LOCATION COWSLY OR

Established Series
Rev. JAS/WEL/RWL
03/2013

COWSLY SERIES

The Cowsly series consists of deep or very deep, moderately well drained soils that formed in loess with an influence of volcanic ash overlying older fine textured colluvium and residuum weathered from volcanic tuff and basalt. Cowsly soils are on plateaus. Slopes are 2 to 30 percent. The mean annual precipitation is about 23 inches and the mean annual temperature is about 44 degrees F.

TAXONOMIC CLASS: Fine, smectitic, frigid Xerertic Argialbolls

TYPICAL PEDON: Cowsly ashy silt loam, meadow, on a 4 percent slope at an elevation of 4160 feet. (Colors are for moist soil unless otherwise noted.)

A1--0 to 3 inches; very dark grayish brown (10YR 3/2) ashy silt loam, dark grayish brown (10YR 4/2) dry; weak thin platy and weak fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular pores; slightly acid (pH 6.2); clear wavy boundary.

A2--3 to 5 inches; very dark grayish brown (10YR 3/2) ashy silt loam, dark grayish brown (10YR 4/2) dry; moderate medium platy structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular pores; slightly acid (pH 6.2); clear wavy boundary.

A3--5 to 15 inches; dark brown (10YR 3/3) ashy silt loam, brown (10YR 5/3) dry; weak medium prismatic structure parting to weak medium subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular pores; neutral (pH 6.6); clear wavy boundary. (Combined thickness of the A horizon is 10 to 30 inches)

E1--15 to 17 inches; grayish brown (10YR 5/2) ashy silt loam, light gray (10YR 7/2) dry; weak medium prismatic structure parting to weak medium subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular pores; neutral (pH 6.8); clear wavy boundary. (0 to 5 inches thick)

E2--17 to 19 inches; grayish brown (10YR 5/2) ashy silt loam, light gray (10YR 7/1) dry; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; many very fine tubular pores; neutral (pH 6.8); abrupt wavy boundary. (1/2 to 12 inches thick)

2Bt1--19 to 24 inches; dark brown (10YR 3/3) clay, dark grayish brown (10YR 4/2) dry; weak medium prismatic structure parting to moderate fine blocky; very hard, very firm, very sticky and very plastic; few very fine roots; common very fine tubular pores; continuous prominent clay films on surfaces of peds and in pores; inter-fingering of E material into cracks of the clay; common 1 to 3 mm black concretions and masses of iron accumulation; neutral (pH 6.8); clear wavy boundary. (4 to 15 inches thick)

2Bt2--24 to 42 inches; dark brown (10YR 3/3) clay, dark grayish brown (10YR 4/2) dry; very dark gray organic coatings on surfaces of peds; strong coarse prismatic structure; extremely hard, very sticky and very plastic; few very fine roots; few very fine tubular pores; continuous prominent clay films on surfaces of peds and in pores; common 1 to 3 mm black concentrations and masses or iron accumulation; neutral (pH 6.8); clear wavy boundary. (0 to 20 inches thick)

2Bt3--42 to 60 inches; dark brown (10YR 4/3) cobbly clay, brown (10YR 5/2) dry; moderate medium subangular blocky structure; hard, firm, very sticky and very plastic; few very fine roots; few very fine tubular pores; common faint clay films on surfaces of peds and in pores; about 10 percent gravel and 15 percent cobbles; neutral (pH 7.0).

TYPE LOCATION: Union County, Oregon; Meadow Area, about 8 miles east of Elgin, OR., 2100 feet south and 180 feet west of the NE corner of section 24, T. 1 N., R. 40 E. (Latitude 45 degrees, 33 minutes, 11 seconds N, Longitude 117 degrees, 44 minutes, 48 seconds W)

RANGE IN CHARACTERISTICS: The mean annual soil temperature is 44 to 47 degrees F. The soil is usually moist but is dry between depths of 4 and 12 inches for 45 to 60 days following the summer solstice. Depth to bedrock is 40 inches or more. The mollic epipedon is 10 to 30 inches thick and the depth to the clayey argillic horizon is 12 to 40 inches. The soil reaction is slightly acid or neutral to about 40 inches and ranges to mildly alkaline below. Secondary accumulation of carbonates is present below 40 inches in some pedons. Redox concentrations typically occur between depths of 20 to 40 inches.

The A horizon has value of 2 or 3 moist, 4 or 5 dry and chroma of 1 to 3 moist and dry. It is ashy silt loam, cobbly ashy silt loam, or stony ashy silt loam. It has 0 to 15 percent stones, 0 to 25 percent cobbles and 0 to 15 percent gravel. The lower part of this horizon is a silt loam or silty clay loam.

The Bw horizon, where present, has value of 3 moist, 5 dry and chroma of 2 or 3 moist and dry. It is ashy silt loam or ashy silty clay loam.

The E horizon has value of 4 or 5 moist, 6 or 7 dry and chroma of 1 or 2 moist and dry. A stone line is at the lower boundary in some pedons.

The 2Bt horizon has hue of 7.5YR or 10YR, value of 3 or 4 moist, 4 to 6 dry and chroma of 2 to 4 moist and dry. It is silty clay or clay and averages 40 to 60 percent clay. The lower part of the horizon has 0 to 15 percent cobbles and 0 to 20 percent gravel. It is silty clay, clay, clay loam, or silty clay loam with 35 to 50 percent clay.

The 2C horizon, where present, has hue of 10YR or 2.5YR, value of 5 or 6 moist, 6 or 7 dry and chroma of 2 or 3 moist and dry. It is clay loam, silty clay loam or light clay and averages 27 to 45 percent clay. Rock fragments range from 0 to 30 percent cobbles and 0 to 15 percent gravel.

COMPETING SERIES: These are the Boles and Wilkins series. Boles soils have a bisequal profile. Wilkins soils are somewhat poorly drained and are mottled in some part of the A and B horizons.

GEOGRAPHIC SETTING: Cowsly soils are on plateaus. Elevation is 2800 to 5000 feet. Slopes are 2 to 30 percent. The soils formed in loess and some volcanic ash overlying older fine textured residuum or colluvium weathered from volcanic tuff and basalt. The climate is characterized by cold wet winters and hot dry summers. The mean annual precipitation is 17 to 30 inches, and the mean annual temperature is 42 to 45 degrees F. The frost-free period is 60 to 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Anatone, Hall Ranch, Klicker and Tolo soils and the competing Wilkins soils. Anatone soils occur on plateaus, ridgetops, and south-facing side slopes and are less than 20 inches deep to bedrock. Hall Ranch and Klicker soils are less than 40 inches deep to bedrock. The Hall Ranch soils occur on mountains. The Klicker soils occur on mountains, plateaus, and structural benches. Tolo soils are ashy over loamy and occur on north-facing mountain side-slopes and footslopes.

DRAINAGE AND PERMEABILITY: Moderately well drained; very slow permeability; a seasonal water table is as high as a depth of 1.5 to 2.5 feet from the soil surface from March through May.

USE AND VEGETATION: These soils are used primarily for timber production. Other uses are dryland small grain, pasture, wildlife habitat and water supply. Native vegetation is ponderosa pine and Douglas fir with an understory of spirea, ocean spray, snowberry, Idaho fescue, pinegrass and elksedge.

DISTRIBUTION AND EXTENT: Northeastern Oregon; MLRA 9. The series is of moderate extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Union County, Oregon 1978.

REMARKS: This draft reflects a change in classification from Xeric Argialbolls to Xerertic Argialbolls based on revisions to Taxonomy.

Diagnostic horizons and features recognized in this pedon are:

mollic epipedon - from the surface to 15 inches (A1, A2, and A3 horizons)

albic horizon - from 15 to 19 inches (E1 and E2 horizons)

argillic horizon - from 19 to 60 inches (2Bt1, 2Bt2, and 2Bt3 horizons)

xerertic feature - from 19 to 60 inches (2Bt1, 2Bt2, and 2Bt3 horizons) with montmorillonitic mineralogy, 40 to 60 percent clay, and high shrink-swell.

andic feature - from 0 to 19 inches having ((aluminum plus 1/2 iron, percent extracted by ammonium oxalate) times 60) plus the volcanic glass (percent) equal to 30 or more. Based on laboratory data from similar soils.

particle-size control section - from 19 to 39 inches (the upper 20 inches of the argillic horizon).

ADDITIONAL DATA: Reference samples Umatilla County; sample numbers 83T7797-7800.

National Cooperative Soil Survey
U.S.A.