LOCATION DUROC              WY+NE SD

Established Series
Rev. MCS/DH/PRF
02/2006

DUROC SERIES

The Duroc series consists of very deep, well drained soils formed in loamy alluvium and eolian deposits in swales, on toeslopes and stream terraces. Slopes are 0 to 6 percent. The average annual precipitation is about 41 centimeters (16 inches). The average annual air temperature is about 8 degrees C. (46 degrees F.) at the type location.

TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Pachic Haplustolls

TYPICAL PEDON: Duroc loam, grassland. (Colors are for dry soil unless otherwise stated.)

A--0 to 15 centimeters (0 to 6 inches); grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; strong very fine granular structure; soft, very friable, slightly sticky and slightly plastic; neutral (pH 7.2); clear smooth boundary. (10 to 51 centimeters (4 to 20 inches) thick)

Bw1--15 to 51 centimeters (6 to 20 inches); grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; slightly alkaline (pH 7.4); clear smooth boundary. (13 to 66 centimeters (6 to 26 inches) thick)

Bw2--51 to 71 centimeters (20 to 28 inches); brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; slightly effervescent; disseminated calcium carbonate; moderately alkaline (pH 8.0); gradual smooth boundary. (0 to 36 centimeters (0 to 14 inches) thick)

Bk--71 to 203 centimeters (28 to 80 inches); light brownish gray (10YR 6/2) loam, dark grayish brown (10YR 4/2) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; strongly effervescent; calcium carbonate occurring as soft masses and thin seams and streaks; moderately alkaline (pH 8.3).

TYPE LOCATION: Goshen County, Wyoming; 579 meters (1900 feet) north and 594 meters (1950 feet) east of the southwest corner of section 12, T.22 N., R.61 W.

RANGE IN CHARACTERISTICS:
Depth to carbonates: 38 to 91 centimeters (15 to 36 inches)
Mean annual soil temperature: 8 to 14 degrees C. (47 to 58 degrees F.)
Mollic epipedon thickness: 51 to 127 centimeters (20 to 50 inches)
Organic carbon: decreases uniformly with depth
Particle size control section:
Texture: loam or silt loam
Clay content: 18 to 35 percent
Silt content: 30 to 70 percent
Sand content: 10 to 45 percent, less than 15 percent being fine sand or coarser
Rock fragments: usually 0 but range to 10 percent

A horizon:
Hue: 10YR
Value: 4 to 5, 2 to 3 moist
Chroma: 1 to 3
Reaction: neutral to moderately alkaline
Texture: loam, silt loam, very fine sandy loam
Comments: Some pedons have an AC horizon with properties similar to the A horizon.

Bw horizons:
Hue: 10YR
Value: 3 to 6, 2 to 4 moist
Chroma: 2 to 3
Reaction: neutral or slightly alkaline
Texture: loam, silt loam, very fine sandy loam

The Bk horizon (if it occurs):
Hue: 10YR
Value: 5 to 7, 3 to 5 moist
Chroma: 2 to 3
Reaction: moderately or strongly alkaline
Texture: loam, silt loam, very fine sandy loam

C horizon (if it occurs):
Hue: 10YR
Value: 5 to 7, 3 to 7 moist
Chroma: 2 to 3
Reaction: slightly to strongly alkaline
Texture: loam, silt loam, very fine sandy loam

COMPETING SERIES: These are the Blackwood, Eltree, Graceville, Trent, Viborg and Yankton series.
Blackwood soils have a polygenetic profile involving soil horizons of different soil-forming periods.
Eltree soils have calcium carbonate accumulations at less than 15 inches.
Graceville soils have stratified sand and gravel (2C horizon) at 102 to 152 centimeters (40 to 60 inches).
Trent soils are mottled in Bw and C horizons.
Viborg soils formed in silty deposits over glacial till discontinuities.
Yankton soils formed in silty deposits over glacial till discontinuities.

GEOGRAPHIC SETTING:
Landscape: river valleys, tablelands, uplands
Landform: stream terraces, toeslopes, swales
Slopes: 0 to 6 percent
Elevation: 1067 to 1737 meters (3500 to 5700 feet)
Parent material: loamy alluvium and eolian deposits
Mean annual air temperature: 8 to 15 degrees C. (47 to 58 degrees F.)
Mean annual precipitation: 33 to 46 centimeters (13 to 18 inches)
Frost-free period: 120 to 150 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Goshen and Kuma series.
Goshen and Kuma soils have an argillic horizon.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage: well
Runoff: medium to low
Saturated hydraulic conductivity: high

USE AND VEGETATION: These soils are used as native pasture or for dry and irrigated cropland.
Native vegetation is western wheatgrass, needleandthread, big bluestem and little bluestem.

DISTRIBUTION AND EXTENT: Nebraska, South Dakota and Wyoming. The series is of moderate extent.

MLRA OFFICE RESPONSIBLE: Salina, Kansas

SERIES ESTABLISHED: Mellette County, South Dakota, 1971.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: 0 to 71 centimeters (0 to 28 inches) (A, Bw1, Bw2)
Cambic horizon: 15 to 51 centimeters (6 to 20 inches) (Bw1)

SIRs- WY0046, WY0441, WY0997, WY0998

ADDITIONAL DATA:
T: 5
K: .28
WEG: 5
WEI: 56

Modified format by LRM in 1/2006 to include metric conversion and change permeability to saturated hydraulic conductivity.

National Cooperative Soil Survey
U.S.A.