LOCATION MARKHAM IL+IN WIEstablished Series
TAXONOMIC CLASS: Fine, illitic, mesic Mollic Oxyaquic Hapludalfs
TYPICAL PEDON: Markham silt loam on a north-facing slope of 3 percent at an elevation of 236 meters (775 feet) above mean sea level. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 13 cm (0 to 5 inches); very dark grayish brown (10YR 3/2) silt loam, grayish brown (10YR 5/2) dry; moderate fine granular structure; friable; common very fine roots; moderately acid; clear smooth boundary.
A--13 to 20 cm (5 to 8 inches); very dark grayish brown (10YR 3/2) silt loam, grayish brown (10YR 5/2) dry; moderate fine subangular blocky structure parting to weak fine granular; friable; common very fine roots; moderately acid; abrupt smooth boundary. [Combined thickness of the A horizon is 15 to 23 cm (6 to 9 inches).]
BA--20 to 30 cm (8 to 12 inches); brown (10YR 4/3) silty clay loam; moderate fine subangular blocky structure; friable; common very fine roots; common distinct very dark grayish brown (10YR 3/2) organic coatings on faces of peds; moderately acid; clear wavy boundary. [0 to 15 cm (0 to 6 inches) thick]
2Bt1--30 to 53 cm (12 to 21 inches); dark yellowish brown (10YR 4/4) silty clay loam; moderate fine and medium prismatic structure parting to moderate fine subangular blocky; friable; common very fine and fine roots; few distinct very dark gray (10YR 3/1) organic coatings on faces of peds; common distinct brown (10YR 4/3) clay films on faces of peds; common fine strong brown (7.5YR 4/6) very weakly cemented iron oxide concretions throughout; 2 percent gravel; slightly acid; clear wavy boundary.
2Bt2--53 to 66 cm (21 to 26 inches); yellowish brown (10YR 5/4) silty clay loam; weak medium subangular blocky structure; friable; common very fine and fine roots; few distinct brown (10YR 4/3) clay films on faces of peds and in pores; common fine yellowish red (5YR 4/6) very weakly cemented iron oxide concretions throughout; common fine distinct grayish brown (10YR 5/2) iron depletions in the matrix; 7 percent gravel; slightly effervescent; slightly alkaline; gradual wavy boundary. [Combined thickness of the 2Bt horizon is 25 to 89 cm (10 to 35 inches).]
2BC--66 to 81 cm (26 to 32 inches); yellowish brown (10YR 5/4) silty clay loam; weak medium and coarse angular blocky structure; firm; common very fine roots; common fine yellowish red (5YR 5/6) very weakly cemented iron oxide concretions throughout; common fine distinct grayish brown (10YR 5/2) iron depletions in the matrix; 6 percent gravel; strongly effervescent; slightly alkaline; gradual wavy boundary. [0 to 25 cm (0 to 10 inches) thick]
2Cd1--81 to 99 cm (32 to 39 inches); yellowish brown (10YR 5/4) silty clay loam; massive; very firm; few very fine roots; common fine yellowish red (5YR 5/6) very weakly cemented iron oxide concretions throughout; 6 percent gravel; violently effervescent; moderately alkaline; gradual wavy boundary.
2Cd2--99 to 152 cm (39 to 60 inches); brown (10YR 5/3) silty clay loam; massive; very firm; common fine yellowish red (5YR 5/6) very weakly cemented iron oxide concretions throughout; 7 percent gravel; violently effervescent; moderately alkaline.
TYPE LOCATION: DuPage County, Illinois; 648 meters (2,125 feet) south and 419 meters (1,375 feet) east of the northwest corner of sec. 16, T. 40 N., R.9 E.; USGS West Chicago topographic quadrangle; lat. 41 degrees 57 minutes 09 seconds N. and long. 88 degrees 13 minutes 04 seconds W., NAD 27; UTM Zone 16, 399060E, 4645222N, NAD 83.
RANGE IN CHARACTERISTICS: Depth to the base of soil development is 51 to 140 cm (20 to 55 inches). Illite is the dominant clay mineral.
The upper part of the series control section (Ap or A horizon) has 10YR hue, value of 2 or 3 and chroma of 1 or 2. It is silt loam or silty clay loam.
Some pedons have an E horizon with hue of 10YR, value of 4 or 5, and chroma of 2 or 3.
The middle part of the series control section (Bt or 2Bt horizon) has hue of 10YR or 2.5Y, value of 4 or 5, and chroma of 2 to 8. It is silty clay loam or silty clay. The particle-size control section of the Bt horizon averages between 35 and 45 percent clay and contains less than 50 percent clay in any subhorizon. Reaction ranges from strongly acid to slightly acid in the upper part and from slightly acid to moderately alkaline in the lower part.
The lower part of the series control section (BC, 2BC, Cd or 2Cd horizon) has hue of 10YR or 2.5Y, value of 4 to 6, and chroma of 1 to 8. It is silty clay loam or clay loam. It is slightly to moderately alkaline and commonly contains carbonates.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Markham soils are typically in transition areas between the Mollisols and Alfisols on Wisconsin till plains. Slopes are dominantly between 3 and 12 percent, and they range from 0 to 20 percent. The soils are formed in silty clay loam till of Wisconsin Age that has, in some places, mantles of less than 46 cm (18 inches) of loess or other silty material. Mean annual air temperature ranges from 7 to 11 degrees C (45 to 52 degrees F.), mean annual precipitation is 740 to 1020 mm (29 to 40 inches), frost free days is 140 to 180 days, and the elevation ranges from 165 to 311 meters (540 to 1020 feet) above sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ashkum, Beecher, Elliott, Morley, Ozaukee, and Varna soils. The poorly drained Ashkum soils have a mollic epipedon and are lower positions on the landform. The somewhat poorly drained Beecher and Elliott soils are on slightly lower landform positions. Morley, Ozaukee, and Varna soils are also on similar landform positions. Morley and Ozaukee soils have surface layers with moist color values of 4 or more, and Varna soils have mollic epipedons.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Moderately well drained. The depth to a perched seasonal high water table is 61 to 107 cm (2.0 to 3.5 feet) at some time during the spring in most years. The potential for surface runoff is low to high. Saturated hydraulic conductivity is moderately low to moderately high (0.42 to 1.41 micrometers per second). Permeability is slow.
USE AND VEGETATION: Largely cropped to corn, soybeans, small grains, and hay. Native vegetation was probably prairie grass having recent encroachment of hardwood trees.
DISTRIBUTION AND EXTENT: Northern Illinois, southeastern Wisconsin, northern Indiana, and southern Michigan.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana.
SERIES ESTABLISHED: Lake County, Illinois, 1961.
REMARKS: Diagnostic horizons and features recognized in this pedon are: ochric epipedon (mollic intergrade) - the zone from the surface to 30 cm (12 inches) (Ap, A and BA horizons); argillic horizon - the zone from 30 to 66 cm (12 to 26 inches) (2Bt1 and 2Bt2 horizons); udic moisture regime.