LOCATION OTTUMWA SD

Established Series
Rev. RDN-KEC, NCJ
08/2014

OTTUMWA SERIES

The Ottumwa series consists of deep, well drained soils formed in clayey sediments on upland plains. Slopes range from 0 to 12 percent. Mean annual precipitation is about 410 millimeters (16 inches) and mean annual temperature is about 8 degrees C (47 degrees F).

TAXONOMIC CLASS: Fine, smectitic, mesic Vertic Haplustolls

TYPICAL PEDON: Ottumwa clay - on a 3 percent slope in a cultivated field. When described, the soil was moist to about 107 centimeters (42 inches). (Colors are for dry soil unless otherwise stated.)

Ap--0 to 18 centimeters (0 to 7 inches); olive gray (5Y 4/2) clay, dark olive gray (5Y 3/2) moist; weak medium subangular blocky structure parting to weak fine granular; hard, firm, sticky and plastic; few fine and medium roots; slight effervescence; moderately alkaline; clear smooth boundary. [10 to 20 centimeters (4 to 8 inches thick)]

Bw1--18 to 41 centimeters (7 to 16 inches); olive gray (5Y 4/2) clay, dark olive gray (5Y 3/2) moist; moderate fine and medium subangular blocky structure; hard, firm, sticky and plastic; few fine and medium roots; slight effervescence; strongly alkaline; clear wavy boundary.

Bw2--41 to 64 centimeters (16 to 25 inches); olive gray (5Y 5/2) clay, olive (5Y 4/3) moist; tongues of dark olive gray (5Y 3/2) moist; moderate medium blocky structure parting to moderate fine blocky; hard, firm, sticky and plastic; few slickensides; few fine roots; slight effervescence; moderately alkaline; clear wavy boundary. [Combined Bw horizons is 18 to 53 centimeters (7 to 21 inches thick)]

Bk--64 to 81 centimeters (25 to 32 inches); olive gray (5Y 5/2) clay, olive (5Y 4/3) moist; strong medium and coarse blocky structure parting to moderate medium and fine blocky; very hard, very firm, sticky and plastic; few slickensides; few fine roots; few fine accumulations of carbonate; slight effervescence; moderately alkaline; clear wavy boundary. [13 to 81 centimeters (5 to 32 inches thick)]

Bky--81 to 107 centimeters (32 to 42 inchesa0; olive (5Y 5/3) clay, olive gray (5Y 5/2) moist; few fine yellowish brown (10YR 5/6) moist iron stains; weak coarse subangular blocky structure; hard, firm, sticky and plastic; about 30 percent soft shale fragments; few fine roots; common fine accumulations of carbonate; few fine accumulations of gypsum; slight effervescence; slightly alkaline; gradual wavy boundary. [0 to 61 centimeters (0 to 24 inches thick)]

C--107 to 130 centimeters (42 to 51 inchesa0; olive gray (5Y 5/2) silty clay, dark gray (5Y 4/1) moist; few fine yellowish brown (10YR 5/6) moist iron stains; massive; hard, firm, sticky and plastic; about 55 percent soft shale fragments; few fine roots; slight effervescence; neutral; gradual wavy boundary. [0 to 38 centimeters (0 to 15 inches thick)]

Cr--130 to 152 centimeters (51 to 60 inches); gray (5Y 6/1) bedded soft shale, dark gray (5Y 4/1) moist; yellowish brown (10YR 5/6) moist iron stains.

TYPE LOCATION: Pennington County, South Dakota; about 9 miles east and 12 miles north of Wall; 850 feet west and 2100 feet south of the northeast corner of section 11, T. 2 N., R. 17 E.

RANGE IN CHARACTERISTICS: The depth to carbonates ranges from about 0 to 20 centimeters (0 to 8 inches). The thickness of the mollic epipedon ranges from about 20 to 51 centimeters (8 to 20 inches). Soft clayey shale is commonly between depths of about 102 and 152 centimeters (40 and 60 inches) but may be absent in some pedons. When the soil is dry, cracks about 1 to 3 centimeters (1/2 to 1 inch) wide extend through the solum. The control section contains 45 to 60 percent clay and less than 15 percent sand that is coarser than very fine.

A Horizon:
Hue: 10YR, 2.5Y or 5Y
Value: 4 or 5 dry and 2 or 3 moist
Chroma: 1 to 3
Texture: clay or silty clay, some pedons are silty clay loam
Reaction: slightly acid to moderately alkaline

Bw Horizon:
Hue: 2.5Y or 5Y
Value: 4 to 6 dry and 3 or 4 moist
Chroma: 2 to 4
Texture: silty clay or clay
Reaction: slightly acid to strongly acid

Bk Horizon:
Hue: 2.5Y or 5Y
Value: 5 or 6 dry and 4 or 5 moist
Chroma: 2 to 4
Texture: silty clay or clay
Reaction: slightly alkaline to strongly alkaline
Some pedons do not have a Bky horizon.

C Horizon:
Hue: 2.5Y or 5Y
Value: 5 to 7 dry and 4 to 6 moist
Chroma: 1 to 4
Texture: silty clay or clay, some pedons have thin layers of silty clay loam below a depth of about 102 centimeters (40 inches)
Reaction: neutral to strongly alkaline
Some pedons do not have a C horizon. The Cr horizon is soft clayey shale.

COMPETING SERIES: These are the Artesian and Verdel series. Artesian soils have a mollic epipedon more than 51 centimeters (20 inches) thick. Verdel soils do not have carbonates above depths of 41 centimeters (16 inches).

GEOGRAPHIC SETTING: Ottumwa soils are on nearly level to strongly sloping uplands. Slopes range from 0 to 12 percent. Ottumwa soils formed in clayey sediments weathered from shale. Mean annual temperature ranges from about 7 to 9 degrees C (45 to 48 degrees F). Mean annual precipitation ranges from about 360 to 460 millmeters (14 to 18 inches). Growing season is about 130 to 150 days; average growing season precipitation ranges from about 280 to 360 millimeters (11 to 14 inches.

GEOGRAPHICALLY ASSOCIATED SOILS: These include the Capa, Kirley, Mosher, Opal and Wendte soils. The Capa and Mosher soils have a natric horizon. Kirley soils also have an argillic horizon. Opal and Wendte soils do not have mollice epipedons. Opal soils have shale bedrock at depths of 50 to 100 centimeters (about 20 to 40 inches). Wendte soils are on floodplains.

DRAINAGE AND PERMEABILITY: Well drained. Runoff is low or medium. Permeability is slow but initially infiltration is moderately rapid or rapid when the soil is dry and cracked.

USE AND VEGETATION: Primarily used as cropland. Winter wheat and grain sorghum are the main crops. Native vegetation is principally western wheatgrass, buffalograss, blue grama forbs, and sedges.

DISTRIBUTION AND EXTENT: Southwest South Dakota. It is moderately extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado

SERIES ESTABLISHED: Pennington County, South Dakota, 1986.

REMARKS: Diagnostic horizons and features in these pedons are: mollic epipedon - the zone from the surface of the soil to a depth of about 41 centimeters [16 inches (Ap and Bw1 horizons)]; cambic horizon - the zone from about 41 to 64 centimeters [16 to 25 inches (Bw2 horizon)].

NJ 8/2014 Updated competing series deleting those that do not have the same classification. Updated to the tabular format.

ADDITIONAL DATA: See KSSL pedon numbers 85SD055001, 85SD103001 and 85SD103002.

National Cooperative Soil Survey
U.S.A.