LOCATION NIMBRO SD+NEEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, calcareous, mesic Mollic Ustifluvents
TYPICAL PEDON: Nimbro silty clay loam - on a plane slope of less than 1 percent in a cultivated field. When described the soil was dry throughout. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 8 inches; gray (10YR 5/1) silty clay loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky and moderate fine granular structure; hard, friable, slightly sticky and slightly plastic; slight effervescence; slightly alkaline; clear smooth boundary. (5 to 9 inches thick)
AC--8 to 16 inches; grayish brown (10YR 5/2) silty clay loam, very dark grayish brown (10YR 3/2) and dark grayish brown (10YR 4/2) moist; weak very thick platy and weak medium and fine subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few very thin layers (less than 1/8 inch thick) of light brownish gray (2.5Y 6/2); strong effervescence; slightly alkaline; clear wavy boundary. (0 to 15 inches thick)
C--16 to 60 inches; light brownish gray (2.5Y 6/2) clay loam stratified with thin layers of fine sand, dark grayish brown (2.5Y 4/2) moist; few fine faint and distinct mottles of reddish yellow (7.5YR 6/6) moist in some layers; massive; slightly hard, friable; strong effervescence; slightly alkaline.
TYPE LOCATION: Stanley County, South Dakota; about 2 1/2 miles southwest of Fort Pierre along Bad River road; 1056 feet north and 1424 feet east of the southwest corner, sec. 3, T. 4 N., R. 31 E.
RANGE IN CHARACTERISTICS: The control section averages between 25 and 35 percent clay. Typically the soil is calcareous throughout but has thin layers that are noncalcareous in some pedons. The soil is slightly alkaline or moderately alkaline throughout. Some pedons have buried horizons.
The A horizon has hue of 10YR or 2.5Y, value of 4 or 5 and 2 or 3 moist, and chroma of 1 or 2. Thin strata of soil materials with higher values are in most pedons, but when mixed have moist values of less than 3.5. It commonly is silty clay loam or loam but is silt loam or very fine sandy loam in some pedons. It has thin to thick platy structure in areas of native grass.
The AC and C horizons have hue of 2.5Y, 10YR, or 5Y; value of 4 to 7 and 3 to 5 moist; and chroma of 2 to 4. The C horizon typically is stratified clay loam but is silt loam, or silty clay loam with thin layers of fine sand in some pedons. Thin layers of fine sand to clay are in most pedons. Few or common mottles are in some layers in most pedons. Sand and gravel substrata are between depths of 40 and 60 inches in some pedons.
COMPETING SERIES: There are no other series in the same family.
GEOGRAPHIC SETTING: Nimbro soils are on flood plains and low terraces. Slope gradients are less than 2 percent. The soils formed in calcareous alluvium. The mean annual temperature ranges from 45 to 52 degrees F, and the mean annual precipitation ranges from 15 to 24 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Munjor, Promise, Swanboy, and Wendte soils. Munjor soils are coarse-loamy and do not have a mollic epipedon. Wendte soils are fine textured. Both Munjor and Wendte soils are in similar positions on the landscape. Promise and Swanboy soils contain more clay and are on foot slopes and fans above areas of Nimbro soils.
DRAINAGE AND PERMEABILITY: Well drained and moderately well drained. Runoff is low. Permeability is moderate. Most areas are subject to rare or occasional flooding from stream overflow. Some areas are protected from flooding by large dams on major streams.
USE AND VEGETATION: Most areas are cultivated. Corn and alfalfa are the principal crops. Native grasses are dominantly big bluestem and western wheatgrass. Shrubs and a few deciduous trees are in some of the lower lying areas.
DISTRIBUTION AND EXTENT: Central and south-central South Dakota and north-central Nebraska. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Stanley County, South Dakota, 1977.
REMARKS: Diagnostic horizons and features recognized in this pedon are: ochric epipedon - the zone from the surface of the soil to a depth of about 8 inches (Ap horizon)
ADDITIONAL DATA: Mechanical analysis of the series control section, Sample No. 75L129, Lincoln SSIU, August 1975.