LOCATION ASHKUM IL+IN MI WI
Established Series
Rev. GOW-JWS-DEC
12/2015
ASHKUM SERIES
The Ashkum series consists of very deep, poorly drained soils on till plains. They formed in colluvial sediments and in the underlying silty clay loam till. Slope ranges from 0 to 3 percent. Mean annual precipitation is about 890 mm (35 inches), and mean annual air temperature is about 10 degrees C (50 degrees F).
TAXONOMIC CLASS: Fine, mixed, superactive, mesic Typic Endoaquolls
TYPICAL PEDON: Ashkum silty clay loam, on a concave slope with less than a 1 percent gradient in a cultivated field at an elevation of 215 meters (705 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 fine granular structure; friable; many very fine roots; neutral; clear smooth boundary.
A-- 18 to 30 cm (7 to 12 inches); black (10YR 2/1) silty clay loam, dark gray (10YR 4/1) dry; moderate fine and medium granular structure; friable; common very fine roots; neutral; clear smooth boundary. [Combined thickness of the A horizon is 25 to 51 cm (10 to 20 inches)].
BAg-- 30 to 46 cm (12 to 18 inches); dark gray (2.5Y 4/1) silty clay loam; moderate very fine and fine subangular blocky structure; firm; common very fine roots; many distinct continuous black (10YR 2/1) organic coatings on faces of peds; common fine very dark gray (7.5YR 3/1) very weakly cemented iron-manganese concretions throughout; neutral; clear smooth boundary. [ 0 to 18 cm (0 to 7 inches) thick]
Bg1--46 to 74 cm (18 to 29 inches); grayish brown (2.5Y 5/2) silty clay; moderate medium prismatic structure parting to moderate medium angular blocky; firm; common very fine roots; few distinct very dark gray (10YR 3/1) organic coatings on faces of peds; common fine very dark gray (7.5YR 3/1) very weakly cemented iron-manganese concretions throughout; common fine prominent yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; common fine faint gray (2.5Y 5/1) iron depletions in the matrix; neutral; clear wavy boundary. [0 to 56 cm (0 to 22 inches) thick]
2Bg2--74 to 124 cm (29 to 49 inches); grayish brown (2.5Y 5/2) silty clay loam; weak medium prismatic structure parting to moderate medium angular blocky; firm; few very fine roots; few distinct very dark gray (10YR 3/1) organic coatings on faces of peds; common fine very dark gray (10YR 3/1) very weakly cemented iron-manganese concretions throughout; common fine and medium prominent yellowish brown (10YR 5/8) and faint brown (10YR 5/3) masses of oxidized iron in the matrix; common fine and medium faint gray (5Y 5/1) iron depletions in the matrix; about 8 percent gravel; neutral; gradual wavy boundary. [0 to 51 cm (0 to 20 inches) thick]
2BCg--124 to 137 cm (49 to 54 inches); grayish brown (2.5Y 5/2) silty clay loam; weak medium prismatic structure parting to weak coarse angular blocky; firm; few very fine roots; common fine very dark gray (10YR 3/1) very weakly cemented iron-manganese concretions throughout; common fine and medium prominent yellowish brown (10YR 5/6) and faint brown (10YR 5/3) masses of oxidized iron in the matrix; common fine and medium faint gray (2.5Y 5/1) iron depletions in the matrix; about 8 percent gravel; slightly effervescent; slightly alkaline; gradual wavy boundary. [0 to 36 cm (0 to 14 inches) thick]
2Cg--137 to 152 cm (54 to 60 inches); grayish brown (2.5Y 5/2) silty clay loam; massive; firm; common fine prominent yellowish brown (10YR 5/6) and common fine and medium faint brown (10YR 5/3) masses of oxidized iron in the matrix; common fine faint gray (2.5Y 5/1) iron depletions in the matrix; about 8 percent gravel; strongly effervescent; slightly alkaline.
TYPE LOCATION: Will County, Illinois, about 1.5 miles east of Manhattan; 96 feet south and 2,030 feet east of the northwest corner of sec. 22, T. 34 N., R. 11 E.; Will County, Illinois; USGS Manhattan topographic quadrangle; lat. 41 degrees 25 minutes 30 seconds N. and long. 87 degrees 57 minutes 19 seconds W., NAD 27; UTM Zone 16, 420168 easting and 4586370 northing, NAD 83:
RANGE IN CHARACTERISTICS: The depth to the base of soil development ranges from 76 to 152 cm (30 to 60 inches). Thickness of the colluvial sediments ranges from 38 to 102 cm (15 to 40 inches). Depth to carbonates ranges from 61 to 122 cm (24 to 48 inches), but can be as deep as 152 cm (60 inches) in some pedons. The mollic epipedon ranges from 25 to 61 cm (10 to 24 inches) in thickness. It includes the upper part of the Bg horizon in some pedons. The particle-size control section averages between 35 and 42 percent clay. Rock fragment content is less than 15 percent throughout the series control section.
The Ap or A horizon has hue of 10YR, 2.5Y, or is neutral; value of 2 to 3; and chroma of 0 or 1. It is silt loam, silty clay loam, or silty clay. Reaction is moderately acid to slightly alkaline.
Some pedons have an AB horizon rather than a BA horizon.
The BA, Bg, 2Bg, or 2BCg horizon has hue of 10YR, 2.5Y, 5Y, 5GY, or is neutral; value of 3 to 6; and chroma of 2 or less or may have a chroma of 3 in pedons with hue of 5Y. Redoximorphic features commonly are present with chroma of 2 to 8. It is silty clay loam or silty clay. Reaction ranges from slightly acid to moderately alkaline.
The 2Cg horizon commonly has hue of 2.5Y, 5Y, 5GY, or is neutral, but includes 10YR in some pedons; value of 4 to 6, and chroma of 0 to 8. It is silty clay loam. Reaction ranges from slightly acid to moderately alkaline.
COMPETING SERIES: These are the
Milford,
Secondcreek, and
Woldale series. Milford soils have subhorizons (thin strata or varves) in the lower part of the series control section that have poorly graded soil separates. Secondcreek soils are greater than 152 cm (60 inches) to the base of soil development. Woldale soils contain more than 15 percent rock fragments in the lower part of the series control section.
GEOGRAPHIC SETTING: Ashkum soils are on nearly level and gently sloping till plains of Wisconsinan Age in colluvial positions on the low parts of the topography and along upland drainageways. The soils formed in colluvial sediments consisting of erosional sediments from till and loess or shallow lacustrine materials less than 40 inches (102 cm) thick and in the underlying silty clay loam till. Slope gradients commonly are less than 1 percent and range from 0 to 3 percent. Mean annual air temperature ranges from 8 to 12 degrees C (47 to 54 degrees F), mean annual precipitation ranges from 740 to 1030 mm (29 to 40 inches), frost-free period ranges from 160 to 190 days, and elevation ranges from 165 to 311 meters (540 to 1020 feet) above mean sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the
Andres,
Elliott,
Symerton, and
Varna soils. The Symerton and Varna soils are moderately well drained and the Andres and Elliott soils are somewhat poorly drained. All of these soils generally are on higher elevations.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Poorly drained. The potential for surface runoff is low. Permeability is moderately slow. Saturated hydraulic conductivity is moderately high (1.41 to 4.23 micrometers/s). Where drained, an intermittent apparent seasonal high water table is 0.5 foot (15 cm) above the surface to 1.0 foot (30 cm) below the surface at some time between January and May in normal years.
USE AND VEGETATION: Most areas are used for cropland. Principal crops are corn and soybeans and other crops include small grain and meadow. Native vegetation is marsh grasses and sedges.
DISTRIBUTION AND EXTENT: Northeastern Illinois, southeastern Wisconsin, and west-central Indiana. These soils are extensive in MLRAs 95B, 108A, and 110.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana.
SERIES ESTABLISHED: Iroquois County, Illinois, 1940.
REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface to a depth of 30 cm (12 inches) (Ap and A horizons); cambic horizon - the zone from a depth of 30 to 137 cm (12 to 54 inches) (BAg, Bg1, 2Bg2, and 2BCg horizons); aquic moisture regime - chroma of 2 or less in the matrix and redoximorphic features present in the zone from 30 to 152 cm (12 to 60 inches) (BAg, Bg1, 2Bg2, 2BCg, and 2Cg horizons).
ADDITIONAL DATA: Refer to pedon number S57ILL-99-2 and University of Illinois laboratory numbers 6918-6925, published in SSIR No. 19, which is near the type location.
National Cooperative Soil Survey
U.S.A.