LOCATION CHATT TXEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, thermic Vertic Calciustolls
TYPICAL PEDON: Chatt clay--cropland.
(Colors are for dry soil unless otherwise stated.)
Ap--0 to 8 inches; dark grayish brown (10YR 4/2) clay, very
dark grayish brown (10YR 3/2) moist; moderate medium blocky and
fine granular structure; very hard, firm, plastic; few fibrous
roots; few rounded pebbles of quartz; moderately alkaline, calcareous; clear smooth boundary. (4 to 8 inches thick)
A1--8 to 17 inches; dark brown (7.5YR 4/2) clay, dark brown (7.5YR 3/2) moist; strong coarse subangular blocky structure; very hard, firm, plastic; few fine roots; common medium pores; few dark wormcasts; a few small pressure faces in lower part; few pebbles
of quartz; few calcium carbonate concretions; moderately alkaline, calcareous; gradual wavy boundary. (8 to 18 inches thick)
B21--17 to 27 inches; reddish brown (5YR 5/4) clay, reddish brown (5YR 4/4) moist; strong fine and medium subangular blocky structure; very hard, firm, plastic; few fine roots; few medium pores; few dark channels and brown wormcasts; few small
slickensides that do not intersect; few calcium carbonate concretions; few pebbles of quartz; moderately alkaline,
calcareous; gradual smooth boundary. (8 to 12 inches thick)
B22ca--27 to 49 inches; reddish yellow (7.5YR 6/6) clay,
strong brown (7.5YR 5/6) moist; moderate medium subangular blocky structure; very hard, firm, plastic; few fine roots; dark reddish brown clay balls ranging up to 1 inch in size; common masses of
soft lime; common calcium carbonate concretions; few pebbles of quartz; moderately alkaline, calcareous; gradual smooth boundary. (15 to 25 inches thick)
B23ca--49 to 80 inches; reddish yellow (7.5YR 6/6) clay loam, strong brown (7.5YR 5/6) moist; weak fine subangular blocky structure; hard, firm, slightly plastic; dark reddish brown clay balls; common calcium carbonate concretions; common pebbles of quartz; moderately alkaline, calcareous; gradual smooth boundary. (20 to 40 inches thick)
Cca--80 to 90 inches; mottled light gray (10YR 7/2) clay
loam, light brownish gray (10YR 6/2) moist and yellow (10YR 7/6), brownish yellow (10YR 6/6) moist; massive and platy structure;
hard, firm; common calcium carbonate concretions; few black concretions; many pebbles of quartz; moderately alkaline,
calcareous.
TYPE LOCATION: Hill County, Texas; about 7 miles south of
Hillsboro. South from Hillsboro on I-35 to Chatt road overpass,
east on Chatt road for 0.5 mile; then 2.0 miles south on old
Abbott road, and east on dirt road to railroad crossing; site is 1,000 feet south in field and about 50 feet east of railroad right-of-way.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 40 to more than 70 inches. Total clay content of the control section ranges from 40 to 60 percent. Silicate clay ranges from 35 to 50
percent. The soils are calcareous throughout and weighted calcium carbonate equivalent of the control section ranges from 25 to 40 percent. Visible soft lime ranges from 5 to 20 percent of the
mass at depths of 30 to more than 50 inches. Pebbles of quartz
less than 3/4 inch in diameter range from 0 to 15 percent.
Pressure faces and small shiny wedge-shaped peds are common.
The A horizon is dark reddish brown (5YR 3/2, 3/3), dark brown
(7.5YR 4/2, 3/2), dark grayish brown (10YR 4/2), dark gray (10YR 4/1), very dark gray (10YR 3/1), and very dark grayish brown (10YR 3/2). It is clay or silty clay.
The B2 horizon is reddish brown (5YR 5/3, 5/4, 4/3, 4/4),
yellowish red (5YR 5/6), dark brown (7.5YR 4/4), brown (7.5YR
5/4), reddish yellow (7.5YR 6/6), strong brown (7.5YR 5/6),
grayish brown (10YR 5/2), brown (10YR 5/3), and yellow (10YR 7/6). It is clay, silty clay, or clay loam.
The Cca horizon is light brownish gray, grayish brown, or pale
brown and is generally mottled with few to many mottles of brown, very pale brown, yellow, and brownish yellow. It is loam or clay loam.
COMPETING SERIES: These are the
Austin,
Bolar,
Denton,
Engle,
Knippa,
Krum,
Lewisville,
Nuvalde,
Quanah,
Rowena,
Sunev, and
Venus series. Austin, Bolar, and Rowena soils have a solum
thickness of less than 40 inches. In addition, Austin soils have
a paralithic contact to chalk and Bolar soils have fine-loamy
control sections. Denton soils have a lithic contact to hard limestone. Engle, Sunev, and Venus soils have fine-loamy control sections. Knippa soils are drier for longer periods of time and
have warmer soil temperatures. Krum soils have less than 25
percent calcium carbonate equivalent in the control section and
have montmorillonitic mineralogy. Lewisville and Quanah soils
have fine-silty control sections. Nuvalde soils lack vertic properties.
GEOGRAPHIC SETTING: The Chatt series is on nearly level to gently sloping terraces in the Blacklands. Slope gradients range from 0
to 3 percent. The soil formed in deep clayey sediments that are
high in calcium carbonate. Climate is moist subhumid. Mean
annual rainfall ranges from 28 to 35 inches. Mean annual
temperature ranges from 64 degrees to 68 degrees F. Thornthwaite
P-E indices range from 48 to 62.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing
Lewisville series, and the
Branyon,
Burleson, and
Houston Black series. Branyon, Burleson, and Houston Black soils have montmorillonitic mineralogy, lack calcic horizons, and have thick very dark gray A horizons with common coarse slickensides that intersect.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderately slow permeability.
USE AND VEGETATION: Mainly cropped to cotton, grain sorghum,
corn, and small grain. Native vegetation includes big bluestem, indiangrass, little bluestem, switchgrass, and a few cottonwood
and pecan trees in some areas.
DISTRIBUTION AND EXTENT: Central Texas, mainly on old stream terraces within the Blackland and Grand Prairie land resource
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
areas. These soils are of moderate extent.
Series Establised: Hill County, Texas; 1975.
REMARKS: These soils were formerly classified in the Rendzina
great soil group. This series was included in the Lewisville and Krum series.
ADDITIONAL DATA: Texas Highway Department (Soils and Base
Material Test Report) Laboratory No. 73-61-R and 73-62-R.