LOCATION CURTISTOWN TNEstablished Series
TAXONOMIC CLASS: Fine-silty, siliceous, semiactive, thermic Typic Paleudults
TYPICAL PEDON: Curtistown silt loam - cultivated.
(Colors are for moist soil unless otherwise stated.)
Ap--0 to 8 inches; dark brown (7.5YR 3/2) silt loam; moderate fine granular structure; friable; many fine roots; slightly acid; abrupt smooth boundary. (6 to 12 inches thick)
Bt1--8 to 17 inches; yellowish red (5YR 4/6) silty clay loam; moderate medium subangular blocky structure; friable; common fine roots; few faint clay films on faces of peds; few fine dark brown concretions; strongly acid; clear smooth boundary.
Bt2--17 to 28 inches; red (2.5YR 4/6) silty clay loam; moderate medium subangular blocky structure; friable; common fine roots; common distinct clay films on faces of peds and in pores; few dark brown concretions; strongly acid; gradual wavy boundary.
Bt3--28 to 38 inches; dark red (2.5YR 3/6) silty clay loam; strong medium and fine subangular blocky structure; firm; common distinct clay films on faces of peds; few dark brown concretions; strongly acid; gradual wavy boundary.
2Bt4--38 to 55 inches; dark red (2.5YR 3/6) clay; strong medium and fine subangular blocky structure; firm; common distinct clay films on faces of peds; strongly acid; gradual wavy boundary.
2Bt5--55 to 75 inches; dark red (2.5YR 3/6) clay, few medium distinct brown (7.5YR 5/4) mottles; strong fine subangular blocky structure; firm; clay films on faces of peds; strongly acid; gradual wavy boundary. Combined thickness of the Bt horizons ranges from 50 to more than 80 inches.)
TYPE LOCATION: White County, Tennessee; 1 mile south of Walnut Grove Church; 100 yards northeast of cemetery.
RANGE IN CHARACTERISTICS: Thickness of the solum is more than 60 inches. The soil is strongly acid or very strongly acid in each horizon except the surface layer where limed.
The A or Ap horizon has hue of 7.5YR or 10YR, value of 3 and chroma of 2 or 3. Texture is silt loam or, where severely eroded, silty clay loam.
The Bt horizons have hue of 7.5YR, 5YR, or 2.5YR, value of 3 or 4, and chroma of 3, 4, or 6. The darker colors are in the lower part. Texture is silty clay loam in the upper part and clay or silty clay in the lower part.
COMPETING SERIES: These are Blevins, Crider, Etowah, Mountview, Pembroke and Pickwick series. Blevins soils have yellowish brown and brownish yellow B horizons and high content of very fine sand. Crider and Pembroke soils have base saturation greater than 35 percent and soil temperature less than 59 degrees F. Etowah soils have more than 15 percent fine and coarser sand including coarse fragments in the B horizon. Mountview soils have yellowish brown or strong brown colors in the upper part of the B horizon. Pickwick soils have greater than 10 percent weatherable minerals in the B horizon.
GEOGRAPHIC SETTING: Curtistown soils are on broad, nearly level to sloping uplands. Slopes range from 0 to 10 percent. The soils formed in a mixture of loess and old alluvium in the upper part, and old alluvium in the lower part. Bedrock is limestone. Near the type location, mean annual temperature is 59 degrees F., and mean annual precipitation is 51 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Mountview series and the Emory, Decatur and Waynesboro series. Decatur and Waynesboro soils are clayey. Emory soils do not have argillic horizons and are in depressions and along drainageways.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderate permeability.
USE AND VEGETATION: Nearly all of this soil is used for farm crops including corn, alfalfa, small grains, tobacco, and pasture. Native vegetation is mixed hardwoods forests of oak, hickory, beech, and poplar.
DISTRIBUTION AND EXTENT: The Highland Rim and Great Valley of Tennessee and possibly Alabama and Georgia. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: White County, Tennessee; 1975.
REMARKS: Diagnostic horizons recognized in this pedon are:
Umbric epipedon - the zone from 0 to 8 inches (Ap horizon).
Argillic horizon - the zone from 8 to 75 inches (Bt1, Bt2, Bt3, Bt4, Bt5).