LOCATION SAWMILL IL+IA MN MOEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Cumulic Endoaquolls
TYPICAL PEDON: Sawmill silty clay loam - on a nearly level flood plain in a cultivated field at an elevation of 163 meters (535 feet) above mean sea level. (Colors are for moist soil unless otherwise stated. When described the soil was wet below 117 cm (46 inches).
Ap--0 to 25 cm (0 to 10 inches); very dark gray (10YR 3/1) with very dark grayish brown (10YR 3/2) silty clay loam, gray (10YR 5/1) dry; weak fine subangular blocky structure; firm; few fine roots; few subrounded pebbles 1 to 3 mm in diameter; slightly acid; clear smooth boundary.
A1--25 to 43 cm (10 to 17 inches); black (10YR 2/1) with very dark grayish brown (10YR 3/2) silty clay loam, dark gray (10YR 4/1) dry; moderate fine subangular blocky structure; firm; few fine roots; few subrounded pebbles 1 to 3 mm in diameter; few fine rounded black (7.5YR 2.5/1) weakly cemented iron-manganese concretions with diffuse boundaries lining root channels and pores; few fine prominent yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; neutral; clear smooth boundary.
A2--43 to 64 cm (17 to 25 inches); black (10YR 2/1) silty clay loam, dark gray (10YR 4/1) dry; moderate fine and medium angular blocky structure; firm; few fine roots; few fine rounded black (7.5YR 2.5/1) weakly cemented iron-manganese concretions with diffuse boundaries on surfaces along root channels and pores; few fine prominent yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; neutral; clear smooth boundary.
AB--64 to 81 cm (25 to 32 inches); very dark gray (10YR 3/1) silty clay loam, gray (10YR 5/1) dry; weak medium prismatic structure parting to moderate fine subangular blocky; firm; few fine roots; few fine rounded black (7.5YR 2.5/1) weakly cemented iron-manganese concretions with diffuse boundaries on surfaces along root channels and pores; few fine prominent yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; neutral; clear smooth boundary. [Combined thickness of the A horizon is 46 to 91 cm (18 to 36 inches).]
Bg--81 to 102 cm (32 to 40 inches); dark gray (10YR 4/1) silty clay loam; weak medium prismatic structure parting to moderate fine and medium angular blocky; firm; common faint very dark gray (10YR 3/1) organic coatings on faces of peds; few fine roots; few fine rounded black (7.5YR 2.5/1) weakly cemented iron-manganese concretions with diffuse boundaries on surfaces along root channels and pores; few fine prominent strong brown (7.5YR 5/6) masses of oxidized iron in the matrix; slightly alkaline; clear smooth boundary.
Btg1--102 to 124 cm (40 to 49 inches); grayish brown (10YR 5/2) silty clay loam; moderate medium prismatic structure parting to weak medium angular blocky; firm; common distinct dark gray (10YR 4/1) clay films on faces of peds; few fine rounded black (7.5YR 2.5/1) weakly cemented iron-manganese concretions with diffuse boundaries on surfaces along root channels and pores; few fine prominent strong brown (7.5YR 5/6) and common fine distinct yellowish brown (10YR 5/4) masses of oxidized iron in the matrix; slightly alkaline; clear smooth boundary.
Btg2--124 to 147 cm (49 to 58 inches); grayish brown (2.5Y 5/2) silty clay loam; moderate medium prismatic structure; firm; common distinct gray (10YR 5/1) clay films on faces of peds; few fine rounded black (7.5YR 2.5/1) weakly cemented iron-manganese concretions with diffuse boundaries on surfaces along pores; few fine prominent yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; slightly alkaline; clear smooth boundary. [Combined thickness of the Bg and/or Btg horizons is 20 to 76 cm (8 to 30 inches).]
Cg--147 to 165 cm (58 to 65 inches); grayish brown (2.5Y 5/2) silty clay loam; massive; firm; very dark gray (10YR 3/1) channel linings and fillings; many medium prominent yellowish brown (10YR 5/6) masses of oxidized iron on surfaces along pores; slightly alkaline.
TYPE LOCATION: Sangamon County, Illinois; about 2 miles (3.2 kilometers) southwest of Rochester on the flood plain of the South Fork of the Sangamon River; 750 feet (229 meters) east and 300 feet (91 meters) south of the northwest corner of sec. 20, T. 15 N., R. 4 W.; USGS New City topographic quadrangle; lat. 39 degrees 44 minutes 34 seconds N. and long. 89 degrees 34 minutes 15 seconds W., NAD 27; UTM Zone 16, 279712 easting and 4402375 northing, NAD 83.
RANGE IN CHARACTERISTICS: The depth to the base of the cambic horizon ranges from 91 to 152 cm (36 to 60 inches). The mollic epipedon ranges from 61 to 91 cm (24 to 36 inches) in thickness, and includes the upper part of the B horizon in some pedons. Redoximorphic features are present throughout. The particle-size control section averages between 27 and 35 percent clay. The moisture control section, in most years, is not dry for 30 cumulative days out of the 120 days following the summer solstice.
The Ap, A and AB horizons have hue of 10YR, 2.5Y, 5Y, or is neutral; value of 2 to 3; and chroma of 0 to 2. Texture is silty clay loam. Reaction ranges from slightly acid to slightly alkaline.
An overwash phases with lighter colored silt loam surface layers less than 51 cm (20 inches) thick is recognized.
The Bg or Btg horizon typically has hue of 10YR, 2.5Y, or 5Y; value of 3 to 6; and chroma of 1 or 2. In some pedons individual horizons have hue of 7.5YR. Texture is dominantly silty clay loam but the lower part in some pedons grades to clay loam or loam, and some pedons contain strata of silt loam or sandy loam.
Reaction ranges from slightly acid to slightly alkaline.
The Cg horizon has similar range of colors as the Bg or Btg horizon. It is silty clay loam, clay loam, loam, silt loam, sandy loam, silty clay, or stratified with these textures. Reaction ranges from slightly acid to moderately alkaline.
Some pedons contain carbonates within a depth of 122 cm (48 inches).
COMPETING SERIES: These are the Afton, Catherine, Clementine, Colo, Humansville, Otter, Pastolla, and Whitewood series. Afton soils are less acid in the middle and lower part of the series control section. Catherine, Clementine, and Whitewood soils are dry in the moisture control section for more then 30 cumulative days out of the 120 days following the summer solstice. Colo soils have mollic epipedons more than 36 inches (91 cm) in thickness. Humansville soils average more than 35 percent clay in the middle and lower parts of the series control section. Otter soils average less than 27 percent clay in the particle-size control section. Pastolla soils are less acid in the series control section and do not have a cambic horizon.
GEOGRAPHIC SETTING: The Sawmill soils are on flood plains, on nearly level valley floors, and in some drainageways that extend into the uplands. Slope ranges from 0 to 3 percent. Sawmill soils formed in alluvial sediments from drift thought to be of Wisconsin Age. Mean annual temperature ranges from 7 to 14 degrees C (45 to 57 degrees F), mean annual precipitation ranges from 760 to 1140 mm (30 to 45 inches), frost-free period ranges from 140 to 180 days, and elevation ranges from 340 to 1,000 (104 to 305 meters) feet above sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Otter series and the Beaucoup, Lawson, Tice, Wabash, and Zook series. All these soils are in similar positions on the flood plain, but the somewhat poorly drained Lawson and Tice soils lie in slightly higher positions or are closer to the stream channel. Beaucoup and Tice soils have mollic epipedons less than 61 cm (24 inches) thick. Wabash and Zook soils average more than 35 percent clay in the particle size control section.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Poorly drained and very poorly drained. Where drained, these soils have an apparent seasonal high water table 15 cm (0.5 foot) above the surface to 30 cm (1.0 foot) below the surface at some time between January and May in most years. In undrained conditions, the apparent seasonal high water table is 15 cm (0.5 foot) above the surface to 15 cm (0.5 foot) below the surface at some time between November and June in most years. The potential for surface runoff is negligible. Permeability is moderate. Saturated hydraulic conductivity is moderately high or high (4.23 to 14.11 micrometers per second). Flooding is rare to common for brief to long periods between November and June.
USE AND VEGETATION: Many areas of Sawmill soils are cultivated. Corn, soybeans, and meadow are the principal crops. Undrained areas are mostly used for pasture or woodland. Native vegetation is grasses and trees.
DISTRIBUTION AND EXTENT: Illinois, Iowa, and Minnesota. The extent is large with more than 314,000 acres (127,074 hectares) correlated in MLRAs 95B, 105, 108, 110, 111, and 115.
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana.
SERIES ESTABLISHED: DeWitt County, Illinois, 1937.
REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface of the soil to a depth of 32 inches (0 to 81 cm) (Ap, A1, A2, and AB horizons); cambic horizon - the zone from 32 to 58 inches (81 to 147 cm) (Bg, Btg1, and Btg2 horizons); endosaturation; aquic conditions - chroma of 2 or less and redox concentrations in all layers below the Ap horizon.