LOCATION SIECHE SDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Pachic Argiudolls
TYPICAL PEDON: Sieche loam - on a north-facing, 40 percent slope in a wooded coulee. (Colors are for dry soil unless otherwise stated.)
Oi--1 to 0 inches; very dark gray and black (10YR 3/1 and 2/1) moist and dry; matted leaves and slightly decomposed organic matter.
A1--0 to 6 inches; very dark gray (10YR 3/1) loam, black (10YR 2/1) moist; moderate fine subangular blocky structure parting to weak fine granular; slightly hard, very friable; many small and few large roots; neutral; clear wavy boundary.
A2--6 to 15 inches; very dark gray (10YR 3/1) loam, black (10YR 2/1) moist; weak coarse and medium subangular blocky structure parting to weak very fine granular; slightly hard, very friable; many small and few large roots; slightly acid; clear wavy boundary.
A3--15 to 20 inches; very dark gray (10YR 3/1) clay loam, black (10YR 2/1) moist; moderate medium and fine subangular blocky structure; hard, friable, slightly sticky; many roots; slightly acid; clear wavy boundary. (Combined A horizons is 9 to 24 inches thick.)
B/E--20 to 24 inches; dark gray (10YR 4/1) clay loam, black (10YR 2/1) moist (Bt); common gray (10YR 5/1) and dark gray (10YR 4/1) moist patches of bleached sand grains (E); moderate medium and fine subangular blocky structure; hard, firm, slightly sticky; many roots; neutral; clear wavy boundary. (0 to 4 inches thick)
Bt--24 to 32 inches; grayish brown (10YR 5/2) clay; very dark grayish brown (10YR 3/2) crushing to dark grayish brown (10YR 4/2) moist; weak medium prismatic structure parting to moderate coarse and medium blocky; very hard, firm, sticky and plastic; few bleached sand grains and pockets of gray (10YR 5/1) moist coatings on upper 2 inches of peds; shiny film on faces of peds; neutral; clear wavy boundary. (8 to 15 inches thick)
Bk--32 to 41 inches; light brownish gray (2.5Y 6/2) clay loam, dark grayish brown (2.5Y 4/2) moist; common fine distinct olive yellow (2.5Y 6/6) and few fine distinct mottles of yellowish red (5YR 4/6) redox concentrations, and few fine and medium distinct of gray (5Y 5/1) redox depletions; moderate coarse and medium subangular blocky structure; hard, firm, sticky and plastic; few coarse accumulations of carbonate; strong effervescence; moderately alkaline; clear wavy boundary. (9 to 13 inches thick)
C--41 to 60 inches; light gray (2.5Y 7/2) clay loam, grayish brown (2.5Y 5/2) moist; few fine and medium distinct gray (5Y 5/1) redox depletions and yellowish red (5YR 4/6) redox concretions; weak coarse subangular blocky structure; hard, firm, sticky; strong effervescence; moderately alkaline.
TYPE LOCATION: Marshall County, South Dakota; about 2 miles south and 1 1/2 miles west of Veblen; 2100 feet east and 200 feet north of the southwest corner of sec. 29, T. 128 N., R. 53 W.
RANGE IN CHARACTERISTICS: Depth to free carbonate ranges from 20 to 40 inches. The solum and substratum contain from 2 to 10 percent coarse fragments as pebbles, cobbles, and stones. The mollic epipedon ranges from 16 to 30 inches in thickness.
The A horizon has hue of 10YR, value of 3 or 4 and 2 or 3 moist, and chroma of 1.5 or less. It is loam or clay loam and slightly acid or neutral.
The B/E horizon has hue of 10YR, value of 4 to 6 and 2 to 4 moist, and chroma of 1 or 2. It is slightly acid or neutral. Few or common clean silt and sand grains coat surfaces of some peds. Some pedons have a BE horizon.
The Bt horizon has hue of 10YR, value of 5 or 6 and 3 to 5 moist, and chroma of 2 or 3. It is clay loam or clay averaging between 35 and 50 percent clay. It has weak prismatic structure that parts to moderate or strong, coarse or medium blocky. Few or common clean sand grains form light gray or gray coatings on top of some peds or occur as small pockets in the upper 1 to 2 inches. It is neutral or slightly alkaline.
The Bk horizon has hue of 10YR or 2.5Y, value of 5 to 7 and 4 or 5 moist, and chroma of 2 or 3. It is clay loam or clay and slightly alkaline or moderately alkaline. It contains few to many, fine to coarse accumulations of carbonate.
The C horizon has hue of 2.5Y, value of 6 or 7 and 4 or 5 moist, and chroma of 2 to 4. Mottles in both Bk and C horizons are inherent to the parent material and vary widely in amount and intensity between pedons. The C horizon is slightly alkaline or moderately alkaline.
COMPETING SERIES: These are the Burnel, Harmony, and LaPlatta series. Burnel soils typically have an A horizon less than 9 inches thick and formed in alluvium. Harmony soils have less sand and more silt and are formed in glaciolacustrine silts and clays. LaPlatta soils are at elevations above 5000 feet and formed in weathered tuff, conglomerate, sandstone and limestone.
GEOGRAPHIC SETTING: Sieche soils are on moderately steep to very steep upland wooded draws having smooth to slightly concave surfaces. Slope gradients typically are 25 to 40 percent but range from 6 to 50 percent. They formed in calcareous clay loam glacial till. Mean annual temperature ranges from 38 to 48 degrees F, and the mean annual precipitation ranges from 17 to 24 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Aastad, Buse, and Forman soils. Aastad and Buse soils do not have an argillic horizon and have less clay in the series control section. In addition, Buse soils do not have a mollic epipedon. Aastad soils are in swales and flats. Buse soils are on similar landscapes as Sieche soils. Forman soils are fine-loamy. They are on adjacent less sloping prairie landscapes.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is high or very high. Permeability is moderately slow.
USE AND VEGETATION: Deciduous forest with little grazing value; bur oak, maple, basswood, and green ash, with an understory of shrubs and very sparse cover of grass.
DISTRIBUTION AND EXTENT: Northeastern South Dakota. The Sieche series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Marshall County, South Dakota, 1970.
REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface of the soil to a depth of about 24 inches (A1, A2, A3, and B/E horizons); argillic horizon - the zone from a depth of about 24 to 32 inches (Bt horizons).