LOCATION SWYGERT IL+INEstablished Series
TAXONOMIC CLASS: Fine, mixed, active, mesic Aquic Argiudolls
TYPICAL PEDON: Swygert silty clay loam - on a slope of less than 1 percent in a cultivated field at an elevation of 206 meters (675 feet) above mean sea level. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 18 cm (0 to 7 inches); black (10YR 2/1) silty clay loam, dark gray (10YR 4/1) dry; moderate very fine granular structure; friable; many fine roots; slightly acid; abrupt wavy boundary.
A--18 to 30 cm (7 to 12 inches); black (10YR 2/1) silty clay loam, dark gray (10YR 4/1) dry; weak medium angular blocky structure parting to weak fine subangular blocky; friable; many fine roots; common black (N 2.5/) krotovina; slightly acid; abrupt smooth boundary. [Combined thickness of the A horizon is 25 to 51 cm (10 to 20 inches).]
Bt1--30 to 46 cm (12 to 18 inches); very dark grayish brown (10YR 3/2) silty clay, gray (10YR 5/1) dry; moderate fine subangular blocky structure; friable; many fine roots; many distinct black (10YR 2/1) and very dark gray (10YR 3/1) organo-clay films on faces of peds; common fine black (10YR 2/1) iron-manganese concretions throughout; common fine faint brown (10YR 4/3) iron-manganese accumulations in the matrix; slightly acid; clear wavy boundary.
Bt2--46 to 66 cm (18 to 26 inches); brown (10YR 4/3) silty clay; weak medium prismatic structure parting to moderate medium subangular blocky; friable; common fine roots; many distinct very dark grayish brown (10YR 3/2) organo-clay films and dark grayish brown (10YR 4/2) clay films on faces of peds; common fine prominent strong brown (7.5YR 5/6) masses of oxidized iron and common fine distinct olive gray (5Y 5/2) iron depletions in the matrix; neutral; clear smooth boundary.
Bt3--66 to 79 cm (26 to 31 inches); yellowish brown (10YR 5/4) silty clay; moderate medium prismatic structure parting to weak medium and fine angular blocky; firm; common fine roots; common distinct very dark gray (10YR 3/1) organo-clay films on surfaces along root channels; common distinct dark gray (10YR 4/1) and gray (10YR 5/1) clay films on faces of peds; common very dark gray(10YR 3/1) krotovina; common medium distinct yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; common fine prominent gray (5Y 5/1) iron depletions in the matrix; slightly effervescent (7 percent calcium carbonate equivalent); moderately alkaline; gradual smooth boundary.
2Bt4--79 to 104 cm (31 to 41 inches); light olive brown (2.5Y 5/4) silty clay; moderate medium prismatic structure parting to weak coarse angular blocky; very firm; few fine roots; common prominent very dark gray (10YR 3/1) organo-clay films and gray (5Y 5/1) clay films on faces of peds; common medium prominent gray (5Y 5/1) iron depletions in the matrix; slightly effervescent (16 percent calcium carbonate equivalent); moderately alkaline; gradual smooth boundary.
2Bt5--104 to 130 cm (41 to 51 inches); light olive brown (2.5Y 5/4) silty clay; weak coarse prismatic structure; very firm; few fine roots; common distinct very dark gray (5Y 3/1) organo-clay films on surfaces along root channels; many distinct dark gray (5Y 4/1) clay films on faces of peds; common fine black (10YR 2/1) iron-manganese concretions throughout; few fine distinct olive (5Y 5/6) and few fine prominent strong brown (7.5YR 5/6) masses of oxidized iron in the matrix; common fine prominent gray (5Y 5/1) iron depletions in the matrix; strongly effervescent (18 percent calcium carbonate equivalent); moderately alkaline; gradual smooth boundary. [Combined thickness of the Bt and 2Bt horizons is 38 to 114 cm (15 to 45 inches).]
2Cd--130 to 152 cm (51 to 60 inches); brown (10YR 5/3) silty clay; massive; very firm; many distinct gray (5Y 6/1) pressure faces; common fine black (10YR 2/1) iron-manganese concretions throughout; few coarse prominent strong brown 7.5YR 5/6 and 5/8) masses of oxidized iron in the matrix; strongly effervescent(19 percent calcium carbonate equivalent); moderately alkaline.
TYPE LOCATION: Iroquois County, Illinois; about 8 kilometers (5 miles) north of Cissna Park; 103 meters (339 feet) south and 20 meters (66 feet) east of northwest corner of sec. 7, T. 25 N., R. 13 W.; USGS Onarga East, Illinois topographic quadrangle; lat. 40 degrees 38 minutes 36 seconds N. and long. 87 degrees 53 minutes 04 seconds W., NAD 27; UTM Zone 16, 425215 easting and 4499540 northing, NAD 83.
RANGE IN CHARACTERISTICS: Depth to the base of soil development ranges from 89 to 140 cm (35 to 55 inches). Depth to carbonates ranges from 51 to 127 cm (20 to 50 inches). Thickness of the loess and lacustrine sediments is variable, but the clayey till is within a depth of 114 cm (45 inches). The mollic epipedon ranges from 25 to 51 cm (10 to 20 inches) in thickness and includes the upper part of the B horizon in many pedons. The average clay content of the particle-size control section is 45 to 50 percent. Some subhorizons contain as much as 55 percent clay.
The Ap or A horizon has hue of 10YR, value of 2 or 3 (4 or 5 dry), and chroma of 1 or 2. It is silty clay loam or silt loam. Reaction ranges from moderately acid to neutral.
The BA or upper Bt horizon has hue of 10YR or 2.5Y, value of 3 to 5 (5 to 7 dry), and chroma of 1 to 4. It is silty clay loam or silty clay. Reaction ranges from moderately acid to neutral.
The Bt or 2Bt horizon has hue of 10YR, 2.5Y, or 5Y; value of 4 or 5; and chroma of 2 to 6. It contains common or many redoximorphic features. Chroma of 2 is either in the matrix or in redoximorphic features. Texture is silty clay or clay. Consistence is firm or very firm. Moist bulk density is less than 1.7 g/cm3 and typically is in the range of 1.40 to 1.69 g/cm3 and retards but does not restrict root penetration. Reaction ranges from neutral to moderately alkaline, and many
pedons are slightly or strongly effervescent in one or more of the lower subhorizons.
The BCt, 2BCt, Cd, or 2Cd horizon commonly has hue of 2.5Y or 5Y, and less commonly 10YR; value of 4 to 6; and chroma of 1 to 6. It contains redoximorphic features with hue of 7.5YR, 10YR, 2.5Y, or 5Y; value of 4 to 6; and chroma of 1 to 8. Texture commonly is silty clay but includes silty clay loam and clay. Reaction is slightly alkaline or moderately alkaline and ontains carbonates. Consistence is firm or very firm. The Cd or 2Cd horizon commonly has bulk density greater than 1.7 g/cm3 and is restricting to root and water penetration.
COMPETING SERIES:
Williamsport is the only series in this family. Williamsport has less clay in the subsoil. Soils in similar families are the
Chenoa,
Clarence,
Denrock,
Elliott,
Frankfort,
Rutland, and
Shullsburg series. Chenoa, Elliott, and Rutland soils average less than 45 percent clay in the particle-size control section. Clarence soils average more than 50 percent clay in the particle-size control section. Denrock soils contain hues redder than 10YR. Frankfort soils lack a mollic
epipedon. Shullsburg soils contain a paralithic contact within a depth of 102 cm (40 inches).
GEOGRAPHIC SETTING: The Swygert soils are on convex slopes on relatively undissected parts of the till plain of Wisconsinan Age. Slope gradients range from 0 to 12 percent. The soils formed in calcareous clayey till or silty clay lacustrine sediments and the underlying calcareous clayey till. A surface mantle of loess or silty material as much as 51 cm (20 inches) in thickness is on some pedons. The climate is mid-continental with hot summers and cold winters. Mean annual air temperature ranges from 7 to 11 degrees C (45 to 52 degrees F), mean annual precipitation ranges from 711 to 1016 mm (28 to 40 inches), frost-free period ranges from 140 to 180 days, and elevation ranges from 165 to 311 meters (541 to 1,020 feet) above sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the similar Frankfort and Rutland soils, and the Bryce, Chatsworth, Mokena, and Mona soils. The poorly drained Bryce soils are in a drainage sequence with Swygert soils. They are on low-lying, nearly level areas and lack an argillic horizon. The moderately well drained Chatsworth soils are on severely eroded parts of the landform both above and below Swygert soils. They have thinner sola and lack an argillic horizon. Frankfort soils form a biosequence with Swygert soils. They formed in similar materials and are on nearby landforms. Mokena soils and the moderately well drained Mona soils are on higher positions on the landform and have part of their subsoils formed in loamy outwash and contain less than 35 percent clay in the particle-size control section. Rutland soils are on nearby landscapes where the loess or silty material is thicker.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat poorly drained. An intermittent perched high water table is at a depth of 30 to 61 cm (1 to 2 feet) below the surface at some time between January and May in normal years. The potential for surface runoff is medium to very high. Saturated hydraulic conductivity is moderately high or moderately low (0.42 to 4.23 micrometers per second) in the solum and moderately low (less than 0.42 micrometers per second) in the underlying material. Permeability is moderately slow and slow in the solum and very slow in the underlying material.
USE AND VEGETATION: Most areas are cultivated. Corn, soybeans, small grains, and hay are the principal crops. Native vegetation is prairie grass.
DISTRIBUTION AND EXTENT: Northeastern Illinois and northwestern Indiana. Extent is large in MLRAs 108A, 110, 111C, and 111D.
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana.
SERIES ESTABLISHED: Livingston County, Illinois, 1938.
REMARKS: In soils such as this, with materials in the control section of mixed origin, clay mineralogy determinations are imprecise. Several indicators should be used. The X-ray diffraction patterns at NSSL indicate a smectitic placement. However, that method should be compared to weighted CEC/clay and LE/clay ratios that are outside the limits commonly set for the smectitic mineralogy class. The relative proportion of clay minerals is a function of the kind and amount of
mixing of materials over the till. In all pedons the mineralogy of the till is illitic. Diagnostic horizons and features recognized in this pedon are: mollic epipedon horizon 0 to 46 cm (0 to 18 inches) (Ap, A, and Bt1 horizons); argillic horizon 30 to 130 cm (12 to 51 inches) (Bt1, Bt2, Bt3, 2Bt4, and 2Bt5 horizons).
ADDITIONAL DATA: The typical pedon is S77IL-075-5 (NSSL nos. 77P 1071 - 77P 1078) from a characterization study of soils formed in fine-textured materials in northeastern Illinois.