LOCATION DUBBS MS+AR KY LA MO TNEstablished Series
The Dubbs series consists of very deep, well drained, moderately permeable soils formed in loamy alluvium. These soils are on nearly level to sloping natural levees or low terraces of the Mississippi River and its tributaries in the Southern Mississippi Valley Alluvium Major Land Resource Area. Slopes range from 0 to 8 percent.
TAXONOMIC CLASS: Fine-silty, mixed, active, thermic Typic Hapludalfs
TYPICAL PEDON: Dubbs silt loam - cultivated. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 5 inches; dark grayish brown (10YR 4/2) silt loam; weak fine granular structure; very friable; many fine roots; very strongly acid; abrupt smooth boundary. (4 to 12 inches thick)
Bt1--5 to 23 inches; yellowish brown (10YR 5/6) silty clay loam; moderate coarse prismatic structure parting to moderate fine and medium subangular blocky; friable; few fine roots; nearly continuous clay films on faces of peds; few fine black concretions; very strongly acid; clear smooth boundary.
Bt2--23 to 40 inches; yellowish brown (10YR 5/4) loam; few fine distinct light gray (10YR 7/1) and light brownish gray (10YR 6/2) mottles; weak coarse prismatic structure parting to weak fine and medium subangular blocky; friable; few fine roots; patchy clay films on faces of peds; few fine black concretions; strongly acid; clear smooth boundary. (Combined thickness of the Bt horizon is 20 to 50 inches.)
BC--40 to 60 inches; yellowish brown (10YR 5/4) loam; common medium distinct light gray (10YR 7/1) and light brownish gray (10YR 6/2) mottles; weak medium subangular blocky structure; friable; few fine black concretions; very strongly acid.
TYPE LOCATION: Tallahatchie County, Mississippi; 3 miles north of Sumner, Mississippi, and 0.6 mile west of New Salem Church. Southwest 1/4 southeast 1/4 sec. 24, T. 25 N., R. 2 W.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 20 to 60 inches. The soil ranges from very strongly acid to moderately acid, except for the surface soils that have been limed but may range to neutral from the addition of irrigation waters. Base saturation by sum of cations ranges from 65 to 80 percent at depths of 50 inches below the upper boundary of the B horizon.
The Ap horizon has hue 10YR, value of 3 to 5, and chroma 2, 3, or 4. Where the value moist is 3, the value dry is 6. In eroded pedons the hue is 10YR or 7.5YR, value of 4 or 5, and chroma of 4 to 6. It is very fine sandy loam, fine sandy loam, silt loam, silty clay loam, or loam. Some pedons have thin A1 horizons in hue 10YR, value 3, and chroma 2 or 3. Some pedons have a BA horizon.
The Bt horizon has hue 10YR or 7.5YR, value 4 or 5, and chroma 3 to 6. Mottles in shades of gray and brown range from none to many in the lower part of the Bt horizon. Texture is silty clay loam, clay loam, silt loam, or loam. Clay content of the upper 20 inches of the Bt horizon ranges from 20 to 34 percent. Structure ranges from prismatic to subangular blocky.
The BC horizon is silt loam, loam, or very fine sandy loam and has colors similar to the Bt horizon. The BC horizon may be mottled in shades of brown and gray.
Where present, the C horizon has hue of 10YR, value of 4 to 6, and chroma of 2 to 6. Mottles commonly are few to many in shades of brown and gray. Texture ranges from fine sandy loam and silt loam to sand.
COMPETING SERIES: These are the Gallion, Memphis, Rilla, and Siwell series in the same family and the Askew, Bosket, Dexter, Dossman, Dundee, Goldman, Lexington, Sterlington, and Tutwiler series in closely related families. Gallion soils have Bt horizons with hues of 5YR and redder and are medium acid to mildly alkaline. Memphis soils have silt loam or silty clay loam Bt horizons with less than 5 percent sand throughout. Rilla soils have colors of 5YR hue and silt ped coatings in the Bt horizon. Siwell soils have alkaline clayey 2C horizons. Askew and Goldman soils have colors with few to many chroma 2 mottles in the upper 10 inches of the Bt horizon. Bosket soils have A horizons more than 7 inches thick with value of 3 and chroma of 3 or less and have B horizons with over 15 percent sand coarser than very fine sand. Dexter and Dossman soils have ped coatings of 5YR or redder hue in the Bt horizon and have base saturation that ranges from 35 to 60 percent at 50 inches below the upper boundary of the Bt horizon. Dundee soils have Bt horizons dominated by colors of chroma 2. Sterlington and Tutwiler soils has less than 18 percent clay in the Bt horizon.
GEOGRAPHIC SETTING: Dubbs soils mainly are on natural levees or low terraces along former channels of the Mississippi River and its tributaries. These nearly level to sloping soils, which formed in loamy alluvium, generally are not flooded and the seasonal water table is below six feet. However, an occasionally
flooded phase is recognized where local flooding can occur during winter and spring. In these areas the seasonal high water table fluctuates between a depth of 4 to 6 feet. Slopes range from 0 to 8 percent. The climate is warm and humid. Near the type location the mean annual precipitation is 48 inches and mean annual temperature is 64 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the closely competing
Tutwiler series and the
Forestdale series. Askew soils occupy similar topographic positions and have gray mottles in the upper 10 inches of the argillic horizon. Bosket soils are in a mollic subgroup,
are better drained, and are at high geographic positions on natural levees. Dundee soils are in slightly lower positions on natural levees and are somewhat poorly drained with the argillic horizon dominated by colors of chroma 2. Tutwiler soils have less than 18 percent clay in the argillic horizon, are better drained, and are on higher positions on natural levees. Beulah soils do not have an argillic horizon, are better drained, and are at slightly higher positions. Forestdale soils are clayey, poorly drained, and are in lower landscape positions.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderate permeability.
USE AND VEGETATION: Most areas are cleared and used for growing cotton, corn, soybeans, and pasture. Native vegetation is bottomland hardwoods.
DISTRIBUTION AND EXTENT: Arkansas, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee. The series is of large extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Auburn, Alabama
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 approximately 5 inches (Ap horizon).
Agrillic horizon - the zone from approximately 5 to 40 inches (Bt1, Bt2 horizons).
ADDITIONAL DATA: Laboratory data: soil characterization data for 3 pedons are published in Soil Survey of Coahoma County, Mississippi (issued December 1959) p. 50; soil characterization data for 6 pedons are published in SSIR No. 13, pp. 44-55.