LOCATION MONA ILEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Oxyaquic Argiudolls
TYPICAL PEDON: Mona silt loam - on a south-facing slope of 2 percent in a cultivated field at an elevation of 219 meters (718 feet) above mean sea level. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 28 centimeters (0 to 11 inches); very dark gray (10YR 3/1) silt loam, gray (10YR 5/1) dry; moderate fine granular structure; friable; common fine and medium roots; slightly acid; clear smooth boundary. [25 to 61 cm (10 to 24 inches) thick]
Bt1--28 to 38 centimeters (11 to 15 inches); dark yellowish brown (10YR 4/4) silty clay loam; moderate fine subangular blocky structure; friable; common fine and medium roots; common faint brown (10YR 4/3) clay films on faces of peds; common distinct very dark gray (10YR 3/1) organo-clay films on faces of peds; slightly acid; clear smooth boundary.
2Bt2-- 38 to 56 centimeters (15 to 22 inches); yellowish brown (10YR 5/4) clay loam; moderate fine subangular blocky structure; friable; common medium to very fine roots; common faint brown (10YR 4/3) clay films on faces of peds; few distinct very dark gray (10YR 3/1) organo-clay films on faces of peds; neutral; clear smooth boundary.
2Bt3--56 to 79 centimeters (22 to 31 inches); yellowish brown (10YR 5/4) clay loam; moderate medium subangular blocky structure; firm; few fine roots; common faint brown (10YR 4/3) clay films on faces of peds; few faint very dark gray (10YR 3/1) organo-clay films on faces of peds; few fine prominent yellowish brown (10YR 5/8) masses of oxidized iron in the matrix; neutral; clear smooth boundary.
2Bt4--79 to 99 centimeters (31 to 39 inches); light olive brown (2.5Y 5/4) clay loam; weak medium subangular blocky structure; firm; few fine roots; common faint dark grayish brown (10YR 4/2) clay films on faces of peds; few fine rounded white (10YR 8/1) weakly cemented calcium carbonate nodules throughout; few fine prominent yellowish brown (10YR 5/8) masses of oxidized iron in the matrix; neutral; clear smooth boundary. (Combined thickness of the Bt and 2Bt horizons is 30 to 102 centimeters thick or 12 to 40 inches thick)
3BC--99 to 112 centimeters (39 to 44 inches); grayish brown (2.5Y 5/2) silty clay; weak coarse subangular blocky structure; very firm; few fine rounded white (10YR 8/1) weakly cemented calcium carbonate nodules throughout; few fine irregular strong brown (7.5YR 5/8) weakly cemented iron-manganese nodules throughout; few fine prominent light olive brown (2.5Y 5/6) masses of oxidized iron in the matrix; 3 percent gravel; slightly effervescent; slightly alkaline; clear smooth boundary. [5 to 25 centimeters (2 to 10 inches) thick]
3Cd--112 to 152 centimeters (44 to 60 inches); grayish brown (2.5Y 5/2) silty clay; massive; very firm; few fine rounded white (10YR 8/1) weakly cemented calcium carbonate nodules throughout; few fine irregular strong brown (7.5YR 5/8) weakly cemented iron-manganese nodules throughout; common medium faint gray (10YR 5/1) iron depletions in the matrix; few fine prominent light olive brown (2.5Y 5/6) masses of oxidized iron in the matrix; 3 percent gravel; strongly effervescent; slightly alkaline.
TYPE LOCATION: Vermilion County, Illinois; about 2.4 kilometers (1.5 miles) south and 4.8 kilometers (3 miles) east of Rankin; about 183 meters (600 feet) west and 40 meters (130 feet) south of northeast corner of sec. 20, T. 23 N., R. 13 W.; USGS East Lynn topographic quadrangle; lat. 40 degrees 26 minutes 36 seconds N., and long. 87 degrees 50 minutes 21 seconds W.; NAD27; UTM Zone 16, 0428819 easting and 4477307 northing, NAD 83.
RANGE IN CHARACTERISTICS: The depth to the silty clay or clay layer is 76 to 127 centimeters (30 to 50 inches). Some pedons have a layer of loess as much as 61 centimeters (24 inches) in thickness overlying outwash. The depth to the base of the argillic horizon ranges from 76 to 137 centimeters (30 to 54 inches). The depth to carbonates ranges from 76 to 137 centimeters (30 to 54 inches). The mollic epipedon is 25 to 61 centimeters (10 to 24 inches) in thickness and includes the upper part of the B horizon in some pedons. The particle-size control section averages 25 to 35 percent clay and from 15 to 40 percent fine sand or coarser.
The Ap,or A horizon has hue of 10YR, value of 2 or 3 moist and 4 or 5 dry, and chroma of 1 or 2. It is silt loam or less commonly loam, clay loam, silty clay loam, or sandy clay loam. It is slightly acid to slightly alkaline. Some pedons contain an AB horizon.
The BA or 2BA horizon, where present, has hue of 10YR, value of 3 or 4, and chroma of 2 to 4. It is silty clay loam, clay loam, or sandy clay loam. It is neutral to moderately acid.
The Bt,or 2Bt horizon has hue of 10YR, value of 4 to 6, and chroma of 3 or 4. It is silty clay loam in the part formed in loess, and clay loam, silty clay loam with a high content of sand, or less commonly sandy clay loam in the part formed in outwash. Clay content ranges from 25 to 35 percent and sand content ranges from 15 to 50 percent. Content of rock fragments is less than 10 percent. It is moderately acid to neutral and typically the reaction increases with increasing depth.
The BC,2BC, or 3BC horizon formed in outwash or lacustrine sediments, have hue of 10YR, value of 4 to 6, and chroma of 3 or 4. It is clay loam or silty clay loam. It is neutral or slightly alkaline and contains carbonates in some pedons.
The 2Cd, or 3Cd horizon formed in till or lacustrine sediments, has hue of 10YR, 7.5YR, or 2.5Y, value of 4 to 6, and chroma of 2 to 4. It is silty clay or clay. Clay content ranges from 40 to 50 percent and sand content is less than 10 percent. Content of rock fragments is less than 10 percent. Some pedons contain thin strata of other textures. It is slightly alkaline or moderately alkaline and contains carbonates. Bulk density of the 2Cd or 3Cd horizons ranges from 1.7 to 1.9 gm/cc.
COMPETING SERIES: These are the Balmoral (T), Barce, Symerton, and Wagen Prairie soils. All of these soils , except for the Wagen Prairie soils, have less than 40 percent clay in the lower part of the series control section. Wagen Prairie soils have a paralithic contact within a depth of 100 centimeter (40 inches).
GEOGRAPHIC SETTING: Mona soils are on nearly level to strongly sloping till plains or lake plains of Wisconsinan Age. These soils primarily formed in loamy outwash and silty clay or clay till or lacustrine sediments, but most pedons contain a component of loess or other silty material as much as 61 centimeters (24 inches) in thickness at the surface. Slope gradients range from 0 to 18 percent. Mean annual air temperature varies from about 8 to 12 degrees C (46 to 54 degrees F), mean annual precipitation varies from about 762 to 1,041 millimeters (30 to 41 inches), frost free days ranges from 160 to 180 days, and elevation ranges from 189 to 311 meters (620 to 1,020 feet) above sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bryce, Clarence, Mokena, Proctor, Reddick, Swygert, and Wenona soils. The Bryce, Clarence, Swygert, and Wenona soils contain more than 35 percent clay in the particle-size control section. The poorly drained Bryce soils are on lower parts of the landscape. The somewhat poorly drained Clarence and Swygert soils and the moderately well drained Wenona soils are on similar adjacent parts of the landscape but lack the loamy outwash sediments in the solum. The somewhat poorly drained Mokena soils and the poorly drained Reddick soils are in a drainage sequence with Mona soils. They are lower on the landscape and have redoximorphic features higher in the solum. The well drained Proctor soils are on higher parts of the landscape and have less sand in the particle-size control section and less clay in the lower part of the series control section. They formed in loess and outwash.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Moderately well drained. The depth to a perched seasonal high water table is 61 to 107 centimeters (2.0 to 3.5 feet) at some time between February and April 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: Most of the soil is cropped. Corn, soybeans, small grain, and forages are the principal crops. Native vegetation is tall prairie grasses.
DISTRIBUTION AND EXTENT: Northern and east-central Illinois; extent is small (about 1,400 acres correlated) in MLRA 110.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: La Salle County, Illinois, 1969.
REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface to a depth of 28 centimeters (11 inches) (Ap horizon); argillic horizon - the zone from 28 to 99 centimeters (11 to 39 inches) (Bt1, 2Bt2, 2Bt3, and 2Bt4 horizons); udic moisture regime.