LOCATION SUMTER AL+AR FL GA LA MS OK TN TXEstablished Series
TAXONOMIC CLASS: Fine-silty, carbonatic, thermic Rendollic Eutrudepts
TYPICAL PEDON: Sumter silty clay on a convex 3 percent slope in pasture. (Colors are for moist soil.)
Ap--0 to 6 inches; grayish brown (2.5Y 5/2) silty clay; moderate medium granular structure; friable, plastic, slightly hard; common fine roots; moderately alkaline; strongly effervescent; clear smooth boundary. (4 to 10 inches thick)
Bw1--6 to 10 inches; light yellowish brown (2.5Y 6/4) and grayish brown (2.5Y 5/2) silty clay; moderate medium granular structure; friable, plastic, hard; few fine roots; moderately alkaline; strongly effervescent; gradual wavy boundary.
Bw2--10 to 21 inches; light yellowish brown (2.5Y 6/4) silty clay; few fine distinct brownish yellow (10YR 6/6) mottles; moderate fine subangular blocky structure; friable, plastic, hard; few fine roots; few fine soft calcium carbonate nodules; moderately alkaline; strongly effervescent; gradual wavy boundary.
Bw3--21 to 28 inches; light yellowish brown (2.5Y 6/4) silty clay; common medium distinct light gray (2.5Y 7/2), and yellow (2.5Y 7/6) mottles; moderate fine subangular blocky structure; friable, slightly plastic, hard; few fine soft calcium carbonate nodules; few partially weathered platy fragments of chalk; moderately alkaline; strongly effervescent; gradual wavy boundary. (Combined thickness of the Bw horizon is 14 to 36 inches.)
Cr--28 to 60 inches; light gray (2.5Y 7/2) chalk; mottles and streaks of pale yellow (2.5Y 7/4) yellowish brown (10YR 5/8), white (5Y 8/1), and light olive gray (5Y 6/2) along cracks and seams; moderately alkaline, violently effervescent.
TYPE LOCATION: Dallas County, Alabama; 0.6 mile west of the Black Belt Substation office, 1000 feet east and 75 feet north of the SE corner of the SW1/4, sec. 2, T. 17 N., R. 8 E.
RANGE IN CHARACTERISTICS: Solum thickness and depth to chalk or marly clay ranges from 20 to 40 inches. The calcium carbonate equivalent ranges from 40 to 65 percent. Non-carbonatic clay content ranges from 18 to 35 percent.
The A horizon has hue of 10YR to 5Y, value of 2 to 5, and chroma of 1 or 2. Texture is silt loam, silty clay loam, silty clay, or clay with up to 10 percent by volume of chalk fragments or calcium carbonate nodules 2 mm to 10 mm in size. Some pedons have cobbly or very cobbly silt loam or silty clay loam surface layers with 7 to 74 percent by volume of cobbles 3 to 10 inches in size and 4 to 15 percent by volume of chalk fragments or calcium carbonate nodules smaller than 3 inches. Reaction is neutral to moderately alkaline.
The upper part of the Bw horizon has hue of 10YR to 5Y, value of 4 to 7, and chroma of 3 to 6. Texture is silty clay loam, silty clay, or clay with 2 to 15 percent by volume of chalk fragments and/or calcium carbonate nodules. Reaction is mildly alkaline or moderately alkaline.
The lower part of the Bw horizon and the BC horizon, where present, has hue of 10YR to 5Y, value of 5 to 7, and chroma of 3 to 6. Texture is silty clay loam, silty clay, or clay or their channery analogues with 2 to 25 percent by volume of chalk fragments and/or calcium carbonate nodules. Reaction is mildly alkaline or moderately alkaline.
COMPETING SERIES: There are no other series in this family. Brassfield soils are similar but have mean annual soil temperatures of less than 59 degrees F. and have more than 15 percent sand coarser than very fine sand in the sola.
GEOGRAPHIC SETTING: Sumter soils are on sloping topography in the Blackland Prairie, but slopes range to steep at its contact with the Southern Coastal Plain. Slopes range from 1 to 40 percent. Sumter soils are formed in marly clays and chalk. The climate is warm-humid. Average annual temperature is about 67 degrees F. and average annual precipitation is about 51 inches near the type location.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Binnsville, Brooksville, Demopolis, Houston, Kipling, Maytag, Okolona, Oktibbeha, Vaiden, and Watsonia series. Binnsville, Demopolis, and Watsonia soils have sola less than 20 inches thick. Brooksville, Houston, and Okolona soils are thicker over chalk and the calcium carbonate content is less than 40 percent. Kipling, Oktibbeha, and Vaiden soils have sola that are acid and more plastic and sticky. Maytag soils, on gentler slopes, have vertic properties and montmorillonitic mineralogy.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; slow permeability.
USE AND VEGETATION: Most of the less sloping areas of this soil
are cleared and used for growing pasture, hay, and small grain. Some areas are in redcedar. Steeper areas are in native woodland, mainly oaks and redcedar.
DISTRIBUTION AND EXTENT: Blackland Prairies of Alabama, Arkansas, Georgia, Louisiana, Mississippi, and eastern Texas. The series is of large extent.
MLRA OFFICE RESPONSIBLE: Auburn, Alabama
SERIES ESTABLISHED: Sumter County, Georgia; 1910.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone form the surface to a depth of about 6 inches (Ap horizon).
Cambic horizon - the zone from about 6 inches to a depth of 28 inches (Bw1, Bw2, Bw3 horizons).
Rendollic features - have greater that 40 percent carbonates in and below the cambic horizon.