Established Series


The Cynthiana series consists of shallow, well drained to somewhat excessively drained soils with moderately slow permeability. They formed in residuum from limestone or interbedded limestone and calcareous shale. Most areas are hilly and slopes range from 6 to 60 percent. The average annual precipitation is about 46 inches and the average annual air temperature is about 56 degrees F.

TAXONOMIC CLASS: Clayey, mixed, active, mesic Lithic Hapludalfs

TYPICAL PEDON: Cynthiana silt loam--on a 10 percent concave slope in pasture. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 4 inches; dark grayish brown (10YR 4/2) silt loam, light brownish gray (10YR 6/2) dry; weak fine granular structure; friable; common roots; 5 percent flagstones; few small black concretions; slightly acid; clear smooth boundary. (2 to 6 inches thick)

Bt--4 to 18 inches; yellowish brown (10YR 5/4) flaggy silty clay; moderate medium angular blocky structure; firm, sticky, plastic; common roots; common clay films; 15 percent flagstones; common small black concretions; neutral. (8 to 16 inches thick)

R--18 inches; limestone, interbedded with calcareous shale.

TYPE LOCATION: Harrison County, Kentucky; at northeast corner of intersection of Renaker-Robinson Pike and Lafferty Pike.

RANGE IN CHARACTERISTICS: Solum thickness and depth to bedrock ranges from 10 to 20 inches. Reaction ranges from medium acid through mildly alkaline. Thin flat, limestone and shale fragments from 1 to 15 inches across ranges from 0 to 40 percent in the A horizon and from 5 to 45 percent in the B and C horizons. The weighted average of coarse fragments in the particle size control section is less than 35 percent. Fragments are commonly channery or flaggy.

The Ap or A1 horizon has hue of 10YR or 2.5Y, value of 4 or 5, and chroma of 2 through 4; some pedons have A1 horizons less than 4 inches thick with color value less than 3.5; texture of the fine earth is silt loam, silty clay loam or clay loam. Structure is weak or moderate, very fine to medium, granular or subangular blocky.

Where present, the AB or BA horizons have hue of 10YR or 2.5Y, value of 4 or 5, and chroma of 2 through 6. Thickness ranges from 0 to 6 inches. Texture is silt loam, silty clay loam, or silty clay.

The Bt horizon has hue of 10YR through 5Y, value of 4 or 5, and chroma of 4 through 6. Texture of the fine earth is silty clay or clay; structure is weak to strong, very fine to medium, angular blocky; some pedons have mottles in shades of brown or olive.

Where present, C horizons 3 to 10 inches thick, have matrix and mottle colors in shades of brown, olive, or gray. Texture of the fine earth in silty clay or clay.

COMPETING SERIES: These are the Opequon series in the same family and the Caneyville, Corydon, Eden, Fairmount, and Faywood series in related families. Opequon soils have B horizons with hue of 7.5YR or redder. Caneyville, Eden, and Faywood soils have bedrock at depths greater than 20 inches. Corydon and Fairmount soils have mollic epipedons.

GEOGRAPHIC SETTING: The soil is mostly on hills. They have slopes of about 6 to 60 percent. Some areas have karst topography. The soil formed in residuum weathered from limestone or interbedded limestone and calcareous shale. Average annual precipitation ranges from 44 to 48 inches, and average annual air temperature from 50 degrees to 57 degrees F.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Faywood and Lowell soils. Faywood soils are 20 to 40 inches deep over bedrock and Lowell soils are more than 40 inches to bedrock. Other associates are the competing Eden and Fairmount soils. Many areas are associated with rock outcrops.

DRAINAGE AND PERMEABILITY: Well drained to somewhat excessively drained; rapid runoff; moderately slow permeability.

USE AND VEGETATION: Most of the soil is in pasture, hay, or forest, and some are in brush. The original forest vegetation was elm, hackberry, red bud, black and honey locust, Kentucky coffee-tree, black walnut, ash, oaks, hickory, and yaupon, and in places, red cedar.

DISTRIBUTION AND EXTENT: Kentucky, Tennessee, and possibly Indiana. Total extent is large.


SERIES ESTABLISHED: Harrison County, Kentucky; 1965.

REMARKS: Diagnostic horizons and features recognized in the typical pedon are:

Ochric epipedon - the zone from 0 to 4 inches (Ap).

Argillic horizon - the zone from 4 to 18 inches (Bt).

Lithic contact - at 18 inches (R).

National Cooperative Soil Survey