LOCATION IBERIA LA+FL

Established Series
Rev. JDS
10/2018

IBERIA SERIES

The Iberia series consists of very deep, poorly drained, very slowly permeable soils that formed in alkaline clayey alluvium. They are on backswamp positions flanking natural levees on older deta plains of the Mississippi River. Slope is dominantly less than 0.5 percent but ranges up to 1 percent.

TAXONOMIC CLASS: Very-fine, smectitic, hyperthermic Typic Epiaquerts

TYPICAL PEDON: Iberia clay on a broad, level area in a pasture. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 7 inches; very dark gray (10YR 3/1) clay; moderate fine angular blocky structure; very firm; many fine roots throughout; few medium prominent irregular olive yellow (2.5Y 6/6) masses of iron accumulation throughout; neutral; clear smooth boundary. (2 to 10 inches thick)

A--7 to 15 inches; very dark gray (10YR 3/1) clay; moderate fine angular blocky structure; very firm; many fine roots throughout; few fine tubular pores; few fine prominent irregular olive yellow (2.5Y 6/6) masses of iron accumulation throughout; slightly alkaline; clear wavy boundary. (Combined thickness of the Ap and A horizons is 12 to 24 inches)

Bssg1--15 to 21 inches; olive gray (5Y 5/2) clay; moderate medium angular blocky structure parting to strong medium wedge-shaped aggregates; very firm, very sticky and very plastic; many fine roots in cracks; many distinct pressure faces on vertical and horizontal faces of peds and common distinct intersecting slickensides and many prominent very dark gray (10YR 3/1) organic coats on faces of peds; common medium prominent irregular olive yellow (5Y 6/8) masses of iron accumulation between peds; common fine rounded manganese nodules throughout; slightly alkaline; clear smooth boundary.

Bssg2--21 to 30 inches; olive gray (5Y 5/2) clay; strong medium angular blocky structure parting to strong medium wedge-shaped aggregates; very firm, very sticky and very plastic; few fine roots in cracks; many distinct pressure faces on vertical and horizontal faces of peds and common distinct intersecting slickensides; common medium prominent irregular brownish yellow (10YR 6/6) masses of iron accumulation between peds; few fine rounded iron-manganese nodules throughout; slightly alkaline; clear smooth boundary.

Bssg3--30 to 39 inches; light olive gray (5Y 6/2) clay; strong medium angular blocky structure; very firm, very sticky and very plastic; many prominent N 3/ tubular streaks of krotovina material throughout horizon; many distinct pressure faces on vertical and horizontal faces of peds and few distinct intersecting slickensides; many medium prominent irregular brownish yellow (10YR 6/8) masses of iron accumulation between peds; neutral; clear smooth boundary. (Combined thickness of the Bssg horizon is 10 to more than 60 inches thick)

2Btg1--39 to 52 inches; olive gray (5Y 5/2) clay loam; strong coarse prismatic structure parting to strong medium subangular blocky; firm; few fine roots between peds; few fine tubular pores; common distinct clay films on faces of peds; common prominent dark greenish gray (5GY 4/1) organic coats; common medium prominent irregular yellowish brown (10YR 5/6) masses of iron accumulation between peds; few fine rounded iron-manganese nodules throughout; neutral; clear smooth boundary.

2Btg2--52 to 62 inches; dark gray (5Y 4/1) silty clay loam; moderate coarse prismatic structure parting to moderate medium subangular blocky; firm; few fine roots between peds; few fine tubular pores; many distinct clay films on faces of peds; common prominent dark greenish gray (5GY 4/1) organic coats in root channels and/or pores; many medium prominent irregular yellowish brown (10YR 5/8) masses of iron accumulation between peds; neutral; clear smooth boundary. (Combined thickness of the 2Btg horizon is 0 to 40 inches)

2Cg1--62 to 71 inches; greenish gray (5GY 5/1) silty clay loam; weak coarse prismatic structure; firm; few fine roots between peds; few fine tubular pores; common faint dark greenish gray (5GY 4/1) organic coats on faces of peds and in pores; many medium prominent irregular yellowish brown (10YR 5/8) masses of iron accumulation between peds; few fine rounded manganese concretions throughout; neutral; clear smooth boundary.

2Cg2--71 to 80 inches; greenish gray (5GY 5/1) silty clay loam; moderate coarse subangular blocky structure; firm; few fine roots between peds; few fine tubular pores; few distinct pressure faces; common medium prominent irregular light olive brown (2.5Y 5/3) masses of iron accumulation between peds; neutral; clear smooth boundary.

2Cg3--80 to 93 inches; greenish gray (5GY 5/1) silty clay; moderate coarse subangular blocky structure parting to weak coarse wedge-shaped aggregates; firm; few fine roots between peds; many medium prominent irregular yellowish brown (10YR 5/6) masses of iron accumulation between peds; neutral.

TYPE LOCATION: Iberia Parish, Louisiana; approximately 5 miles east of New Iberia on La. Hwy. 87, 1.8 miles east of junction with Hwy. 320, 1.1 miles north on oil well access road, 550 feet southwest of Texaco well 35; Spanish land Grant sec. 26, T. 12S., R. 7E.; Latitude 29 degrees 58 minutes 53.5 seconds N; Longitude 91 degrees 43 minutes 12.7 seconds W., Jeanerette 7.5 min. USGS Quadrangle.

RANGE IN CHARACTERISTICS: Thickness of the solum ranges from 40 to more than 80 inches. Cracks up to 1 inch wide develop to a depth of 20 inches or more during normal years and remain open for about 10 to 30 days.

The Ap and A horizons have hue of 10YR, value of 2 or 3, and chroma of 1 or 2. Texture is clay, silty clay, or silty clay loam in the Ap horizon, and clay in the A horizon. Reaction ranges from moderately acid to slightly alkaline.

The Bssg horizon has hue of 5Y to 10YR, value of 3 to 5, and chroma of 1 or 2 in the upper part. Where hue is 2.5Y or 10YR, chroma is 1. The lower part of the Bssg horizon has hue of 5Y or 2.5Y, value of 4 to 6, and chroma of 1 or 2; or it is neutral (N/) with value of 4 or 5. Masses of iron accumulation are in shades of brown or yellow and range from few to many. Intersecting slickensides range from few to many. Texture is clay. Reaction ranges from neutral to moderately alkaline. Some pedons have a Bkssg horizon that is calcareous below 20 inches with up to 5 percent calcium carbonate concretions.

The 2Btg horizon, where present has hue of 5Y or 2.5Y, value of 4 to 6, and chroma of 1 or 2; or it is neutral (N/) with value of 4 or 5. Masses of iron accumulation are in shades of brown or yellow and range from few to many. Texture is clay loam, silty clay loam, or silty clay. Reaction is neutral to moderately alkaline.

The Cg or 2Cg horizon has hue of 2.5Y to 5GY, value of 4 to 6, and chroma of 1 or 2; or it is neutral (N/) with value of 4 or 5. Iron accumulations are in shades of brown. Texture ranges from silt loam to clay. Reaction is neutral to moderately alkaline.

COMPETING SERIES: There are no other series in the same family. Schriever soils are in a closely related family, but have a lighter colored surface layer, and formed in more recent alluvium on younger delta plains.

GEOGRAPHIC SETTING: Iberia soils are on backswamp positions flanking natural levees on the older delta plains of the Mississippi River. Slopes are mainly less than 0.5 percent but range up to 1 percent. Mean annual precipitation averages about 60 inches near the type location and is uniformly distributed throughout the year. Mean annual temperature averages about 68 degrees F.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Baldwin, Galvez and Loreauville. Galvez and Loreauville soils are on higher positions on the natural levee and have less than 35 percent clay in the subsoil. Baldwin soils are on intermediate positions on the natural levee and have less than 60 percent clay in the subsoil.

DRAINAGE AND PERMEABILITY: Iberia soils are poorly drained. Runoff is low to negligible and permeability is very slow. A perched saturated zone is at a depth of 0 to 2 feet below the surface during December through April in normal years. Unprotected areas flood commonly.

USE AND VEGETATION: Used mainly for growing sugarcane and soybeans. A few areas are used for pasture and hardwood timber production.

DISTRIBUTION AND EXTENT: Lower Mississippi River delta plain of Louisiana, Southern Mississippi Valley Alluvium (MLRA 131). This series is of moderate extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: AUBURN, ALABAMA

SERIES ESTABLISHED: Iberia Parish, Louisiana; 1911.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Umbric epipedon--0 to 15 inches (Ap and A horizons)
Intersecting slickensides--15 to 39 inches (Bssg horizons)
Lithologic discontinuity--at 39 inches (top of 2Btg horizon)
Argillic horizon--39 to 52 inches (2Btg horizon)

ADDITIONAL DATA: Samples from the type location pedon were analyzed by NSSL, Lincoln, Nebraska (S95LA-045-001).

National Cooperative Soil Survey
U.S.A.