LOCATION MILLSTADT ILEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Aeric Epiaqualfs
TYPICAL PEDON: Millstadt silt loam - nearly level, on a lacustrine terrace tread, in a cultivated field at an elevation of about 410 feet. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 9 inches; dark grayish brown (10YR 4/2) silt loam, light brownish gray (10YR 6/2) dry; moderate fine granular structure; friable; many very fine roots throughout; few fine and medium rounded black (10YR 2/1) iron-manganese nodules with sharp boundaries; about 20 percent clay; neutral; abrupt smooth boundary. (4 to 10 inches thick)
E--9 to 14 inches; pale brown (10YR 6/3) silt loam, very pale brown (10YR 7/3) dry; moderate medium platy structure parting to weak fine granular; friable; common very fine roots throughout; few distinct very pale brown (10YR 8/2, dry) clay depletions on faces of peds; few fine faint light brownish gray (10YR 6/2) iron depletions in the matrix; common fine and medium rounded black (10YR 2/1) iron-manganese nodules with sharp boundaries; about 22 percent clay; slightly acid; clear smooth boundary. (3 to 9 inches thick)
EB--14 to 18 inches; pale brown (10YR 6/3) silt loam, very pale brown (10YR 7/3) dry; moderate fine subangular blocky structure; friable; common very fine roots between peds; many distinct very pale brown (10YR 8/2, dry) clay depletions on faces of peds; common fine faint light brownish gray (10YR 6/2) iron depletions and few fine faint dark yellowish brown (10YR 4/4) masses of iron accumulation in the matrix; common fine and medium rounded black (7.5YR 2.5/1) iron- manganese nodules with clear strong brown (7.5YR 5/6) boundaries; about 26 percent clay; very strongly acid; clear smooth boundary. (0 to 6 inches thick)
Bt1--18 to 28 inches; brown (10YR 4/3) silty clay loam; weak fine prismatic structure parting to moderate medium subangular blocky; firm; common very fine roots between peds; many continuous distinct dark grayish brown (10YR 4/2) clay films on faces of peds; few fine faint grayish brown (10YR 5/2) iron depletions and common fine distinct yellowish brown (10YR 5/6) masses of iron accumulation in the matrix; common fine and medium rounded black (7.5YR 2.5/1) iron-manganese nodules with clear strong brown (7.5YR 5/6) boundaries; about 33 percent clay; very strongly acid; clear smooth boundary.
Bt2--28 to 38 inches; brown (10YR 5/3) silty clay loam; moderate fine prismatic structure parting to moderate medium subangular blocky; firm; common very fine roots between peds; common continuous distinct dark grayish brown (10YR 4/2) clay films on faces of peds; common fine faint grayish brown (10YR 5/2) iron depletions and common fine distinct yellowish brown (10YR 5/6) masses of iron accumulation in the matrix; common fine and medium rounded black (7.5YR 2.5/1) iron- manganese nodules with clear strong brown (7.5YR 5/6) boundaries; about 31 percent clay; very strongly acid; gradual smooth boundary.
Bt3--38 to 53 inches; brown (10YR 5/3) silty clay loam; moderate medium prismatic structure parting to moderate medium subangular blocky; firm; few very fine roots between peds; common continuous distinct dark grayish brown (10YR 4/2) clay films on faces of peds; common fine and medium faint light brownish gray (10YR 6/2) iron depletions in the matrix; common medium distinct yellowish brown (10YR 5/6) and common fine prominent strong brown (7.5YR 5/6) masses of iron accumulation in the matrix; common fine and medium rounded black (7.5YR 2.5/1) iron-manganese nodules with clear strong brown (7.5YR 5/6) boundaries; about 30 percent clay; strongly acid; clear smooth boundary. (Combined thickness of the Bt horizon is 29 to 45 inches.)
2Btg1--53 to 62 inches; grayish brown (2.5Y 5/2) silty clay loam; moderate medium prismatic structure parting to moderate medium subangular blocky; firm; few very fine roots between peds; few discontinuous distinct dark grayish brown (10YR 4/2) clay films on faces of peds; common medium distinct yellowish brown (10YR 5/6) masses of iron accumulation in the matrix; common fine and medium rounded black (7.5YR 2.5/1) iron-manganese nodules with clear strong brown (7.5YR 5/6) boundaries; about 38 percent clay; moderately acid; abrupt smooth boundary.
2Btg2--62 to 67 inches; grayish brown (2.5Y 5/2) silty clay loam; weak medium prismatic structure parting to moderate medium angular blocky; friable; common discontinuous distinct (10YR 4/2) clay films on faces of peds; few fine faint light brownish gray (2.5Y 6/2) iron depletions and common medium prominent yellowish brown (10YR 5/6) masses of iron accumulation in the matrix; common fine and medium irregular black (10YR 2/1) masses of iron-manganese accumulation; about 30 percent clay and 10 percent sand; slightly acid; abrupt smooth boundary.
2Btg3--67 to 80 inches; grayish brown (2.5Y 5/2) silty clay; weak medium prismatic structure parting to moderate fine and medium angular blocky; very firm; common discontinuous distinct dark grayish brown (10YR 4/2) clay films on faces of peds; few fine faint light brownish gray (2.5Y 6/2) iron depletions and common medium prominent yellowish brown (10YR 5/4) masses of iron accumulation in the matrix; few fine and medium irregular black (10YR 2/1) masses of iron-manganese accumulation; about 42 percent clay; slightly effervescent in places; neutral; clear smooth boundary. (Combined thickness of the 2Btg horizon is 24 to 48 inches.)
2Btkg--80 to 100 inches; grayish brown (2.5Y 5/2) silty clay loam; weak medium prismatic structure parting to moderate medium angular blocky; firm; few continuous distinct very dark grayish brown (10YR 3/2) organo-clay coatings lining root channels; common discontinuous distinct dark grayish brown (10YR 4/2) clay films on vertical faces of peds; common fine prominent yellowish brown (10YR 5/4) masses of iron accumulation in the matrix; few fine irregular black (10YR 2/1) masses of iron-manganese accumulation and few fine irregular white (10YR 8/1, dry) masses of carbonate accumulation; several thin strata of brown (10YR 4/3) silt loam; about 38 percent clay; strongly effervescent; slightly alkaline.
TYPE LOCATION: St. Clair County, Illinois; about 1.5 mile south of New Athens; approximately 2,200 feet east and 2,380 feet south of the northwest corner of sec. 4, T. 3 S., R. 7 W.; USGS NEW ATHENS WEST, IL. topographic quadrangle; lat. 38 degrees 18 minutes 05 seconds N. and long. 89 degrees 52 minutes 57 seconds W.
RANGE IN CHARACTERISTICS: Depth to the base of the argillic horizon is 60 to more than 80 inches. Loess thickness typically is 36 to 70 inches. The particle-size control section averages 27 to 35 percent clay. Sand content of the Ap and E or BE horizons is less than 15 percent, and includes iron-manganese nodules and concretions. Sand content is less than 7 percent in the particle-size control section. Carbonates, where present, are below a depth of 4 feet. Some pedons contain krotovina.
The upper part of the control section (Ap) has hue of 10YR, value of 4 or 5 (6 or 7 dry), and chroma of 2 or 3. Commonly, undisturbed pedons have a thin A horizon with a color value of 3 and chroma of 1 or 2. Clay content is 12 to 25 percent. Reaction is strongly acid to neutral, depending on the liming history.
The second part of the control section (E, and EB, where present) has hue of 10YR, value of 4 to 6 (6 to 8 dry), and chroma of 2 or 3. It is silt loam or silty clay loam. Clay content is 12 to 30 percent. Reaction is very strongly acid to slightly acid, where not limed. Pedons that have been limed range to neutral.
The third part of the control section (Bt) has hue of 10YR or 2.5Y; value of 4 to 6; and chroma of 2 to 6. Redoximorphic features have hue of 5YR, 7.5YR, 10YR, 2.5Y, 5Y, or is neutral; value of 2 to 7; and chroma of 0 to 8. It is silty clay loam or silt loam. Clay content is 22 to 35 percent. Reaction is extremely acid to moderately acid.
The lower part of the control section (2Bt, 2BC) has hue of 7.5YR, 10YR, 2.5Y, or 5Y; value of 4 to 7; and chroma of 2 to 4. It is clay, silty clay, silty clay loam, and silt loam. Clay content is 24 to 55 percent and sand content is less than 15 percent. Some pedons contain pressure faces or slickensides, and some pedons contain carbonates in the lower part. Reaction is very strongly acid to moderately alkaline.
COMPETING SERIES: These are the Bromer, Coulterville, Fincastle, Lauer, Taggart, and Tiro series.
Bromer, Fincastle and Tiro soils have rock fragments in the lower part of the series control section. Coulterville soils contain a concentration of exchangeable sodium in the subsoil. Lauer soils average more than 15 percent sand in the particle-size control section. Taggart soils contain more than 7 percent sand in the lower part of the series control section.
GEOGRAPHIC SETTING: Millstadt soils are on nearly level or gently sloping loess-covered lacustrine terraces treads. Slope ranges from 0 to 5 percent. These soils formed in 36 to 70 inches of loess (Peoria Silt), and the underlying lacustrine sediments (Equality Formation). In some pedons the loess and lacustrine sediments are interbedded. Mean annual temperature is 54 to 57 degrees F., mean annual precipitation is 36 to 40 inches, frost-free period is 170 to 200 days, and elevation is 340 to 430 feet above sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bartelso, Floraville, Lakaskia, Redbud, and Wabash soils.
The somewhat poorly drained Bartelso soils have a mollic horizon and are on similar landform positions nearby. They form a biosequence with the Millstadt soils. The poorly drained Floraville and Lakaskia soils are on nearly level or slightly depressional treads of the lacustrine terrace. Also, the Lakaskia soils have a mollic epipedon. The moderately well drained Redbud soils are on more convex or more sloping parts of the lacustrine terrace. The Redbud and Floraville soils form a hydrosequence with the Millstadt soils. The very poorly drained Wabash soils have a mollic epipedon and are in drainageways on the lacustrine terraces.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Permeability is slow. Surface runoff is slow or medium. In drained areas depth to an intermittent perched high water table is 0.5 foot to 2.0 feet from December to April in most years.
USE AND VEGETATION: Most areas are cropped to corn, soybeans, and small grain. A few areas are pastured or wooded. Native vegetation is mixed hardwood forest.
DISTRIBUTION AND EXTENT: Southwestern and southern Illinois. Extent is moderate, and mainly in MLRA(s) 113 and 114.
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: St. Clair County, Illinois, 1997. The Millstadt series was named for a town in St. Clair County.
REMARKS: Millstadt soils were formerly included with the terrace variant of the Iva series.
Diagnostic horizons and features recognized in this pedon are: Ochric epipedon - the zone from the surface to a depth of 18 inches (Ap, E, and EB horizons). Albic horizon - the zone from approximately 9 to 18 inches (E and EB horizons). Argillic horizon - the zone from approximately 18 to 100 inches (Bt1, Bt2, Bt3, 2Btg1, 2Btg2, 2Btg3, and 2Btkg horizons). Aquic conditions - periodic saturation and reduction indicated by redoximorphic features throughout the soil.
ADDITIONAL DATA: For lab analysis refer to a pedon from the St. Clair County Glacial Lake Kaskaskia Study, Part I (S92IL-163-012; NSSL pedon number: 92P-582-3430-3442).