LOCATION LEVAC TXEstablished Series
TAXONOMIC CLASS: Fine, smectitic, hyperthermic Oxyaquic Vertic Hapludalfs
TYPICAL PEDON: Levac silt loam--cropland. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 5 inches; very dark grayish brown (10YR 3/2) silt loam; weak fine subangular structure; hard, friable; many fine roots; few dark reddish brown (5YR 3/4) iron accumulations along root channels; neutral; abrupt smooth boundary. (4 to 8 inches thick)
Bt--5 to 18 inches; grayish brown (10YR 5/2) silty clay loam; weak fine subangular blocky structure; hard, friable; common fine and few medium roots; few fine pores; few dark reddish brown (5YR 3/4) iron accumulations along root channels; few faint clay films; few iron-manganese concretions; moderately alkaline; gradual wavy boundary. (5 to 20 inches thick)
Btssg--18 to 34 inches; light brownish gray (10YR 6/2) clay; moderate medium prismatic structure parting to moderate fine subangular blocky; very hard, very firm; few fine roots; few fine pores; common medium distinct yellowish brown (10YR 5/6) and yellowish red (5YR 5/6) iron accumulations; few distinct slickensides; few faint clay films; few very dark gray (10YR 3/1) krotovinas; few very coarse calcium carbonate concretions; very slightly effervescent; moderately alkaline; gradual wavy boundary. (10 to 35 inches thick)
Btkg--34 to 52 inches; light brownish gray (10YR 6/2) silty clay; moderate medium prismatic structure parting to moderate fine subangular blocky; very hard, very firm; few fine roots; few fine pores; common medium distinct yellowish brown (10YR 5/6) iron accumulations; few faint clay films; few very dark gray (10YR 3/1) krotovinas; 15 to 20 percent coarse and very coarse calcium carbonate concretions; strongly effervescent; moderately alkaline; gradual wavy boundary. (10 to 35 inches thick)
Btg--52 to 80 inches; light brownish gray (10YR 6/2) silty clay; moderate medium prismatic structure parting to moderate fine subangular blocky; very hard, very firm; common medium distinct yellowish brown (10YR 5/6) and yellowish red (5YR 5/6) iron accumulations; few faint clay films; few coarse calcium carbonate concretions; strongly effervescent; moderately alkaline.
TYPE LOCATION: Jefferson County, Texas; from the intersection of Texas Highway 73 and 124 southwest of Hampshire; 11.9 miles east on Texas Highway 73; 0.9 mile south on private road; 0.15 mile east on field road; 500 feet north in cropland. (Latitude 29N, 49, 50; Longitude 94W, 09, 30)
RANGE IN CHARACTERISTICS: Solum thickness is more than 80 inches. Weighted average clay content of the particle-size control section ranges from 35 to 45 percent. Depth to carbonates and depth to matrix that effervesces ranges from 10 to 30 inches. The soil is usually moist, but during the summer of some years cracks 1/2 to 1 inch wide extend to a depth greater than 20 inches. Depth to wedge shaped peds and slickensides ranges from 15 to 25 inches. Linear extensibility ranges from 6.0 to 8.0 cm in the upper 40 inches of the soil. The surface layers are saturated 30 to 40 days mainly during late winter and early spring. Redoximorphic features are considered both contemporary and relict. This soil does not have aquic conditions in most years in the upper 40 inches. SAR ranges from 4 to 13 throughout the pedon.
The Ap horizon has color with hue of 10YR or 2.5Y, value of 3 or 4, and chroma of 1 or 2. Texture is loam or silt loam. Reaction ranges from slightly acid to slightly alkaline.
The E horizon, where present, has color with hue of 10YR or 2.5Y, value of 5 or 6, and chroma of 1 or 2. Iron accumulations range from few to many in shades of yellow, brown, and red. Texture is loam or silt loam. Reaction ranges from slightly acid to slightly alkaline. Combined thickness of the Ap and E horizon ranges from 4 to 7 inches.
The Bt horizon has color with hue 10YR to 5Y, value of 4 or 5, and chroma of 1 or 2. Iron accumulations range from few to many in shades of red, yellow, and brown. Texture is silt loam or silty clay loam. Reaction ranges from neutral to moderately alkaline.
The Btssg horizon has color with hue 10YR to 5Y, value of 4 to 6, and chroma of 1 or 2. Iron accumulations range from few to many in shades of red, yellow, and brown. Texture is silty clay or clay. Reaction ranges from neutral to moderately alkaline.
The Btkg and Btg horizons have color with hue of 10YR or 2.5Y, value of 5 or 6, and chroma of 1 or 2. Iron accumulations range from few to many in shades of red, yellow, and brown. Texture is silty clay or clay. Reaction ranges from neutral to moderately alkaline. Calcium carbonate concretions range from coarse to extremely coarse and are up to 4 or 5 inches in length and 2 inches in diameter.
COMPETING SERIES: There are no competing series. Similar soils include Algoa, Bernard, Labelle, Mocarey, Morey, and Viterbo. Algoa and Mocarey soils have a fine-loamy particle-size control section. Bernard, Morey, and Labelle soils have a mollic epipedon. Viterbo soils are acid throughout.
GEOGRAPHIC SETTING: Levac soils are on nearly level uplands. Slopes range from 0 to 1 percent but are mainly less than 0.2 percent. These soils are on the Coast Prairie east of the Trinity River. The soils formed in silty and clayey sediments of the Beaumont Formation of Pleistocene age. These soils have been smoothed and levelled during preparation for rice production. Originally the area these soils occur had a microtopography of intermounds with common mounds and few depressions. Mean annual precipitation ranges from 50 to 60 inches. Mean annual temperature ranges from 70 to 72 degrees F. Frost free days range from 250 to 270 and elevation ranges from 5 to 35 ft above sea level. The Thornthwaite P-E index ranges from 68 to 80.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Anahuac, Labelle, Morey, Spindletop, and Viterbo soils. Anahuac and Spindletop soils have loamy surface layers more than 20 inches thick. Anahuac soils are on low ridges. Spindletop soils are the original mounds of these Levac soils. Labelle and Morey soils are on the same position in the landscape. Viterbo soils are in slightly lower landscape positions next to poorly defined drainageways.
DRAINAGE AND PERMEABILITY: Levac soils are somewhat poorly drained. Permeability is very slow. Runoff is low. These soils are saturated from about 12 to 18 inches below the soil surface, for a period of 30 days or more in most years, mainly from January through March. In 2 to 4 years out of 10 these soils have aquic conditions in the surface layer.
USE AND VEGETATION: Used for rice production or pasture. Pasture is mainly bahiagrass. Native grasses include species of sedges, andropogon, paspalum and panicum.
DISTRIBUTION AND EXTENT: The Gulf Coast Prairie (MLRA 150A) of southeast Texas east of the Trinity River and possibly Louisiana. The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Jefferson County, Texas; 1996
REMARKS: Levac soils are developing in areas that were originally Spindletop soils. The Spindletop soils were on mounds that consisted of windblown silty materials deposited over clayey sediments. These mounds were levelled and an Ap horizon formed during leveling operations.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 5 inches (Ap horizon).
Argillic horizon - 5 to 80 inches (Bt, Btssg, Btkg, and Btg horizons).
Calcic horizon - 34 to 52 inches (Btkg horizon).
Vertic features - Slickensides at a depth of 18 to 34 inches
Oxaquic features - Saturated in the surface and subsurface layer for 30 or more days in most years. In 2 to 4 years out of 10 these soils have aquic conditions.
SOIL INTERPRETATION RECORD NUMBER: TX1009