LOCATION BRAXTON TN+AL KYEstablished Series
TAXONOMIC CLASS: Fine, mixed, active, thermic Typic Paleudalfs
TYPICAL PEDON: Braxton gravelly silt loam--cultivated. (Colors are for moist soil)
Ap--0 to 6 inches; dark brown (7.5YR 3/2) gravelly silt loam; moderate medium granular structure; friable; many fine roots; about 18 percent fragments of chert up to 3 inches across; strongly acid; clear smooth boundary. (4 to 8 inches thick)
Bt1--6 to 14 inches; reddish brown (5YR 4/4) clay; few streaks and coatings of dark brown (7.5YR 3/2) clay; moderate medium subangular blocky structure; firm; many fine roots; few faint clay films on faces of peds; about 14 percent fragments of chert up to 3 inches across; strongly acid; gradual smooth boundary.
Bt2--14 to 24 inches; yellowish red (5YR 4/6) clay; few streaks of brown (10YR 4/3) along old root channels; moderate medium subangular blocky structure; firm, few distinct clay films on faces of peds; about 10 percent fragments of chert up to 3 inches across; strongly acid; clear wavy boundary.
Bt3--24 to 36 inches; strong brown (7.5YR 5/6) clay; moderate medium angular blocky structure; very firm; common distinct clay films on faces of peds; few small black concretions, about 2 percent fragments of chert; strongly acid; gradual smooth boundary.
Bt4--36 to 65 inches; strong brown (7.5YR 5/6) clay, few fine and medium prominent pale brown (10YR 6/3) mottles; moderate fine angular blocky structure; very firm; few distinct clay films on faces of peds; common fine black concretions; strongly acid; gradual smooth boundary. (Combined thickness of the Bt horizons ranges from 50 to 80 inches or more.)
C--65 to 80 inches; brown (7.5YR 4/4) clay; massive; very firm; many fine black concretions; strongly acid. (0 to 18 inches thick)
R--80 inches; phosphatic limestone rock.
TYPE LOCATION: Williamson County, Tennessee; 2 miles east of Arrington on Adams Farm; 50 yards north of east-west gravel road on top of hill.
RANGE IN CHARACTERISTICS: Solum thickness and depth to bedrock range from 60 to 80 inches or more. Fragments of chert in the Ap horizon range from none to as much as 30 percent. Fragments of chert in the Bt horizons range from none to about 15 percent. The soil is strongly acid to moderately acid throughout except that the horizon above the bedrock is only slightly acid in some pedons. Base saturation ranges from 35 to about 50 percent. Transition horizons have colors and texture similar to adjacent horizons.
The A or Ap horizon has hue of 5YR, 7.5YR or 10YR, value of 3 to 5 and chroma of 2 to 4. Severely eroded areas also have chroma of 6. Pedons with value of 3 and chroma of 2 are less than 7 inches thick. The fine earth texture is silt loam, loam, or silty clay loam.
Some pedons have A and E horizons or transitional horizon that formed in loamy colluvium from sandstone and have loam texture.
The Bt horizon has hue of 7.5YR to 2.5YR, value of 4 or 5 and chroma of 4 to 8. Texture of the Bt horizon is silty clay or clay except the upper few inches in some pedons is silty clay loam. Most pedons have mottles in shades of red or brown in the lower part.
The C horizon has colors and texture similar to the lower part of the Bt horizon. Mottles in shades of brown, yellow and red ranges from none to common.
COMPETING SERIES: These are the Boxville series in the same family. Similar soils are the Capshaw, Dewey, Hampshire, Mimosa, and Talbott series. Boxville soils have more than 60 percent base saturation. Capshaw and Hampshire soils have a solum thickness of less than 60 inches. Dewey soils have base saturation less than 35 percent and kaolinitic mineralogy. Mimosa and Talbott soils have sola less than 60 inches thick over hard bedrock.
GEOGRAPHIC SETTING: These soils are on undulating to hilly uplands and high terraces. Slopes range from about 2 to 50 percent. They formed in old clayey alluvium or valley fill and residuum weathered from limestone. Near the type location, the average annual temperature is about 60 degrees F., and average annual precipitation is about 49 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the similar Hampshire and Mimosa series and the Armour, Maury and Stiversville series. Armour and Stiversville soils are fine-loamy. Maury soils are mesic.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.
USE AND VEGETATION: Most of the soil is cleared and used largely for growing hay and pasture. A few areas are used for growing corn, tobacco, cotton, and small grains. The native vegetation was mixed hardwood forest.
DISTRIBUTION AND EXTENT: The Central Basin in Tennessee and possibly the inner bluegrass region of Kentucky. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: Mercer County, Kentucky; 1930.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - from 0 to about 6 inches (Ap horizon).
Argillic horizon - the zone from about 6 to 65 inches (Bt horizon).