LOCATION TOISNOT NC
Established Series
Rev. REH:CMM:DLN
10/2021
TOISNOT SERIES
The Toisnot series consists of poorly drained, slowly permeable soils that formed in fluvial or marine sediments in the upper Coastal Plain. Slopes range from 0 to 2 percent.
TAXONOMIC CLASS: Coarse-loamy, siliceous, semiactive, thermic Typic Fragiaquults
TYPICAL PEDON: Toisnot loam--on a nearly level slope under mixed hardwood and pine at an elevation of about 160 feet. (Colors are for moist soil unless otherwise stated.)
Oi--0 to 1 inch; partially decayed leaves, moss, and twigs.
A--1 to 7 inches; very dark gray (10YR 3/1) loam; weak medium granular structure; very friable; many medium and coarse roots; very strongly acid; clear wavy boundary. (3 to 8 inches thick)
Eg--7 to 14 inches; gray (10YR 6/1) loamy sand; massive; friable (slightly brittle); few medium and fine roots; about 5 percent of this horizon is A1 material; few small bodies of clean sand; very strongly acid; clear wavy boundary. (5 to 20 inches thick)
Btg/Eg--14 to 29 inches; dark gray (10YR 4/1) sandy loam; about 15 percent of this horizon is gray (10YR 6/1) loamy sand; brittle; weak medium subangular blocky structure; friable; few fine roots; few small bodies of clean sand; few irregular tongues 3 to 8 inches in diameter and 2 to 5 feet apart; very strongly acid; clear irregular boundary. (10 to 24 inches thick)
Ex--29 to 46 inches; light gray (10YR 7/1) sandy loam; massive; very hard (difficult to cut with spade) dry or very slightly moist, when adjacent horizons are saturated; common medium distinct grayish brown (10YR 5/2) and light brownish gray (10YR 6/2) masses of iron accumulation; very strongly acid; gradual irregular boundary. (10 to 30 inches thick)
Btg--46 to 62 inches; gray (10YR 6/1) sandy clay loam; weak medium subangular blocky structure; friable; few fine roots; sandy loam decreases with depth and is brittle; few small bodies of clean sand; many coarse faint light gray (10YR 7/1) sandy loam iron depletions; very strongly acid; gradual wavy boundary. (10 to 24 inches thick)
2Cg1--62 to 81 inches; gray (10YR 5/1, 10YR 6/1) sandy clay; massive; firm; few fine roots; common medium faint light brownish gray (10YR 6/2) and light gray (10YR 7/2) iron accumulations and common fine faint dark gray (10YR 4/1) iron depletions; very strongly acid; gradual wavy boundary.
2Cg2--81 to 91 inches; light gray (10YR 7/1) clay; massive; very firm, plastic; few fine roots; few fine distinct yellow (10YR 7/6) iron accumulations; very strongly acid.
TYPE LOCATION: Robeson County, North Carolina; 2 miles south of St. Pauls; 1-1/8 miles south of Great Marsh Church; 100 feet east of SR 1759.
RANGE IN CHARACTERISTICS: Depth to the upper boundary of the fragipan commonly ranges from 20 to 40 inches but in some areas it ranges from 10 to 45 inches. In wet seasons, the fragipan is dry to moist, whereas, the adjacent horizons are saturated. Reaction ranges from extremely acid to strongly acid throughout the profile, unless the surface has been limed.
The Ap or A horizon has hue of 10YR, value of 2 to 4, and chroma of 1 or 2, or hue of N, value of 2 or 3. Texture is loam, sandy loam, loamy sand, or silt loam.
The Eg horizon has hue of 10YR or 2.5Y, value of 5 to 7, and chroma of 1 or 2, or hue of N, value of 6 or 7. Texture is commonly loamy sand, sandy loam, sand, or silt loam.
The Btg/Eg horizon has hue of 10YR, value of 4 to 7, and chroma of 1 or 2. It is sandy loam, fine sandy loam, or silt loam.
The Ex horizon has hue of 10YR, value of 7, and chroma of 1 or 2, and may have white or pale brown mottles or bodies. Texture is fine sandy loam, sandy loam, loamy fine sand, or loamy sand. The clay content ranges from 2 to 18 percent and is usually on the lower end of the range. The white bodies have less clay, whereas, the grayer and browner materials have more clay. The proportion of brittle material is about 60 percent of the matrix which is brittle or slightly hard. A dry fragment slakes or fractures when placed in water.
The Btg horizon has hue of 10YR, value of 4 to 6, and chroma of 1 or 2. Masses of iron accumulation in shades of brown and yellow range from few to many. In some pedons, the Btg2 horizon is mottled in shades of gray, yellow, and brown. Texture is commonly sandy clay loam, but ranges to include fine sandy loam, sandy loam, or sandy clay.
The 2Cg horizon is gray or is mottled. Texture is variable including sandy, loamy, or clayey sediments. This horizon is stratified and includes gravelly layers in some pedons.
COMPETING SERIES:
Mashulaville is the only series in the same family.
Bibb,
Lynchburg,
Myatt,
Plummer,
Rains, and
Rutlege series are in related families. Mashulaville soils contain more silt or more very fine sand in all horizons and more clay in the fragipan. Bibb, Lynchburg, Myatt, Plummer, Rains, and Rutlege soils lack fragipans. In addition, Lynchburg soils have browner colors.
GEOGRAPHIC SETTING: Toisnot soils are in shallow depressions, around the heads of drainageways, and on the outer fringe of stream terraces next to the better drained uplands, in the upper Coastal Plain. They occupy the transition areas between soils with contrasting drainage. On some landscapes, these soils extend down shallow drainageways for short distances. Slopes are generally less than 2 percent. The soil formed in moderately coarse textured fluvial or marine sediments. Near the type location, the mean annual rainfall is 49 inches and mean annual temperature is 62 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing
Bibb,
Plummer,
Rains, and
Rutlege series, and the
Dunbar,
Goldsboro,
Norfolk,
Portsmouth, and
Wagram series. Except for Portsmouth soils, all of these soils are on the adjacent higher landscapes and have better drainage and lack fragipans. Portsmouth soils have umbric epipedons, are fine-loamy, and lack fragipans.
DRAINAGE AND PERMEABILITY: Poorly drained; slow to ponded runoff; slow permeability.
USE AND VEGETATION: Most areas are in mixed forests of hardwoods and pine. Native trees include oak, maple, sweetgum, yellow-poplar, and loblolly pine, with understory plants as sweet bay, myrtle, gallberry, and smilax. Small acreages have been cleared and used for pasture, corn, and soybeans.
DISTRIBUTION AND EXTENT: Upper Coastal Plain areas of North Carolina and possibly South Carolina and Virginia. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina
SERIES ESTABLISHED: Robeson County, North Carolina; 1972.
REMARKS: Toisnot soils formerly were included in the Bibb, Plummer, and Rains series and classified in the Low Humic-Gley great soil group. The brittle layer of this soil will not qualify as a fragipan, but is placed here due to pragmatic reasons. This layer appears to fit the concept of a densipan as described by Dr. Smith in SSSA Proceedings, volume 39, page 369-370. The soil horizon depths were revised on 10/2021 to ensure the description began at the soil surface.
ADDITIONAL DATA: North Carolina State University Soils Department. Laboratory data for two pedons from Robeson County, North Carolina, from the fragipan horizon.
Bulk
Depth % Sand % Silt % Clay Density
inches gm/cc
1. 21-38 67.0 31.0 2.2 2.1
2 30-46 67.4 27.0 5.7 ---
TABULAR SERIES DATA:
SOI-5 Soil Name Slope Airtemp FrFr/Seas Precip Elevation
NC0086 TOISNOT 0- 2 60- 65 190-230 45- 52 100- 300
NC0142 TOISNOT 0- 2 60- 65 190-230 45- 52 100- 300
SOI-5 FloodL FloodH Watertable Kind Months Bedrock Hardness
NC0086 NONE COMMON 0-1.0 APPARENT DEC-APR 60-60
NC0142 NONE - APPARENT - 60-60
SOI-5 Depth Texture 3-Inch No-10 Clay% -CEC-
NC0086 0-14 L SIL 0- 0 100-100 5-25 1- 7
NC0086 0-14 LS SL 0- 0 100-100 5-15 1- 5
NC0086 14-29 SL FSL SIL 0- 0 100-100 5-15 1- 3
NC0086 29-46 LS SL 0- 0 100-100 5-15 1- 3
NC0086 46-81 SR S L 0- 0 100-100 15-30 3- 6
NC0142 0-14 L 0- 0 100-100 7-17 1- 7
NC0142 0-14 LS SL 0- 0 100-100 5-15 1- 5
NC0142 14-29 SL FSL 0- 0 100-100 5-15 1- 3
NC0142 29-46 LS SL 0- 0 100-100 7-17 1- 3
NC0142 46-81 SR S L 0- 0 100-100 15-30 3- 6
SOI-5 Depth -pH- O.M. Salin Permeab Shnk-Swll
NC0086 0-14 4.5- 5.5 .5-2. 0- 0 2.0- 6.0 LOW
NC0086 0-14 4.5- 5.5 .5-2. 0- 0 2.0- 6.0 LOW
NC0086 14-29 4.5- 5.5 0.-1. 0- 0 0.2- 0.6 LOW
NC0086 29-46 4.5- 5.5 0.-.5 0- 0 0.06- 0.2 LOW
NC0086 46-81 4.5- 5.5 0.-.5 0- 0 0.06- 0.2 LOW
NC0142 0-14 4.5- 5.5 .5-2. 0- 0 2.0- 6.0 LOW
NC0142 0-14 4.5- 5.5 .5-2. 0- 0 2.0- 6.0 LOW
NC0142 14-29 4.5- 5.5 0.-1. 0- 0 0.2- 0.6 LOW
NC0142 29-46 4.5- 5.5 0.-.5 0- 0 0.06- 0.2 LOW
NC0142 46-81 4.5- 5.5 0.-.5 0- 0 0.06- 0.2 LOW
National Cooperative Soil Survey
U.S.A.