LOCATION MANDAN NDEstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, frigid Pachic Haplustolls
TYPICAL PEDON: Mandan silt loam - grassland. (Colors are for dry soil unless otherwise stated)
A1--0 to 13 inches; dark grayish brown (10YR 4/2) silt loam, very dark brown (10YR 2/2) moist; weak coarse prismatic structure parting to weak coarse and fine subangular blocky; hard, very friable, slightly sticky and slightly plastic; many roots; many fine pores; slightly alkaline; gradual wavy boundary.
A2--13 to 20 inches; grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; weak coarse prismatic structure parting to weak coarse subangular blocky; hard, very friable, slightly sticky and slightly plastic; common roots; many fine pores; slight effervescence; moderately alkaline; gradual wavy boundary. (Combined A horizons 12 to 30 inches thick)
Bw--20 to 29 inches; grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; weak coarse prismatic structure parting to weak subangular blocky; hard, very friable, slightly sticky and slightly plastic; common fine roots; many fine pores; few masses of carbonates; strong effervescence; moderately alkaline; gradual wavy boundary. (7 to 30 inches thick)
Bk--29 to 38 inches; light brownish gray (2.5Y 6/2) silt loam, dark grayish brown (2.5Y 4/2) moist; weak coarse prismatic and subangular blocky structure; hard, very friable, slightly sticky and slightly plastic; few fine roots; common very fine pores; common masses of carbonates; violent effervescence; moderately alkaline; gradual smooth boundary.
BCk--38 to 47 inches; light brownish gray (2.5Y 6/2) silt loam, grayish brown (2.5Y 5/2) moist; massive; hard, very friable, slightly sticky and slightly plastic; few fine roots; few small pebbles with carbonate crusts on undersides are near base of horizon; common fine masses of carbonates; violent effervescence; strongly alkaline; clear smooth boundary.
2C1--47 to 56 inches; light brownish gray (10YR 6/2) loam, dark grayish brown (10YR 4/2) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few small pebbles; few masses of carbonates; strongly alkaline; clear wavy boundary.
3C2--56 to 60 inches; dark brown (10YR 3/3) fine sandy loam; violent effervescence; strongly alkaline.
TYPE LOCATION: Burleigh County, North Dakota; about 2 miles south and 1 mile west of Bismarck; approximately 2,240 feet north and 90 feet east of the southwest corner, sec. 15, T. 138 N., R. 80 W. (615 feet north and 20 feet west of the south end of the west windbreak row.)
RANGE IN CHARACTERISTICS: The mollic epipedon ranges from 16 to over 35 inches in thickness and commonly includes the Bw horizon. Depth to carbonates commonly is 8 to 18 inches, but some pedons contain carbonates at depths of 0 to 40 inches. Some pedons have an Ab horizon.
The A horizon has hue of 10YR, value of 4 or 5 and 2 or 3 moist, and chroma of 2. It is silt loam and neutral to moderately alkaline.
The Bw horizon has hue of 10YR or 2.5Y, value of 4 to 6 and 2 to 4 moist, and chroma of 2 or 3. It is silt loam or very fine sandy loam and neutral to moderately alkaline.
The Bk horizon has hue of 2.5Y, value of 5 to 7 and 4 or 5 moist, and chroma of 2 or 3. It is silt loam and slightly alkaline to strongly alkaline. Some pedons have a 2Bk horizon.
The C and 2C horizons have hue of 10YR or 2.5Y, value of 6 and 4 or 5 moist, and chroma of 2 to 4. They are slightly alkaline to strongly alkaline. The C horizon is silt loam. Below a depth of 40 inches the 2C horizon, where present, is loam glacial till or fine sandy loam, sand or gravelly sand.
COMPETING SERIES: There are no other competing series in the family. Other competing series are the Bryant, Grassna, Linton, Temvik and Wilton series. Bryant, Grassna, Temvik and Wilton soils are fine-silty. Linton soils have mollic epipedons less than 16 inches thick.
GEOGRAPHIC SETTING: Mandan soils are on level to moderately steep terraces and uplands that are mantled with silty sediments near the Missouri River. Slopes range from 0 to 25 percent. The silty sediments range from 40 inches to 20 feet in thickness. The mean annual temperature is 40 to 45 degrees F, and the mean annual precipitation is 15 to 18 inches, most of which falls from April through September.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Grassna, Linton and Temvik on nearby silty covered uplands and terraces and the Cabba, Lambert, Lehr, Manning, Parshall, Stady, Wabek and Werner soils. Cabba, Lambert, Wabek and Werner soils are on steep hills and terrace edges. Cabba and Werner soils are shallow. Lambert soils do not have mollic epipedons and Wabek soils are sandy-skeletal. Lehr, Manning, Parshall and Stady soils are on nearby terraces. Lehr, Manning and Stady soils are fine-loamy over sandy or sandy-skeletal. Parshall soils are coarse-loamy.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is slow or moderate. Permeability is moderate, however; glacial till, sandstone and shale substratum phases have moderately slow or slow permeability and gravelly substratum phases have rapid or very rapid permeability below depths of 40 inches.
USE AND VEGETATION: Most areas are used for small grains. Native vegetation is western wheatgrass, green needlegrass, needleandthread, blue grama and upland sedges.
DISTRIBUTION AND EXTENT: Near the Missouri River in North Dakota. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Burleigh County, North Dakota, 1970.
REMARKS: Revised 11/91.
Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface of the soil to a depth of 29 inches (A1, A2, and Bw horizons).
ADDITIONAL DATA: Laboratory data sample numbers S62ND-8-3 and S62ND-8-8 from North Dakota Agricultural Experiment Station.