LOCATION FLORAVILLE ILEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Chromic Vertic Albaqualfs
TYPICAL PEDON: Floraville silt loam - slightly depressional, on a loess-covered lacustrine terrace tread, in a cultivated field at an elevation of about 420 feet. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 9 inches; dark grayish brown (10YR 4/2) silt loam, light brownish gray (10YR 6/2) dry; moderate fine granular structure; friable; many very fine roots throughout; common medium and coarse constricted tubular pores; common fine and medium rounded very dark brown (7.5YR 2.5/2) iron-manganese nodules with sharp boundaries; about 17 percent clay; neutral; abrupt smooth boundary. (6 to 10 inches thick)
Eg--9 to 18 inches; light brownish gray (10YR 6/2) silt loam, light gray (10YR 7/2) dry; moderate medium platy structure parting to weak fine granular; friable; common very fine roots throughout; few fine and medium constricted tubular pores; few distinct light gray (10YR 7/2, dry) clay depletions on faces of peds; common fine and medium rounded very dark brown (7.5YR 2.5/2) iron-manganese nodules with sharp boundaries; about 16 percent clay; slightly acid; abrupt smooth boundary. (6 to 14 inches thick)
Btg1--18 to 23 inches; grayish brown (2.5Y 5/2) silty clay loam; moderate fine subangular blocky structure; firm; common very fine roots throughout; few fine constricted tubular pores; common distinct light gray (10YR 7/2, dry) clay depletions on faces of peds; many faint grayish brown (10YR 5/2) clay films on faces of peds; few fine prominent yellowish brown (10YR 5/6) masses of iron accumulation in the matrix; common fine and medium rounded dark reddish brown (5YR 3/4) iron-manganese nodules with clear boundaries; about 33 percent clay; strongly acid; clear smooth boundary.
Btg2--23 to 31 inches; grayish brown (2.5Y 5/2) silty clay loam; moderate fine and medium angular blocky structure; firm; few very fine roots between peds; few fine constricted tubular pores; many distinct dark grayish brown (10YR 4/2) clay films on faces of peds; common fine prominent yellowish brown (10YR 5/6) masses of iron accumulation in the matrix; common medium and coarse irregular dark reddish brown (5YR 3/4) iron-manganese nodules with clear boundaries; about 39 percent clay; very strongly acid; gradual smooth boundary.
Btg3--31 to 39 inches; grayish brown (2.5Y 5/2) silty clay loam; weak fine prismatic structure parting to moderate fine and medium angular blocky; firm; few very fine roots between peds; few fine constricted tubular pores; common distinct dark grayish brown (10YR 4/2) clay films on faces of peds; common fine and medium prominent yellowish brown (10YR 5/6) masses of iron accumulation in the matrix; common fine and medium irregular dark reddish brown (5YR 3/4) and strong brown (7.5YR 5/6) iron-manganese nodules with clear boundaries; about 38 percent clay; very strongly acid; clear smooth boundary.
Btg4--39 to 44 inches; variegated light brownish gray (2.5Y 6/2) and yellowish brown (10YR 5/6) silty clay loam; weak fine prismatic structure parting to weak medium angular blocky; firm; few very fine roots between peds; few fine constricted tubular pores; few faint dark grayish brown (10YR 4/2) clay films on faces of peds; common fine distinct brown (10YR 5/3) masses of iron accumulation in the matrix; common fine and medium irregular dark reddish brown (5YR 3/3) and strong brown (7.5YR 4/6) iron-manganese nodules with clear boundaries; about 34 percent clay; strongly acid; clear smooth boundary. (Combined thickness of the Btg horizon is 24 to 36 inches.)
2Btg5--44 to 49 inches; olive gray (5Y 5/2) silty clay; weak medium prismatic structure parting to weak medium angular blocky; very firm; few very fine roots between peds; few fine vesicular pores; few faint dark grayish brown (2.5Y 4/2) clay films on faces of peds and few prominent black (N 2.5/0) iron-manganese coatings in channels and pores; common fine distinct light olive brown (2.5Y 5/3) masses of iron accumulation in the matrix; many fine and medium irregular black (7.5YR 2.5/1) masses of iron-manganese accumulation; about 44 percent clay; moderately acid; clear smooth boundary.
2Btg6--49 to 62 inches; light olive gray (5Y 6/2) silty clay loam; weak medium prismatic structure; firm; few very fine roots between peds; few fine vesicular pores; few faint dark grayish brown (2.5Y 4/2) clay films on faces of peds and few prominent black (N 2.5/0) iron-manganese coatings in channels and pores; common fine distinct light olive brown (2.5Y 5/3) masses of iron accumulation in the matrix; common fine and medium irregular black (7.5YR 2.5/1) masses of iron-manganese accumulation; about 33 percent clay; slightly acid; clear smooth boundary.
2Btg7--62 to 70 inches; grayish brown (2.5Y 5/2) silty clay loam; weak medium prismatic structure; firm; few very fine roots between peds; few fine vesicular pores; few distinct dark grayish brown (2.5Y 4/2) clay films on vertical faces of peds and very few prominent black (N 2.5/0) iron-manganese oxide coatings in channels and pores; common fine prominent yellowish brown (10YR 5/6) masses of iron accumulation in the matrix; common fine and medium irregular black (7.5YR 2.5/1) masses of iron-manganese accumulation; about 38 percent clay; slightly acid; abrupt smooth boundary. (Combined thickness of the 2Btg horizon is 24 to 48 inches.)
3BCg--70 to 78 inches; variegated light brownish gray (10YR 6/2) and yellowish brown (10YR 5/8) silt loam; weak fine prismatic structure; friable; few very fine roots between peds; few distinct dark grayish brown (10YR 4/2) clay films on vertical faces of peds and very few prominent very dark grayish brown (10YR 3/2) organo-clay films lining root channels; common medium distinct strong brown (7.5YR 5/8) masses of iron accumulation in the matrix; common fine and medium black (7.5YR 2.5/1) masses of iron-manganese accumulation; about 26 percent clay; neutral; clear smooth boundary. (0 to 10 inches thick)
3CBg--78 to 94 inches; light brownish gray (10YR 6/2) silt loam; massive; friable; few very fine roots throughout; very few prominent very dark grayish brown (10YR 3/2) organo-clay films lining root channels; common fine and medium prominent strong brown (7.5YR 5/6) masses of iron accumulation in the matrix; few fine black (7.5YR 2.5/1) masses of iron-manganese accumulation; about 25 percent clay; neutral.
TYPE LOCATION: St. Clair County, Illinois; about 5 miles southeast of Mascoutah; approximately 2,500 feet west and 2,600 feet north of the southeast corner of sec. 14, T. 1 S., R. 6 W.; USGS VENEDY, ILL. topographic quadrangle; lat. 38 degrees 26 minutes 40 seconds N. and long. 89 degrees 43 minutes 54 seconds W.
RANGE IN CHARACTERISTICS: Depth to the base of the argillic horizon is 60 to more than 80 inches, and the depth to the base of soil development is more than 80 inches. Loess thickness typically is 36 inches to 70 inches. The particle-size control section averages 35 to 48 percent clay, and the maximum clay content in any subhorizon is 55 percent. Sand content of the Ap and Eg horizons is less than 15 percent, and includes iron-manganese nodules and concretions. Sand content is less than 7 percent in the particle-size control section. Some pedons contain carbonates below a depth of about 4 feet and some pedons contain krotovina. The mean annual soil temperature ranges from 56 to slightly less than 59 degrees F.
The upper part of the control section (Ap) has hue of 10YR, value of 4 or 5 (6 or 7 dry), and chroma of 1 or 2. Some undisturbed pedons have a thin A horizon with a color value of 3. Clay content is 12 to 25 percent. Reaction is strongly acid to neutral, depending on the liming history.
The second part of the control section (Eg) has hue of 10YR or 2.5Y, value of 5 or 6 (6 to 8 dry), and chroma of 1 or 2. It is silt loam or silt. Clay content is 10 to 22 percent. Reaction is very strongly acid to moderately acid when not limed. Pedons that have been limed range to neutral.
Some pedons have an EB or a BE horizon, and some pedons have a B/E horizon less than 3 inches in thickness immediately below the E horizon.
The third part of the control section (Btg) has hue of 10YR, 2.5Y, or 5Y; value of 4 to 6; and chroma of 1 or 2. Redoximorphic features have hue of 5YR, 7.5YR, 10YR, 2.5Y, 5Y, or is neutral; value of 2 to 7; and chroma of 0 to 8. It is silty clay loam or silty clay. Clay content is 35 to 48 percent in the upper part and is 27 to 42 percent in the lower part. Reaction is extremely acid to moderately acid.
The fourth part of the control section (2Btg) has hue of 10YR, 2.5Y, 5Y, or is neutral; value of 4 to 7; chroma of 0 to 2. It is stratified clay, silty clay, silty clay loam, and silt loam. Clay content ranges from 24 to 55 percent. Some pedons contain pressure faces or slickensides, and some pedons contain carbonates in the lower part. Reaction is very strongly acid to slightly alkaline.
The lower part of the control section (2BCg, 2Cg, 3BCg, 3CBg or 3Cg, where present) has hue of 7.5YR, 10YR, 2.5Y, 5Y, or is neutral; value of 4 to 7; and chroma of 0 to 2. It typically is silt loam, but is silty clay loam or silty clay in some pedons. Clay content is 20 to 45 percent and sand content is less than 15 percent. Some pedons contain carbonates, pressure faces, or slickensides. Reaction is moderately acid to moderately alkaline.
COMPETING SERIES: These are the Beckwith, Mariosa, Okaw, Pierron, Rushville, and Wynoose series.
Beckwith and Rushville soils are in areas that have a mean annual soil temperature less than 56 degrees F. Also, Rushville soils have the depth to the base of soil development at less than 60 inches. Mariosa soils have a horizon with brittleness in the lower part of the series control section. Okaw soils have less than 20 inches of loess and have more than 40 percent clay within a depth of 20 inches from the soil surface. Pierron soils have the depth to the base of soil development at less than 80 inches, and have a fine to coarse silt ratio of 1 to 1.5 in the lower part of the Btg horizons. Wynoose soils contain more than 15 percent sand, and have rock fragments in the lower part of the series control section.
GEOGRAPHIC SETTING: Floraville soils are on nearly level or slightly depressional parts of broad treads on loess-covered lacustrine terraces. Slope ranges from 0 to 2 percent. These soils formed in 36 inches to 70 inches of loess (Peoria Silt), and the underlying lacustrine sediments (Equality Formation). In some pedons the loess and the lacustrine sediments are interbedded. In some pedons, the underlying Roxana Silt is within the series control section. 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 340 to 430 feet above sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bartelso, Lakaskia, Millstadt, Redbud, and Wabash soils.
The somewhat poorly drained Bartelso and Millstadt soils are on slightly more convex parts of the lacustrine terrace. Also, Bartelso soils have a mollic epipedon. The poorly drained Lakaskia soils have a mollic epipedon and are on similar landform positions as the Floraville soils. The moderately well drained Redbud soils are on more sloping parts of the lacustrine terrace. The Lakaskia soils form a biosequence with the Floraville soils, and the Redbud and Millstadt soils form a hydrosequence with the Floraville soils. The very poorly drained Wabash soils have a mollic epipedon and are in drainageways on the lacustrine terrace.
DRAINAGE AND PERMEABILITY: Poorly drained. Permeability is very slow. The potential for surface water runoff is very low or negligble. In drained areas, depth to an intermittent perched high water table is 0.5 foot above the surface to 1.0 foot below from December to May in most years.
USE AND VEGETATION: Most areas are cropped to corn, soybeans, and small grain. A few areas are pastured or wooded. Native vegetation is mixed hardwood forest.
DISTRIBUTION AND EXTENT: Southwestern and southern Illinois. Extent is moderate, and mainly in MLRA's 113 and 114.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: St. Clair County, Illinois, 1995. The Floraville series was named for a town in St. Clair County.
REMARKS: Floraville soils were formerly included with the terrace variant of the Rushville series.
Diagnostic horizons and features recognized in this pedon are: Ochric epipedon - the zone from the surface to a depth of 18 inches (Ap and Eg horizons). Albic horizon - the zone from 9 to 18 inches (Eg horizon). Albaqualf feature - abrupt textural change from the Eg horizon to the Btg1 horizon.
Argillic horizon - the zone from approximately 18 to 70 inches (Btg1, Btg2, Btg3, Btg4, 2Btg5, 2Btg6, and 2Btg7 horizons).
Aquic conditions - periodic saturation and reduction indicated by redoximorphic features throughout the soil.
ADDITIONAL DATA: See the St. Clair County Pedon from the Glacial Lake Kaskaskia Study, Part I (S92IL-163-016, NSSL pedon number: 92P-586-3478-3491).