LOCATION LOUDON                  OH+KY

Established Series
Rev. DRM-TEL-DBD
11/2021

LOUDON SERIES

The Loudon series consists of deep or very deep, moderately well drained soils formed in a mantle of loess and the underlying till and residuum from calcareous gray shale and thin strata of limestone. These soils are on uplands. Slope ranges from 0 to 25 percent. Mean annual precipitation is about 1092 mm (43 inches), and mean annual air temperature is about 12 degrees C (53 degrees F).

TAXONOMIC CLASS: Fine, mixed, active, mesic Aquic Hapludalfs

TYPICAL PEDON: Loudon silt loam, on a convex, 3 percent slope in a cultivated field. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 20 cm (0 to 8 inches); dark grayish brown (10YR 4/2) silt loam, light brownish gray (10YR 6/2) dry; moderate fine and medium granular structure; friable; many roots; moderately acid; abrupt smooth boundary. [13 to 25 cm (5 to 10 inches) thick]

BE--20 to 30 cm (8 to 12 inches); yellowish brown (10YR 5/4) silt loam; weak medium subangular blocky structure; friable; common roots; strongly acid; clear wavy boundary. [0 to 23 cm (9 inches) thick]

Bt1--30 to 48 cm (12 to 19 inches); yellowish brown (10YR 5/4) silty clay loam; moderate fine and medium subangular blocky structure; friable; few roots; common faint brown (10YR 4/3) clay films on faces of peds; common medium distinct yellowish brown (10YR 5/6) masses of iron accumulation; few fine prominent strong brown (7.5YR5/8) masses of iron accumulation; very strongly acid; clear wavy boundary. [0 to 25 cm (10 inches) thick]

2Bt2--48 to 66 cm (19 to 26 inches); yellowish brown (10YR 5/4) silty clay loam; moderate fine and medium subangular blocky structure; firm; few roots; many faint light yellowish brown (10YR 6/4) clay films on vertical faces of peds; common distinct brown (10YR 4/3) clay films on horizontal faces of peds; common fine distinct light brownish gray (10YR 6/2) iron depletions; common faint pale brown (10YR 6/3) clay depletions on faces of peds; common medium distinct strong brown (7.5YR 5/6) masses of iron accumulation; 8 percent angular glacial pebbles; very strongly acid; clear wavy boundary.

2Bt3--66 to 96 cm (26 to 38 inches); yellowish brown (10YR 5/6) silty clay; weak coarse subangular blocky structure; firm; few roots; few distinct gray (10YR 5/1) clay films on faces of peds; common medium prominent gray (10YR 6/1) iron depletions; few medium prominent dark masses and concretions of iron and manganese oxides; 10 percent angular glacial pebbles; strongly acid; abrupt wavy boundary. [Combined thickness of the 2Bt horizon is 15 to 76 cm (6 to 30 inches).]

3BC--96 to 147 cm (38 to 58 inches); yellowish brown (10YR 5/4) and gray (N 6/) silty clay; weak coarse prismatic structure parting to weak coarse angular blocky in the upper part; very firm; few roots along vertical faces of peds; few medium distinct gray (10YR 5/1) iron depletions; common medium distinct strong brown (7.5YR 5/6) masses of iron accumulation; strongly effervescent at a depth of 114 cm (45 inches); slightly alkaline in the upper part and moderately alkaline in the lower part; gradual smooth boundary. [25 to 81 cm (10 to 32 inches) thick]

3C--147 to 178 cm (58 to 70 inches); reddish gray (10R 5/1) silty clay loam; massive, but parts to weak thick platy bedding planes; very firm; common medium prominent light greenish gray (5BG 7/1) iron depletions; strongly effervescent; moderately alkaline; clear smooth boundary. [0 to 112 cm (44 inches) thick]

3Cr--178 cm (70 inches); variegated reddish gray (10R 5/1), yellowish brown (10YR 5/4 and 5/8) and light greenish gray (5BG 7/1) partly weathered shale; moderate thick platy (rock) structure; firm; highly fragmental in places, but easily crushed and deformed; strongly effervescent; moderately alkaline.

TYPE LOCATION: Highland County, Ohio; about 4 miles west of Hillsboro on U.S. Highway 50, in New Market Township; 990 feet south of Hoagland on Mad River Road, and 660 feet west of Mad River Road; lat. 39 degrees 12 minutes 02 seconds N. and long. 83 degrees 41 minutes 02 seconds W., NAD 27.

RANGE IN CHARACTERISTICS:
Thickness of the solum: 40 to 70 inches
Depth to carbonates: 32 to 65 inches
Thickness of the loess: 10 to 24 inches
Depth to clayey residuum: 30 to 55 inches
Depth to a paralithic contact: 40 to 80 inches
Particle-size control section: averages 35 to 55 percent clay
Rock fragments: glacial erratics in the upper part; shale, limestone, and chert in the lower part

Ap horizon:
Hue: 10YR
Value: 4 or 5 (6 or 7 dry)
Chroma: 1 to 3
Texture: commonly is silt loam, but may be silty clay loam in eroded pedons
Rock fragment content: 0 to 2 percent
Reaction: strongly acid or moderately acid unless limed

A horizon, where present:
Thickness: up to 10 cm (4 inches)
Hue: 10YR
Value: 3 or 4
Chroma: 1 or 2
Texture: silt loam
Rock fragment content: 0 to 2 percent
Reaction: strongly acid or moderately acid unless limed

E horizon, where present:
Thickness: 8 to 15 cm (3 to 6 inches)
Hue: 10YR
Value: 5
Chroma: 3 or 4
Texture: silt loam
Rock fragment content: 0 to 2 percent
Reaction: very strongly acid to moderately acid

BE horizon:
Hue: 10YR
Value: 5
Chroma: 4
Texture: silt loam
Rock fragment content: 0 to 2 percent
Reaction: strongly acid

Bt horizon:
Hue: 10YR
Value: 4 or 5
Chroma: 3 to 6
Texture: silt loam or silty clay loam
Rock fragment content: 0 to 2 percent
Reaction: very strongly acid to moderately acid

2Bt horizon:
Hue: 7.5YR, 10YR, or 2.5Y
Value: 4 or 5
Chroma: 3 to 8
Texture: silty clay loam, silty clay, or clay
Rock fragment content: 2 to 14 percent
Reaction: very strongly acid to moderately acid

3BC or 3Bt horizon:
Hue: 10YR, 2.5Y, or 5Y, or is neutral
Value: 4 to 6
Chroma: 1 to 6
Texture: silty clay or clay
Clay content: 40 to 65 percent
Rock fragment content: 0 to 14 percent
Reaction: neutral to moderately alkaline

3C horizon:
Hue: ranging from 5BG to 10R, or is neutral; commonly variegated
Value: 5 or 6
Chroma: 1 to 8
Texture: silty clay loam, silty clay, or clay
Rock fragment content: 0 to 14 percent
Reaction: slightly alkaline or moderately alkaline

3Cr horizon:
Bedrock: calcareous soft shale with some thin strata of limestone
Colors: commonly shades of gray or olive but is brown in some pedons

COMPETING SERIES: These are the Banister, Branchville, Cardinal, Celina, Eudy, Hartville, Jerktail, Tarlton, and Whippany series. Banister soils formed in clayey alluvium and do not have glacial erratics within the series control section. Branchville soils have more than 2 percent rock fragments in the upper part of the argillic horizon. Cardinal soils have less than 2 percent rock fragments in all parts of the argillic horizon. Celina soils have sola less than 102 cm (40 inches) thick. Eudy soils have a lithic contact within a depth of 102 cm (40 inches). Hartville soils formed in alluvium or colluvium and do not have glacial erratics within the series control section. Jerktail soils formed in colluvium and residuum and do not have glacial erratics within the series control section. Tarlton soils have a paralithic contact within a depth of 102 cm (40 inches). Whippany soils formed in silty and clayey sediments and do not have glacial erratics within the series control section.

GEOGRAPHIC SETTING: Loudon soils are on glaciated uplands near the margin of the Illinoian till sheet. They are on broad interfluves, narrow beveled ridges below broader interfluves. Slope ranges from 0 to 25 percent. The soils formed in a mantle of loess 25 to 61 cm (10 to 24 inches) thick and the underlying till and residuum from interbedded calcareous shale and thin strata of limestone. Mean annual precipitation ranges from 965 to 112 cm (38 to 44 inches). Mean annual air temperature ranges from 11 to 13 degrees C (52 to 56 degrees F).

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cynthiana, Eden, Edenton, Fairmount, Faywood, Grayford, Jessup, Morrisville, Opequon, and Rossmoyne soils. Cynthiana, Eden, Fairmount, Faywood, and Opequon soils commonly are on steeper slopes in unglaciated areas, and where limestone is more dominant. The well drained Edenton soils are moderately deep to bedrock and are on backslopes and upper shoulder positions, typically on more sloping areas. The well drained Grayford soils commonly are on areas dominated by limestone, contain less clay, and have lower base saturation. The well drained Jessup soils are in a toposequence with Loudon soils and are on shoulder positions or on narrow, beveled interfluves. The Morrisville soils have iron depletions below the upper 25 cm (10 inches) of the argillic and are on backslopes and shoulder slopes. Rossmoyne soils are on interfluves having a thicker deposit of till and have a fragipan.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Moderately well drained. The potential for surface runoff is negligible to very high. Saturated hydraulic conductivity is moderately low. Permeability is slow.

USE AND VEGETATION: Loudon soils are in cropland and pasture. Corn, wheat, and clover-grass hay are the principal crops with some tobacco on less sloping areas. Native vegetation is hardwood forest.

DISTRIBUTION AND EXTENT: MLRA 114A in southwestern Ohio and MLRA 121 in northern Kentucky. The type location is in MLRA 114A. The series is of small extent, with approximately 6000 acres in Ohio.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: AMHERST, MASSACHUSETTS

SERIES ESTABLISHED: Brown County, Ohio, 1930.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: from the surface to a depth of 30 cm (Ap, BE horizons).
Argillic horizon: from a depth of 30 to 96 cm (Bt, 2Bt horizons).
Aquic conditions: iron depletions or low chroma matrix in all horizons below a depth of 48 cm.
Paralithic contact: at 178 cm (top of the 3Cr horizon).

ADDITIONAL DATA: Characterization data for this soil is available through the Soil Characterization Laboratory, Ohio State University pedon HY-62.

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National Cooperative Soil Survey
U.S.A.