LOCATION PATRICK TXEstablished Series
TAXONOMIC CLASS: Clayey over sandy or sandy-skeletal, carbonatic, thermic Typic Calciustolls
TYPICAL PEDON: Patrick clay--pasture.
(Colors are for dry soil unless otherwise
stated.)
A--0 to 10 inches; dark grayish brown (10YR 4/2) clay, very
dark grayish brown (10YR 3/2) moist; moderate fine granular structure; hard, friable; few roots; few rounded limestone and
chert pebbles; calcareous; moderately alkaline; clear smooth boundary. (8 to 14 inches thick)
Bw--10 to 22 inches; brown (7.5YR 5/4) clay, dark brown
(7.5YR 4/4) moist; weak fine subangular blocky and moderate
medium granular structure; hard, friable; few roots; few chert
and limestone pebbles; calcareous; moderately alkaline; abrupt
wavy boundary. (6 to 16 inches thick)
2Ck--22 to 120 inches; brownish very gravelly loamy sand; structureless; weakly cemented by calcium carbonate and fractured
in upper part, loose below; about 20 percent of soft masses and concretions of calcium carbonate; about 60 percent by volume of rounded limestone and chert gravel; calcareous; moderately
alkaline.
TYPE LOCATION: Travis County, Texas; 500 feet south of the
junction of U.S. Highway 183 and Onion Creek; in a pit 100 feet
east of U.S. Highway 183.
RANGE IN CHARACTERISTICS: Solum thickness above the very gravelly 2Ck horizon ranges from 20 to 30 inches. Coarse fragments of
rounded limestone and chert pebbles above the 2Ck horizon range
from a few to about 20 percent. Coarse fragments in the 2Ck
horizon are 50 to about 75 percent. Calcium carbonate equivalent
of the soil fraction smaller than 20 mm, is 40 to 70 percent by weight in the upper 10- to 40-inch section with the highest percentage occurring in the 2Ck horizon.
The A horizon is dark grayish brown (10YR 4/2), brown (7.5YR 4/2),
or dark brown (7.5YR 3/2). It is clay loam or clay and their gravelly counterparts.
The B horizon is brown (7.5YR 5/4; 10YR 5/3), light brown (7.5YR 6/4), light yellowish brown (10YR 6/4), reddish yellow (7.5YR
6/6), brownish yellow (10YR 6/6), yellowish brown (10YR 5/4, 5/6),
or strong brown (7.5YR 5/6). It is clay loam or clay. The fine-earth in the 2Ck horizon is mostly fragmented limestone with
an estimated texture of sand or loamy sand.
COMPETING SERIES: There are no series in the same family.
Similar soils include the
Austin,
Bolar,
Doss,
Purves,
Real, and
Somervell series. None of these series have strongly contrasting particle-size classes in their control sections. Austin soils
lack calcic horizons. Bolar, Doss, Real, and Somervell soils have
a paralithic or lithic contact with limestone. In addition, Doss
and Real soils, as well as Purves soils, have sola less than 20 inches thick and Somervell and Real soils have more than 35
percent coarse fragments in the upper part of the control
section.
GEOGRAPHIC SETTING: Patrick soils occur on nearly level to
strongly sloping uplands on ancient terraces of about Pleistocene age. Slope gradients are plane to convex, and are dominantly less than 5 percent but range from 0 to 10 percent. The soil formed in calcareous clay over very gravelly sediments. The climate is dry subhumid to moist subhumid. The average annual rainfall is 30 to
36 inches and the Thornthwaite P-E indices are 40 to 58. The mean annual temperature is 67 to 70 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Altoga, Karnes, Lewisville, and Venus soils. Altoga and Karnes soils lack mollic epipedons. Lewisville and Venus soils have thicker sola, and lack very gravelly horizons.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderate permeability.
USE AND VEGETATION: Principal use is pasture and range. Some
areas are used for growing small grain and grain sorghums. Native vegetation is mainly buffalograss, threeawn, Texas wintergrass, sideoats grama, and a few mesquite trees. Many areas have been
mined for road building materials.
DISTRIBUTION AND EXTENT: Central Texas along major streams.
Series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: McLennan County, Texas; 1939.