LOCATION REDRIDGE COEstablished Series
TAXONOMIC CLASS: Fine-loamy over sandy or sandy-skeletal, mixed, superactive, mesic Aridic Argiustolls
TYPICAL PEDON: Redridge gravelly coarse sandy loam - grassland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 7 inches; reddish gray (5YR 5/2) gravelly coarse sandy loam, dark reddish brown (5YR 3/2) moist; moderate very fine granular structure; soft, very friable; 15 percent gravel; neutral clear smooth boundary. (5 to 10 inches thick)
A3--7 to 10 inches; reddish brown (5YR 5/3) gravelly coarse sandy loam, dark reddish brown (5YR 3/3) moist; moderate medium subaugular blocky structure that parts to fine granules; slightly hard, very friable; peds are hard, very friable; 15 percent gravel; neutral; clear smooth boundary. (3 to 6 inches thick)
B2t--10 to 20 inches; reddish brown (2.5YR 5/4) gravelly sandy clay loam, reddish brown (2.5YR 4/4) moist; moderate medium prismatic structure that parts to medium subangular blocks; very hard, very friable, slightly sticky, slightly plastic; peds are extremely hard, very friable; nearly continuous clay films on peds and in root channels and pores; 20 percent gravel; neutral; clear smooth boundary. (7 to 10 inches)
B3t--20 to 26 inches; reddish brown (2.5YR 5/4) gravelly heavy sandy loam, reddish brown (2.5YR 4/4) moist; weak medium subangular structure; very hard, very friable; peds are extremely hard, very friable; few thin patchy clay films on peds and in some root channels and pores; 20 percent gravel; neutral; clear wavy boundary. (0 to 8 inches thick)
IIC--26 to 60 inches; red (2.5YR 5/6) very gravelly loamy coarse sand, red (2.5YR 4/6) moist; massive; very hard, loose; 60 percent gravel; neutral.
TYPE LOCATION: Douglas County, Colorado; 500 feet west and 700 feet north of the center of Sec. 9, T. 95., R. 68 W.
RANGE IN CHARACTERISTICS: Redridge soils typically are noncalcareous to depths of more than 60 inches but depth to uniformly calcareous material normally ranges from 40 to more than 60 inches. Base saturation typically is greater than 80 percent and ranges from 60 to 100 percent. Depth to the sandy skeletal IIC horizon ranges from 20 to 40 inches. Depth to the base of the argillic horizon ranges from 15 to 40 inches. Rock fragments range from 15 to 35 percent by volume in a major part of the solum and are mainly less than 3 inches in diameter but range from 1/8 to 10 inches in diameter. The solum and C horizons range from slightly acid through mildly alkaline. The mean annual soil temperature is 49 degrees F., and the mean summer soil temperature is 65 degrees F.
The A horizon has hue of 10YR through 5YR, value of 4 or 5 dry, 2 or 3 moist, and chroma of 1 through 3.
The B2t horizon has hue of 5YR through 1OR, value of 5 through 7 dry, 4 through 6 moist, and chroma of 1 through 6. It averages 18 to 35 percent clay and 40 to 75 percent sand, with more than 35 percent being fine or coarser sand. A large proportion of the sand fraction is medium, coarse, and very coarse angular sand which has a high percentage of flat bearing surfaces between sand grains.
COMPETING SERIES: These are the Altvan, Archerson, Atencio, Bresser, Eckley, Newlin, Tuthill, and Wheatridge series. Altvan and Atencio soils are calcareous in the lower part of the solum and in the C horizon and have continuous horizons of secondary calcium carbonate. Archerson and Bresser soils have hue of 7.5YR or yellower. Eckley soils have hue of 7.5YR or yellower, have solums less than 15 inches thick to the base of the argillic horizon and have a sandy-skeletal IIC horizon at depths of less than 20 inches. Newlin soils have hue of 7.5YR or yellower and contain only small amounts of medium, coarse, and very coarse arkosic sand. Tuthill soils have hue of 7.5YR or yellower and have only small amounts of medium, coarse and very coarse angular granitic sand.
GEOGRAPHIC SETTING: Redridge soils are on fans, terraces, valley side slopes, and stream bottoms. Slope gradients range from 2 to 15 or more percent. The soil formed in materials derived principally from the red arkosic Fountain and Lyons formations. At the type location the average annual precipitation is 17 inches, with peak periods of precipitation occurring in the spring and summer.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Garber and Lonetree soils. Garber soils have more than 35 percent rock fragments, have mollic epipedons more than 16 inches thick, and lack argillic horizons. Lonetree soils lack argillic horizons and are coarse textured.
DRAINAGE AND PERMEABILITY: Well drained; medium to slow runoff; moderate permeability.
USE AND VEGETATION: These soils are used principally as native pastureland; however, they are tilled in some localities. Native vegetation is mainly big bluestem, little bluestem, prairie sand reedgrass, needleandthread grass, and blue grama.
DISTRIBUTION AND EXTENT: The foothill areas of east-central Colorado. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Douglas County, Colorado, 1974.
REMARKS: Last updated by the state 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.