LOCATION NORREST SD+NEEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Aridic Haplustalfs
TYPICAL PEDON: Norrest silt loam - on a convex surface having a 6 percent slope in native grass. When described the soil was dry throughout. (Colors are for dry soil unless otherwise stated)
A--0 to 6 inches; grayish brown (10YR 5/2) silt loam, dark grayish brown (10YR 4/2) moist; moderate fine granular and subangular blocky structure; hard, friable; many roots; many very fine hard fragments of siltstone throughout; upper 1 inch is a fragile crust of silt loam; strong effervescence; slightly alkaline; clear smooth boundary. (4 to 8 inches thick)
Bt--6 to 18 inches; light gray (10YR 7/1) and grayish brown (10YR 5/2) silty clay loam, gray (10YR 5/1) and dark grayish brown (10YR 4/2) crushing to grayish brown (10YR 5/2) moist; moderate medium prismatic structure parting to moderate medium blocky; very hard, firm; few fine rounded fragments of siltstone; violent effervescence; slightly alkaline; gradual smooth boundary. (4 to 18 inches thick)
Btk--18 to 26 inches; light gray (5Y 7/1) and grayish brown (10YR 5/2) clay loam, olive gray (5Y 5/2) and dark grayish brown (10YR 4/2) moist; strong, medium and coarse prismatic structure parting to moderate medium and coarse blocky; extremely hard, very firm, but crumbly; common fine roots mostly along faces of peds; common fine threads of carbonate on faces of peds and throughout the interior; few fine fragments of siltstone; violent effervescence; slightly alkaline; gradual smooth boundary. (0 to 12 inches thick)
Bk--26 to 32 inches; light brownish gray (10YR 6/2) and light olive gray (5Y 6/2) clay loam, grayish brown (10YR 5/2) and olive (5Y 5/3) moist; moderate medium and coarse prismatic structure parting to weak coarse blocky; extremely hard, very friable; common white threads of carbonate in the matrix and on faces of peds; common fine fragments of siltstone; violent effervescence; slightly alkaline; gradual wavy boundary. (0 to 10 inches thick)
Cr--32 to 36 inches; light gray (5Y 7/1) soft siltstone; few roots in cracks and fractures; siltstone is hard and brittle, but crumbles readily on wetting; fragments are dark grayish brown (10YR 4/2) on surface; violent effervescence; slightly alkaline.
TYPE LOCATION: Mellette County, South Dakota; about 8 miles north and 1 mile west of Cedar Butte; 2080 feet west and 1600 feet north of the southeast corner of sec. 18, T. 43 N., R. 31 W.
RANGE IN CHARACTERISTICS: The depth to bedrock ranges from 20 to 40 inches. It contains free carbonates throughout except for the surface inch or two under native vegetation in some pedons. The soil is mildly or moderately alkaline throughout. The A horizon may be darker than value of 3.5 moist, but is too thin to qualify as a mollic epipedon. Some pedons have up to 25 percent by volume of pebbles and cobblestones on the surface and in the upper part of the Bt horizon.
The A horizon has hue of 10YR, value of 4 to 6 and 2 to 5 moist, and chroma of 1 to 3. It is silt loam, loam, silty clay loam, or clay loam or cobbly silty clay loam.
The Bt horizon has hue of 10YR, 2.5Y, or 5Y; value of 5 to 8 and 4 to 6 moist; and chroma of 1 to 3. It is clay loam, silty clay, silty clay loam, or clay averaging between 35 and 45 percent clay. It typically has few to common accumulation of carbonates.
The Bk horizon has the same range in color as the Bt horizon. It is loam, silty clay loam, or clay loam and contains 1 to 15 percent by volume of fragments of siltstone. It has common or many accumulations of carbonate as threads and fine masses.
Some pedons have a C horizon that contains 5 to 35 percent by volume of fragments of siltstone and are clay loam or loam.
The Cr horizon is soft bedrock and can be readily dug with a spade. Fractures extend into the siltstone forming prism like masses.
COMPETING SERIES: These are the Agua Fria, Arp, Baca, Hesper, Manzanola, Mughouse, Mughut, Panky, Rencalson, Renohill, Thurlow, Ulm, and Wyarno soils. Agua Fria, Arp, and Panky soils have redder hue; in addition Agua Fria soils are underlain by gravelly alluvium at depths of 18 to 36 inches and Panky soils do not have Cr horizons within depths of 20 to 40 inches. Baca, Hesper, Manzanola, Thurlow, Ulm, and Wyarno soils do not have Cr horizons within depth of 40 inches. Mughouse, Mughut, and Rencalson soils are noncalcareous throughout. Renohill soils are leached of carbonates in the upper horizons.
GEOGRAPHIC SETTING: Norrest soils are on nearly level to steep convex surfaces on smooth ridges, crests, and side slopes of the uplands. Slope gradients range from 0 to 40 percent. These soils formed in residuum weathered from siltstone or soft shale, some are interbedded with sandstone. Mean annual temperature ranges from 43 to 50 degreees F, and the mean annual precipitation ranges from 12 to 18 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Blackpipe, Cedar Butte, Okreek, and Imlay soils. Blackpipe soils have a mollic epipedon and are at heads of drainageways in shallow swales. Cedar Butte soils are on lower nearly level flats, have natric horizons, and do not have bedrock within depths of 20 to 40 inches. Okreek soils are on the broader, more stable ridges and nearly level benches. Imlay soils are on the more steeply sloping areas having sharp, convex surfaces. Okreek soils have mollic epipedons and Imlay soils have bedrock within a depth of 20 inches.
DRAINAGE AND PERMEABILITY: Well drained. Runoff ranges from low to high depending on slope. Permeability is moderately slow.
USE AND VEGETATION: Mostly in rangeland. Native vegetation is mid and short grasses; mostly western wheatgrass, green needlegrass, blue grama, sideoats grama, buffalograss, sedges and forbs.
DISTRIBUTION AND EXTENT: Of moderate extent in southwestern South Dakota and northwest Nebraska.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Mellette County, South Dakota, 1971.
REMARKS: Diagnostic horizons and features recognized in the pedon are: ochric epipedon - the zone from the surface to a depth of about 6 inches (A horizon); argillic horizon - the zone from about 6 to 18 inches (Bt, Btk horizon).