LOCATION FETT TXEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic, thermic Aquic Paleustalfs
TYPICAL PEDON: Fett gravelly sandy loam--pasture.
(Colors are for dry soil unless otherwise stated.)
A--0 to 9 inches; brown (10YR 5/3) gravelly sandy loam, dark brown (10YR 4/3) moist; weak fine granular structure; hard, very friable; many roots; 30 percent by volume of siliceous pebbles; slightly acid; abrupt smooth boundary. (7 to 18 inches thick)
E--9 to 14 inches; very pale brown (10YR 7/3) very gravelly sandy loam, pale brown (10YR 6/3) moist; weak fine granular structure; slightly hard, very friable, many roots; 80 percent by volume of siliceous pebbles; slightly acid; abrupt wavy boundary.
(3 to 6 inches thick)
Bt1--14 to 30 inches; prominently mottled yellowish red (5YR 5/8), light brownish gray (10YR 6/2), and yellowish brown (10YR
5/8) very gravelly clay; moderate coarse blocky structure;
extremely hard, very firm, many roots; 70 percent siliceous
pebbles; evident clay films on faces of peds and pebbles; medium acid; abrupt wavy boundary. (10 to 25 inches thick)
Bt2--30 to 70 inches; light brownish gray (10YR 6/2)
gravelly clay; grayish brown (10YR 5/2) moist; many distinct
coarse yellowish brown (10YR 5/8) and red (2.5YR 4/8) mottles; moderate medium and fine angular blocky structure; hard, firm; 10 percent chert pebbles; medium acid; clear smooth boundary. (15 to
45 inches thick)
Bw--70 to 84 inches; brownish yellow (10YR 6/6) sandy clay, yellowish brown (10YR 5/6) moist; common distinct medium light brownish gray (10YR 6/2) mottles; moderate medium and fine angular blocky structure; hard, firm, an estimated 10 percent siliceous pebbles and stones occurring in discontinuous strata; medium
acid.
TYPE LOCATION: Caldwell County, Texas; 7.4 miles south of county courthouse in Lockhart on U.S. Highway 183 and 400 feet east into pasture.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 60 to more than 80 inches. Clay content in the fine-earth fraction of the
upper 20 inches of the Bt horizon is 35 to 60 percent. Siliceous pebbles and a few cobbles comprise 35 to 75 percent of the upper
20 inches of the Bt horizon.
The A horizon is grayish brown, brown, yellowish brown, or pale
brown in hues of 7.5YR and 10YR with value of 5 and 6, and chroma
of 2 through 4. It is gravelly or very gravelly sandy loam or gravelly or very gravelly loamy sand. Reaction ranges from
neutral through medium acid.
The E horizon is pale brown, very pale brown, or light brown in
hue of 7.5YR and 10YR with value of 6 or 7 and chroma of 2 through
4. Texture and reaction are the same as the A horizon.
The Bt horizon is prominently or distinctly mottled in shades of
red, yellow, brown, and gray in hues of 2.5YR through 10YR. The fine-earth fraction is clay or sandy clay. The reaction is
neutral through strongly acid. The lower Bt horizon and Bw
horizon contain 5 to 40 percent siliceous pebbles and cobbles.
The fine-earth fraction is sandy clay loam, sandy clay, or clay
with 25 to 42 percent clay. Secondary accumulation of calcium carbonate occur in some pedons at depth of 50 to 80 inches.
Reaction is medium acid through moderately alkaline. Shaly clay occurs at depths below 60 inches in some pedons.
COMPETING SERIES: There are no series in the same family.
Similar soils include
Axtell,
Chaney,
Crockett,
Hornsby,
Riesel,
Selden, and
Tabor series. All of these soils except Hornsby and Riesel soils and have less than 35 percent coarse fragments in the control section. Hornsby soils have less than 35 percent clay in
the fine-earth fraction of the Bt horizon. Riesel soils lack low chroma mottles due to wetness.
GEOGRAPHIC SETTING: Fett soils occur on nearly level to strongly sloping uplands ridges. Slopes range from 0 to 12 percent and the surfaces are plane to convex. The soil formed in a gravelly
mantle of ancient outwash like those of the Uvalde formation that were deposited over calcareous shaly clay. The climate is moist subhumid. Annual rainfall ranges from 30 to 40 inches.
Thornthwaite P-E indices range from 42 to 55. Mean average annual temperature ranges from 67 to 70 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Crockett and Tabor series of the competing series. The soils occur at slightly lower elevations.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; medium
runoff; very slow permeability.
USE AND VEGETATION: Mostly used for pasture and rangeland.
Native grasses are little bluestem, big bluestem, lovegrass, and panicum species. Post oak and mesquite are the main woody
species.
DISTRIBUTION AND EXTENT: Texas claypan area of central Texas. Series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Caldwell County, Texas; 1972.
REMARKS: The Fett series was formerly included in the Crockett series.