LOCATION KURK KY

Established Series
JEM:JCJ Rev. MAV
10/2018

KURK SERIES

The Kurk series consists of very deep, somewhat poorly drained soils that formed in 2 to 5 feet of silty alluvium over loess on stream terraces and upland depressions. These soils have moderately slow permeability. Slopes range from 0 to 3 percent.

TAXONOMIC CLASS: Fine-silty, mixed, active, thermic Aeric Epiaqualfs

TYPICAL PEDON: Kurk silt loam on a smooth 1 percent slope in a cultivated field. (Colors are for moist soil unless otherwise stated)

Ap--0 to 8 inches; brown (10YR 4/3) silt loam; weak fine granular structure; very friable; common fine roots; neutral; clear smooth boundary. (3 to 11 inches thick)

BE--8 to 16 inches; brown (10YR 5/3) silt loam; weak fine subangular blocky structure; friable; common fine roots; common medium distinct light brownish gray (10YR 6/2) iron depletions; common medium distinct brown (7.5YR 4/3) masses of iron accumulation; common prominent black (N 2/0) iron-manganese stains on faces of peds; moderately acid; clear smooth boundary. (5 to 12 inches thick)

Btg1--16 to 31 inches; light brownish gray (10YR 6/2) silty clay loam; moderate medium subangular blocky structure; firm; few fine roots; common fine prominent yellowish brown (10YR 5/6) masses of iron accumulation; common distinct pale brown (10YR 6/3) clay depletions along ped faces; common distinct grayish brown (10YR 5/2) clay skins in root channels and pores; common prominent black (N 2/0) iron-manganese stains and concretions; strongly acid; gradual smooth boundary.

Btg2--31 to 38 inches; grayish brown (10YR 5/2) silty clay loam; moderate medium subangular blocky structure; firm; few fine roots; many medium prominent gray (10YR 6/1) iron depletions; common fine distinct yellowish brown (10YR 5/6) masses of iron accumulation; many distinct gray (10YR 5/1) clay skins in root channels and pores; common prominent black (N 2/0) iron-manganese stains and soft strong brown (7.5YR 4/6) concretions; very strongly acid; clear smooth boundary. (Combined thickness of the Btg horizon is 12 to 30 inches)

2Bt1--38 to 55 inches; yellowish brown (10YR 5/6) silt loam; moderate medium subangular blocky structure; firm; very few fine roots; common coarse prominent light brownish gray (10YR 6/2) iron depletions; common prominent black (N 2/0) iron-manganese stains; strongly acid; gradual smooth boundary.

2Bt2--55 to 65 inches; yellowish brown (10YR 5/6) silt loam; moderate medium prismatic structure parting to moderate medium subangular blocky; firm; very few fine roots; common coarse prominent light brownish gray (10YR 6/2) iron depletions; common distinct gray (10YR 5/1) and grayish brown (2.5Y 5/2) clay skins in root channels; common prominent black (N 2/0) carbonaceous stains along old root channels; strongly acid; gradual smooth boundary. (Combined thickness of the 2Bt is 10 to 30 inches)

2BC--65 to 80 inches; strong brown (7.5YR 4/6) silt loam; weak medium subangular blocky structure; firm; few fine distinct pale brown (10YR 6/3) iron depletions; moderately acid acid.

TYPE LOCATION: Graves County, Kentucky; 1.8 miles north of Sedalia, 2,100 feet east of the junction of Ford Creek and Kentucky Highway 97 in a cultivated field; Farmington 7.5 minute USGS quadrangle; Lat. 36 degrees 40 minutes 02 seconds N/ Long. 88 degrees 36 minutes 26 seconds W.
RANGE IN CHARACTERISTICS: Thickness of the solum ranges from 60 to 80 inches or more. Reaction ranges from strongly acid to neutral in the surface and subsurface, and very strongly acid to neutral in the subsoil, and strongly acid to slightly alkaline below the discontinuity.

The A or Ap horizon has hue of 10YR, value of 4 or 5, and chroma of 2 to 4. Texture is silt loam. The BE horizon, or Bt and Bw horizons where present, has hue of 10YR or 2.5Y, value of 4 to 6, and chroma of 3 to 6. Redoximorphic features are in shades of brown and gray. Texture is silt loam.

Some pedons contain an E or Eg horizon with hue of 10YR or 2.5Y, value of 6 or 7, and chroma of 2 or 3. Redoximorphic features are in shades of brown and gray. Texture is silt loam.

The Btg horizon has hue of 10YR or 2.5Y, value of 5 to 7, and chroma of 1 or 2. Redoximorphic features are in shades of brown and red. Texture is silt loam or silty clay loam.

The 2Bt and 2BC horizons have hue of 7.5YR or 10YR, value of 4 to 6, and chroma 4 to 6. Redoximorphic features are in shades of gray and brown. Texture is silt loam, silty clay loam, or loam.

Some pedons contain a 2Btx horizon below 40 inches with brittle matrix constituting up to 40 percent by volume. Color and texture range similar to the 2Bt and 2BC.

COMPETING SERIES: These include the Hebert and McGehee series in the same family. Hebert soils do not have a lithologic discontinuity and McGehee soils have slow permeability and have more clay below the discontinuity.

GEOGRAPHIC SETTING: Kurk soils are on nearly level to gently sloping stream terraces and slightly concave upland depressions near drainageways. Slopes range from 0 to 3 percent. They formed in 2 to 5 feet of silty alluvium over loess. Loamy Coastal Plain sediments may occur below the series control section. Near the type location the mean annual temperature is about 59 degrees F, and the mean annual precipitation is about 48 inches.

GEOGRAPHICALLY ASSOCIATED SOILS: These include the Adaton, Center, Collins, Deanburg, Falaya, Grenada, Lexington, Loring, Providence, Routon, and Smithdale series. Adaton and Routon soils are poorly drained. Center soils are moderately well drained and are on similar positions. Collins and Falaya soils lack argillic horizons and occur on adjacent flood plains. Deanburg soils are well drained and are on higher terrace positions. Grenada, Loring, and Providence soils contain fragipans and occur on higher upland positions. Lexington and Smithdale soils are well drained and occur on higher upland positions.

DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Runoff is slow. Permeability is moderately slow. A perched water table occurs from about 14 to 20 inches during the winter months.

USE AND VEGETATION: Most areas of this soil are cleared and used for growing cultivated crops such as soybeans, corn, wheat, grain sorghum, and cotton. A small acreage is in mixed hardwoods consisting primarily of white oak, hickory, southern red oak, maples, and green ash.

DISTRIBUTION AND EXTENT: The loess belt of western Kentucky, west Tennessee, and northern Mississippi; possibly in similar areas in Missouri and Arkansas. The series is of moderate extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: AUBURN, ALABAMA

SERIES ESTABLISHED: Hardeman County Tennessee, 1995.

REMARKS: The proposed Kurk series has previously been included with the Bude, Calloway, Center, and Hatchie series.

Diagnostic horizons and features in this pedon are:

Ochric Epipedon - the zone from the surface to about 16 inches (Ap and BE horizons)

Argillic Horizon - the zone from 16 to about 65 inches (Btg1, Btg2, 2Bt1, 2Bt2)

Lithologic Discontinuity - the zone from about 38 to 80 inches (2Bt1, 2Bt2, 2BC)

National Cooperative Soil Survey
U.S.A.