LOCATION BONNIE IL+IN KY MOEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, active, acid, mesic Typic Fluvaquents
TYPICAL PEDON: Bonnie silt loam - on a nearly level floodplain in a cultivated field at an elevation of about 422 feet above MSL. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 8 inches; 90 percent dark grayish brown (10YR 4/2), light brownish gray (10YR 6/2) dry; and 10 percent light brownish gray (10YR 6/2) silt loam; 90 percent weak fine granular structure and 10 percent weak medium subangular soil fragments; friable; common fine roots; many fine dark yellowish brown (10YR 3/4) iron and manganese concretions throughout; neutral; abrupt smooth boundary. (6 to 10 inches thick)
Cg1--8 to 11 inches; light gray (10YR 7/2) silt loam; rock structure of the strata of deposition are evident, massive within strata; friable but compact in upper part as a plow pan; common fine roots; many coarse distinct yellowish brown (10YR 5/4) masses of iron and manganese and few medium prominent yellowish brown (10YR 5/8) masses of iron accumulation in the matrix; many fine very dark grayish brown (10YR 3/2) and black (10YR 2/1) iron and manganese concretions throughout; strongly acid; abrupt smooth boundary. (2 to 12 inches thick)
Cg2--11 to 25 inches; light gray (10YR 7/2) silt loam; massive; friable; few fine roots; many coarse distinct brown (10YR 5/3) and common medium prominent brown (7.5YR 4/4) masses of iron and manganese accumulation in the matrix; common medium prominent yellowish brown (10YR 5/6) masses of iron accumulation in the matrix; many fine very dark grayish brown (10YR 3/2) and black (10YR 2/1) iron and manganese concretions throughout; strongly acid; clear smooth boundary. (5 inches to 5 feet thick)
Cg3--25 to 44 inches; 80 percent gray (10YR 6/1) and 20 percent light gray (10YR 7/1) silt loam; massive; friable; few fine roots; few thin light gray (10YR 7/2) silt coatings in major cracks; many coarse distinct brown (10YR 4/3) masses of iron and manganese accumulation and few fine prominent yellowish brown (10YR 5/6) masses of iron accumulation in the matrix; many fine very dark grayish brown (10YR 3/2) and black (10YR 2/1) iron and manganese concretions throughout; strongly acid; diffuse smooth boundary. (0 to 30 inches thick)
Cg4--44 to 60 inches; gray (5Y 6/1) silty clay loam; massive; friable; many coarse prominent brown (10YR 4/3) masses of iron and manganese accumulation in the matrix; common fine prominent yellowish brown (10YR 5/6), and few fine prominent strong brown (7.5YR 5/6) masses of iron accumulation in the matrix; many fine very dark grayish brown (10YR 3/2) and black (10YR 2/1) iron and manganese concretions that are medium in size as depth increases; strongly acid.
TYPE LOCATION: Wayne County, Illinois; about 3 miles south of Orchardville; 290 feet east and 770 feet north of the center of sec. 4, T. 1 S., R. 5 E.; USGS Shields, IL topographic quadrangle; lat. 38 degrees, 28 minutes, 12 seconds North and long. 88 degrees, 39 minutes, 03 seconds West; NAD 27.
RANGE IN CHARACTERISTICS: The particle-size control section averages between 18 and 27 percent clay and less than 10 percent sand. Reaction below a depth of 10 inches is strongly acid or very strongly acid. These soils have an irregular decrease in organic carbon with increasing depth, but in some pedons it is barely detectable.
The Ap or A horizon has hue of 10YR or 2.5Y, value of 3 to 6, and chroma of 1 to 3. It is commonly silt loam, and less commonly silty clay loam. Reaction ranges from very strongly acid to neutral.
The Cg horizon to depth of 40 inches has hue of 10YR, 2.5Y, 5Y, or is neutral; value of 5 to 7; and chroma of 0 to 2. Redox accumulations also have redder hue and higher chroma. It is dominantly silt loam. Reaction is strongly acid or very strongly acid.
The Cg horizon below a depth of 40 inches has hue of 10YR, 2.5Y, 5Y, or is neutral; value of 5 to 7; and chroma of 0 to 2. Redox accumulations also have redder hue and higher chroma. It is silt loam or silty clay loam. Reaction is very strongly acid to slightly alkaline.
COMPETING SERIES: This is the Piopolis series. Piopolis soils average more than 27 percent clay in the particle-size control section.
GEOGRAPHIC SETTING: Bonnie soils are on nearly level flood plains and, in some places, on flood-plain steps. Slope gradient ranges from 0 to 2 percent. They formed in light colored, recently deposited, acid, silty alluvium. Mean annual air temperature ranges from 53 to 57 degrees F., mean annual precipitation ranges from 38 to 46 inches, frost free period ranges from 170 to 210 days, and elevation ranges from 340 to 700 feet above mean sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Belknap, Birds, Petrolia, Piopolis, and Racoon soils. The somewhat poorly drained Belknap soils are on adjacent slightly higher parts of the flood plains. The poorly drained Birds and Petrolia soils are on similar positions, but formed in alluvium that is less acid. The poorly drained and very poorly drained Piopolis soils are in similar parts of flood plains nearby and contain more clay throughout. The poorly drained Racoon soils are on adjacent or nearby stream terraces. In Indiana, Bonnie soils are associated with the somewhat poorly drained Stendal and moderately well drained Steff soils. These soils are on higher lying parts of flood plains.
DRAINAGE AND PERMEABILITY: Poorly drained and very poorly drained. The potential for surface water runoff is low or medium. Permeability is moderately slow. Flooding from stream overflow ranges from frequent to rare periods, and commonly occurs in the winter and spring. In the undrained condition, these soils have an intermittent apparent water table from as much as 2.0 feet above the surface to 0.5 foot below the surface, typically between October and July in most years. Where drained, an intermittent water table is within 1 foot of the surface, typically between December and May in most years.
USE AND VEGETATION: Most areas are used to grow corn and soybeans. Some areas are in woodland, or are used for pasture. Native vegetation is hardwood forest.
DISTRIBUTION AND EXTENT: Southern Illinois, southern Indiana, Missouri and Kentucky. Bonnie soils are of large extent (more than 150,000 acres correlated). They are mainly in flood plains within MLRA's 113, 114, 115 and 120.
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Washington County, Illinois, 1927.
REMARKS: In some areas these soils have been described as having weak or moderate blocky structure through the middle part of the control section. These soils will be evaluated during MLRA updating to determine if placement in order Entisols is correct or new series in order Inceptisols is needed.
Diagnostic horizons and features recognized in this pedon are:
ochric epipedon - the zone from the surface to a depth of 8 inches (Ap horizon); irregular decrease in organic carbon; aquic conditions - chroma 1 or 2 matrix and redox accumulations in all layers below the Ap horizon.
ADDITIONAL DATA: Characterization data is on file at the East Central Glaciated Regional Office (MLRA NO. 11) at Indianapolis, and at the Illinois State Office.