LOCATION MARINE ILEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Aeric Albaqualfs
TYPICAL PEDON: Marine silt loam - with a slope of 1 percent on a broad, slightly convex summit in a cultivated field at an elevation of about 500 feet above mean sea level. (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; weak fine granular structure; friable; many very fine roots; few very fine continuous tubular pores; few fine rounded black (N 2.5/0) iron-manganese nodules with sharp boundaries; strongly acid; abrupt smooth boundary. (6 to 12 inches thick)
E--9 to 17 inches; light brownish gray (10YR 6/2) silt loam, white (10YR 8/1) dry; weak thin platy structure; friable; common very fine roots; few very fine continuous pores; few fine prominent yellowish brown (10YR 5/8) masses of iron accumulation in the matrix; few fine rounded black (N 2.5/0) iron-manganese nodules with sharp boundaries; very strongly acid; abrupt smooth boundary. (6 to 11 inches thick)
Bt1--17 to 25 inches; brown (10YR 4/3) silty clay; moderate medium prismatic structure parting to strong fine angular blocky; very firm; common very fine roots; many distinct dark grayish brown (10YR 4/2) clay films on faces of peds; few fine faint grayish brown (10YR 5/2) iron depletions and few fine prominent yellowish brown (10YR 5/8) masses of iron accumulation in the matrix; common fine and medium rounded black (5YR 2.5/1) iron-manganese nodules with clear strong brown (7.5YR 5/6) boundaries; very strongly acid; clear smooth boundary.
Bt2--25 to 34 inches; brown (10YR 5/3) silty clay loam; moderate medium prismatic structure parting to moderate medium angular blocky; very firm; few very fine roots; many distinct grayish brown (10YR 5/2) clay films on faces of peds; common fine distinct grayish brown (2.5Y 5/2) iron depletions and common medium prominent brownish yellow (10YR 6/8) masses of iron accumulation in the matrix; common fine and medium rounded dark reddish brown (5YR 2.5/2) iron-manganese nodules with clear strong brown (7.5YR 5/6) boundaries; very strongly acid; clear smooth boundary.
Btg1--34 to 43 inches; grayish brown (10YR 5/2) silty clay loam; moderate coarse prismatic structure parting to moderate medium subangular blocky; firm; few very fine roots; many distinct grayish brown (10YR 5/2) clay films on faces of peds; common medium prominent light olive brown (2.5Y 5/4) and common coarse prominent brownish yellow (10YR 6/8) masses of iron accumulation in the matrix; few medium rounded black (N 2.5/0) iron-manganese nodules with strong brown (7.5YR 4/6) boundaries; very strongly acid; clear smooth boundary.
Btg2--43 to 52 inches; light brownish gray (2.5Y 6/2) silty clay loam; weak coarse prismatic structure; firm; few very fine roots; many faint grayish brown (2.5Y 5/2) clay films on faces of peds; common coarse prominent brownish yellow (10YR 6/8) and common medium prominent strong brown (7.5YR 5/8) masses of iron accumulation in the matrix; few fine and medium rounded black (10YR 2/1) iron-manganese nodules with sharp boundaries; slightly acid; gradual smooth boundary. (Combined thickness of the Bt horizon is 30 to 48 inches.)
BCtg--52 to 62 inches; light brownish gray (2.5Y 6/2) silt loam; weak coarse subangular blocky structure; friable; few faint grayish brown (2.5Y 5/2) clay films on vertical faces of peds and few distinct dark grayish brown (10YR 4/2) clay films in root channels and in pores; common coarse prominent strong brown (7.5YR 5/8) masses of iron accumulation in the matrix; few fine and medium rounded black (10YR 2/1) iron-manganese nodules with sharp boundaries; slightly acid; gradual smooth boundary. (0 to 12 inches thick)
2C--62 to 80 inches; brown (7.5YR 5/3) silt loam; massive; friable; many medium faint brown (7.5YR 5/2) iron depletions and many coarse distinct strong brown (7.5YR 5/6) masses of iron accumulation in the matrix; few fine irregular black (10YR 2/1) iron-manganese nodules with sharp boundaries; about 8 percent sand; neutral.
TYPE LOCATION: Madison County, Illinois; about 3 miles south of Highland; approximately 2,030 feet east and 650 feet south of the northwest corner of sec. 21, T. 3 N., R. 5 W.; USGS St. Jacob, IL. topographic quadrangle; lat. 38 degrees 41 minutes 18 seconds N. and long. 89 degrees 46 minutes 14 seconds W.
RANGE IN CHARACTERISTICS: Depth to the base of the argillic horizon is greater than 42 inches. Loess thickness typically is greater than 60 inches, but in some pedons, is as thin as 55 inches. The particle-size control section averages 35 to 48 percent clay and contains less than 7 percent sand. The A and E horizons contain less than 10 percent sand that includes iron-manganese nodules and concretions.
The upper part of the series control section (Ap or A, and E) has properties as follows: The Ap horizon has value of 4 or 5 (6 or 7 dry) and chroma of 2 or 3. Uncultivated pedons have an A horizon 2 to 6 inches in thickness with value of 2 to 4 (4 to 6 dry), and chroma of 1 or 2. Texture is silt loam or silt. Clay content is 10 to 18 percent. Reaction is strongly acid to neutral.
The E horizon has value of 5 to 7 (6 to 8 dry) and chroma of 1 or 2, and typically has redoximorphic features. Redoximorphic masses of iron accumulation in the matrix have hue of 7.5YR, 10YR, or 2.5Y; value of 4 to 6; and chroma of 3 to 8. The E horizon is silt or silt loam and contains 8 to 18 percent clay. Reaction commonly is very strongly acid to moderately acid, but is slightly acid in some pedons.
Some pedons have a B/E horizon about 2 or 3 inches in thickness. These horizons are characterized as having peds of Bt material that have clay depletions (E material) on faces of peds.
The middle part of the series control section (Bt and Btg) has hue of 10YR or 2.5Y, value of 4 to 7, and chroma of 3 or 4 in the upper part and typically grading to 2, but ranging from 1 to 3, in the lower subhorizons. Redoximorphic iron depletions and accumulations have hue of 7.5YR, 10YR, or 2.5Y; value of 4 to 6; and chroma of 1 to 8. Some pedons have subhorizons in the upper part of the Bt horizon that have common or many clay depletions on faces of peds. Texture is silty clay loam or silty clay in the upper part and is silty clay loam or silt loam in the lower part. Clay content averages 35 to 48 percent in the upper part and averages 15 to 35 percent in the lower part. Individual subhorizons in the lower part of some pedons range to 38 percent clay. Sand content is less than 7 percent. Reaction is very strongly acid or strongly acid in the upper part and is strongly acid to neutral in the lower part.
The BCg horizon, where present, has hue of 10YR or 2.5Y, value of 4 to 7, and chroma of 1 or 2. Texture is silty clay loam or silt loam. Clay content is 15 to 30 percent and sand content is less than 7 percent. Reaction is strongly acid to neutral.
The lower part of the series control section (C or 2C) has hue of 7.5YR, 10YR, or 2.5Y; value of 5 to 7; and chroma of 1 to 3. Yellowish brown or strong brown redoximorphic masses of iron accumulation in the matrix are common. The C horizon typically is silt loam, but some pedons have a 2C horizon or horizons of older soils below a depth of 55 inches. These horizons are silt loam, loam, silty clay loam, or clay loam. Clay content is 12 to 35 percent and sand content is 5 to 40 percent. Reaction is strongly acid to slightly alkaline.
COMPETING SERIES: This is the Auxvasse series. The Auxvasse soils are less than 40 inches to the base of the argillic horizon and formed in alluvium.
GEOGRAPHIC SETTING: Marine soils are on nearly level or gently sloping interfluves and slightly convex summits of the Illinoian till plain. Slope ranges from 0 to 5 percent. These soils formed in 55 to more than 80 inches of loess, and the underlying silty pedisediment. The material beneath the loess is the silty pedisediment that lies above the till and contains a component of sand. The loess is late Wisconsinan Peoria Loess and the underlying silty material is early Wisconsinan Roxana Silt. The soils are underlain at depths of about 5 to 8 feet by Illinoian till that commonly contains a strongly developed paleosol. The parent materials in and underlying these soils are weathered to depths of 10 or 12 feet. 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 400 to 800 feet above mean sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Blair, Bunkum, Coulterville, Darmstadt, Hickory, Homen, and Pierron soils. All of the associated soils except for Pierron soils do not have an abrupt textural change from the E horizon to the Bt horizon. The somewhat poorly drained Blair and Bunkum soils and the well drained Hickory soils are on side slopes of drainageways below the Marine soils. Also, Blair and Bunkum soils are in a fine-silty family while Hickory soils are in a fine-loamy family. The somewhat poorly drained Coulterville and Darmstadt soils contain a concentration of exchangeable sodium in the subsoil. The moderately well drained Homen soils are on higher or narrower convex summits. The poorly drained Pierron soils are on nearly level areas that are slightly depressional in some places, and are adjacent to Marine soils in many places.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained and slow permeability. The potential for surface water runoff is low. In drained areas, depth to an intermittent perched high water table is 0.5 foot to 2.0 feet from November to May in most years.
USE AND VEGETATION: Most areas are cropped. Corn, soybeans, and small grain are the principal crops. Native vegetation is hardwood forest.
DISTRIBUTION AND EXTENT: Southern Illinois; extent is moderate, and mainly in MLRA(s) 113 and 114.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Madison County, Illinois, 1982.
REMARKS: The typical pedon was resampled and described to 80 inches for this revision.
Diagnostic horizons and features in this soil include:
Ochric epipedon - from the surface of the soil to a depth of 17 inches (Ap and E horizons). Albic horizon - from a depth of 9 to 17 inches (E horizon). Argillic horizon - from a depth of approximately 17 to 62 inches (Bt1, Bt2, Btg1, Btg2, and BCtg horizons). Albaqualf feature - abrupt textural change from the E horizon to the Bt1 horizon. Aquic conditions - periodic saturation and reduction, indicated by redoximorphic features throughout the soil.
ADDITIONAL DATA: Particle-size analysis by University of Illinois for pedon no. S76IL-119-002 is on file at the NRCS/USDA state office in Champaign, Illinois.