LOCATION MAHAN                   LA

Established Series
Rev. WWK-JLD-MJB
12/2022

MAHAN SERIES

The Mahan series consists of very deep, well drained, moderately permeable soils that formed in loamy and clayey sediments. These soils are on uplands in the Western Coastal Plains. Slopes range from 1 to 15 percent. Mean annual precipitation is about 1448 mm (57 in) and the mean annual air temperature is about 14.1 degrees C (57.5 degrees F)

TAXONOMIC CLASS: Fine, kaolinitic, thermic Typic Hapludults

TYPICAL PEDON: Mahan fine sandy loam, on a convex 3 percent slope, in clear cut area, at an elevation of 102 m (330 ft). (Colors are for moist soil unless otherwise stated)

Ap--0 to 13 cm (0 to 5 in); yellowish red (5YR 4/6) fine sandy loam, weak fine subangular blocky structure; friable; many medium and fine roots; common coarse roots; about 12 percent (by volume) ironstone nodules, 2 to 10 mm, nonflat, subrounded strongly cemented; strongly acid; clear smooth boundary. (Thickness of the A horizon is 8 to 20 cm [3 to 8 in])

Bt1--13 to 53 cm (5 to 21 in); red (2.5YR 5/6) sandy clay; moderate coarse subangular blocky structure; friable; common medium and fine roots; common fine tubular pores; many thin continuous clay films on surfaces of peds; about 2 percent by volume ironstone nodules, 2 to 10 mm, nonflat, subrounded, strongly cemented ; strongly acid; clear wavy boundary.

Bt2--53 to 89 cm (21 to 35 in); red (2.5YR 5/8) sandy clay loam; moderate medium subangular blocky structure; friable; few medium and common fine roots; common medium and fine tubular pores; common thin discontinuous clay films on surfaces of peds; common medium distinct yellowish red (5YR 4/6) masses of oxidized iron throughout matrix; about 3 percent by volume ironstone nodules, 2 to 10 mm, nonflat, subrounded, strongly cemented; strongly acid; clear smooth boundary.

Bt3--89 to 127 cm (35 to 50 in); red (2.5YR 4/6) sandy clay loam; weak medium subangular blocky structure; friable; few fine roots; common thick discontinuous clay films on surfaces of peds; about 7 percent by volume ironstone nodules, 2-10 mm, nonflat, subrounded, strongly cemented ; few petroferric fragments that are 8 to 25 cm (3 to 10 in) across the long axis; common white (10YR 8/1) platy clay bodies (kaolin) up to 2.5 cm (1 in) thick oriented along relict bedding planes; strongly acid; clear smooth boundary. (Combined thickness of Bt horizon is 51 to 127 cm [20 to 50 in])

BC--127 to 150 cm (50 to 59 in); red (2.5YR 5/6) sandy clay loam; many coarse distinct yellowish red (5YR 5/8) masses of oxidized iron throughout matrix; weak medium blocky structure; friable; few slightly brittle peds; few fine roots; few thin discontinuous clay films on surfaces of peds; about 9 percent by volume ironstone nodules, 2 to 10 mm, nonflat, subrounded, strongly cemented; few petroferric fragments 8 to 25 cm (3 to 10 in) across the long axis, flat, angular, strongly cemented; common fine white bodies of clay (kaolin); common fine pockets of strong brown (7.5YR 5/6) sandy loam; strongly acid; clear smooth boundary. (Thickness of the BC horizon is 0 to 61 cm [0 to 24 in])

C--150 to 208 cm (59 to 82 in); stratified yellowish red (5YR 5/8) sandy clay loam and yellowish brown (10YR 5/8) sandy loam; massive; friable; common prominent white (10YR 8/1) clay bodies of kaolin, maximum thickness of alternating layers is 15 cm (6 in); very strongly acid.

TYPE LOCATION: Claiborne Parish, Louisiana; about 7.25 miles west northwest of Athens; about 2,300 feet north and 3,200 feet east of the southwest corner of sec. 1, T. 19 N., R. 8 W.

USGS topographic quadrangle: Langston, LA
Latitude: 32 degrees 39 minutes 54.003 seconds N
Longitude: 93 degrees 8 minutes 30.13 seconds W
Datum: WSG84
UTM Easting 486712.91 m
UTM Northing 3614158.84 m
UTM Zone 15.

RANGE IN CHARACTERISTICS:
Solum thickness: 100 to more than 152 cm (40 to more than 60 in)
Gravel-sized ironstone nodules: comprise 1 to 40 percent of the volume of the A horizon and 0 to 15 percent of the Bt, BC, and C horizons.
Fragments: few coarse petroferric fragments 8 to 51 cm (3 to 20 in) across are in the Bt, and BC horizons of most pedons.

Particle-size control section (weighted average):
Clay content: 35 to 60 percent

A or Ap horizon
Hue: 5YR, 7.5YR or 10YR
Value: 3 to 5
Chroma: 2 to 6
Texture: sandy loam, fine sandy loam, or their gravelly counterparts
Rock fragments: amount-1 to 40 percent; size-2 to 10 mm; kind-ironstone
Reaction: strongly acid to moderately acid (5.1-6.0) except where limed

E horizon (where present)
Hue: 5YR or 7.5YR
Value: 4 or 5
Chroma: 4 to 6
Texture: loamy fine sandy, sandy loam, or fine sandy loam
Rock fragments: amount-1 to 15 percent; size-2 to 10 mm; kind-ironstone
Reaction: strongly acid to moderately acid (5.1-6.0)

Bt horizons
Hue: 10R, 2.5YR or 5YR
Value: 4 or 5
Chroma: 6 or 8
Texture: clay, sandy clay, sandy clay loam, clay loam or loam
Silt content of the Bt horizon: less than 30 percent
Clay films: location-on ped surfaces; contrast-faint to distinct
Redox concentrations: amount-0 to 19 percent; size-fine to medium; contrast-faint to distinct; boundary-sharp; location-throughout matrix
Mottles (lithochromic): amount-0 to 10 percent; size-fine to medium; contrast-faint to distinct; boundary-sharp
Rock fragments: 0 to 15 percent total; 0 to 8 percent nodules; 0 to 10 percent fragments; mostly ironstone fragments with some sandstone
Other features: amount-0 to 19 percent; size-fine to medium; kind-fine white bodies of clay (kaolin) throughout
Reaction: very strongly acid to moderately acid (4.5 to 6.0)

BC horizon (where present)
Hue: 10R, 2.5YR or 5YR
Value: 4 or 5
Chroma: 6 or 8
Texture: sandy clay, sandy clay loam, clay loam, sandy loam, fine sandy loam
Clay films: location-surfaces of peds; contrast-faint to distinct
Redox Concentrations: amount-0 to 19 percent; size-fine to medium; contrast-faint to distinct; boundary-sharp; location-throughout matrix
Redox depletions: amount-0-5 percent; size-very fine to fine; contrast-faint to prominent; boundary-diffuse; location-old root channels
Iron-manganese concentrations: amount-0 to 25 percent; size-fine to coarse; kind-oxidized iron
Mottles (lithochromic): amount-0 to 10 percent; size-fine to medium; contrast-faint to distinct; boundary-sharp
Rock fragments: 0 to 15 percent total; 0 to 10 percent nodules; 0 to 30 percent fragments; mostly ironstone fragments with some sandstone
Other features: amount-0 to 19 percent; size-fine to medium; kind-fine white masses of clay (kaolin) throughout; amount-0 to 19 percent; size-fine to medium; kind-pockets of strong brown (7.5YR 5/6) of sandy loam
Reaction: very strongly acid to moderately acid (4.5 to 6.0)

C horizon (where present)
Hue: 5YR to 10YR
Value: 5 or 6
Chroma: 6 or 8
Texture: stratified sandy clay loam, sandy loam, or clay loam
Other features: small pockets and horizontal seams of whitish clay (kaolin) range from none to many. Thin to thick layers of fractured weakly cemented sandstone are in some pedons
Reaction: very strongly acid to moderately acid (4.5 to 6.0)

COMPETING SERIES: Soils in the same family are Appling(NC), Aragon(GA), Cecil(NC), Chestatee(GA), Georgeville(SC), Herndon(SC), Hulett(AL), Kolmoki(GA), Madison(NC), Mayodan(NC), Nankin(GA), Pacolet(SC), Spotsylvania(VA), and Wedowee(NC). Similar competing series include Alto(TX), Bub(TX), Cuthbert(TX), Kirvin(TX), Luverne(AL), Hallsummit(LA), Nacogdoches(TX), Redsprings(TX), Sacul(AR), Sweatman(MS), and Trawick(TX).
Appling, Cecil, Chestatee, Georgeville, Herndon, Hulett, Madison, Mayodan, Pacolet, Spotsylvania, and Wedowee soils formed in acid residuum on the Piedmont uplands and are underlain by residuum, saprolite, or crystalline rock.
Alto, Bub, Hallsummit, Nacogdoches, Redsprings, and Trawick soils have a base saturation of more than 35 percent within 50 inches below the top of the argillic horizon.
Aragon soils have chert fragments throughout.
Cuthbert, Kirvin, Luverne, Sacul, and Sweatman soils have mixed mineralogy and do not have a high content of siderite.
Kolomoki soils are on stream terraces and formed in fluvial sediments that contain an appreciable amount of silt.
Nankin soils are less red than the Mahan soils, and they do not contain fragments of ironstone.

GEOGRAPHIC SETTING:
Parent Material: iron-rich clayey fluviomarine sediments high in siderite derived from unspecified sedimentary rock
Landscape: Coastal Plain
Landform: interfluve
Slope: 1 to 15 percent
Mean annual precipitation: 1143 to 1626 mm (45 to 64 in)
Mean annual air temperature: 8.9 to 21.0 (48 to 70 degrees F)
Frost free days: 200 to 270
Elevation: 48.8 to 154.4 m (160 to 510 ft)

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Sacul(AR) soils and the Betis(TX), Bowie(TX), Briley(TX), Darley(LA), Eastwood (TX) Ruple(LA), and Ruston(LA), and Woodtell soils.
Betis and Briley soils are on similar positions, have thick sandy epipedons, and loamy particle-size control sections.
Bowie and Ruston soils are on similar positions and have fine-loamy control sections.
Darley and Ruple soils are on slightly higher positions and have nearly continuous layers of ironstone in the lower parts of the soil
Eastwood soils are on similar positions and have smectitic mineralogy and vertic properties
Sacul soils are on similar positions and have mixed mineralogy
Woodtell soils are on lower side slopes and have base saturation that is greater than 35 percent at a depth of 50 inches below the top of the argillic horizon.

DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderate to moderately slow. Runoff is low on 1 to 5 percent slopes, and medium on 5 to 15 percent slopes.

USE AND VEGETATION: Most areas are in woodland. Forest vegetation includes loblolly and shortleaf pines, hickory, southern red oak, sweetgum, and other hardwood trees.

DISTRIBUTION AND EXTENT: Louisiana and east Texas. LRR-P; MLRA 133B. The series is of large extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas

SERIES ESTABLISHED: Claiborne Parish, Louisiana; 1986. The series name was taken from that of a small community in Claiborne Parish, Louisiana.

REMARKS: The Mahan soils were formerly included with the Kirvin series.

Diagnostic horizons recognized in this pedon:
Particle-size control section: 13 to 64 cm (5 to 25 in) (Bt1, Bt2 horizons)
Ochric epipedon: 0 to 13 cm (0 to 5 in) (Ap horizon)
Argillic horizon: 13 to 127 (5 to 50 in) (Bt1, Bt2, Bt3 horizons)
Redoximorphic concentrations: 35 to 150 cm (13.7 to 59 in) (Bt2 and BC horizon)
Other features recognized in this pedon:
Ironstone nodules: 0 to 150 cm (0 to 59 in), (Ap, Bt1, Bt2, Bt3, and BC horizons)
Petroferric fragments: 89 to 150 cm (35 to 59 in), (Bt3 and BC horizon)

ADDITIONAL DATA: Laboratory data for the typifying pedon were obtained from the Louisiana Agricultural Experiment Station, sample S83LA027-5(1-8).

Taxonomic Version: Keys to Soil Taxonomy, Twelfth Edition, 2014

---

National Cooperative Soil Survey
U.S.A.