LOCATION ZACHARY                 LA+AR MO

Established Series
Rev. DFS
11/2018

ZACHARY SERIES

The Zachary series consists of deep, poorly drained, slowly permeable soils that formed in alluvium. These soils are on nearly level flood plains. Slopes range from 0 to 1 percent.

TAXONOMIC CLASS: Fine-silty, mixed, active, thermic Typic Albaqualfs

TYPICAL PEDON: Zachary silt loam--wooded. (Colors are for moist soil unless otherwise stated.)

A1--0 to 2 inches; grayish brown (10YR 5/2) silt loam; moderate medium granular structure; friable; very strongly acid; clear boundary. (1 to 4 inches thick)

A21--2 to 7 inches; light brownish gray (10YR 6/2) silt loam; massive; friable; common brown coatings along root channels; very strongly acid; gradual smooth boundary. (3 to 10 inches thick)

A22g--7 to 28 inches; gray (10YR 6/1) silt loam; common fine distinct yellowish brown (10YR 5/6) and dark brown (7.5YR 4/4) mottles and streaks along root channels; massive; friable; common fine pores; a few vertical streaks of light brownish gray; very strongly acid; abrupt smooth to wavy boundary. (15 to 30 inches thick)

B21tg--28 to 34 inches; gray (10YR 6/1) silty clay loam; common fine distinct yellowish brown (10YR 5/6) and dark brown (7.5YR 4/4) mottles and streaks along root channels; moderate medium and fine prismatic structure; slightly plastic; few thin patchy gray and dark gray clay films; upper 2 inches has distinct coatings of A2 material; few vertical silt coats about 1 mm wide extend throughout the horizon; strongly acid; gradual boundary. (5 to 15 inches thick)

B22tg--34 to 50 inches; light olive gray (5Y 6/2) silty clay loam; few fine distinct yellowish brown (10YR 5/6) mottles and streaks along root channels; moderate fine and medium prismatic structure; slightly plastic; thin clay films; few brown and black concretions; few thin vertical coatings of gray silt loam; strongly acid; gradual boundary. (10 to 20 inches thick) B3g--50 to 60 inches; light olive gray (5Y 6/2) silty clay loam; few fine distinct yellowish brown (10YR 5/6) mottles; weak medium prismatic structure; strongly acid.

TYPE LOCATION: East Baton Rouge Parish, Louisiana; 2.1 miles southeast of junction of Louisiana Highways 19 and 64, NE1/4 sec. 73, T. 5 S., R 1 W., in public park area.

RANGE IN CHARACTERISTICS: Solum thickness ranges from 50 to 70 inches.

The A horizon averages between 10 and 15 percent clay and 8 to 12 percent very fine sand. It ranges from slightly acid through very strongly acid. The A1 or Ap horizon is grayish brown (10YR 5/2), dark grayish brown (10YR 4/2), light gray (10YR 5/1), or dark gray (10YR 4/1). The A2 horizon is gray (10YR 5/1, 6/1), light brownish gray (10YR 6/2), or light gray (10YR 7/1, 7/2). Mottles are few to common in shades of brown. Total thickness of the A1 or Ap and A2 horizon is 24 to 40 inches.

The B2t horizon is gray (10YR 5/1, 6/2; 2.5Y 5/1; 5Y 5/1, 6/1), light brownish gray (10YR 6/2; 2.5Y 6/2), light olive gray (5Y 6/2), or olive gray (5Y 5/2) silty clay loam. Mottles, where present, are in shades of brown. The B2t horizon averages between 27 and 35 percent clay and 10 to 15 percent very fine sand. The clay content of the B2t horizon is at least twice as much as that of the A2 horizon. The clay increase occurs within a vertical distance of 2 inches or less. The B2t horizon is medium acid through very strongly acid.

The B3 horizon is silty clay loam or silt loam.

COMPETING SERIES: There are no other series in this family. Other similar series are the Calhoun, Crowley, Frost, Guyton, Henry, Waverly, and Wrightsville series. Calhoun soils have an A horizon less than 24 inches thick. Calhoun, Frost, Guyton, and Wrightsville soils have tonguing of the A2 horizon into the argillic horizons. Crowley and Wrightsville soils contain more than 35 percent clay in the upper 20 inches of the Bt horizon. Henry soils lack an abrupt change in texture between the A and B horizon and have a fragipan. Waverly soils lack a Bt (argillic) horizon.

GEOGRAPHIC SETTING: Zachary soils are on nearly level flood plains within reach of present flood stages except where protected by levees. The thick A horizon is considered to be the result of slow accumulation of alluvium. The regolith is silty sediments washed from soils formed in late Pleistocene alluvium or aeolian deposits. Mean annual temperature at the type location is about 68 degrees F., and mean annual precipitation is about 60 inches.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Calhoun, Frost, and Waverly soils.

DRAINAGE AND PERMEABILITY: Poorly drained; runoff is slow to very slow; internal drainage is very slow; permeability is slow. Apparent water table is from 0.5 foot to 1.5 feet below the surface December through April.

USE AND VEGETATION: Mostly in hardwood forest and in pasture. A few areas are in cropland.

DISTRIBUTION AND EXTENT: Arkansas, Louisiana, Mississippi, and Tennessee. The series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: AUBURN, ALABAMA

SERIES ESTABLISHED: East Baton Rouge Parish, Louisiana; 1965.

REMARKS: The Racoon series is very similar, but it has soil temperatures of less than 59 degrees F.

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National Cooperative Soil Survey
U.S.A.