LOCATION BIG BLUE CO+WYEstablished Series
TAXONOMIC CLASS: Fine, smectitic, calcareous, frigid Fluvaquentic Endoaquolls
TYPICAL PEDON: Big Blue loam, grassland. (Colors are for dry soil unless otherwise noted.)
A--0 to 10 inches; dark gray (10YR 4/1) loam, black (10YR 2/1) moist; moderate very fine granular structure; soft, very friable, slightly sticky and slightly plastic; calcareous; moderately alkaline (pH 8.0); clear smooth boundary. (4 to 12 inches thick)
A2g--10 to 18 inches; dark gray (10YR 4/1) loam, black (10YR 2/1) moist; common medium distinct olive (5Y 5/6) mottles; weak medium subangular blocky structure that parts to medium granules; slightly hard, friable, sticky and plastic; peds are extremely hard, very firm; calcareous; moderately alkaline (pH 8.2); clear wavy boundary. (6 to 12 inches thick)
Bg1--18 to 40 inches; light gray (5YR 6/1) heavy clay loam, dark gray (5Y 4/1) moist; many large prominent olive (5Y 5/6) mottles; weak coarse subangular blocky structure; slightly hard, friable, sticky and plastic; peds are very hard, firm; calcareous; moderately alkaline (pH 8.1); gradual smooth boundary. (12 to 30 inches thick)
Bg2--40 to 60 inches; light gray (5Y 6/1) heavy clay loam, gray (5Y 5/1) moist; many large prominent olive (5Y 5/6) mottles; massive; very hard, firm, sticky and plastic; mildly alkaline (pH 7.8).
TYPE LOCATION: Saguache County, Colorado; SE1/4 sec. 13, T.48N., R.3E.
RANGE IN CHARACTERISTICS: Depth to uniformly calcareous material ranges from 0 to 6 inches. The mollic epipedon ranges from 10 to 24 inches but typically is 14 to 18 inches thick. The control section is calcareous in all parts between depths of 10 to 20 inches, but is noncalcareous in the lower part in some pedons. Continuous concentrated horizons of visible secondary calcium carbonate and/or sulfate do not occur within the control section although some visible carbonate or other accumulation is present in some pedons at any depth as a characteristic of the parent material. The control section is heavy clay loam, silty clay or clay and has 35 to 50 percent clay, 5 to 50 percent silt and 10 to 55 percent sand. Rock fragments range from 0 to 15 percent in a major part of the control section and range from 1/8 to 10 inches in diameter. The solum ranges from mildly to strongly
alkaline. The average annual soil temperature ranges from 40 degrees to 44 degrees F., and average summer soil temperature is 61 degrees to 63 degrees F. without an 0 horizon. A seasonally high water table ranges from one-half to one foot from the surface.
The A horizon has hue of 5Y through 7.5YR, value of 3 through 5, 2 or 3 moist, and chroma of 0 through 2.
The Bg horizon has hue of 5Y to 7.5YR, value of 5 through 7, 4 through 6 moist and chroma of 0 through 4.
The Cg horizon where present, has hue of 5Y through 10YR, value of 5 through 7, 4 through 6 moist and chroma of 0 through 2. Textures of gravelly or cobbly sand occur in this horizon at depths below 50 inches.
COMPETING SERIES: This is the tentative Clearwater series and the similar soils, Brownton and Egas series. Clearwater soils have much higher rates of mean annual precipitation (21 inches) at lower elevations and longer frost-free periods of about 30 days. The Brownton soils lack salts at or near the surface. The Egas soils have Csa horizons in the control section. The Brownton and Egas soils also have mesic temperatures.
GEOGRAPHIC SETTING: The Big Blue soils are on flood plains and terraces. Slope gradients range from 0 to 6 percent. The soils formed in recent alluvium from sedimentary rock. The average annual precipitation ranges from 10 to 14 inches with a spring and summer peak rainfall pattern. The frost free period is 90 to 100 days and the mean annual temperature is 38 degrees to 42 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gas Creek and Irim soils. Gas Creek soils are gravelly or very gravelly loamy sand or sand. Irim soils are gravelly or very gravelly, medium to moderately fine textured.
DRAINAGE AND PERMEABILITY: Poorly or somewhat poorly drained; very slow or slow runoff; slow permeability.
USE AND VEGETATION: These soils re used as native pastureland, and native hay meadows. Native vegetation is timothy, redtop, alsike clover, fescues, sedges, and rushes.
DISTRIBUTION AND EXTENT: Mountain areas of central Colorado. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Saguache county, Colorado, 1974.