for dry soil unless otherwise noted.)
O1--4 to 2 inches; undecomposed organic material, chiefly needles, bark, and twigs.
02--2 to 0 inches; partially decomposed organic material like that of the horizon above.
A1--0 to 3 inches; dark grayish brown (10YR 4/2) sandy loam, very dark brown (10YR 2/2) moist; strong fine crumb structure; soft, very friable; very finely divided mica; 15 to 20 percent stones, mostly gnesis and schist; slightly acid (pH 6.4) clear smooth boundary. (0 to 4 inches thick)
A2--3 to 20 inches; light gray (10YR 7/2) sandy loam (10YR 5/2) moist; weak thin platy structure that parts to moderate fine granules; soft, very friable; much finely divided mica; 15 to 20 percent stones, mostly schist; medium acid (pH 5.6); gradual wavy boundary. (10 to 20 inches thick)
A&B--20 to 29 inches; mixed light gray (10YR 7/2) and yellowish brown (10YR 5/4) heavy sandy loam; weak fine subangular blocky structure; clayey peds are very hard, friable, plastic; thin nearly continuous glossy coatings on some faces of peds; horizon consists of clayey material like the lamellae of the underlying horizon embedded in a lighter colored matrix like that of the overlying horizon; much finely divided mica; 20 percent stones; slightly acid (pH 6.2) diffuse wavy boundary. (6 to 12 inches thick)
B2t--29 to 60 inches; mixed light brownish gray (10YR 5/4) sandy clay loam; dark grayish brown (10YR 4/2) and dark yellowish brown (10YR 4/4) moist; matrix to massive; clayey laminae have moderate medium subangular blocky structure; slightly hard, very friable matrix, peds in clayey seams and lamellae are very hard, friable, plastic; thin continuous wax-like coatings on faces of peds in the lamellae; some clay bridging in matrix; this horizon consists of matrix of sandy loam in which is embedded 1/2 to 2 inches thick discontinuous layers of clayey material; 20 percent stones; slightly acid (pH 6.4); gradual wavy boundary. (22 to 44 inches thick)
C--60 to 80 inches; light yellowish brown (10YR 6/3) sandy loam, light olive brown (2.5Y 5/3) moist; slightly hard, very friable; much finely divided mica; 60 percent stones; slightly acid (pH 6.4)
TYPE LOCATION: Boulder County, Colorado; 1,400 feet south and 2,400 feet west of NE corner of Sec. 5, T. 1 N., R. 71 W.
RANGE IN CHARACTERISTICS: The 01, 02, and A1 horizons are absent to some pedons. Thickness of solum exceeds 40 inches. Exchangeable sodium is usually less than 3 percent and does not exceed 14 percent in any part of the solum. The soil is 60 to 100 percent base saturated. Rock fragments in the solum range from 0 to 35 percent and tend to increase with increasing depth. These soils are dry in all parts of the moisture control section for 60 to 150 days (cumulative) in most years and the whole soil is dry for periods of 10 to 30 days at some time nearly every year. Mean annual soil temperature ranges from 40 to 47 degrees F. and mean summer soil temperature ranges from 50 to 58 degrees F. in soils with an O horizon at least 4 inches thick.
The A2 horizon has hue of 2.5Y through 7.5YR, value of 6 through 8 dry, 4 through 6 moist, and chroma of 2 through 4. It is usually platy but has granular or subangular blocky structure in some pedons. This horizon is soft to slightly hard and has high mica content. It is strongly acid to mildly alkaline (pH 5.5 to 7.8).
The B2t horizon has hue of 2.5Y through 7.5YR, value of 5 through 8 dry, 4 through 6 moist, and chroma of 2 through 5, and pH 6.1 to 7.8. The lamellae of the B2t horizon are typically sandy clay loam or clay loam but have 18 to 35 percent clay, 5 to 40 percent silt, and 30 to 70 percent percent sand with more than 35 percent fine sand or coarser. The matrix of the B2t horizon is typically sandy loam and the mixed texture is typically light sandy clay loam or heavy loam with more than 35 percent fine or coarser sand and with high mica content. This horizon is slightly acid to mildly alkaline (pH 6.1 to 7.8).
The C horizon has hue of 2.5Y to 7.5YR. Gnesis and schist rock in the C horizon are strongly weathered and frequently can be crushed in the hand. Mica content is high. This horizon is slightly acid to mildly alkaline (pH 6.1 to 7.8).
COMPETING SERIES: These are the Hardscrabble and Kettle series. Hardscrabble soils have a lithic contact at depths of less than 40 inches. Kettle soils have coarse fragments consisting mainly of fine and very fine angular pebbles, have a large percentage of medium and coarse angular granite sands, have hard setting properties when dry in the horizons of low organic matter content, and have very gravelly loamy sand or sand C horizons.
GEOGRAPHIC SETTING: These soils are on gently to moderately steep alluvial fans and valley side slopes in foothill and mountain areas. Slope gradients are dominantly 2 to 30 percent. The soil formed in thick micaceous alluvial fan sediments derived principally from gnesis and schist bedrock. At the type location, the average annual precipitation is 18 inches with peak period of precipitation during the spring and summer. Mean annual temperature is 42 degrees F. and mean summer temperature is 62 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Goldvale and Allens Park soils. Goldvale soils have more than 35 percent clay in continuous argillic horizons. Allens Park soils have continuous argillic horizons and have hard bedrock at depths of 20 to 40 inches.
DRAINAGE AND PERMEABILITY: Well-drained; slow to medium runoff; medium to rapid permeability.
USE AND VEGETATION: These soils are used as native pastureland, for recreation, and limited forestry. Principal native vegetation is lodgepole pine, spruce, and a sparse understory of grasses and shrubs.
DISTRIBUTION AND EXTENT: Foothill areas of the front range in central Colorado. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Boulder County, Boulder Area, Colorado, 1971.
REMARKS: Last updated by the State 11/73.