LOCATION TUNICA MS+AR KY LA MO TN
Established Series
Rev.WMM-RSE-AMS
11/2018
TUNICA SERIES
The Tunica series consists of deep, poorly drained soils that formed in clayey alluvium and the underlying loamy alluvium. These soils are on the lower parts of natural levees on the younger meander belts of the Mississippi River and its tributaries of the Lower Mississippi Valley. Slope is dominantly 0 to 3 percent but ranges to 5 percent on narrow ridges within the flood plain. Mean annual precipitation is about 1371 millimeters (54 inches) and the mean annual air temperature is about 16.5 degrees C (62 degrees F).
TAXONOMIC CLASS: Clayey over loamy, smectitic over mixed, superactive, nonacid, thermic Vertic Epiaquepts
TYPICAL PEDON: Tunica clay, on a 1 percent slope in forest at an elevation of 57.9 meters (190 feet). (Colors are for moist soil unless otherwise stated.)
Ap--0 to 8 centimeters (0 to 3 inches); dark gray (10YR 4/1) clay; moderate fine and medium subangular blocky structure; firm, moderately sticky, moderately plastic; slightly acid; clear smooth boundary. [8 to 30 centimeters (3 to 12 inches) thick]
Bg1--8 to 38 centimeters (3 to 15 inches); dark gray (2.5Y 4/1), exterior, and dark grayish brown (2.5Y 4/2), interior, silty clay; moderate fine and medium subangular blocky structure; firm, very sticky, very plastic; common shiny pressure faces; few non-intersecting slickensides; common medium distinct strong brown (7.5YR 5/6) masses of oxidized iron; slightly acid; gradual wavy boundary. [25 to 38 centimeters (10 to 15 inches) thick]
Bg2--38 to 65 centimeters (15 to 26 inches); dark gray (2.5Y 4/1) exterior, and dark grayish brown (2.5Y 4/2), interior silty clay; moderate fine and medium subangular blocky structure; firm, very sticky, very plastic; common shiny pressure faces; few non-intersecting slickensides; common medium distinct strong brown (7.5YR 5/6) masses of oxidized iron; slightly acid; clear smooth boundary. [18 to 36 centimeters (7 to 14 inches) thick]
2CBg--65 to 83 centimeters (26 to 33 inches); dark grayish brown (10YR 4/2) silt loam; weak fine granular structure; friable, nonsticky, nonplastic; fine and medium distinct irregular yellowish brown (10YR 5/4) masses of oxidized iron in matrix; clay films lining pores; common fine prominent irregular yellowish brown (10YR 5/6) masses of oxidized iron in matrix; common fine and medium faint irregular gray (2.5Y 5/1) masses of reduced iron in matrix; moderately alkaline; clear smooth boundary.
2Cg1--83 to 140 centimeters (33 to 55 inches); dark grayish brown (10YR 4/2) stratified very fine sandy loam; structureless; friable, nonsticky, nonplastic; common fine and medium prominent irregular yellowish brown (10YR 5/6) masses of oxidized iron in matrix; common fine distinct irregular yellowish brown (10YR 5/4) masses of oxidized iron in matrix; moderately alkaline; gradual wavy boundary.
2Cg2--140 to 160 centimeters (55 to 63 inches); grayish brown (10YR 5/2) stratified very fine sandy loam; structureless; loose, nonsticky, nonplastic; common fine and medium distinct irregular yellowish brown (10YR 5/4) masses of oxidized iron in matrix; common fine and medium prominent irregular yellowish brown (10YR 5/6) masses of oxidized iron in matrix; moderately alkaline; clear wavy boundary.
2Cg3--160 to 203 centimeters (63 to 80 inches); grayish brown (10YR 5/2) stratified very fine sandy loam; structureless; loose, nonsticky, nonplastic; common fine and medium distinct irregular yellowish brown (10YR 5/4) masses of oxidized iron in matrix; common medium prominent irregular yellowish brown (10YR 5/6) masses of oxidized iron in matrix; common fine and medium distinct irregular masses of oxidized iron in matrix; moderately alkaline.
TYPE LOCATION: Tunica County, Mississippi; located 9.9 kilometers (6.2 miles) north on U. S. Hwy. 61 from the intersection with State Hwy. 4 in Tunica, MS., then 5.6 kilometers (3.5 miles) west on county road to levee, then 2.4 kilometers (1.5 miles) northwest on a woods trail to a small clearing, then 305 meters (1,000 feet) east-northeast into woods; 747 meters (2,450 feet) east and 655 meters (2,150 feet) south of the NW corner Sec. 36, T. 3 S., R. 12 W.; 34 degrees, 46 minutes, 51.8 seconds N. Latitude, 90 degrees, 25 minutes, 22.4 seconds W. Longitude, WGS84. Council, Arkansas USGS 7.5 Minute Quadrangle.
RANGE IN CHARACTERISTICS:
Particle size control section: 25 to 100 centimeters (10 to 40 inches)
Average clay content in the Control Section: 35 to 75 percent above the discontinuity; and 10 to 32 percent below the discontinuity.
Soil reaction: moderately acid to moderately alkaline
Thickness of the ochric epipedon: 8 to 20 centimeters (3 to 8 inches)
Thickness of the cambic horizon: 36 to 66 centimeters (14 to 26 inches)
Redoximorphic features: Depleted matrix and Masses of oxidized iron in shades of brown throughout the solum.
Other distinctive soil features: Depth to the contrasting loamy discontinuity ranges from 51 to 91 centimeters (20 to 36 inches).
A horizon:
Color: Hue of 10YR or 2.5Y, value of 4 or 5, and chroma of 1 or 2, or it is neutral with value of 4, and chroma of 0. Some pedons have an A horizon that is less than 6 inches thick with hue of 10YR or 2.5Y, value of 3, and chroma of 2.
Redoximorphic features: None
Texture: silty clay or clay. Some pedons have an overwash of silt loam or silty clay loam.
Reaction: Moderately acid to slightly alkaline, except where limed.
Bg horizon:
Color: The upper part has hue of 10YR, 2.5Y, or 5Y, value of 4 or 5, and chroma of 1, or value of 6, and chroma of 1 or 2, or it is neutral with value of 4 to 6, and chroma of 0. The lower part has hue of 10YR, 2.5Y, or 5Y, value of 4 to 6, and chroma of 1 or 2. In some pedons, it is neutral, with value 4 to 6 and chroma of 0.
Redoximorphic features: Masses of oxidized iron in shades of brown are few to common throughout the B horizon.
Texture: Silty clay or clay
Other features: Pressure faces and slickensides
Reaction: Moderately acid to slightly alkaline
2CB or 2BC horizon (where present):
Color: Hue of 10YR, 2.5Y, or 5Y, value of 4 to 6, and chroma of 1 or 2. In some pedons, it is neutral, with value 4 to 6 and chroma of 0.
Redoximorphic features: Masses of oxidized iron in shades of brown are few to common throughout. Masses of reduced iron in shades of gray are few to common throughout.
Texture: Silt loam, loam, silty clay loam, sandy loam, fine sandy loam or very fine sandy loam
Other features--Weak, subangular blocky structure and faint clay films on pores and ped faces in some pedons.
Reaction: Moderately acid to moderately alkaline
2C horizon:
Color: Hue of 10YR, 2.5Y, or 5Y, value of 4 to 6, and chroma of 1 or 2. In some pedons, it is neutral, with value 4 to 6 and chroma of 0; also, below a depth of 76 centimeters (30 inches), some pedons are variegated in shades of brown, yellow, and gray.
Redoximorphic features: Masses of oxidized iron in shades of brown are few to common throughout.
Texture: Silt loam, loam, silty clay loam, sandy loam, fine sandy loam or very fine sandy loam, and the lower part in some pedons is loamy fine sand.
Reaction: Moderately acid to moderately alkaline
COMPETING SERIES:
Keyespoint series is the only other series in the same family.
Alligator,
Bowdre,
Earle,
Forestdale,
Newellton,
Perry,
Sharkey, and
Tensas soils are in closely related families.
Keyespoint - Keyespoint soils are in similar landscape positions, have value of 4 or 5 and chroma of 2 in the upper part of the Bg horizon and are somewhat poorly drained.
Alligator,
Perry, and
Sharkey soils have a very-fine particle-size class and do not have a contrasting texture within a depth of 100 centimeters (40 inches).
Bowdre and
Newellton soils have a clayey upper solum that is less than 51 centimeters (20 inches) thick over loamy material; also, Bowdre soils have a mollic epipedon.
Earle soils have an acid reaction class.
Forestdale and
Tensas soils have an argillic horizon.
GEOGRAPHIC SETTING:
Parent material: Clayey over loamy alluvium
Landscape: Younger meander belts of the Mississippi River and its tributaries
Landform(s): lower part of natural levees
Geomorphic component (3D): rises and talfs
Slope: 0 to 5 percent
Elevation: 0 to 32 meters (0 to 105 feet)
Mean annual air temperature: 13 to 20 degrees C (56 to 68 degrees F)
Mean annual precipitation: 1117 to 1625 millimeters (44 to 64 inches)
Frost-free period: 198 to 289 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the closely related
Bowdre,
Earle,
Forestdale,
Newellton, and
Sharkey series and the
Bruin,
Commerce,
Convent, and
Mhoon series. All these soils are associated across the nearly linear surface of the broad floodplain of the Mississippi River.
Bowdre - The somewhat poorly drained Bowdre soils are found in slightly higher positions on natural levees and have a mollic epipedon and have a clayey upper solum that is less than 51 centimeters (20 inches) thick over loamy material.
Bruin - The moderately well drained Bruin soils are found on top of natural levees and have a cambic horizon with a brown matrix and are coarse-silty in the 100 centimeters (40 inches) particle-size control section.
Commerce - The somewhat poorly drained Commerce soils are in higher positions on natural levees and are fine-silty in the 25 to 100 centimeters (10 to 40 inches) particle-size control section.
Convent - The somewhat poorly drained Convent soils are coarse-silty in the 25 to 100 centimeters (10 to 40 inches) particle-size control section.
Earle - The poorly drained Earle soils have an acid reaction class.
Forestdale - The poorly drained Forestdale soils are found on low natural levees, have a fine particle-size class, and have an argillic horizon.
Mhoon - The poorly drained Mhoon soils are found on level to slightly depressed floodplains and are fine-silty in the 25 to 100 centimeters (10 to 40 inches) particle-size control section.
Newellton - The somewhat poorly drained Newellton soils are found in slightly higher positions on natural levees and have a clayey upper solum that is less than 51 centimeters (20 inches) thick over loamy material.
Sharkey - The poorly drained Sharkey soils are found in lower positions on the landscape, have a very-fine particle-size class and do not have a contrasting texture within a depth of 100 centimeters (40 inches).
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class: Poorly drained
Saturated hydraulic conductivity (Ksat): slow to very slow in the Ap and Bg horizons (0.01 to 1.40 um/sec) to moderate in the 2CBg and 2Cg horizons (4.00 to 14.00 um/sec).
Permeability: slow to very slow in Ap and Bg horizons: 0.01 to 1.4 um/sec (0.00 to 0.2 in/hr) and moderate in the 2CBg and 2Cg horizons: 4.00 to 14 um/sec (0.6 to 2.0 in/hr).
Surface runoff: high on slopes less than 1 percent, and very high on slopes of 1 percent or more
Depth to seasonal high water table: Episaturation - They are saturated in the surface layer and along cracks and slickenside faces in the subsoil during December through April in normal years.
Flooding frequency and duration: These soils are frequently flooded unless protected by levees, especially during the spring and fall months.
Ponding frequency and duration: None
USE AND VEGETATION: Most of the Tunica soils are used for growing cotton, soybeans, small grains, corn, hay, and pasture. A small amount is in bottomland hardwoods. Important commercial trees are cherrybark oak, eastern cottonwood, green ash, Nuttall oak, sweetgum, and American sycamore. Native vegetation includes elm, water oak, hackberry, pecan, and water hickory.
DISTRIBUTION AND EXTENT:
Major Land Resource Areas (MLRA): Southern Mississippi Valley Alluvium (131A).
Extent: Large
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Auburn, Alabama
SERIES ESTABLISHED: Tunica County, Mississippi; 1949.
REMARKS: The series type location pedon was moved from Adams County, Mississippi, to Tunica County, Mississippi in 2004.
Particle-size control section: the zone from 25 to 100 centimeters (10 to 40 inches).
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the surface to a depth of about 8 centimeters (3 inches) (Ap horizon)
Cambic horizon - the zone from approximately 8 to 65 centimeters (3 to 26 inches) (Bg1, Bg2 horizons)
Non-intersecting Slickensides - the zone from approximately 8 to 65 centimeters (3 to 26 inches)(Bg1, Bg2 horizons)
Lithologic Discontinuity - at 65 centimeters (26 inches)
Soil classified according to the 12th Edition of the Keys to Soil Taxonomy, 2014
ADDITIONAL DATA:
Lab data for samples from the type location pedon were run at Mississippi State University (S01-MS143-003).
OSD User Site ID: 2001MS143500
OSD User Pedon ID: 2001MS143500
National Cooperative Soil Survey
U.S.A.