LOCATION EDWARDSVILLE IL+INEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Aquic Argiudolls
TYPICAL PEDON: Edwardsville silt loam - with a southwest-facing slope with a 2 percent gradient on a concave summit in a cultivated field at an elevation of about 525 feet above sea level. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 8 inches; very dark grayish brown (10YR 3/2) silt loam, dark grayish brown (10YR 4/2) dry; weak fine granular structure; friable; common very fine roots; about 23 percent clay; neutral; abrupt smooth boundary.
A--8 to 15 inches; very dark grayish brown (10YR 3/2) silt loam, dark grayish brown (10YR 4/2) dry; moderate very fine and fine subangular blocky structure parting to moderate fine granular; friable; common very fine roots; about 24 percent clay; neutral; clear smooth boundary. (Combined thickness of the Ap and A horizons is 12 to 22 inches.)
Bt--15 to 20 inches; dark grayish brown (10YR 4/2) silty clay loam; moderate fine and medium subangular blocky structure; friable; common very fine roots; common distinct very dark grayish brown (10YR 3/2) organo-clay films on faces of peds; few fine distinct yellowish brown (10YR 5/6) and few medium prominent strong brown (7.5YR 5/8) masses of iron accumulation in the matrix; few fine rounded black (10YR 2/1) iron-manganese nodules with clear strong brown (7.5YR 4/6) boundaries; about 30 percent clay; neutral; clear smooth boundary.
Btg1--20 to 27 inches; grayish brown (10YR 5/2) silty clay loam; moderate medium subangular blocky structure; friable; few very fine roots; common distinct very dark grayish brown (10YR 3/2) organo-clay films on faces of peds; common medium distinct yellowish brown (10YR 5/6) and common fine and medium prominent strong brown (7.5YR 5/8) masses of iron accumulation in the matrix; few fine and medium rounded black (10YR 2/1) iron-manganese nodules with clear strong brown (7.5YR 4/6) boundaries; about 32 percent clay; slightly acid; clear smooth boundary.
Btg2--27 to 37 inches; grayish brown (2.5Y 5/2) silty clay loam; weak medium prismatic structure parting to moderate medium subangular blocky; friable; few very fine roots; few distinct very dark grayish brown (10YR 3/2) organo-clay films on faces of peds; many fine and medium prominent yellowish brown (10YR 5/6) and common fine and medium prominent strong brown (7.5YR 5/8) masses of iron accumulation in the matrix; common fine and medium rounded black (10YR 2/1) iron-manganese nodules with clear strong brown (7.5YR 4/6) boundaries; about 30 percent clay; slightly acid; clear smooth boundary.
Btg3--37 to 49 inches; light brownish gray (2.5Y 6/2) silty clay loam; weak medium prismatic structure parting to weak medium subangular blocky; friable; few very fine roots; few faint dark grayish brown (10YR 4/2) clay films on faces of peds and few distinct very dark grayish brown (10YR 3/2) organo-clay films lining root channels; many fine and medium prominent yellowish brown (10YR 5/6) and common fine prominent strong brown (7.5YR 5/8) masses of iron accumulation in the matrix; few fine and medium rounded black (10YR 2/1) iron-manganese nodules with clear strong brown (7.5YR 4/6) boundaries; about 28 percent clay; neutral; clear smooth boundary. (Combined thickness of the Bt horizon is 30 to 46 inches.)
BCg--49 to 57 inches; light brownish gray (2.5Y 6/2) silt loam; weak medium prismatic structure; friable; few very fine roots; few distinct very dark grayish brown (10YR 3/2) and dark grayish brown (10YR 4/2) organo-clay films lining root channels; common medium prominent strong brown (7.5YR 5/8) masses of iron accumulation in the matrix; few medium irregular black (7.5YR 2.5/1) masses of iron-manganese accumulation with diffuse strong brown (7.5YR 5/6) boundaries; about 25 percent clay; neutral; gradual smooth boundary. (0 to 10 inches thick)
CBg--57 to 80 inches; light brownish gray (2.5Y 6/2) silt loam; massive; friable; few distinct dark grayish brown (10YR 4/2) organo-clay films lining root channels; few fine prominent yellowish brown (10YR 5/6) masses of iron accumulation in the matrix; common medium and coarse irregular black (7.5YR 2.5/1) masses of iron-manganese accumulation with diffuse strong brown (7.5YR 5/6) boundaries; about 22 percent clay; neutral.
TYPE LOCATION: Madison County, Illinois; about 1 mile east of Bethalto; approximately 700 feet north and 1,640 feet east of the southwest corner of sec. 5, T. 5 N., R. 8 W.; USGS BETHALTO, ILL. topographic quadrangle; lat. 38 degrees 54 minutes 30 seconds N., and long. 90 degrees 00 minutes 54 seconds W.
RANGE IN CHARACTERISTICS: Depth to the base of the argillic horizon ranges from 40 to 70 inches. The mollic epipedon is 12 to 24 inches in thickness and extends into the upper part of the B horizon in some pedons. Depth to carbonates is greater than 40 inches. The particle-size control section averages 27 to 35 percent clay and less than 7 percent sand.
The Ap or A horizon has value of 2 or 3 (4 or 5 dry) and chroma of 1 or 2. It is silt loam, but it is silty clay loam in the lower part of the A horizon in some pedons. Clay content is 20 to 30 percent. Reaction is moderately acid to neutral depending upon liming practices.
Some pedons have an AB or a BA horizon. Other pedons have a BE horizon.
The Bt, Btg, BC or BCg horizon has hue of 10YR or 2.5Y, value of 3 to 6, and chroma of 2 to 4. Redoximorphic iron depletions and concentrations have hue of 7.5YR, 10YR, or 2.5Y; value of 4 to 7; and chroma of 1 to 8. It is silty clay loam in the upper part and silty clay loam or silt loam in the lower part. Clay content is 27 to 35 percent in the upper part and is 20 and 30 percent in the lower part. Reaction is strongly acid to neutral, and ranges to slightly alkaline in the lower part.
The CBg, Cg or C horizon has hue of 10YR or 2.5Y, value of 5 or 6, and chroma 1 to 4. Redoximorphic iron depletions and concentrations commonly have hue of 7.5YR, 10YR, or 2.5Y; value of 5 or 6; and chroma of 1 to 8. Clay content is 18 to 25 percent. Reaction is moderately acid to moderately alkaline.
COMPETING SERIES: These are the Brenton, Elburn, Frankenmuth, Hacreek, Harco, Higginsville, Keller, Lafayette, Lawndale, Lisbon, Loran, Mundelein, Muscatune, Nevin, Raub, Rooks, Rowley, and Shannondale series. Brenton, Elburn, Frankenmuth, Keller, Lafayette, Lawndale, Lisbon, Mundelein, Raub, Rowley, and Shannondale soils contain more than 7 percent sand in the lower part of the series control section. Harco soils contain carbonates within a depth of 40 inches. Hacreek and Loran soils have a paralithic contact in the series control section. Higginsville soils average less than 25 percent clay in the lower part of the series control section. Muscatune and Nevin soils have a mean annual soil temperature less than 56 degrees F. Rooks soils have rock fragments in the lower part of the series control section.
GEOGRAPHIC SETTING: Edwardsville soils are on nearly level or gently sloping summits on till plains. Slope gradients typically are between 1 and 3 percent and range from 0 to 5 percent. These soils formed in loess. Mean annual temperature is 54 to 57 degrees F., mean annual precipitation is 36 to 40 inches, frost-free period is 170 to 200 days, and elevation is 400 to 800 feet above sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bethalto, Downsouth, Mascoutah, and Wakenda soils. The well drained Wakenda soils are on more sloping or are on narrower summits in areas with greater relief. The somewhat poorly drained Bethalto soils and the moderately well drained Downsouth soils do not have a mollic epipedon and typically are nearer the drainageways. The poorly drained Mascoutah soils are on lower parts of the landform nearby. They contain more clay in the surface layer and do not have an argillic horizon.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Permeability is moderate. The potential for surface runoff is low or medium. In drained areas, depth to an intermittent apparent high water table is 1.0 foot to 2.0 feet from December to April in most years.
USE AND VEGETATION: Most areas are cropped to corn, soybeans, and small grain. Native vegetation is tall prairie grasses.
DISTRIBUTION AND EXTENT: Southwestern Illinois and western Indiana. Extent is moderate, and mainly in MLRA 115.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Madison County, Illinois, 1997. The Edwardsville series was named for a city in Madison County.
REMARKS: Edwardsville soils were formerly correlated as a taxadjunct of the Muscatine series (Aquic Hapludolls).
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from the surface to a depth of 15 inches (Ap and A horizons).
Argillic horizon - the zone from approximately 15 to 49 inches (Bt, Btg1, Btg2, and Btg3 horizons).
Udic moisture regime.