LOCATION TUSCOR ORTentative Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic, frigid Vertic Argixerolls
TYPICAL PEDON: Tuscor very cobbly loam, on a 50 percent south slope, rangeland. (Colors are for moist soils unless otherwise noted.)
A--0 to 4 inches; very dark grayish brown (10YR 3/2) very cobbly loam, grayish brown (10YR 5/2) dry; weak very fine granular structure; soft, very friable, slightly sticky and nonplastic; common very fine roots; many very fine interstitial pores; 30 percent cobbles and 25 percent gravel; neutral (pH 6.8); clear wavy boundary. ( 2 to 4 inches thick)
Bt1--4 to 15 inches; very dark grayish brown (7.5YR 3/2) very cobbly clay loam, grayish brown (7.5YR 5/2) dry; moderate fine subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine and few fine roots; common very fine tubular pores; common distinct clay films on faces of peds and in pores; 20 percent cobbles and 20 percent gravel; neutral (pH 7.0); clear wavy boundary. ( 9 to 13 inches thick)
Bt2--15 to 28 inches; very dark grayish brown (7.5YR 3/2) very cobbly clay loam, grayish brown (7.5YR 5/2) dry; moderate medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; few very fine roots; common very fine and common fine tubular pores; common distinct clay films on faces of peds and in pores; 30 percent cobbles and 15 percent gravel; neutral (pH 7.2); clear wavy boundary. (9 to 15 inches thick)
Bt3--28 to 37 inches; dark brown (7.5YR 3/3) very cobbly clay, light brownish gray (7.5YR 6/2) dry; strong medium subangular blocky structure; very hard, firm, moderately sticky and very plastic; few coarse roots; few very fine tubular pores; common distinct clay films on faces of peds and in pores; 30 percent cobbles and 20 percent gravel; neutral (pH 7.2); clear wavy boundary. (7 to 11 inches thick)
Bt4--37 to 47 inches; dark brown (7.5YR 3/3) extremely cobbly clay loam, light brownish gray (7.5YR 6/2) dry; weak medium subangular blocky structure; extremely hard, firm, moderately sticky and very plastic; few very fine roots; common distinct clay films on faces of peds; 60 percent cobbles and 15 percent gravel; slightly alkaline (pH 7.4); gradual wavy boundary. ( 8 to 12 inches thick)
Bt5--47 to 53 inches; dark brown (7.5YR 3/3) extremely cobbly clay, light brownish gray (7.5YR 6/2) dry; massive; extremely hard, firm, moderately sticky and moderately plastic; common distinct clay films on faces of peds; 60 percent cobbles and 15 percent gravel; slightly alkaline (pH 7.4); clear wavy boundary.
(2 to 8 inches thick)
R-- 53 inches; fractured rhyolite .
TYPE LOCATION: Crook County, Oregon; located 1300 feet south and 1500 feet east of the NW corner of section 18, T. 16 S., R. 15 E.; about 4.5 miles southeast of the community of Powell Butte.
RANGE OF CHARACTERISTICS: These soils are usually moist, but are dry in the moisture control section for 70 to 90 days following the summer solstice. The mollic epipedon is 20 to 30 inches thick. The particle-size control section has 35 to 45 percent clay. The mean annual soil temperature ranges from 42 to 47 degrees F. Depth to bedrock is 40 to 60 inches. Linear extensibility from the soil surface to 40 inches 6.0 to 8.0 centimeters.
The A horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry. It contains 15 to 30 percent gravel and 20 to 40 percent cobbles.
The Bt horizon has value of 3 or 4 moist, 5 or 6 dry, and chroma of 2 or 3 moist and dry. It is clay or clay loam and contains 15 to 40 percent gravel and 20 to 60 percent cobbles.
COMPETING SERIES: These are the Mound series. The Mound soils are dry in the moisture control section for 45 to 60 days following the summer solstice.
GEOGRAPHIC SETTING: Tuscor soils are on mountains at elevations of 4,000 to 5,100 feet. Slopes range from 12 to 65 percent. These soils formed in colluvium and residuum derived from rhyolite. The climate is characterized by cold wet winters and hot dry summers. The mean annual precipitation is 12 to 16 inches, the mean annual temperature is 40 to 46 degrees F., and the frost-free period is 50 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hatrock, Ginserly, Anatone and Tristan soils. Anatone soils are loamy-skeletal and shallow to bedrock and are on adjacent ridgetops. Hatrock soils are ashy-skeletal, greater than 60 inches to bedrock and are on adjacent north slopes. Ginserly soils are loamy-skeletal and are on adjacent north slopes. Tristan soils are loamy-skeletal and are on adjacent south slopes at lower elevations.
DRAINAGE AND PERMEABILITY: Well drained, permeability is slow
USE AND VEGETATION: Tuscor soils are used mainly for livestock grazing and wildlife habitat. The native vegetation is Idaho fescue, bluebunch wheatgrass, antelope bitterbrush and mountain big sagebrush.
DISTRIBUTION AND EXTENT: Central Oregon; MLRA 10, John Day area. This series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Crook County Area, Oregon; 1999.
REMARKS: Diagnostic horizons and features include:
Mollic epipedon (Pachic) - from the surface to a depth of 28 inches (A, Bt1 and Bt2 horizons)
Argillic horizon - the zone from 4 to 53 inches (Bt1, Bt2, Bt3, Bt4 and Bt5 horizons)
Vertic properties with LE of 7.0 cm from 0 to 40 inches.