LOCATION FORBING LA+AREstablished Series
TAXONOMIC CLASS: Very-fine, smectitic, thermic Vertic Paleudalfs
TYPICAL PEDON: Forbing silt loam on a smooth 2 percent side
slope, in pine woodland.
(Colors are for moist soil unless otherwise
stated.)
A1--0 to 4 inches; brown (10YR 4/3) silt loam; weak medium granular structure; friable; many fine and medium roots; common
fine pores; strongly acid; clear wavy boundary. (2 to 6 inches thick)
B21t--4 to 12 inches; yellowish red (5YR 4/6) clay; common medium distinct pale brown (10YR 6/3) and light yellowish brown
(10YR 6/4) mottles; weak medium subangular blocky structure; firm; plastic; common fine roots; common fine pores; thin patchy clay
films on surfaces of peds; medium acid; clear wavy boundary. (6
to 12 inches thick)
B22t--12 to 18 inches; yellowish red (5YR 4/6) clay; weak
medium subangular blocky structure; firm; plastic; common roots; common fine pores; thin patchy clay films on surfaces of peds;
medium acid; clear wavy boundary. (5 to 12 inches thick)
B23t--18 to 24 inches; red (2.5YR 4/6) clay; weak medium subangular blocky strucuture; firm, plastic; common fine roots and pores; common black stains on surfaces of peds; neutral; clear
wavy boundary. (6 to 15 inches thick)
B24t--24 to 36 inches; red (2.5YR 4/6) clay; weak medium subangular blocky structure; firm; plastic; few common
slickensides; shiny surfaces on peds; common medium and coarse calcium carbonate concretions; few black stains; moderately
alkaline; strong effervescence; gradual wavy boundary. (0 to 15 inches thick)
B25t--36 to 61 inches; dark red (2.5YR 3/6) clay; weak medium subangular blocky structure; very firm, few fine roots; common slickensides that do not intersect; common fine and coarse calcium carbonate accumulations; few black stains; strong effervescence; moderately alkaline; gradual wavy boundary. (0 to 30 inches
thick)
B3--61 to 75 inches; dark red (2.5YR 3/6) clay; common medium light olive gray (5Y 6/2) mottles; massive; very firm; common
coarse slickensides; common black stains; strong effervescence; moderately alkaline.
TYPE LOCATION: Caddo Parish, Louisiana; 1200 feet north of
Kingston Road, 240 feet west of powerline; SW1/4SW1/4, Section 5, T16N, R14W.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 60 to 80 inches. The A horizon is very dark grayish brown (10YR 3/2), dark grayish brown (10YR 4/1), or brown (10YR 4/3; 7.5YR 4/4). It is
silt loam or silty clay loam. Some pedons have a thin brownish A2 horizon. The A horizon ranges from slightly acid through strongly acid.
The B2t horizon is yellowish red (5YR 5/6, 4/6), reddish brown
(5YR 4/4), red (2.5YR 4/6), or dark red (2.5YR 3/6). In some
pedons the B2t horizon has few or common brownish mottles. Clay content of the Bt horizon ranges from 60 to 80 percent. Reaction ranges from medium acid through neutral in the upper part and
neutral through moderately alkaline in the lower part. Calcium carbonate concretions that are 2 to 20 mm in diameter make up 1 to
5 percent of the lower Bt horizon in some pedons.
The B3 horizon is reddish brown (5YR 4/4), yellowish red (5YR
4/6), red (2.5YR 4/6), or dark red (2.5YR 3/6), with grayish
mottles. It is clay or silty clay. This horizon is mildly
alkaline or moderately alkaline and has up to 5 percent calcium carbonate concretions in some pedons.
COMPETING SERIES: These are
Annona,
Boswell,
Bryarly,
Counts,
Gore,
McKamie,
Millwood,
Morse,
Stigler,
Tamaha, and
Woodtell
series. Annona and Bryarly soils have less than 60 percent clay
and gray mottles in the B2t horizon. Boswell and Millwood soils
are acid throughout the solum and lack free calcium carbonate. Counts, Stigler, and Tamaha soils have gray mottles within 30
inches of the surface. Gore soils have grayish subhorizons.
McKamie soils have mixed mineralogy and a decrease in clay within
60 inches of the surface. Morse soils are calcareous throughout. Woodtell soils have gray mottles and a decrease in clay within 60 inches.
GEOGRAPHIC SETTING: Forbing soils are on dissected stream
terraces of Pleistocene age. Dominant slopes range from 1 to 8 percent, but some slopes are as steep as 20 percent. Forbing
soils formed in red clayey alluvium most likely eroded from
Permian Red Beds. Climate is warm and humid, mean annual precipitaton is 48 inches, and mean annual temperature is 64
degrees F. at the type location.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing
Gore,
McKamie, and
Morse series and the
Kolin and
Muskogee series.
Kolin and Muskogee soils have yellowish brown silty clay loam
upper Bt horizons.
DRAINAGE AND PERMEABILITY: Forbing soils are moderately well drained. Runoff is medium to rapid and permeability is very slow.
USE AND VEGETATION: Most of the soil is in mixed hardwood and
pine forest. A small part is used for growing crops and pasture.
DISTRIBUTION AND EXTENT: Louisiana, possibly southern Arkansas, eastern Oklahoma, and eastern Texas. The series is of small
extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Caddo Parish, Louisiana, 1978.
REMARKS: These soils were formerly classified in the Red-Yellow Podzolic great soil group. For the most part, in mapping they
were previously included with the McKamie and Morse series.