Sumter Series

The Sumter series consists of moderately deep, well drained soils that formed in materials weathered from alkaline clays and soft limestone (chalk). These soils are on side slopes in uplands of the Blackland Prairie. Slopes range from 5 to 25 percent. These soils are fine-silty, carbonatic, thermic Rendollic Eutrochrepts.

Sumter soils are commonly associated on the landscape with Hannon soils. Hannon soils are in slightly higher positions than those of the Sumter soils. They have a reddish argillic horizon and are acid in the upper part of the subsoil.

Typical pedon of Sumter silty clay loam, in an area of Sumter-Hannon complex, 12 to 25 percent slopes, severely eroded; about 5 miles south of Marvyn, 1,800 feet east and 2,000 feet north of the southwest corner of sec. 12, T. 16 N., R. 26 E.

• Ap—0 to 3 inches; very dark grayish brown (2.5Y 3/2) silty clay loam; weak coarse granular structure; firm; many fine roots; common fragments of fossil oyster shell; common fine soft masses of calcium carbonate; strongly effervescent; moderately alkaline; clear wavy boundary.
• Bk1—3 to 21 inches; pale olive (5Y 6/4) silty clay loam; moderate medium subangular blocky structure; firm; few fine and medium roots; few fine fragments of soft limestone (chalk); many fine, medium, and coarse soft masses of calcium carbonate; strongly effervescent; moderately alkaline; gradual wavy boundary.
• Bk2—21 to 28 inches; light olive brown (2.5Y 5/4) silty clay loam; moderate medium subangular blocky structure; firm; few fine roots; common fine fragments of soft limestone (chalk); few fossil oyster shells; many fine, medium, and coarse soft masses of calcium carbonate; strongly effervescent; moderately alkaline; clear wavy boundary.
• Bk3—28 to 38 inches; light olive brown (2.5Y 5/6) silty clay loam; moderate medium subangular blocky structure; firm; common fine fragments of soft limestone (chalk); few fossil oyster shells; many fine, medium, and coarse soft masses of calcium carbonate; common medium distinct pale olive (5Y 6/3) iron depletions; strongly effervescent; moderately alkaline; clear wavy boundary.
• Cr—38 to 80 inches; weathered, soft limestone (chalk) bedrock; massive; very firm; common thin strata of fossil oyster shell; violently effervescent; moderately alkaline.

The thickness of the solum and depth to soft bedrock ranges from 20 to 40 inches. Reaction is slightly alkaline or moderately alkaline throughout the profile.

The A horizon has hue of 10YR or 2.5Y, value of 3 or 4, and chroma of 1 or 2. The texture is silty clay loam or silty clay.

The Bk horizon has hue of 2.5Y or 5Y, value of 4 to 7, and chroma of 3 to 6. It has common or many soft masses or concretions or both of calcium carbonate. The texture is silty clay loam, silty clay, or clay.

The Cr horizon is weathered, soft limestone (chalk) bedrock. It is massive or has thick platy rock structure. It can be cut with difficulty using hand tools and is rippable by heavy equipment. In most pedons it has strata of fossil oyster shell. These strata range in thickness from a few inches to a few feet.

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