LOCATION LEXINGTON TN+AR KY LA MS

Established Series
Rev. DLN:JCJ
02/2013

LEXINGTON SERIES

The Lexington series consists of very deep, well drained soils on level to moderately steep uplands. The soil formed in a mantle of loess about 2 to 3 feet thick and in the underlying loamy and sandy marine sediments. Slopes range from 0 to 30 percent.

TAXONOMIC CLASS: Fine-silty, mixed, active, thermic Ultic Hapludalfs

TYPICAL PEDON: Lexington silt loam, in a gently sloping cultivated field. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 7 inches; brown (10YR 4/3) silt loam; weak fine granular structure; very friable; many fine roots; many fine and medium pores; strongly acid; abrupt smooth boundary. (5 to 8 inches thick)

Bt1--7 to 20 inches; reddish brown (5YR 4/4) silty clay loam; strong medium subangular blocky structure; friable; common fine roots; common fine and medium pores; few faint reddish brown (5YR 4/3) clay films on vertical and horizontal faces of peds; strongly acid; clear smooth boundary.

Bt2--20 to 35 inches; yellowish red (5YR 4/6) silt loam, moderate medium subangular blocky structure; friable; few fine roots; common fine pores; few faint reddish brown (5YR 4/4) clay films on faces of peds; strongly acid; clear smooth boundary. (Combined thickness of the Bt horizons ranges from 20 to 40 inches.)

2Bt3--35 to 48 inches; dark brown (7.5YR 4/4) sandy loam; few small brown (10YR 5/3) pockets of loamy sand; weak medium subangular blocky structure; very friable; few fine roots; many fine and medium pores; few faint dark brown (7.5YR 3/4) clay films on faces of peds; strongly acid; clear smooth boundary.

2Bt4--48 to 55 inches; dark reddish brown (5YR 3/4) sandy loam; many brownish yellow (10YR 6/6) pockets of loamy sand; weak medium subangular blocky structure; very friable; many fine and medium pores; few faint dark reddish brown (5YR 3/3) clay films on ped faces and bridging sand grains; strongly acid; clear smooth boundary. (Combined thickness of the 2Bt horizons ranges from 0 to 60 inches).

2E and Bt--55 to 72 inches; stratified brownish yellow (10YR 6/6) loamy sand (E) and brown (7.5YR 4/4) sandy loam lamella (Bt); E part is 1 to 3 inches thick; single grain; loose; many white (10YR 8/2) uncoated sand grains; Bt part is lamella, 1/4 inch to 1 inch thick; weak fine subangular blocky structure; very friable; many fine and medium pores; small pockets of yellow (10YR 7/6) sand or loamy sand make up about 10 percent of the strata; strongly acid.

TYPE LOCATION: Madison County, Tennessee; 3.6 miles northeast of Pinson, 2.6 miles northeast of the intersection of TN Highway 197 and allen Road, 0.4 mile southeast of the intersection of TN Highway 197 and Woodruff Road, 200 feet north of Woodruff Road in cultivated field.

RANGE IN CHARACTERISTICS: Solum thickness exceeds 60 inches. Combined thickness of the A and B horizons containing less than 15 percent sand coarser than very fine sand commonly is about 35 inches, and is everywhere less than 48 inches. Reaction ranges from moderately acid to very strongly acid in each horizon, except where lime has been added. Base saturation 50 inches below the top of the argillic horizon ranges from 36 percent to 59 percent, but is commonly less than 40 percent.

The Ap horizon or A horizon has hue of 10YR or 7.5YR, value of 4 or 5, and chroma of 2 through 6. Some pedons have a thin (less than 6 inches) A horizon with hue of 10YR, value of 3, and chroma of 2 or 3. Texture is silt loam. In severely eroded areas texture is silt loam or silty clay loam.

Some pedons have an E horizon with hue of 10YR, value of 5 or 6, and chroma 3 to 6. Texture is silt loam.

The Bt horizon has hue of 10YR to 5YR, value of 4 or 5, and chroma of 4 to 8. Texture is silt loam or silty clay loam. Clay content commonly is 20 to 30 percent, but ranges from 18 to 35 percent. The upper 20 inches of the Bt horizon commonly contains 5 to 10 percent fine and coarser sand. The amount of sand gradually increases with depth.

The 2Bt horizon has hue of 2.5YR through 7.5YR, value of 4 or 5, and chroma of 4 through 8. Texture is sandy loam, silt loam, loam, sandy clay loam or clay loam. Most pedons have few to many brownish or yellowish pockets of sand or loamy sand.

The 2E and Bt horizon is not a requirement for the series. Where present, the E material has hue of 10YR, value of 5 or 6, and chroma of 3 to 6. Texture is sand or loamy sand. The Bt material consists of thin lamella of sandy loam commonly in shades of brown.

COMPETING SERIES: These are the Armour, Barnsdall, Dexter, Dossman, Feliciana, Goodwill, and Hicks series. Armour soils formed in limestone residuum, valley fill, and alluvium and do not have a significant increase in sand content in the lower subsoil. Barnsdall soils have redder colors and are on flood plains. Dexter soils have a thinner solum and are on stream terraces. Dossman soils formed in deep loess and have less sand in the particle size control section. Goodwill soils have yellower colors in the Bt horizon and are on low stream terraces. Hicks soils formed in a silty mantle over siltstone residuum and have a Cr horizon between 40 and 60 inches. Feliciana soils formed in deep loess and have less sand in the solum.

GEOGRAPHIC SETTING: Lexington soils are on level to moderately steep uplands that have a thin mantle of loess, about 2 to 3 feet thick, underlain by loamy and sandy marine sediments. Slopes range from 0 to 30 percent. Near the type location the average annual precipitation is about 51 inches. Average annual temperature is about 60 degrees F.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Feliciana series and the Memphis, Deanburg, Providence, Collins, Iuka, Smithdale, and Vicksburg series. Memphis soils are on broader ridgetops and have less sand in the solum. Deanburg soils are fine-loamy and on stream terraces. Providence soils have a fragipan in the subsoil. Smithdale soils are fine-loamy and are on adjacent steeper side slopes. Collins, Iuka, and Vicksburg soils are coarse-silty and are on flood plains.

DRAINAGE AND PERMEABILITY: Lexington soils are well drained. Moderate permeability in the upper part and moderately rapid permeability in the lower part. Runoff is slow to rapid.

USE AND VEGETATION: Used mainly for growing cotton, corn, soybeans, small grain, hay, and pasture. A small portion is in forest of oaks, yellow poplar, hickory, gum, beech, and elm.

DISTRIBUTION AND EXTENT: West Tennessee, west Kentucky, Louisiana, west Mississippi, and possibly Arkansas and southeast Missouri. The series is of moderate extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: AUBURN, ALABAMA

SERIES ESTABLISHED: Henderson County, Tennessee; 1905.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon - the zone from 0 to 7 inches (Ap horizon).

Argillic horizon - the zone from 7 to 72 inches (Bt1, Bt2, 2Bt3, 2Bt4, Bt part of 2E and Bt).

Lithologic discontinuity - the zone from 35 to 72 inches (2Bt3, 2Bt4, 2E and Bt).

National Cooperative Soil Survey
U.S.A.