LOCATION RIDD UTEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Typic Argixerolls
TYPICAL PEDON: Ridd very stony sandy loam--rangeland. (Colors are for air-dry soil unless otherwise stated.)
A1--0 to 5 inches; dark grayish brown (10YR 4/2) very stony sandy loam, very dark grayish brown (10YR 3/2) moist; moderate thick platy structure parting to weak fine granular; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; many vesicular pores; common mica flakes; neutral (pH 6.7); clear wavy boundary. (4 to 13 inches thick)
A2--5 to 9 inches; dark grayish brown (10YR 4/2) very stony sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine subangular blocky structure parting to moderate medium and fine granular; hard, friable, sticky and plastic; many fine roots; common mica flakes; neutral (pH 7.2); clear wavy boundary. (0 to 7 inches thick)
Bt--9 to 18 inches; brown (10YR 5/3) very cobbly sandy loam, dark brown (10YR 4/3) moist; moderate medium and fine subangular blocky structure; hard, firm, sticky and plastic; many fine roots; common fine pores; common thin clay films on peds and in pores; many mica flakes; neutral (pH 7.0); gradual wavy boundary. (7 to 15 inches thick)
BC--18 to 26 inches; light olive brown (2.5Y 5/4) very gravelly sandy loam; olive brown (2.5Y 4/4) moist; moderate medium subangular blocky structure; hard, firm, slightly sticky and slightly plastic; few fine roots; few medium shape pores; common thin clay films on vertical ped surface; many mica flakes; neutral (pH 6.8); gradual wavy boundary. (6 to 10 inches thick)
C--26 to 36 inches; light olive brown (2.5Y 5/4) very gravelly sandy loam, olive (5Y 4/3) moist; structureless, massive; slightly hard, friable, slightly sticky and slightly plastic; neutral (pH 7.0); abrupt smooth boundary (0 to 12 inches thick).
R--36 inches; gneiss and schist bedrock.
TYPE LOCATION: Davis County, Utah; south and east of Farmington, 1,250 feet east and 250 feet south of the west 1/4 corner, sec. 32, T. 3 W., R. 1 E.
RANGE IN CHARACTERISTICS: Depth to bedrock is 20 to 40 inches. The mollic epipedon is 10 to 20 inches thick. The particle-size control section is 35 to 70 percent rock fragments. Stones 10 to 48 inches in diameter cover from 10 to 60 percent of the surface. Ridd soils are usually moist. They are dry for more than 60 consecutive days in all parts between 7 and 20 inches, in 7 out of 10 years. The mean annual soil temperature is 47 to 52 degrees F.
The A horizon has hue of 10YR, value of 4 or 5 dry, 2 or 3.5 moist and chroma of 2 or 3. Organic matter content is 1 to 6 percent. Clay content is 6 to 15 percent. Rock fragment content is 35 to 60 percent. Texture is very stony sandy loam.
The Bt horizon has hue of 10YR or 2.5Y, value is 4 to 6 dry, 3 or 4 moist, and chroma of 2 to 4. Textures are very stony sandy loam, very cobbly sandy loam, very gravelly sandy loam and extremely gravelly loam. Clay content is 10 to 18 percent.
The BC horizons have hue of 10YR and 2.5Y, value of 5 to 7 dry, 3 or 4 moist, and chroma is 3 or 4. Texture is very stony sandy loam or very gravelly sandy loam. Clay content is 5 to 18 percent. Rock fragment content is 35 to 60 percent.
The C horizon has hue of 10YR, 2.5Y and 5Y, value of 5 to 7 dry 3 or 4 moist and chroma of 3 or 4. Rock fragment content is 35 to 75 percent. Texture is very stony sandy loam, very gravelly sandy loam or extremely gravelly sandy loam.
COMPETING SERIES: These are the Badenaugh, Badge, Kusshi (T), Phys and Whitinger (T) series. Badenaugh, Badge and Phys soils are more than 60 inches to bedrock and have from 25 to 35 percent clay in the Bt horizons. In addition, Badge soils have lime and silica coating on the underneath side of rock fragments in the C horizon. Kusshi soils are more than 40 inches to bedrock. Whitinger soils have 20 to 25 percent clay in the control section.
GEOGRAPHIC SETTING: The Ridd soils are at elevations of 4,200 to 6,500 feet. Slopes are 6 to 70 percent. The soils occur on hillsides and mountainsides and formed in residuum and colluvium from gneiss, schist and quartzite rocks. The climate is moist subhumid. The average annual precipitation is 14 to 25 inches. Mean annual temperature is 45 to 51 degrees F. and the average summer temperature is 66 to 72 degrees F. The freeze-free period is 130 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kilburn, Reywat, Sterling and Wasatch soils. Kilburn, Sterling and Wasatch soils are more than 60 inches deep to bedrock. Sterling soils are strongly calcareous below a depth of 9 inches. Reywat soils have bedrock at depths of 10 to 20 inches.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderate permeability.
USE AND VEGETATION: Used mainly for watershed, range and wildlife areas. The native vegetation is mainly big sagebrush, bluebunch wheatgrass and scattered oakbrush. The potential vegetation under a high level of management is bluebunch wheatgrass, tall native bluegrass, slender wheatgrass, Great Basin wildrye, lupine, herbaceous sage, yarrow, buckwheat, bitterbrush, big sagebrush and snowberry.
DISTRIBUTION AND EXTENT: Along the western face of the Wasatch Mountains in Utah. This soil is extensive. It is also found on Antelope Island.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Davis County (Davis-Weber Area), Utah, 1967.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone of dark colored soil material from the soil surface to a depth of 9 inches. (A1, A2 horizons)
Argillic horizon - the zone of clay accumulation from a depth of 9 inches to a depth of 18 inches. (Bt horizon)
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 Reno MLRA office, without review of the soil series property data. The remainder of this document has not been updated.