LOCATION LOGHILL COTentative Series
TAXONOMIC CLASS: Fine, smectitic, frigid Typic Haplustalfs
TYPICAL PEDON: Loghill clay loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 6 inches; dark reddish gray (5YR 4/2) clay loam, dark reddish brown (5YR 3/2) moist; moderate fine granular structure; hard, friable, slightly sticky and slightly plastic; neutral (pH 7.2); clear smooth boundary. (4 to 7 inches thick)
Bt1--6 to 13 inches; reddish brown (5YR 4/3) clay loam, dark reddish brown (5YR 3/4) moist; moderate fine and medium subangular blocky structure; very hard, firm, sticky and plastic; continuous thin clay films in ped faces; mildly alkaline (pH 7.4); gradual wavy boundary. (5 to 23 inches thick)
Bt2--13 to 29 inches; reddish brown (5YR 5/3) clay, reddish brown (5YR 4/4) moist; strong medium angular blocky structure; very hard, firm, sticky and very plastic; continuous moderately thick clay films on ped faces; mildly alkaline (pH 7.6); clear smooth boundary. (5 to 25 inches thick)
Btk--29 to 42 inches; light reddish brown (5YR 6/4) very cobbly sandy clay loam, brown (7.5YR 5/4) moist; weak fine and coarse subangular blocky structure; very hard, firm, sticky and plastic; few thin clay films on ped faces; 15 percent pebbles, 35 percent cobbles as a strata in the horizon; moderately alkaline (pH 8.2); weakly calcareous in spots, visible lime as pendants on rocks; clear smooth boundary. (0 to 14 inches thick)
Bk--42 to 45 inches; light reddish brown (5YR 6/4) gravelly sandy clay loam, brown (7.5YR 5/4) moist; weak coarse subangular blocky structure; very hard, firm, sticky and plastic; 20 percent pebbles; moderately alkaline (pH 8.2); calcareous; visible lime as pendants on rocks; abrupt smooth boundary. (3 to 40 inches thick)
R--45 inches; sandstone.
TYPE LOCATION: Ouray County, Colorado; near McKenzie Butte about 2,500 feet north and 1,050 feet east of the southwest corner of Sec. 6, T. 46 N., R. 8 W.
RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 44 to 47 degrees F., and mean summer soil temperature ranges from 58 to 64 degrees F. Depth to bedrock is 40 to 60 inches or more. Rock fragments range from 0 to 20 percent in the A and Bt horizons and from 15 to 50 percent in the Btk and Bk horizons. Depth to the base of the argillic horizon ranges from 14 to 55 inches, but it is typically 20 to
40 inches. Depth to lime ranges from 15 to 46 inches. The Bt horizons are leached. Lime is leaches to the top of the Btk horizon, when present, or at the top of the Bk horizons.
The A horizon has hue of 7.5YR or 5YR, value of 4 or 5, 2 or 3 moist, and chroma of 2 or 3. Reaction is neutral or mildly alkaline.
The Bt horizon is clay loam or clay. Clay content ranges from 35 to 60 percent. It has hue of 7.5YR or 5YR, value of 4 through 6, 3 through 5 moist, and chroma of 2 through 4. Reaction is neutral or mildly alkaline.
The Btk and Bk horizons are very cobbly sandy clay loam, cobbly or very gravelly clay loam, or extremely gravelly clay loam. They have hue of 10YR through 5YR, value of 5 through 8, 4 through 7 moist, and chroma of 2 through 6. Reaction is mildly or moderately alkaline.
COMPETING SERIES: These are the Acel, Bario, Burnac, Dandrea, Iles, Siesta, (T) Silesca, and Spud soils. Acel soils have cracks wider than 1 centimeter at twenty inches. Burnac soils have an E horizon abruptly over the argillic horizon. Dandrea soils have a paralithic contact at 20 to 40 inches. Silesca soils have a lithic contact above 40 inches. Bario and Iles soils have a calcic horizon. Siesta soils have cinders above the bedrock and lack calcium carbonate as pendants on coarse fragments above the bedrock. Spud soils have a solum depth from 40 to greater than 60 inches.
GEOGRAPHIC SETTING: Loghill soils are on mesas and benches. Slopes range from 3 to 20 percent. The soil formed in residuum derived from interbedded sandstone and shale. Elevation ranges from 7,000 to 7,800 feet. The mean annual precipitation ranges from 14 to 16 inches. Mean annual air temperature ranges from 42 to 45 degrees F. The frost-free season is 80 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Silesca soils and the Transfer soils. Transfer soils have bedrock above 20 inches.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; slow permeability.
USE AND VEGETATION: These soils are used for livestock grazing and wildlife habitat. Native vegetation consists of western wheatgrass, muttongrass, Wyoming big sagebrush, black sagebrush, prairie junegrass, needleandhtread, Indian ricegrass, and bottlebrush squirreltail.
DISTRIBUTION AND EXTENT: Western Colorado and possibly adjacent parts of Utah. The series is of minor extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Ridgway Soil Survey Area, Ouray County, Colorado; 1986.