LOCATION RULE COInactive Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Typic Haplustalfs
TYPICAL PEDON: Rule gravelly sandy loam - forest. (Colors are for dry soil unless otherwise noted.)
01--3 to 1 inch; undecomposed organic material principally needles, bark, and twigs.
02--1 inch to 0; partially decomposed organic material like that of the horizon above.
A2--0 to 12 inches; pinkish gray (7.5YR 6/2) gravelly coarse sandy loam, brown (7.5YR 5/2) moist; weak fine platy structure that parts to fine and very fine granules; soft, very friable, nonsticky, nonplastic; 25 percent fine and very fine angular gravel; noncalcareous; neutral (pH 6.8); gradual wavy boundary. (4 to 15 inches thick)
A&B--12 to 18 inches; reddish brown (2.5YR 5/3) and pinkish gray (7.5YR 6/2) gravelly coarse sandy loam, reddish brown (2.5YR 4/3) and brown (7.5YR 5/2) moist; weak medium subangular blocky structure; slightly hard, very friable, nonsticky, nonplastic; a few of the more clayey peds are hard; few glossy patches on the faces of some peds in the more clayey portions of the horizon; 25 percent fine and very fine angular granite gravel; this horizon consists of nodules and seams of clayey material like that of the underlying horizon embedded in a lighter textured matrix like that of the overlying horizon; noncalcareous; neutral (pH 6.6); gradual smooth boundary. (3 to 10 inches thick)
B2t--18 to 28 inches; reddish brown (2.5YR 5/4) gravelly coarse sandy clay loam, reddish brown (2.5YR 4/4) moist; moderate medium subangular blocky structure; slightly hard, very friable, slightly sticky, slightly plastic; peds are extremely hard; thin continuous wax-like coatings on faces of peds and wax-like coatings in root channels and pores; wax-like rims around the entrance to some soil pores; 25 percent fine and very fine angular granite gravel; noncalcareous; neutral (pH 6.6); gradual smooth boundary. (5 to 37 inches thick)
B3--28 to 32 inches; reddish brown (2.5YR 5/4) gravelly coarse sandy loam, reddish brown (2.5YR 4/4) moist; weak medium subangular blocky structure; slightly hard, very friable, nonsticky, nonplastic; peds are extremely hard; few thin glossy patches on the faces of some peds and discontinuous glossy coatings on the inside of some root channels and pores; 25 percent fine and very fine angular granite gravel; noncalcareous; neutral (pH 6.6); gradual wavy boundary. (0 to 6 inches thick)
IIC--32 to 60 inches; reddish brown noncalcareous arkose beds of the Fountain Formation containing thin and discontinuous lenses of arkosic sandstone.
TYPE LOCATION: Douglas County, Colorado; approximately .9 mile north of the south county line in NW1/4 Sec. 33, T. 10 S. R. 69 W.
RANGE IN CHARACTERISTICS: Thin A1 horizons occur in some pedons. The soils are noncalcareous throughout except that very thin and discontinuous subhorizons immediately above the bedrock are weakly calcareous in a few pedons. Base saturation ranges from 60 to 100 percent. Depth to the paralithic contact ranges from 20 to 40 inches. Depth to the base of the argillic horizon ranges from 17 to 40 inches. Rock fragments range from 0 to 35 percent in a major part of the solum and any C horizon. These are mainly 1/8 to 1/2 inch in diameter. A majority of subhorizons above the bedrock have hue of 5YR or redder. Within the sand fraction the content of medium and coarse angular sand having a large proportion of flat bearing surfaces between sand grains ranges from 15 to about 90 percent and horizons of low organic matter content have a differential between dry and moist conditions that is 1 to 3 times greater than that of similar soils having finer and more rounded sand grains.
The A2 horizon has hue of 10YR through 2.5YR, value of 5 through 8 dry, 4 through 7 moist, and chroma of 1 through 4. It ranges from slightly acid to mildly alkaline (1:5 dilution unbuffered organic dye). The B2t horizon has hue of 5YR through 10R, value of 5 through 7 dry, 4 through 6 moist, and chroma of 1 through 6. It is typically gravelly coarse sandy clay loam but clay ranges from 18 to 35 percent, silt from 5 to 35 percent, and sand from 40 to 75 percent with more than 35 percent being fine or coarser sand much of which is medium and coarse sandy. This horizon ranges from slightly acid to mildly alkaline.
The C horizon if present has hue of 5YR through 10R. It is typically coarser than the B2t horizon and usually is coarse sandy loam but clay ranges from 5 to 35 percent, silt from 5 to 40 percent, and sand from 47 to 82 percent with more than 35 percent fine or coarser sand, much of which is medium and coarse sand. This horizon ranges from slightly acid to mildly alkaline (1:5 dilution unbuffered organic dye).
COMPETING SERIES: These are the Allens Park, Bayerton, Bradford, Fairport, Gateson, Greenough, Haugan, Kruse, Nebish, Nunica, Omena, Plome, Underhill, and Warba series. Allens Park, Bayerton, and Fairport soils have a lithic contact at depths of less than 40 inches. Bradford, Haugan, Kruse, Nunica, Omena, Plome, Underhill, and Warba soils lack paralithic contacts at depths of less than 40 inches. Bradford, Gateson, Greenough, Haugan, Kruse, Nebish, Nunica, Omena, and Warba soils have hue of 7.5YR or yellower in a majority of subhorizons.
GEOGRAPHIC SETTING: The Rule soils are on gently to moderately steeply sloping hills, ridges, and mountainsides. Slopes typically range from about 2 to 40 percent or more. The soils formed in moderately thin noncalcareous moderately coarse to moderately fine materials weathered residually or locally transported from reddish brown arkose beds. At the type location the mean annual precipitation is about 18 inches with peak periods of precipitation occurring in the spring and early summer months. Mean annual temperature is 41 degrees F. and mean summer temperature is 62 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Perry Park soils and the competing Plome soils. Perry Park soils have a mollic epipedon and lack an albic horizon.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderate to rapid permeability.
USE AND VEGETATION: Used principally as grazing land or for timber reproduction. Native vegetation is ponderosa pine, lodgepole, native Junegrass, and shrubs.
DISTRIBUTION AND EXTENT: East-central Colorado. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: West Plum Creek Soil Conservation District, Douglas County, Colorado, 1942.
REMARKS: OSED scanned by NSSQA and cleaned up by Colorado. Last revised by state on 1/73.