LOCATION DEWITT AR

Established Series
LBW
11/2014

DEWITT SERIES

The Dewitt series consists of very deep, poorly drained, slowly permeable soils that formed in alluvium. These soils are on broad, level to nearly level Prairie terraces in MLRA 131. Slope is dominantly less than 1 percent, but ranges to 3 percent. Near the type location, the average annual temperature is about 63 degrees F and the average annual precipitation is about 53 inches.

TAXONOMIC CLASS: Fine, smectitic, thermic Typic Albaqualfs

TYPICAL PEDON: Dewitt silt loam, in an idle field. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 7 inches; dark grayish brown (10YR 4/2) silt loam; moderate medium granular and weak medium and coarse subangular blocky structure; friable; bottom 2 to 3 inches of horizon is compacted and dense; common fine and medium pores; common fine roots; common medium distinct dark brown (7.5YR 3/2) iron accumulations; common very fine distinct brown (7.5YR 4/4) oxidized rhizosheres around old root channels; common fine and medium iron-manganese concretions; slightly acid; clear smooth boundary. (4 to 9 inches thick)

Eg1--7 to 15 inches; grayish brown (10YR 5/2) silt loam; weak coarse subangular blocky structure; friable; many fine and medium pores; few fine roots; common medium distinct dark yellowish brown (10YR 4/4) and few medium distinct dark brown (10YR 3/3) iron accumulations; few fine dark brown (10YR 3/3) soft iron-manganese masses; common fine and medium iron-manganese concretions; neutral; gradual smooth boundary.

Eg2--15 to 22 inches; light brownish gray (10YR 6/2) silt loam; weak medium and coarse subangular blocky structure; friable; many fine and medium pores; few fine roots; common medium distinct dark yellowish brown (10YR 4/6) iron accumulations; common fine and medium distinct dark yellowish brown (10YR 3/4) soft iron masses; many fine, medium and coarse rounded iron-manganese concretions; neutral; abrupt smooth boundary. (Combined thickness of the Eg horizons ranges from 8 to 20 inches thick.)

Btg1--22 to 33 inches; gray (10YR 5/1) silty clay loam; moderate fine and medium subangular blocky structure; firm; many distinct clay films on faces of peds and lining pores; common fine pores; few fine roots; common fine and medium prominant red (2.5YR 4/6) and few medium faint brown (10YR 5/3) iron accumulations; common fine and medium iron-manganese concretions; few fine and medium soft iron-manganese masses; strongly acid; gradual smooth boundary

Btg2--33 to 43 inches; grayish brown (10YR 5/2) silty clay loam; moderate medium and coarse subangular blocky structure; firm; many distinct clay films on faces of peds and lining pores; few fine pores; few fine roots; common medium and coarse faint brown (10YR 5/3) and few medium and coarse distinct yellowish brown (10YR 5/6) iron accumulations; common fine iron-manganese concretions; common fine to medium brown to black soft iron-manganese masses; few medium black manganese accumulations on ped faces; strongly acid; gradual smooth boundary.

Btg3--43 to 53 inches; grayish brown (10YR 5/2) silty clay loam; moderate medium and coarse subangular blocky structure; firm; many distinct clay films on faces of peds and lining pores; few fine pores; few fine roots; common medium and coarse faint brown (10YR 5/3) and few medium and coarse distinct yellowish brown (10YR 5/6) iron accumulations; common fine iron-manganese concretions; common fine to medium brown to black soft iron-manganese masses; few medium black manganese accumulations on faces of some peds; strongly acid; gradual smooth boundary.

Btg4--53 to 80 inches; light brownish gray (10YR 6/2) silty clay loam; weak coarse and very coarse prismatic parting to moderate medium and coarse subangular blocky structure; firm; common distinct clay films on faces of peds and lining most pores; common fine pores many of which are lined with manganese and some lined with brown (7.5YR 4/4) clay films; many medium and coarse distinct strong brown (7.5YR 5/6) and yellowish brown (10YR 5/6) iron accumulatations; common fine and medium yellow to brown soft iron-manganese masses; many coarse black manganese accumulatins on faces of peds; common coarse and medium black manganese accumulations on some very coarse prism faces; common fine iron-manganese concretions; strongly acid. (Combined thickness of the Btg horizons ranges from 48 to more 60 inches.)

TYPE LOCATION: Arkansas County, Arkansas; NW1/4NW1/4NE1/4, sec. 16, T. 2 S., R. 5 W.

RANGE IN CHARACTERISTICS: Combined thickness of the A and E horizons typically ranges from 12 to 24 inches. Solum thickness is typically more than 80 inches. The content of exchangeable sodium usually increases with depth and may range up to 20 percent in the lower part of the solum, but is too deep to meet the requirements of a natric horizon. Total sand content is less than 10 percent throughout.

The A or Ap horizon has hue of 10YR, value of 3 to 5, and chroma of 1 or 2. A horizons with value of 3 are less 7 inches thick. Reaction normally ranges from very strongly acid to moderately acid, but because of the addition of lime or irrigation water, it can range to neutral. Iron accumulations and depletions are in shades of brown or gray.

The Eg horizon has hue of 10YR or 2.5Y, value of 5 to 7, and chroma of 1 or 2. Texture is silt loam or silt. Iron accumulations and depletions are in shades of brown and gray. Reaction normally ranges from very strongly acid to moderately acid, but because of the addition of lime or irrigation water, it can range to neutral.

The Btg horizon has hue of 10YR or 2.5Y, value of 4 to 6, and chroma of 1 or 2. The upper part of the Btg horizon has common to many, prominent yellowish red, red, or dark red iron accumulations. Brown and gray iron accumulations and depletions may be present throughout. Texture is clay, silty clay, silty clay loam in the upper part and ranges to silt loam in the lower part. Reaction ranges from very strongly acid to neutral.

In some pedons, a 2Bt horizon may be present at depths greater than 60 inches. It has hue of 5YR or 2.5YR, value of 3 to 5, and chroma of 3 through 6. Iron accumulations and depletions are in shades of brown and gray. Texture ranges from silt loam to clay. Reaction ranges from moderately acid to moderately alkaline.

COMPETING SERIES: These are Alusa, Crowley, Kemah, Leaksville, and Meikle series in the same family and Cherokee and Meggett series in closely related families. Alusa soils have A and E horizons less than 12 inches thick and generally contains more sand throughout. Crowley soils have higher soil temperatures and are somewhat poorly drained. Kemah soils contain more sand throughout the solum and are somewhat poorly drained. Leaksville soils have 20 to 40 in sola over shale bedrock and contain shale and quartz fragments throughout. Meikle soils have mean annual precipitation of about 14 inches. In addition, they have sola less than 40 inches thick and contain more sand throughout. Cherokee soils have mixed mineralogy and do not have red iron accumulations in the upper B horizon. Meggett soils have mixed mineralogy and contain more sand throughout.

GEOGRAPHIC SETTING: Dewitt soils are on the Grand Prairie of Arkansas and other similar Prairie terraces in the lower Mississippi Valley; MLRA 131. Slopes are typically less than 1 percent, but ranges to 3 percent. Circular mounds of about 50 to 75 feet in diameter and 15 to 30 inches high were common, but
most of these have been leveled. The parent material is mainly alluvium, but some areas may have been mixed with loess. The average annual temperature ranges from about 60 to 65 degrees F. and the average annual rainfall ranges from about 50 to 55 inches.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ethel, Immanuel, Stuttgart and Tichnor series. Ethel soils, which occur on similar landscapes are in fine-silty particle size family; do not have an abrupt texture and contain a glossic horizon. Immanuel soils, typically occur on more dissected landscapes nearer the terrace escarpment, are in a fine-silty particle size family; contain a glossic horizon and are moderately well drained. Stuttgart soils, which occur on slightly higher positions are moderately well drained. Tichnor soils, which occur on floodplains, have a combined A and E horizon thickness greater than 24 inches and are in a fine-silty particle size family.

DRAINAGE AND PERMEABILITY: Dewitt soils are poorly drained. Runoff is negligible to medium. Permeability is slow. The soils are saturated above the clayey subsoil at a depth of 0.5 to 1.5 feet from December through April.

USE AND VEGETATION: Native vegetation was tall prairie grasses and scattered hardwood timber. Most areas of the soils are now cultivated and used for rice, soybeans, and wheat.

DISTRIBUTION AND EXTENT: Arkansas and possibly Louisiana, and Texas. The series is moderately extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: TEMPLE, TEXAS

SERIES ESTABLISHED: Arkansas County, Arkansas; 1995.

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

Ochric epipedon........0 to 22 inches (Ap,Eg1,Eg2)
Albic horizon..........7 to 22 inches (Eg1, Eg2)
Abrupt texture change..contact between Eg2 and Bgt1
Argillic horizon.......22 to 80 inches (Btg)

These soils were formally mapped in the Crowley series.

National Cooperative Soil Survey
U.S.A.