LOCATION SEN ND
Established Series
Rev. CJH
01/2023
SEN SERIES
The Sen series consists of well drained, moderately permeable soils that formed in calcareous siltstone or shale. They are moderately deep to soft bedrock. These soils are on upland plains and have slope of 0 to 25 percent. Mean annual air temperature is 42 degrees F, and mean annual precipitation is 15 inches.
TAXONOMIC CLASS: Fine-silty, mixed, superactive, frigid Typic Haplustolls
TYPICAL PEDON: Sen silt loam - on a northeast-facing slope of 4 percent in a cultivated field. (Colors are for dry soil unless otherwise stated)
Ap--0 to 6 inches; grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; moderate medium granular structure; slightly hard, friable, slightly sticky and nonplastic; common roots; neutral; abrupt smooth boundary. (5 to 8 inches thick)
Bw1--6 to 10 inches; grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; weak coarse prismatic structure parting to moderate coarse and medium subangular blocky; slightly hard, friable, slightly sticky and nonplastic; common roots; neutral; clear wavy boundary.
Bw2--10 to 17 inches; light yellowish brown (2.5Y 6/3) silt loam, olive brown (2.5Y 4/3) moist; moderate coarse prismatic structure parting to moderate medium subangular blocky; slightly hard, friable, sticky and slightly plastic; common roots; slightly alkaline; clear wavy boundary. (Combined Bw horizons 7 to 20 inches thick)
Bk1--17 to 23 inches; pale yellow (2.5Y 7/3) silt loam, light olive brown (2.5Y 5/4) moist; weak coarse prismatic structure parting to moderate medium subangular blocky; slightly hard, friable, sticky and slightly plastic; common roots; medium generally rounded masses of carbonates; violent effervescence; slightly alkaline; clear wavy boundary.
Bk2--23 to 34 inches; pale yellow (2.5Y 8/2) silt loam, light yellowish brown (2.5Y 6/4) moist; weak medium subangular blocky structure; slightly hard, friable, sticky and slightly plastic; common roots; many small iron concretions; strong effervescence; moderately alkaline; clear wavy boundary. (Combined Bk horizons 5 to 20 inches thick)
Cr--34 to 60 inches; pale yellow (5Y 7/3) and pale olive (5Y 6/3) soft stratified siltstone, pale olive (5Y 6/3) moist; slight effervescence.
TYPE LOCATION: Slope County, North Dakota; about 3 1/2 miles north of West Rainy Butte; 180 feet west and 1,990 feet north of the southeast corner of sec. 36, T. 139 N., R. 99 W.
RANGE IN CHARACTERISTICS: The depth to soft bedrock typically is 30 to 40 inches, but ranges from 20 to 40 inches. Depth to carbonates ranges from 10 to 30 inches. The 10- to 40-inch particle-size control section averages between 18 and 35 percent clay and less than 15 percent fine and coarser sand. Stony phases are recognized.
The A horizon has hue of 10YR, value of 3 to 5 and 2 or 3 moist, and chroma of 2 or 3. It is loam, silt loam or silty clay loam. It is neutral or slightly alkaline.
The Bw horizon has hue of 10YR or 2.5Y, value of 3 to 6 and 3 to 5 moist, and chroma of 2 to 4. It typically is silt loam, but some is loam or silty clay loam. It has weak or moderate prismatic structure that parts to weak or moderate, medium or coarse subangular blocky. It is neutral to moderately alkaline. Some pedons have BC horizons.
The Bk horizon has hue of 2.5Y or 5Y, value of 5 to 8 and 4 to 6 moist, and chroma of 2 to 4. It typically is silt loam or silty clay loam, but some is loam. Carbonates are both diffused and in soft accumulations. The Bk horizon contains 10 to 30 percent calcium carbonate equivalent. It is slightly alkaline or moderately alkaline.
The Cr horizon is soft bedrock that is massive or stratified siltstone or silty shale.
COMPETING SERIES: These are the
Amsterdam,
Bryant,
Golva,
Omio,
Peritsa and
Temvik series. Amsterdam soils contain significant quantities of glass shards and are in intermountain valleys. Bryant, Golva, Peritsa and Temvik soils do not have siltstone within depths of 40 inches. Omio soils do not have Bk horizons and formed in calcareous loess overlying soft siltstone.
GEOGRAPHIC SETTING: Sen soils are level to strongly sloping on upland plains. Slope gradients commonly are 3 to 8 percent, but range from 0 to 25 percent. The soils formed in calcareous siltstone or sandstone. The climate is cool, semiarid. Mean annual air temperature ranges from about 39 F to 45 degrees F, and mean annual precipitation from 13 to 18 inches. Most of the precipitation comes in the spring and summer.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Amor,
Cabba,
Chama,
Farland,
Grail,
Grassna,
Morton and
Wyola soils. Amor soils are on nearby upland plains where the bedrock contains more sand. They are fine-loamy. Cabba soils are on the crests of hills and steep side slopes. They do not have Bw horizons and have siltstone within depths of 20 inches. Chama soils are on convex areas in the same landscape as the Sen soils. They have carbonates within depths of 10 inches. Farland soils are on nearly level terraces and Morton soils are on well drained uplands and in complex with Sen soils in some places. Both of these soils have an argillic horizon. In addition, Farland soils do not have siltstone within depths of 40 inches. Grail soils are in concave swales and fans and Wyola soils are on nearly level terraces. Both these soils contain more than 35 percent clay in the particle-size control section and have argillic horizons. Grassna soils are in concave swales and on foot slopes. They have a mollic epipedon more than 16 inches thick and are very deep.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is slow, medium or rapid. Permeability is moderate.
USE AND VEGETATION: Soils are cropped to small grains in a crop-summer fallow rotation. Native vegetation is mid and short prairie grasses as green needlegrass, needleandthread, western wheatgrass, blue grama and a variety of forbs.
DISTRIBUTION AND EXTENT: Western North Dakota and possibly northwestern South Dakota, and eastern Montana. The series is of large extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Salina, Kansas
SERIES ESTABLISHED: Burleigh County, North Dakota, 1971.
REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface of the soil to a depth of 10 inches (Ap and Bw1 horizons); cambic horizon - the zone from 10 to 17 inches (Bw2 horizon).
ADDITIONAL DATA: Laboratory data No. SU7OND-44-2. Other data, S58ND-17-1 and S59ND-17-1 in Soil Survey Investigations Report No. 2.
National Cooperative Soil Survey
U.S.A.