LOCATION SYLVAN IL&INEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Typic Hapludalfs
TYPICAL PEDON: Sylvan silt loam on a southwest facing, convex side slope with a gradient of 27 percent in a wooded area at an elevation of 620 feet. (Colors are for moist soil unless otherwise stated.)
A--0 to 4 inches; dark grayish brown (10YR 4/2) silt loam, brown (10YR 5/3) dry; weak fine and medium subangular blocky structure parting to weak fine granular; friable; common very fine roots; few faint very dark grayish brown (10YR 3/2) organic coats on faces of peds; neutral; clear smooth boundary. (3 to 6 inches thick)
E1--4 to 8 inches; dark brown (10YR 4/3) silt loam, pale brown (10YR 6/3) dry; weak medium platy structure parting to weak fine subangular blocky; friable; few very fine and medium roots; many faint dark grayish brown (10YR 4/2) organic coats on faces of peds; moderately acid; clear smooth boundary.
E2--8 to 10 inches; dark yellowish brown (10YR 4/4) silt loam, light yellowish brown (10YR 6/4) dry; weak fine and medium subangular blocky structure; friable; few very fine roots; common distinct dark grayish brown (10YR 4/2) organic coats on faces of peds; slightly acid; clear smooth boundary. (Combined thickness of the E horizon is 0 to 10 inches.)
Bt1--10 to 17 inches; dark yellowish brown (10YR 4/4) silty clay loam; weak fine subangular blocky structure; friable; few very fine roots; common distinct brown (10YR 4/3) clay films on faces of peds; slightly acid; clear smooth boundary.
Bt2--17 to 23 inches; yellowish brown (10YR 5/6) silty clay loam; moderate fine angular and subangular blocky structure; friable; few very fine and medium roots; many distinct dark yellowish brown (10YR 4/4) and few distinct brown (10YR 4/3) clay films on faces of peds; slightly acid; clear smooth boundary. (Combined thickness of the Bt horizon is 9 to 30 inches.)
BCt--23 to 27 inches; yellowish brown (10YR 5/6) silt loam; weak fine and medium subangular blocky structure; friable; few very fine roots; few distinct dark yellowish brown (10YR 4/4) clay films lining pores; neutral; clear smooth boundary. (0 to 9 inches thick)
C1--27 to 41 inches; 80 percent yellowish brown (10YR 5/6) and 20 percent light brownish gray (10YR 6/2) silt loam; massive; friable; few very fine roots; the light brownish gray matrix color is a relict feature; few fine and medium snail shells; strongly effervescent; slightly alkaline; clear smooth boundary.
C2--41 to 64 inches; 60 percent light brownish gray (10YR 6/2) and 40 percent yellowish brown (10YR 5/6) silt loam; massive; friable; few very fine roots; the light brownish gray matrix color is a relict feature; common fine and medium snail shells; strongly effervescent; moderately alkaline; clear smooth boundary.
Cg--64 to 80 inches; 55 percent light brownish gray (10YR 6/2) and 45 percent yellowish brown (10YR 5/6) silt loam; massive; friable; common medium prominent irregular reddish yellow (7.5YR 6/8) and few fine prominent irregular strong brown (7.5YR 4/6) masses of iron oxides with diffuse boundaries lining pores; common fine and medium snail shells; strongly effervescent; moderately alkaline.
TYPE LOCATION: Cass County, Illinois; about 2 miles north and 1 mile west of Virginia; 210 feet south and 2,580 feet west of the northeast corner of sec. 28, T. 18 N., R. 10 W.; USGS Virginia, IL. topographic quadrangle; lat. 39 degrees 59 minutes 22 seconds N. and long. 90 degrees 13 minutes 43 seconds W.
RANGE IN CHARACTERISTICS: The depth to the base of the argillic horizon is typically 22 to 35 inches, but ranges to 40 inches in some pedons. The depth to carbonates is 22 to 40 inches and the BC horizon contains free carbonates in some pedons. Relict redoximorphic masses with chroma of 2 or less are in pedons where the soil formed in deoxidized loess. Loess thickness typically is greater than 60 inches. The particle-size control section averages between 25 and 35 percent clay and less than 15 percent sand.
The upper part of the control section (Ap, A, and/or E horizons) has properties as follows: The Ap horizon has a color value of 4 to 6 (6 or 7 dry), and chroma of 2 to 4. Uncultivated areas have an A horizon 2 to 6 inches thick with value of 3 to 5 (5 or 6 dry), and chroma of 2 or 3. The Ap or A horizon commonly is silt loam, except some eroded pedons are silty clay loam. Clay content ranges from 18 to 32 percent. Reaction is moderately acid to neutral.
The E horizon has hue of 10YR, value of 4 or 5, (5 or 6 dry) and chroma of 2 to 4. Clay content ranges from 15 to 25 percent. Reaction is commonly moderately acid or slightly acid, but ranges to neutral in some pedons. In cultivated areas the E is commonly mixed with the Ap horizon. Some pedons have an EB or BE horizon.
The middle part of the control section (Bt horizon) has hue of 10YR or 7.5YR, value of 4 or 5, and chroma of 3 to 6. The Bt horizon typically is silty clay loam, but some pedons contain silt loam subhorizons. Clay content ranges from 25 to 35 percent. Reaction ranges from moderately acid to neutral.
The BCt or BC horizon, where present, has colors in the range as defined for the Bt horizon. It is typically silt loam or less commonly silty clay loam. Clay content ranges from 25 to 35 percent. Reaction ranges from moderately acid to slightly alkaline.
The lower part of the control section (C and/or Cg horizon) has hue of 10YR or 2.5Y, value of 4 to 6, and chroma of 2 to 6. Redoximorphic masses of iron oxides with hue of 10YR or 7.5YR, value of 4 or 6, and chroma of 4 through 8, are present below depths of 40 inches. The C horizon is silt loam or silt. Clay content ranges from 10 to 27 percent. Reaction is neutral to moderately alkaline.
COMPETING SERIES: These are the Baraboo, Bertrand, Blackhammer, Cadiz, Camden, Dodge, Dubuque, Fayette, Flagg, Hackers, Jackson, Jemerson, Knowles, La Farge, Lomira, Marseilles, Martinsburg, Mayville, Menfro, Mentor, Minnith, Palsgrove, Ridgeway, Rush, Russell, Sandview, Seaton, Uniontown, Weingarten, Westbent, Westmore, Yellowriver, and Aurich series. Baraboo, Dubuque, Knowles, La Farge, and Marseilles soils have a lithic or paralithic contact within a depth of 40 inches. Bertrand, Blackhammer, Camden, Dodge, Flagg, Jackson, Lomira, Mayville, Minnith, Ridgeway, Rush, Russell, and Zurich soils have subhorizons in the lower part of the control section that have more than 15 percent sand. Cadiz soils have subhorizons in the lower part of the control section that have more than 5 percent rock fragments. Fayette, Jemerson, Martinsburg, and Seaton soils have the base of the argillic horizon and free carbonates at depths greater than 40 inches. Hackers soils have hue redder than 7.5YR in at least one subhorizon of the lower part of the control section. Menfro, Mentor, and Yellowriver soils have free carbonates at depths greater than 40 inches. Palsgrove, Sandview, Weingarten and Westmore soils have more than 35 percent clay in the lower part of the control section. In addition, Palsgrove soils have a lithic contact in the lower part of the control section. Uniontown soils have redoximorphic features in the middle part of the control section. Westbend soils have a paralithic contact within a depth of 60 inches.
GEOGRAPHIC SETTING: Sylvan soils are on convex side slopes on till plains and risers on stream terraces. Slopes range from 2 to 60 percent on till plains and from 2 to 10 percent on the stream terraces. Sylvan soils formed in 5 to more than 20 feet of calcareous loess. Mean annual temperature ranges from 45 to 57 degrees F, mean annual precipitation ranges from 30 to 45 inches, frost free days range from 140 to 200 days, and elevation ranges from 350 feet to 1350 feet above sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are Fayette, Menfro, Bold, Hamburg, Hickory, Iona, Rozetta, and Timula soils. The Bold and Timula soils average less than 18 percent clay in the particle-size control section, and are on similar landforms. The Fayette, and Menfro soils are on nearby landforms typically upslope, and have free carbonates at depths greater than 40 inches. The somewhat excessively drained Hamburg soils average less than 18 percent clay in the particle-size control section and are on side slopes on bluffs above Sylvan soils. The Hickory soils average more than 15 percent sand in the particle-size control section, formed in till, and are downslope from the Sylvan soils. The moderately well drained Iona and Rozetta soils are upslope from the Sylvan soils.
DRAINAGE AND PERMEABILITY: Well drained.(See Remarks). Surface runoff is medium to rapid. Permeability is moderate. The seasonal high water table is more than six feet below the surface in the spring.
USE AND VEGETATION: The steeper slopes are wooded or used for pasture. The less sloping areas are used for corn, soybean, small grain, and forages. Native vegetation is hardwood forest.
DISTRIBUTION AND EXTENT: Illinois and Indiana. These soils have large extent in MLRA's 105, 108 and 115.
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Cass County, Illinois, 1939.
REMARKS: Extent of moderately well drained profiles is small. The moderately wet phase (IL0362) will probably be correlated as a different series when the subset soil surveys in which it occurs are updated.
Diagnostic horizons and features recognized in this pedon are: Ochric epipedon - the zone from the surface to a depth of approximately 10 inches (A and E horizons). Argillic horizon - the zone from approximately 10 to 23 inches. (Bt1 and Bt2 horizons). Udic moisture regime.
ADDITIONAL DATA: Particle-size data are on file for several pedons of the Sylvan soils at the NRCS MLRA Region 11.