LOCATION TRIMBLE KY+TNEstablished Series
TAXONOMIC CLASS: Fine-loamy, siliceous, semiactive, mesic Typic Paleudults
TYPICAL PEDON: Trimble gravelly silt loam--cultivated. (Colors are for moist soils unless otherwise stated.)
Ap--0 to 7 inches; dark grayish brown (10YR 4/2) gravelly silt loam; weak fine granular structure; very friable; many roots; 25 percent chert fragments; a few fragments of siltstone; strongly acid; abrupt smooth boundary. (5 to 9 inches thick)
BA--7 to 16 inches; yellowish brown (10YR 5/6 5/4) gravelly silt loam; weak fine and very fine subangular blocky structure; friable; common fine roots; few thin clay films on pores and root channels; 20 percent chert fragments; a few fragments of siltstone; very strongly acid; gradual wavy boundary. (0 to 15 inches thick)
Bt1--16 to 46 inches; strong brown (7.5YR 5/6) gravelly silty clay loam; moderate fine subangular blocky structure; friable; few fine roots; few thin clay films on peds and in pores and root channels; 30 percent chert fragments; a few fragments of siltstone; very strongly acid; gradual wavy boundary.
Bt2--46 to 68 inches; mottled yellowish brown (10YR 5/6), pale brown (10YR 6/3) and light gray (10YR 6/1) gravelly silt loam; weak fine subangular blocky structure; friable; few thin clay films on faces of peds and in pores; 30 percent chert fragments; a few fragments of sandstone and siltstone; very strongly acid. (Combined thickness of the Bt horizon is 36 to more than 70 inches)
TYPE LOCATION: Pulaski County, Kentucky; 12 1/2 miles northeast of Somerset on north side of road, 5400 feet due east of Hazeldell Church and 500 feet northeast of confluence of Rocky Branch and Clifty Creek.
RANGE IN CHARACTERISTICS: Thickness of the solum ranges from 60 to more than 72 inches. Depth to bedrock ranges from 60 to to more than 100 inches. The soil ranges from extremely acid to medium acid, Rock fragments are mostly chert, but may include limestone and sandstone fragments and are mostly gravel or cobble size. Content of rock fragments ranges from 10 to 50 percent in individual horizons but the particle-size control section averages less than 35 percent.
The Ap horizon has hue of 10YR or 7.5YR, values of 4 to 6, and chroma of 2 to 4. Some wooded areas have thin A horizons with value of 3 and chroma of 0 to 1. Texture of the fine earth is silt loam or loam.
Some pedons have AB or E horizons with colors and textures similar to the Ap or A horizon.
The BA horizon has hue of 10YR or 7.5YR, value of 4 to 6, and chroma of 4 to 8. Texture of the fine earth is silt loam, silty clay loam, or loam.
The Bt horizon has hue that is dominantly 10YR or 7.5YR but ranges to 5YR, value of 4 to 6, and chroma of 4 to 8. Some pedons have subhorizons with hue of 5YR. The lower part of the Bt horizon may have few to many mottles in shades of brown, gray, or red. Texture of the fine earth is silt loam, silty clay loam, loam, or clay loam. Some pedons may have subhorizons with texture of clay.
Some pedons have BC or C horizons with colors and textures similar to the lower part of the Bt horizon.
COMPETING SERIES: These are the Brocket, Claiborne, and Nolichucky series. Brocket soils have loam, sandy clay loam, or clay loam Bt horizons with less than 15 percent sandstone fragments. Claiborne and Nolichucky soils have Bt horizons with hue that are mostly 2.5YR. Nolichucky soils form in alliuium direct from sandstone, shale, quartzite, and limestone rocks.
GEOGRAPHIC SETTING: Trimble soils occupy narrow ridgetops, sideslopes, and toeslopes. These soils are developed in a regolith from cherty limestone but in some areas it is interbedded with siltstone or fine grained sandstone. Slopes range from 2 to 45 percent. At the type location, average annual precipitation is 49 inches and mean annual air temperature is 56 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Baxter, Bedford, Bewleyville, Caneyville, Frederick, Garmon, Tarklin, and Waynesboro series. Baxter, Frederick, and Waynesboro soils have B2 horizons with more than 35 percent clay. Bedford and Tarklin soils have fragipans. Bewleyville soils have less than 15 percent chert in the upper solum. Caneyville and Garmon soils have bedrock at less than 40 inches.
DRAINAGE AND PERMEABILITY: Well drained with medium runoff and moderate permeability.
USE AND VEGETATION: Most cleared areas are used for pasture and hay. Many of the steeper slopes are in forest. Native vegetation is oak, hickory, ash, elm, maple, beech, dogwood, cedar, and pine.
DISTRIBUTION AND EXTENT: The Mississipian Plateau region of Kentucky and northern part of Great Valley in East Tennessee. Total extent is large.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: Pulaski County, Kentucky, 1969.
REMARKS: These soils previously were mapped as Clarksville, Frankstown, and Humphreys series.
Diagnostic horizons and features recognized in this pedon are:
a. Ochric horizon, the part from 0 to 7 inches (Ap)
b. Agrillic horizon, the part from 16 to 68 inches (Bt1, Bt2)