LOCATION DESCOT UTEstablished Series
TAXONOMIC CLASS: Coarse-loamy, carbonatic, frigid Ustic
Torriorthents
TYPICAL PEDON: Descot silt loam--rangeland. (Colors are for air-dry soil unless otherwise stated.)
A--0 to 5 inches; pink (7.5YR 7/4) silt loam, brown (7.5YR 4/4) moist; weak medium platy structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and few medium roots; common very fine and few fine tubular pores; very strongly calcareous; strongly alkaline (pH 8.6); clear smooth boundary. (4 to 8 inches thick)
C--5 to 22 inches; pink (7.5YR 7/4) very fine sandy loam, brown (7.5YR 5/4) moist; weak medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common fine and few medium roots; common very fine, and few fine and medium tubular pores; very strongly calcareous; strongly alkaline (pH 8.8); clear smooth boundary. (17 to 27 inches thick)
C2--22 to 39 inches; pink (7.5YR 7/4) very fine sandy loam, brown (7.5YR 5/4) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; common fine and few medium roots; few fine and medium tubular pores; lenses of fine sandy loam 2 to 4 inches thick; very strongly calcareous; strongly alkaline (pH 8.5).
C3--39 to 60 inches; pink (7.5YR 7/4) very fine sandy loam, brown (7.5YR 5/4) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; common fine and few medium roots; common fine tubular pores; very strongly calcareous; strongly alkaline (pH 8.5).
TYPE LOCATION: Garfield County, Utah; 1 mile west of mouth of Casto Canyon; 2,600 feet west and 2,600 feet south of northeast corner of sec. 7, T. 35 S., R. 4 W., SLBM.
RANGE IN CHARACTERISTICS: The mean annual soil temperature at depth 20 inches ranges from 43 to 45 degrees F. The mean summer temperature ranges from 62 to 64 degrees F. The soils are dry in parts of the moisture control section for 75 to 90 days during the winter, and are dry in all parts of the moisture control section 50 to 65 percent of the time when the soil temperature at depth of 20 inches is more than 41 degrees F. The calcium carbonate equivalent is 40 to 50 percent throughout.
The A horizon has hue of 7.5YR or 5YR, value of 6 or 7 dry, 4 or 5 moist, chroma of 3 or 4 dry or moist. It is moderately alkaline or strongly alkaline.
The C horizon has hue of 7.5YR or 5YR, value of 6 to 8 dry, 5 or 6 moist, chroma of 4 to 6 dry or moist. The texture ranges from silt loam to very fine sandy loam, or fine sandy loam. Some pedons have thin lenses of loamy sand 1 to 5 inches thick. The particle size control section averages less than 18 percent clay and 15 to 30 percent sand coarser than very fine. The C horizon is moderately alkaline or strongly alkaline.
COMPETING SERIES: There are no other series in the same family. Similar soils are the Alldown, Codley and Tebbs series. Alldown and Tebbs soils have less than 40 percent calcium carbonate equivalent. Codley soils have a fine-silty particle size control section.
GEOGRAPHIC SETTING: The Descot soils are at elevations of 6,500 to 7,500 feet. Slopes are 1 to 5 percent. They are on alluvial valley fill and formed in alluvium from sandstone and limestone alluvium. The climate is semi-arid, the average annual precipitation is 9 to 14 inches. The mean annual temperature is 40 to 45 degrees F., and the freeze-free period is 70 to 100 days.
GEOGRAPHICALLY ASSOCIATE SOILS: These are the Bruman, Luhon and Notter soils and the competing Tebbs soils. These soils all have less than 40 percent calcium carbonate in the particle size control section. Bruman, Luhon and Notter soils are on the upper, more stable alluvial fans. Tebbs soils are on similar landscapes.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderately rapid permeability.
USE AND VEGETATION: These soils are used for rangeland. The native vegetation is winterfat, big sagebrush, western wheatgrass, snakeweed, blue grama and sand dropseed.
DISTRIBUTION AND EXTENT: South-central Utah, western Garfield County. The series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Garfield County (Panguitch Soil Survey Area), Utah, 1984.
REMARKS: Descot soils were previously classified as Torrifluvents, but are on relatively stable, nonflooding landscapes and lack the irregular decrease in organic matter required for that placement. Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the surface of the soil to a depth of 5 inches (A horizon)
Orthent feature - lack of diagnostic horizons below the ochric and regular decrease in organic matter
Ustic feature - dry in some or all parts of the moisture control section for 90 or more days cumulative, but not dry in all parts more than half the time that the soil temperature at 20 inches is 41 degrees F. or more