LOCATION PHYS OREstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Typic Argixerolls
TYPICAL PEDON: Phys gravelly silt loam, cultivated, on a 4 percent north-facing slope at an elevation of 2770 feet. (Colors are for moist soil unless otherwise noted.),
Ap--0 to 7 inches; very dark brown (10YR 2/2) gravelly silt loam, dark gray (10YR 4/1) dry; weak fine granular structure; soft, friable, moderately sticky and moderately plastic; many very fine and fine roots; many very fine tubular pores; 15 percent gravel and 5 percent cobbles; slightly acid (pH 6.4); clear smooth boundary.
A--7 to 11 inches; very dark brown (10YR 2/2) gravelly silt loam, dark gray (10YR 4/1) dry; weak fine and medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; many very fine and fine roots; many very fine and fine tubular pores; 15 percent gravel and 5 percent cobbles; slightly acid (pH 6.4); clear smooth boundary. (Combined thickness of the A horizon is 7 to 18 inches)
Bw--11 to 16 inches; very dark brown (10YR 2/2) very cobbly clay loam, dark grayish brown (10YR 4/2) dry; weak fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; many very fine and fine roots; many very fine tubular pores; 15 percent gravel, 20 percent cobbles, and 5 percent stones; neutral (pH 6.6); clear smooth boundary. (3 to 8 inches thick)
Bt--16 to 21 inches; dark brown (10YR 3/3) very cobbly clay loam, brown (10YR 5/3) dry; weak fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; many very fine roots; many very fine tubular pores; many faint clay films on faces of peds; 15 percent gravel, 25 percent cobbles, and 5 percent stones; neutral (pH 6.8); clear smooth boundary. (4 to 8 inches thick)
C--21 to 60 inches; brown (10YR 4/3) extremely cobbly loam, brown (10YR 5/3) dry; massive; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; many very fine pores; 20 percent gravel, 40 percent cobbles, and 10 percent stones; neutral (pH 6.8).
TYPE LOCATION: Union County, Oregon; Oregon State Game Farm; 400 feet north of center of section 1, T. 4 S., R. 38 E. (Latitude 45 degrees, 14 minutes, 50 seconds N, Longitude 118 degrees, 00 minutes, 11 seconds W)
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 49 to 53 degrees F. These soils are usually moist, but are dry in all parts between depths of 4 and 12 inches for 60 to 90 consecutive days during the summer and early fall. The solum is 14 to 28 inches thick. The mollic epipedon is 12 to 20 inches thick. Depth to bedrock is 60 inches or more.
The A horizon has value of 2 or 3 moist, 3 or 4 dry, and chroma of 1 or 2 moist and dry. It is gravelly silt loam, silt loam, or cobbly loam with 18 to 27 percent clay. It has 0 to 25 percent gravel, 0 to 15 percent cobbles, and 0 to 5 percent stones. Cobbles and stones have been removed from cultivated areas. Soil reaction is slightly acid or neutral.
The Bw horizon has value of 2 or 3 moist, 4 or 5 dry and chroma of 2 or 3 moist and dry. It is very cobbly clay loam or cobbly loam and averages 20 to 30 percent clay. It has 10 to 25 percent gravel, 10 to 20 percent cobbles, and 0 to 5 percent stones. Soil reaction is slightly acid or neutral.
The Bt horizon has value of 3 or 4 moist, 4 or 5 dry, and chroma of 2 to 4 moist and dry. It is clay loam and averages 27 to 35 percent clay. It has 35 to 60 percent rock fragments of which 10 to 40 percent are gravel, 20 to 35 percent are cobbles, and 0 to 10 percent are stones. Soil reaction is slightly acid or neutral.
The C horizon has color similar to the Bt horizon. It is loam or sandy clay loam with 15 to 25 percent clay. It has 50 to 80 percent rock fragments of which 10 to 30 percent are gravel, 20 to 50 percent are cobbles, and 0 to 20 percent are stones. In some pedons, secondary carbonates may occur below 44 inches. Soil reaction is slightly acid or slightly alkaline.
COMPETING SERIES: These are the Baboon, Badge, Collard, Dixiejett, Garloaf (T), Goodnoe, Hooverton, Kusshi (T), Ridd and Whitinger series. All of these series are 20 to 40 inches deep to a lithic contact except for Badge, Collard, Dixiejett and Kusshi. Badge soils are dry for 90 to 105 days. Collard soils have a mean annual soil temperature of 47 to 49 degrees F and have a very cobbly loamy sand substratum with less than 10 percent clay. Dixiejett soils are 40 to 60 inches to a lithic contact. Kusshi soils have an O horizon. Garloaf soils are not in the database and cannot be competed.
GEOGRAPHIC SETTING: Phys soils are on alluvial fans extending to the valley floor and have slopes of 0 to 30 percent. Elevations are 1,700 to 3,400 feet. The rock fragments mainly are basalt and some andesite. The climate is characterized by cool wet winters and hot dry summers. The mean annual precipitation is 13 to 21 inches. The mean annual temperature is 47 to 51 degrees F. The frost-free period is 100 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Catherine and La Grande soils. Catherine and La Grande soils are fine-silty.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.
USE AND VEGETATION: Phys soils are used mainly for growing hay and pasture. Potential native vegetation dominantly is Idaho fescue and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: Northeast and East-central Oregon, MLRA 9, 10. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Union County, Oregon, 1978.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
mollic epipedon - from the surface to 16 inches (Ap, A, and Bw horizons)
argillic horizon - from 16 to 21 inches (Bt horizon)
particle-size control section - from 16 to 21 inches (Bt horizon)
organic matter is 1 to 2 percent from the surface to 16 inches.