LOCATION KNOWLTON KY+WV
Established Series
Rev. RAH-JMR-JDM
01/2015
KNOWLTON SERIES
The Knowlton series consists of very deep, poorly drained soils that formed in alluvium weathered from interbedded Mississippian aged shale, sandstone, siltstone, limestone, and dolomite. Slopes range from 0 to 4 percent, but are dominantly 2 percent or less.
TAXONOMIC CLASS: Fine-silty, mixed, semiactive, mesic Typic Endoaquults
TYPICAL PEDON: Knowlton silt loam in nearly level pasture (colors are for moist soil).
Ap--0 to 6 inches; grayish brown (2.5Y 5/2) silt loam; weak fine granular structure; very friable; many fine and medium roots; few fine rounded quartzite gravels; strongly acid; clear wavy boundary. (4 to 10 inches thick)
BE--6 to 17 inches; light brownish gray (10YR 6/2) silt loam; weak medium subangular blocky structure and weak medium platy structure; friable; common fine and medium roots; few fine rounded quartzite gravels; strongly acid; gradual smooth boundary. (4 to 15 inches thick)
Btg1--17 to 27 inches; light brownish gray (2.5Y 6/2) silt loam; weak coarse angular blocky structure; firm; few fine roots; many medium prominent brownish yellow (10YR 6/8) irregular hypocoats with clear boundaries infused into the matrix on faces of peds; few faint clay films on faces of peds; few fine and medium rounded quartzite gravels; very strongly acid; clear smooth boundary.
Btg2--27 to 46 inches; light gray (10YR 7/1) silt loam; moderate medium prismatic structure parting to moderate coarse angular blocky structure; firm; many medium prominent strong brown (7.5YR 5/8) irregular soft iron masses with clear boundaries on faces of peds; few faint clay films on faces of peds; few fine and medium rounded quartzite gravels; very strongly acid; gradual wavy boundary.
Btg3--46 to 66 inches; light gray (10YR 7/1) silt loam; moderate medium prismatic structure parting to moderate medium subangular blocky structure; firm; few fine roots; many medium prominent strong brown (7.5YR 5/8) irregular soft iron masses with diffuse boundaries on faces of peds; few faint clay films on faces of peds at top of horizon; few fine and medium rounded quartzite gravels; very strongly acid. (Combined thickness of the Bt horizon is 28 to 45 inches)
TYPE LOCATION: Powell County, Kentucky in pasture on a low terrace along the eastern shore of Red River; about 0.6 mile southeast of the intersection of Kentucky Highway 11 and a hard surface road that crosses Red River at Clay City; USGS Clay City Quadrangle; 37 degrees, 51 minutes, 19 seconds N. Latitude and 83 degrees, 54 minutes, 28 seconds W. Longitude; NAD 1927.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 40 to 60 inches or more. Depth to bedrock is greater than 60 inches. Coarse fragments, mostly rounded quartzite or sandstone gravels, range from 0 to 15 percent throughout the profile. Reaction is strongly acid to neutral in the surface layer and very strongly acid to moderately acid in the subsoil.
The A or Ap horizon has hue of 10YR to 5Y, value of 4 to 6, and chroma of 1 to 4. Texture is silt loam or loam.
The E horizon, where present, has hue of 10YR, value of 5 to 7, and chroma of 1 or 2. Texture is silt loam or loam.
The BE horizon has hue of 10YR to 5Y, value of 4 to 7, and chroma of 1 or 2. Texture is silt loam, loam, silty clay loam or clay loam.
The Btg horizons have hues of 10YR to 5Y, value of 5 to 7, and chroma of 1 or 2. They commonly have soft iron masses in shades of yellow, red or brown. Texture is silt loam, silty clay loam, clay loam, or less commonly, loam.
The CBg or Cg horizons, where present, have hues of 7.5YR to 5Y or neutral, value of 1 to 7 and chroma of 1 to 4. Textures and amount of redoximorphic features is similar to the lower Btg horizons.
COMPETING SERIES: There are no other series in this family. The
Othello series is in an active reaction class, but is otherwise a close competitor.
GEOGRAPHIC SETTING: Knowlton soils are commonly located on nearly level, relatively broad, low stream terraces. Some areas are subject to rare flooding. Near the type location, mean annual precipitation is about 48 inches and ranges from 44 to 52 inches. Mean annual temperature is about 54 degrees F. and ranges from 52 to 56 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Allegheny,
Cotaco,
Grigsby,
Lindside,
Morehead,
Melvin,
Newark,
Nolin,
Orrville,
Rowdy and
Skidmore soils on adjacent alluvial landforms. Allegheny, Cotaco, Orrville and Rowdy soils are fine-loamy. Grigsby soils are coarse-loamy. Skidmore soils are loamy-skeletal. Allegheny, Grigsby, Nolin, Rowdy and Skidmore soils are well drained. Cotaco and Morehead soils are moderately well or somewhat poorly drained. Newark and Orrville soils are somewhat poorly drained. Grigsby, Lindside, Morehead, Melvin, Newark, Nolin, Rowdy and Skidmore soils lack argillic horizons.
DRAINAGE AND PERMEABILITY: Poorly drained with slow permeability.
USE AND VEGETATION: Chiefly used as pasture, but some areas under artificial drainage are cropped to corn, soybeans, and legume-grass hay. A few isolated areas remain in woodland.
DISTRIBUTION AND EXTENT: Kentucky and possibly in Tennessee, Ohio or West Virginia. Series is moderate in extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: Powell County, Kentucky 1989. The name is from a small community near the Red River in Powell County.
REMARKS: The Knowlton series replaces areas previously included with the Morehead or Melvin series. The series may also be useful in replacing 1,210 acres of Peoga soils with a low base that were correlated in Montgomery County, Kentucky. The 2005 update revises the pedon description with terminology from version 2.0 of the "Field Book for Describing and Sampling Soils" after review of the original field notes. A map compilation error has placed the OSD location for this series in a delineation of Ne-Newark silt loam, frequently flooded map unit and is slated for correction during routine maintenance (Soil Survey of Powell and Wolfe Counties, Kentucky, 1993).
Diagnostic horizons and features recognized in this pedon are:
Ochric epidepon - The zone from the surface to a depth of about 6 inches. (Ap)
Argillic horizon - The zone from approximately 6 to 66 inches. (BE, Btg1, Btg2, Btg3)
Redoximorphic features - The zone from 0 to 66 inches.
ADDITIONAL DATA: Characterization data pedon S86-KY-197-2.
National Cooperative Soil Survey
U.S.A.