LOCATION TALLULA IL+IA MNEstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, mesic Typic Hapludolls
TYPICAL PEDON: Tallula silt loam - on a 10 percent slope with a southeast aspect in a pastured area. (Colors are for moist soil unless otherwise stated.
A1--0 to 4 inches; very dark grayish brown (10YR 3/2) silt loam, grayish brown (10YR 5/2) dry; strong fine granular structure; friable; common very fine roots; neutral; abrupt smooth boundary.
A2--4 to 10 inches; very dark grayish brown (10YR 3/2) silt loam, brown (10YR 5/3) dry; moderate fine and medium granular structure; friable; common very fine roots; neutral; clear smooth boundary. (Combined thickness of the A horizons is 7 to 15 inches.)
Bw1--10 to 16 inches; brown (10YR 4/3) silt loam; weak very fine and fine subangular blocky structure; friable; few very fine roots; many faint dark brown (10YR 3/3) organic coats on faces of peds; neutral; clear smooth boundary.
Bw2--16 to 26 inches; yellowish brown (10YR 5/4) silt loam; weak fine and medium subangular blocky structure; friable; few very fine roots; common faint brown (10YR 4/3) coatings on faces of peds; neutral; clear smooth boundary. (Combined thickness of the Bw horizons is 5 to 22 inches thick.)
C1--26 to 31 inches; pale brown (10YR 6/3) silt loam; many medium distinct yellowish brown (10YR 5/6) mottles; massive; friable; few very fine roots; slight effervescence; mildly alkaline; clear smooth boundary.
C2--31 to 60 inches; light brownish gray (10YR 6/2) silt; many medium and coarse distinct yellowish brown (10YR 5/6) mottles; massive; friable; few very fine roots; few fine concretions (calcium carbonate); few fine dark accumulations (iron and manganese oxides); slight effervescence; mildly alkaline.
TYPE LOCATION: Cass County, Illinois; about 1 mile northwest of Virginia; 1330 feet south and 154 feet east of the northwest corner of sec. 4, T. 17 N., R. 10 W.
RANGE IN CHARACTERISTICS: The solum thickness and depth to free carbonates commonly are 20 to 30 inches, but range from 15 to 35 inches. The mollic epipedon commonly is 7 to 15 inches in thickness.
The A horizon has hue of 10YR, value of 2 or 3 (4 or 5 dry), and chroma of 1 through 3. It is neutral or mildly alkaline.
The Bw horizon has hue of 10YR, value of 4 or 5, and chroma of 3 or 4. It is neutral or mildly alkaline
The C horizon has hue 10YR, value of 5 or 6, and chroma of 2 through 6. It is silt loam or silt. It is mildly alkaline or moderately alkaline and is calcareous.
COMPETING SERIES: These are the Gagetown and Grogan series in the same family and the Bold, Port Byron, and Timula series. Gagetown soils have thinner sola. Grogan soils contain more sand in the 10 to 40 inch control section, having formed in lacustrine sediments. Bold and Timula soils do not have a mollic epipedon. In addition, Bold soils do not have a cambic horizon, and they contain free carbonates throughout. Port Byron soils have a thicker solum and are fine-silty.
GEOGRAPHIC SETTING: Tallula soils are on side slopes of uplands. Slopes range from 2 to 30 percent. The soils formed in loess. Mean annual temperature varies from 45 to 53 degrees F, and mean annual precipitation varies from 28 to 36 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Bold and Port Byron soils and the Elkhart and Tama soils. Bold soils are downslope from the Tallula soils, or are on similar parts of the landscape nearby. The fine-silty Port Byron, Elkhart, and Tama soils are on nearby landscapes typically upslope from the Tallula soils or on the crests of interstream divides.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is medium to rapid. Permeability is moderate.
USE AND VEGETATION: The less sloping areas are used for corn, soybeans, small grain, and meadow; the steeper slopes are used for pasture. Native vegetation was prairie grasses.
DISTRIBUTION AND EXTENT: Illinois, Minnesota, and Iowa. These soils have small extent.
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Cass County, Illinois, 1939.
REMARKS: These soils were previously called well drained and moderately well drained. The mottles in the C horizon are believed to be unrelated to present drainage conditions. These soils do not have a water table above a depth of 6 feet for 30 consecutive days.
Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface to a depth of 10 inches (A1 and A2 horizons); cambic horizon - the zone from approximately 10 to 26 inches (Bw1 and Bw2 horizons).