LOCATION CONVENT LA+AR KY MO MS TN

Established Series
Rev. JDS
02/2013

CONVENT SERIES

The Convent series consists of very deep, somewhat poorly drained, moderately permeable soils that formed in recent loamy alluvium. These soils are on nearly level to very gently sloping natural levee positions on flood plains, mainly along the Mississippi River and its distributaries. Slopes range from 0 to 3 percent.

TAXONOMIC CLASS: Coarse-silty, mixed, superactive, nonacid, thermic Fluvaquentic Endoaquepts

TYPICAL PEDON: Convent silt loam, in hardwoods. (Colors are for moist soil unless otherwise stated.)

A--0 to 4 inches; dark grayish brown (10YR 4/2) silt loam; weak fine subangular blocky structure; friable; common fine and medium roots throughout; 1 percent fine faint irregular brown (10YR 5/3) masses of oxidized iron lining pores; 1 percent fine faint irregular grayish brown (10YR 5/2) iron depletions lining pores; slightly acid; clear smooth boundary. (0 to 10 inches thick)

Bg1--4 to 12 inches; grayish brown (10YR 5/2) very fine sandy loam; weak fine subangular blocky structure; friable; few fine roots throughout; 3 percent fine distinct irregular yellowish brown (10YR 5/4) masses of oxidized iron lining pores; 3 percent fine faint irregular grayish brown (10YR 5/2) iron depletions lining pores; slightly alkaline; clear wavy boundary.

Bg2--12 to 24 inches; dark grayish brown (10YR 4/2) silt loam; weak medium subangular blocky structure; friable; 1 percent fine faint irregular grayish brown (10YR 5/2) iron depletions lining pores; 3 percent medium faint irregular brown (10YR 4/3) masses of oxidized iron lining pores; moderately alkaline; clear wavy boundary.

Bg3--24 to 36 inches; grayish brown (10YR 5/2) silt loam; weak medium subangular blocky structure; friable; 3 percent medium prominent irregular strong brown (7.5YR 4/6) masses of oxidized iron lining pores; 1 percent charcoal fragments; moderately alkaline; clear wavy boundary. (Combined thickness of the Bg horizons is 6 to 40 inches)

BCg--36 to 52 inches; grayish brown (10YR 5/2) stratified very fine sandy loam to silt loam; weak medium subangular blocky structure; friable; 3 percent medium distinct irregular dark yellowish brown (10YR 4/4) masses of oxidized iron lining pores; moderately alkaline; clear wavy boundary. (0 to 20 inches thick).

Cg1--52 to 68 inches; grayish brown (10YR 5/2) very fine sandy loam; structureless massive; friable; 3 percent medium distinct irregular yellowish brown (10YR 5/4) masses of oxidized iron throughout; moderately alkaline; clear wavy boundary.

Cg2--68 to 80 inches; grayish brown (10YR 5/2) stratified very fine sandy loam to silt loam; structureless massive; friable; few thin silty clay loam strata 1 to 2 cm. thick; 1 percent fine iron-manganese masses lining pores; 3 percent medium distinct irregular dark yellowish brown (10YR 4/4) masses of oxidized iron throughout; moderately alkaline.

TYPE LOCATION: East Baton Rouge Parish, Louisiana; located 12.7 miles north of State Capitol Building on U.S. Highway 61 to Irene, La., then 2.3 miles southwest on West Irene Road, then 2.23 miles west on river access road, then 1.05 miles northwest along woods trail, then 280 feet east of trail; W. 1/2 Sec. 51; 30 degrees, 36 minutes, 45.76 seconds N. Latitude, 91 degrees, 17 minutes, 24.94 seconds W. Longitude; Walls USGS 7.5 Minute Quadrangle, Louisiana.

RANGE IN CHARACTERISTICS: Solum thickness ranges from 6 to 60 inches. Reaction ranges from moderately acid through moderately alkaline throughout. Many pedons have carbonates in some strata below a depth of 20 inches.

The A or Ap horizon has hue of 10YR, value of 4 or 5, and chroma of 2 or 3; or hue of 7.5YR, value of 4 and chroma of 2. Iron accumulations in shades of brown and iron depletions in shades of gray are present in some pedons. Texture is silt loam, very fine sandy loam, or fine sandy loam.

A thin AB or Bw horizon with hue of 10YR or 2.5Y, value of 4 or 5, and chroma of 3 is present in some pedons. It has common to many iron depletions and masses of iron accumulation. Texture is silt loam, loam, or very fine sandy loam. Where present, the horizon does not extend deeper than 16 inches below the surface.

The Bg horizon has hue of 10YR or 2.5Y, value of 4 or 5, and chroma of 2. Iron accumulations in shades of brown and iron depletions in shades of gray range from few to many. Texture is silt loam, loam, or very fine sandy loam.

The Cg horizon has hue of 10YR or 2.5Y, value of 4 or 5, and chroma of 2, however the range also includes value 6 in the lower part. Iron accumulations in shades of brown and iron depletions in shades of gray range from few to many. Some pedons have thin strata with hue of 10YR, value of 3 to 6, and chroma of 3 or 4; hue of 7.5YR, value of 4 and chroma of 2 to 4; or hue of 5YR, value of 4 and chroma of 2 that comprise up to 40 percent of the 10 to 40 inch control section. Some pedons have thin subhorizons with hue of 10YR, value of 4 or 5, and chroma of 1, or value of 5 and chroma of 3. Texture dominantly is silt loam, loam, or very fine sandy loam, but some pedons have thin strata of finer or coarser material.

An Ab horizon is below a depth of 40 inches in some pedons. The Ab horizon, where present, has hue of 10YR, value of 4 or 5, and chroma of 2. Texture is fine sandy loam, loamy very fine sand, very fine sandy loam, loam, silt loam, silty clay loam, clay loam, silty clay, or clay.

COMPETING SERIES: There are no other series in the same family. The Adler, Commerce, Falaya, McRaven, Vacherie, and Waverly series are in closely related families. Adler soils do not have aquic conditions within the upper 20 inches of the solum. Commerce soils have a fine-silty control section. Falaya and McRaven soils are on flood plains of upland streams and have a buried subsoil. In addition, Falaya soils are more acid. Vacherie soils have a clayey discontinuity within a depth of 40 inches. Waverly soils are on upland streams or alluvial fans and have an active activity class.

GEOGRAPHIC SETTING: Convent soils are on nearly level to very gently sloping natural levee positions on flood plains along the Mississippi River and its distributaries. The soil formed in recent loamy alluvium. Most areas are protected from flooding by levees. The climate is humid temperate. Near the type location, mean annual precipitation is 60 inches and mean annual temperature is 67 degrees F.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the closely related Adler, Cancienne, Commerce, and Vacherie series, and the Crevasse, Bruin, Mhoon, Morganfield, Newellton, Sharkey, and Tunica series. Bruin soils have a cambic horizon and do not have aquic conditions within the upper 20 inches. Crevasse soils are sandy throughout. Mhoon soils have a fine-silty control section and have dominant chroma 1 colors throughout the substratum. Morganfield soils are browner throughout and do not have aquic conditions within a depth of 40 inches. Newelton soils have a clayey solum that extends to a depth of 12 to 20 inches. Sharkey soils are clayey throughout. Tunica soils have a clayey solum that extends to a depth of 20 to 36 inches.

DRAINAGE AND PERMEABILITY: Somewhat poorly drained; low to negligible runoff; moderate permeability. The soil is saturated in all layers below depths of 1.5 to 4 feet from December through June in normal years. It stays saturated within a depth of 20 inches for periods of up to 1 month duration in normal years. Flooding frequency ranges from none to common.

USE AND VEGETATION: Most areas have been cleared and are primarily used for cotton, sugarcane, small grain, soybeans, corn, truck crops, pasture, and hay crops. The native forest vegetation was predominantly oaks, cottonwood, hickories, and sweetgum with an undergrowth of vines and canes.

DISTRIBUTION AND EXTENT: Southern Mississippi Valley alluvium (MLRA 131) in Arkansas, Mississippi, Louisiana, Tennessee, Kentucky and Missouri. The series is of large extent.

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

SERIES ESTABLISHED: St. John the Baptist Parish, Louisiana; 1970.

REMARKS: The series was retypified in East Baton Rouge Parish, Louisiana in 2002 and the classification was changed from an Aeric Fluvaquent to a Fluvaquentic Endoaquept due to the presence of a cambic horizon in most correlated areas.
Diagnostic horizons and features recognized in the type location pedon include:
Ochric epipedon: 0 to 4 inches (A horizon).
Cambic horizon: 4 to 52 inches (Bg horizons).
Aquic conditions: saturation reduction, and redoximorphic features beginning at 16 inches deep (Bg2 horizon)
Irregular organic carbon distribution: 0 to 50 inches (A, Bg, and BCg horizons)

National Cooperative Soil Survey
U.S.A.