LOCATION TOMAH COEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Alfic Argiustolls
TYPICAL PEDON: Tomah sandy loam, forested. (Colors are for fey soil unless otherwise noted.)
A1--0 to 11 inches; dark grayish brown (10YR 4/2) sandy loam, very dark brown (10YR 2/2) moist; moderate fine granular structure; soft, very friable; 10 percent gravel; slightly acid; clear smooth boundary. (7 to 15 inches thick)
A2--11 to 20 inches; light gray (10YR 7/2) loamy coarse and sand, brown (10YR 5/3) moist; weak plates that part to fine structure; hard, loose, 10 percent fine and very fine angular granite gravel; slightly acid; diffuse wavy boundary. (4 to 15 inches thick)
B2t--20 to 50 inches; yellowish brown (10YR 5/4) loamy coarse sand in which there are embedded many thin bands and lamellae of coarse sandy clay loam, dark yellowish brown (10YR 4/4) moist; weak fine subangular blocky structure; hard, loose, more clayey peds are extremely hard, very friable; nearly continuous clay films on peds that are within lamellae and bands; clay bridges occur between sand grains; 10 percent fine and very fine angular granite gravel; slightly acid; gradual wavy boundary. (13 to 35 inches thick
C--50 to 60 inches; pale brown (10YR 6/3) loamy coarse sand, brown (10YR 5/3) moist; massive; very hard, loose; 10 percent fine and very fine angular granite gravel; slightly acid.
TYPE LOCATION: Douglas County, Colorado; 1,800 feet north of the SE corner of Sec. 34, T. 10 S., R. 66 W.
RANGE IN CHARACTERISTICS: Combined thickness of the bands is more than 6 inches in the B2t horizon. Thickness of the mollic epipedon ranges from 7 to 15 inches. These soils typically are noncalcareous to depths of more than 60 inches and are noncalcareous to depths of more than 40 inches in all pedons. Base saturation ranges from 60 to 100 percent in all subhorizons of the argillic horizon, and typically is more than 80 percent. Depth to the top of the argillic horizon is less than 30 inches. Rock fragments range from 0 to 35 percent by volume in a major part of the solum and C horizon and are mainly 1/8 to 10 inches in diameter but typically are less than 3 inches in diameter. Within the sand fraction, a high percentage is medium and coarser angular sand which has a large proportion of flat bearing surfaces between sand grains. The solum and C horizon range from medium acid to moderately alkaline. The mean annual soil temperature is 60 to 64 degrees F.
The A1 horizon has hue of 2.5Y through 7.5YR, value of 4 or 5 dry, 2 or 3 moist, and chroma of 1 through 3. The A2 horizon has hue of 2.5Y through 7.5YR, value of 5 through 8 dry, 4 through 7 moist, and chroma of 1 through 4.
The B2t horizon has hue of 2.5Y through 7.5YR, value of 5 through 8 dry, 4 through 7 moist, and chroma of 1 through 6. Subhorizons redder than 7.5YR occur in some pedons, particularly where lamellae are thickest. Texture is typically loamy coarse and or sand containing lamellae and thin bands of sandy clay loam or coarse sandy loam.
The C horizon has hue of 2.5YR through 7.5YR. Texture is a loamy coarse sand or coarse sand.
COMPETING SERIES: These are the Crowfoot, Kelvin, Redtom and Westcreek series. Crowfoot, Kelvin and Westcreek soils have continuous argillic horizons. Redtom soils have hue of 5 Yr or redder.
GEOGRAPHIC SETTING: The Tomah soils are on alluvial fans and hills or ridges where bedrock lies at considerable depth. Slope gradients range from 2 to 30 percent. They formed in parent materials from arkose beds. In some locations the soft parent sediments occur above depth of 60 inches but they have so little contrast that they cannot be recognized consistently. The average annual precipitation is 17 inches, with peak periods of precipitation occurring in the spring and summer. The frost-free season is about 115 to 125 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Crowfoot and Redtom soils.
DRAINAGE AND PERMEABILITY: Well drained; slow to very slow runoff; rapid permeability.
USE AND VEGETATION: These soils are used principally for rangeland, recreation and wildlife habitat. Native vegetation is mainly grasses, Gambel oak, shrubs and a few widely spaced ponderosa pine trees.
DISTRIBUTION AND EXTENT: The foothills 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: El Paso County, Colorado, 1975.
REMARKS: OSED scanned by and cleaned up by Colorado. Last revised by state on 5/75.