LOCATION SUNBURY IL+INEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Aquollic Hapludalfs
TYPICAL PEDON: Sunbury silt loam in a nearly level cultivated field at an elevation of about 208 meters (680 feet) above mean sea level. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 20 cm (0 to 8 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 throughout; slightly acid; clear smooth boundary. [18 to 24 cm (7 to 9 inches) thick]
E--20 to 30 cm (8 to 12 inches); brown (10YR 5/3) silt loam; moderate thin and medium platy structure parting to moderate fine granular; friable; common very fine roots throughout; moderately acid; clear smooth boundary. [10 to 20 cm (4 to 8 inches) thick]
BE--30 to 38 cm (12 to 15 inches); brown (10YR 4/3) silty clay loam; moderate fine subangular blocky structure; firm; common very fine and fine roots throughout; many distinct light gray (10YR 7/2) (dry) clay depletions on faces of peds; moderately acid; clear smooth boundary. [7 to 15 cm (3 to 6 inches) thick]
Bt1--38 to 64 cm (15 to 25 inches); brown (10YR 5/3) silty clay loam; moderate medium prismatic structure parting to moderate medium subangular blocky; firm; common very fine and fine roots between peds; many distinct very dark grayish brown (10YR 3/2) organo-clay films on faces of peds; few medium irregular black (7.5YR 2.5/1) weakly cemented iron-manganese nodules throughout; common fine faint dark grayish brown (10YR 4/2) iron depletions in the matrix; few fine distinct yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; moderately acid; clear smooth boundary.
Bt2--64 to 91 cm (25 to 36 inches); yellowish brown (10YR 5/4) silty clay loam; moderate medium prismatic structure parting to moderate medium and coarse subangular blocky; firm; common fine roots between peds; many distinct dark grayish brown 10YR 4/2) clay films on faces of peds; common distinct very dark gray (10YR 3/1) organo-clay films on faces of peds; few medium irregular black (7.5YR 2.5/1) weakly cemented iron-manganese nodules throughout; few medium distinct dark gray (10YR 4/1) iron depletions in the matrix; common medium distinct yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; slightly acid; clear smooth boundary.
Bt3--91 to 109 cm (36 to 43 inches); brown (10YR 5/3) silty clay loam; moderate medium prismatic structure parting to weak coarse subangular blocky; friable; few very fine and fine roots between peds; common distinct dark grayish brown (10YR 4/2) clay films on faces of peds; common distinct very dark gray (10YR 3/1) organo-clay films on faces of peds and on surfaces along pores; common medium rounded and irregular black (7.5YR 2.5/1) iron-manganese nodules throughout; common medium faint light brownish gray (10YR 6/2) iron depletions in the matrix; many medium distinct yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; slightly alkaline; clear smooth boundary. [Combined thickness of the Bt horizon is 50 to 90 cm (20 to 36 inches.)]
2Btg--109 to 119 cm (43 to 47 inches); grayish brown (10YR 5/2) loam; weak coarse subangular blocky structure; firm; few distinct dark grayish brown (10YR 4/2) clay films on faces of peds; few distinct very dark gray (10YR 3/1) organo-clay films on faces of peds and in pores; few fine and medium irregular black (7.5YR 2.5/1) weakly cemented iron-manganese nodules throughout; many medium prominent yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; 1 percent fine gravel; slightly alkaline; abrupt smooth boundary. [10 to 38 cm (4 to 15 inches thick)]
2Cg--119 to 183 cm (47 to 72 inches); 50 percent grayish brown (10YR 5/2) and 50 percent yellowish brown (10YR 5/6) loam; massive; firm; common fine and medium rounded white (10YR 8/1) weakly cemented calcium carbonate nodules throughout; few fine and medium irregular black (7.5YR 2.5/1) weakly cemented iron-manganese nodules throughout; 3 percent fine gravel; strongly effervescent; moderately alkaline.
TYPE LOCATION: Douglas County, Illinois; about 3.2 kilometers (2 miles) north of Atwood; 431 meters (1,410 feet) east and 388 meters (1,270 feet) north of the southwest corner of sec. 19, T. 16 N., R. 7 E.; 15 meters (50 feet) south of the center of the road; USGS Atwood, IL topographic quadrangle; lat. 39 degrees, 49 minutes, 27.3 seconds N., and long. 88 degrees, 27 minutes, 25.9 seconds W.; UTM Zone 16S 0375297E, 4409269N., NAD 83.
RANGE IN CHARACTERISTICS: The depth to the base of the argillic horizon ranges from 115 to 165 cm (45 to 65 inches). The depth to carbonates ranges from about 115 to 150 cm (45 to 60 inches). The depth to horizons with more than 15 percent sand is 100 to 150 cm (40 to 60 inches). The average content of clay in the particle-size control section is between 35 and 45 percent.
The Ap, A, E, or BE horizons has properties as follows. The Ap or A horizon has hue of 10YR or 2.5Y, value of 2 or 3 (4 or 5 dry), and chroma of 1 or 2. It is moderately acid to neutral.
The E horizon has hue of 10YR, value of 3 to 5 (5 to 7 dry), and chroma of 2 or 3. It is moderately acid to neutral. In some cultivated pedons, the E horizon has been mixed with the Ap horizon.
The BE horizon has hue of 10YR, value of 4 or 5 (5 to 7 dry), and chroma of 3 or 4. It is silt loam or silty clay loam. It is moderately acid or slightly acid.
The Bt horizon has hue of 10YR or 2.5Y, value of 4 to 6, and chroma of 2 to 4. It typically is silty clay loam, but some pedons have silty clay subhorizons. Reaction ranges from moderately acid to slightly alkaline.
The 2Bt or 2Btg horizon has hue of 10YR or 2.5Y, value of 4 to 6, and chroma of 2 to 6. It is loam, clay loam, or silt loam. Clay content ranges from 20 to 30 percent and sand content ranges from 15 to 45 percent. Rock fragment content is typically less than 5 percent. Reaction ranges from moderately acid to slightly alkaline and contains carbonates in some pedons.
Some pedons have 2BC horizons or both 2Bt and 2BC horizons.
The 2C or 2Cg horizon has hue of 10YR or 2.5Y, value of 5 or 6, and chroma of 1 to 8. It commonly is loam, but some subhorizons are clay loam, silt loam, or silty clay loam. Clay content ranges from 20 to 30 percent and sand content ranges from 15 to 45 percent. Rock fragment content is less than 15 percent. Reaction is moderately alkaline or slightly alkaline and contains carbonates in most pedons.
COMPETING SERIES: These are the Hoyleton and Sedalia series. Hoyleton soils do not have carbonates within a depth of 150 cm (60 inches). Sedalia soils have 15 percent or more rock fragments in the lower part of the series control section.
GEOGRAPHIC SETTING: Sunbury soils are typically on convex slopes of slightly dissected, nearly level to gently undulating till plains. In many places, they are in narrow bands between soils bordering the streams and having lighter colored surface layers and soils on the undissected interfluves having thicker dark colored surface layers. Slope ranges from 0 to 5 percent. Sunbury soils formed in 100 to 150 cm (40 to 60 inches) of loess or other silty material, and the underlying calcareous loamy till or lacustrine sediments of Wisconsinan age. The mean annual temperature varies from 8 to 12 degrees C. (46 to 54 degrees F), the mean annual precipitation varies from 735 to 1015 mm (29 to 40 inches), frost free period ranges from 160 to 180 days, and elevation ranges from 180 to 310 meters (590 to 1,020 feet) above sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Drummer, Flanagan, and Sabina soils. The poorly drained Drummer soils have a mollic epipedon and have less clay in the subsoil. They are on low lying or nearly level parts of the interfluves below the Sunbury soils. Flanagan soils are adjacent on the generally undissected interfluves at similar or slightly higher topographic positions. Sabina soils are adjacent and closer to the drainageways. They are on similar or slightly lower topographic positions.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat poorly drained. These soils have an apparent seasonal high water table at a depth of 30 to 60 cm (1 to 2 feet) below the surface at some time between January and May in most years. The potential for surface runoff is low. Saturated hydraulic coductivity is moderately high (1.41 to 4.23 micrometers per second). Permeability is moderately slow.
USE AND VEGETATION: Most areas are cultivated. Corn soybeans, small grain, and forages are the principal crops. Native vegetation is grasess and widely spaced deciduous trees.
DISTRIBUTION AND EXTENT: Known distribution is in east central and north central Illinois and west central Indiana in MLRAs 108, 110, and 111. The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: De Witt County, Illinois, 1937.
REMARKS: Diagnostic horizons and features recognized in this pedon are: ochric epipedon - the zone from the surface to a depth of 38 cm (Ap, E, and BE horizons); argillic horizon - the zone from 38 to approximately 119 inches (Bt1, Bt2, Bt3, and 2Btg horizons); aquic conditions - redoximorphic features in all horizons below a depth of 38 cm (Bt1, Bt2, Bt3, 2Btg, and 2Cg horizons).