LOCATION UNCOMPAHGRE COEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, calcareous, mesic Fluvaquentic Endoaquolls
TYPICAL PEDON: Uncompahgre loam - grassland. (colors are for dry soil unless otherwise noted.)
A--0 to 8 inches; gray (10YR 5/1) loam, very dark gray (10YR 3/1) moist; moderate medium granular structure; soft, very friable, slightly sticky and slightly plastic; slightly effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (4 to 12 inches thick)
Ag--8 to 14 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; common medium distinct dark yellowish brown (10YR 4/4) redox concentrations; weak coarse subangular blocky structure parting to coarse granules; slightly hard, very friable, slightly sticky and slightly plastic; slightly effervescent; moderately alkaline (pH 8.0); gradual wavy boundary. (3 to 20 inches thick)
Bwg--14 to 60 inches; light brownish gray (2.5Y 6/2) loam stratified with thin lenses of fine sandy loam and clay loam, grayish brown (2.5Y 5/2) moist; many large distinct dark yellowish brown (10YR 4/4) and light brown (7.5YR 6/4) redox concentrations; massive; slightly hard, friable, slightly sticky and slightly plastic; strongly effervescent; moderately alkaline (pH 8.2).
TYPE LOCATION: Montrose County, Colorado; located about 400 feet east and 400 feet north of the center of Section 7, T. 47 N., R. 8 W.; USGS Colona topographic quadrangle; latitude 38 degrees, 20 minutes, 34 seconds north and longitude 107 degrees, 47 minutes, 14 seconds west.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 49 to 54 degrees F.
Particle-size control section: 18 to 35 percent clay with 0 to 15 percent rock fragments.
Depth to bedrock: 60 or more inches.
Mollic epipedon: 7 to 15 inches thick.
Depth to uniformly calcareous material: 0 to 10 inches.
ESP: 0 to 15.
EC: 0 to 14 millimhos/cm.
A horizon:
Hue: 5Y to 7.5YR.
Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 0 to 3 dry or moist
Texture: loam, fine sandy loam, or clay loam with 10 to 35 percent clay.
Rock fragments: 0 to 15 percent.
Reaction: slightly or moderately alkaline.
Bwg horizon:
Hue: 5Y to 7.5YR.
Value: 5 to 7 dry, 4 to 6 moist.
Chroma: 0 to 2 dry or moist
Texture: loam stratified with fine sandy loam and clay loam with 18 to 35 percent clay.
Rock fragments: 0 to 15 percent.
Calcium carbonate equivalent: 5 to 15 percent.
Reaction: moderately or strongly alkaline.
COMPETING SERIES: These are the Merden (WY), Oshawa (MN), and Voltaire (NV) series. The Merden and Oshawa soils are wetter in the moisture control section during the 120 days following the summer solstice. The Voltaire soils have more than 15 percent exchangeable sodium.
GEOGRAPHIC SETTING: Uncompahgre soils are on floodplains and low terraces. Slopes range from 0 to 6 percent. The soils formed in calcareous alluvium from mixed sources. Elevation ranges from 4,800 to 6,600 feet. The mean annual precipitation is 7 to 11 inches. The mean annual temperature is 47 to 52 degrees F. The frost-free period is 120 to 155 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Sagers and Vernal soils. Sagers and Vernal soils lack a mollic epipedon and are well drained.
DRAINAGE AND PERMEABILITY: Somewhat poorly to poorly drained; negligible to low runoff; moderate to slow permeability; occasional brief flooding April through June.
USE AND VEGETATION: This soil is used for grazing land, native hay meadow, or cropland. Native vegetation is willows, cottonwood, rushes, timothy, and bluegrass.
DISTRIBUTION AND EXTENT: Western Colorado. LRR D, MLRA 34. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Uncompahgre Valley Area, Montrose County, Colorado, 1910.
REMARKS: OSED scanned by NSSQA. Last revised by state 2/96.
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.