LOCATION SWARTZ OREstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Vertic Palexeralfs
TYPICAL PEDON: Swartz silt loam, rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 2 inches; gray (10YR 5/1) silt loam, dark grayish brown (10YR 4/2) moist; weak thin platy structure; soft, friable, sticky and slightly plastic; common very fine roots; many vesicular pores; slightly acid (pH 6.2); clear smooth boundary. (1 to 5 inches thick)
A2--2 to 5 inches; light gray (10YR 7/1) silt loam, gray (2.5Y 5/1) moist; moderate thin platy structure; slightly hard, firm, slightly sticky and slightly plastic; common very fine roots; common very fine tubular pores; neutral (pH 6.6); abrupt irregular boundary. (2 to 6 inches thick)
2Bt1--5 to 13 inches; light brownish gray (2.5Y 6/2) clay, dark grayish brown (2.5Y 4/2) moist; moderate medium columnar structure parting to strong fine blocky; extremely hard, very firm, very sticky and very plastic; few very fine roots on vertical faces of peds; few very fine tubular pores; layer of uncoated silt on top of columns; continuous prominent clay films on peds and in pores; neutral (pH 6.6); clear wavy boundary. (6 to 10 inches thick)
2Bt2--13 to 22 inches; grayish brown (2.5Y 5/2) clay, dark grayish brown (2.5Y 4/2) moist; moderate medium and coarse prismatic structure parting to strong fine and medium blocky; extremely hard, very firm, very sticky and very plastic; few very fine roots; few very fine tubular pores; continuous prominent clay films on peds and in pores; neutral (pH 6.9); gradual smooth boundary. (8 to 14 inches thick)
2BCt--22 to 32 inches; grayish brown (2.5Y 5/2) clay, dark grayish brown (2.5Y 4/2) moist; moderate medium blocky structure; very hard, very firm, very sticky and very plastic; few very fine roots; few fine tubular pores; continuous distinct clay films; slightly alkaline (pH 7.4); gradual smooth boundary. (8 to 12 inches thick)
2C1--32 to 44 inches; grayish brown (2.5Y 5/2) clay, dark grayish brown (2.5Y 4/2) moist; massive; very hard, very firm, very sticky and very plastic; few very fine tubular pores; slightly alkaline (pH 7.6); gradual smooth boundary. (8 to 14 inches thick)
2C2--44 to 60 inches; dark grayish brown (2.5Y 4/2) clay, dark grayish brown (2.5Y 4/2) moist; massive; very hard, very firm, very sticky and very plastic; few very fine tubular pores; slightly alkaline (pH 7.7).
TYPE LOCATION: Crook County, Oregon; about 50 feet north and 1,800 feet west of the SE corner of section 34, T. 14 S., R. 15 E.
RANGE IN CHARACTERISTICS: The soils are usually moist but are dry for 60 to 90 consecutive days within the four-month period following the summer solstice in most years. The mean annual soil temperature ranges from 48 to 52 degrees F. Depth to bedrock is more than 60 inches. Depth to the 2Bt horizon is 3 to 7 inches. The A and Bt horizons are slightly acid or neutral and the BC and C horizons range from neutral to moderately alkaline.
The A1 horizon has hue of 2.5Y or 10YR, value of 5 or 6 dry and 3 or 4 moist. The material contains a significant amount of ash, but not enough to qualify as an ashy textural modifier.
The A2 horizon has hue of 10YR or 2.5Y, value of 6 or 7 dry, 4 or 5 moist, and chroma of 1 or 2 moist and dry. This material contains a significant amount of ash, but not enough to qualify as an ashy textural modifier.
The 2Bt horizon has hue of 10YR or 2.5Y, value of 5 or 6 dry and 3 or 4 moist. It is clay and has 40 to 65 percent clay. It has moderate or strong columnar or prismatic structure parting to moderate or strong angular blocky.
The 2C horizon has value of 5 or 6 dry and 3 or 4 moist. It is clay, silty clay or silty clay loam.
COMPETING SERIES: There are no competing series. The Swalesilver series is similar, it has a frigid soil temperature regime.
GEOGRAPHIC SETTING: Swartz soils are in nearly level basins on lava plains at elevations of 2,900 to 3,200 feet. The soils formed in alluvium. These soils are in a semiarid climate with a mean annual precipitation of 8 to 12 inches. Summers are warm and dry with an average temperature of 61 to 63 degrees F. Winters are cool and moist with an average temperature of 32 to 34 degrees F. The mean annual temperature is 47 to 52 degrees F. The frost-free period (32 degrees F.) is 70 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Deschutes and Redmond soils. Deschutes and Redmond soils are well drained soils and are 20 to 40 inches deep to bedrock.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow runoff with seasonal ponding; very slow permeability.
USE AND VEGETATION: Principal use is for livestock grazing. Other uses are for small grains, pasture, wildlife, and water supply purposes. Native vegetation is mainly silver sagebrush, Nevada bluegrass and creeping wildrye.
DISTRIBUTION AND EXTENT: Central Oregon; MLRA 10, pumice zone. They are inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Prineville Area, Crook County, Oregon, 1963.
REMARKS: Diagnostic horizons and other features
ADDITIONAL DATA: Characterization data for one pedon (S55-Oreg-7-1) reported in Soil Survey Prineville Area, Oregon, 1966.
Ochric epipedon
Argillic horizon from 5 to 32 inches
Abrupt boundary with over 20 percent absolute clay increase at 5 inches.
Vertic properties with LE of over 6.0 cm from 5 to 40 inches.