Established Series


The Forestdale series consists of very deep, poorly drained, very slowly permeable soils that formed in clayey and silty alluvium. These soils are on low terraces or natural levees bordering former channels of the Mississippi River and its major tributaries in the Southern Mississippi Valley Alluvium Major Land Resource Area (131). They are saturated late in winter and early in spring. Water runs off the surface very slowly. Slopes range from 0 to 8 percent.

TAXONOMIC CLASS: Fine, smectitic, thermic Typic Endoaqualfs

TYPICAL PEDON: Forestdale silty clay loam on a nearly level slope in cropland. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 6 inches; dark grayish brown (10YR 4/2) silty clay loam; weak fine granular structure; friable; few fine roots; moderately acid; abrupt smooth boundary. (4 to 10 inches thick)

Btg1--6 to 26 inches; gray (10YR 6/1) silty clay; moderate medium subangular blocky structure; plastic, sticky, firm; few fine roots; many distinct clay films on faces of peds; few medium distinct yellowish brown (10YR 5/6) iron accumulations; strongly acid; clear smooth boundary. (14 to 30 inches thick)

Btg2--26 to 60 inches; gray (10YR 6/1) silty clay loam; weak medium subangular blocky structure; slightly plastic, friable; few faint clay films on faces of peds; common medium distinct yellowish brown (10YR 5/6) iron accumulations; strongly acid. (Combine thickness of the Btg horizon ranges from 34 to more than 54 inches.)

TYPE LOCATION: Tallahatchie County, Mississippi; 1 1/4 miles north of Brazil and 1/4 mile east of State Highway 321 in cultivated field, SW1/4SW1/4 sec. 11, T. 25 N., R. 1 W.

RANGE IN CHARACTERISTICS: Solum thickness is more than 40 inches. The A horizon and the upper part of the Btg horizon range from very strongly acid to moderately acid, except for the surface layer in areas that have been limed. The lower part of the Btg horizon and the Cg horizon range from very strongly acid to slightly alkaline. Black and brown concretions, if present, are few to common.

The A or Ap horizon has hue of 10YR or 2.5Y, value of 4 to 6, and chroma of 2 or less. Some pedons have thin A horizons with values of 3 or less. Texture is very fine sandy loam, fine sandy loam, loam, silt loam, or silty clay loam.

The upper Btg horizon has a matrix with 60 percent or more in hue of 2.5Y or 10YR, and either value of 4 or 5, and chroma of 1, or value of 6 or 7, and chroma of 1 or 2; iron accumulations are in shades of brown or yellow. Texture is silty clay, clay, or silty clay loam. The upper 20 inches has 35 to 60 percent clay and less than 20 percent sand. The lower Btg has hue of 2.5Y or 10YR, value of 4 to 7, and chroma of 1 or 2, and iron accumulations in shades of brown or yellow. Texture is silty clay loam, silt loam, or very fine sandy loam.

Some pedons have a BCg horizon with colors, textures, and reaction similar to the lower Btg horizon.

The Cg horizon, where present, has the same colors as the Btg horizon. It is very fine sandy loam or silt loam.

COMPETING SERIES: Forestdale is the only series in this family.

GEOGRAPHIC SETTING: Forestdale soils are on natural levees or low terraces bordering former channels of the Mississippi River and its tributaries. These are level to gently sloping soils with mainly smooth surfaces. Slopes range from 0 to 8 percent. The soil formed in clayey and silty alluvial sediments. Mean annual temperature is about 62 degrees Fahrenheit, and mean annual precipitation is 53 inches near the type location.

GEOGRAPHICALLY ASSOCIATED SOILS: These include the Alligator, Amagon, Bosket, Dubbs, Dundee, Tensas, Tunica and Tutwiler series. The poorly drained Alligator, Amagon, and Tunica soils are on similar landscapes positions. The well drained Bosket, Dubbs, and Tutwiler soils are on higher positions on terraces and natural levees. The somewhat poorly drained Dundee and Tensas soils are in intermediate positions on terraces and in swales.

DRAINAGE AND PERMEABILITY: Poorly drained; negligible to very high runoff depending on slope; very slow permeability. These soils have a water table at a depth of 0.5 to 2 feet below the surface in wet seasons from January to April. These soils are subject to flooding during late winter and early spring unless

USE AND VEGETATION: Most areas are cleared and used for cotton, soybeans, small grains, and pasture. Native vegetation was bottomland hardwoods. Common trees are eastern cottonwood, green ash, cherrybark oak, nuttall oak, water oak, willow oak, and sweetgum.

DISTRIBUTION AND EXTENT: Alabama, Arkansas, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee. The series is extensive.


SERIES ESTABLISHED: Tunica County, Mississippi; 1949.

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

Ochric epipedon - the zone from the surface to a depth of about 6 inches.

Argillic horizon - the zone from approximately 6 to 60 inches (Btg1, Btg2 horizons).

ADDITIONAL DATA: Engineering test data for two pedons are published respectively in the Soil Survey Coahoma County, Mississippi (issued December 1959) pp. 20-21 and Soil Survey Humphries County, Mississippi (issued September 1959) pp. 14-15. Characterization data for one pedon is published in A Monograph of the Soils of the Southern Mississippi River Valley Alluvium (Southern Cooperative Series Bulletin 178) pp. 44-45.

National Cooperative Soil Survey