LOCATION PORFIRIO TXEstablished Series
TAXONOMIC CLASS: Fine, mixed, active, hyperthermic Aquic Calciustolls
TYPICAL PEDON: Porfirio sandy clay loam--cropland.
(Colors are for dry soil unless otherwise stated.)
Ap--0 to 12 inches; dark gray (10YR 4/1) sandy clay loam,
very dark gray (10YR 3/1) moist; weak medium subangular blocky structure; hard, friable; slightly saline; calcareous; moderately alkaline; clear smooth boundary. (10 to 18 inches thick)
Bk--12 to 20 inches; light brownish gray (10YR 6/2) clay
loam, dark grayish brown (10YR 4/2) moist; moderate medium
prismatic structure parting to moderate fine blocky; hard, firm;
many soft bodies of calcium carbonate; moderately saline;
calcareous; moderately alkaline; gradual smooth boundary. (6 to
16 inches thick)
Bkz--20 to 36 inches; light brownish gray (10YR 6/2) clay
loam, grayish brown (10YR 5/2) moist; few medium distinct
yellowish brown (10YR 5/6) mottles; weak medium prismatic
structure parting to moderate fine blocky; hard, firm; many soft bodies of calcium carbonate; moderately saline, calcareous; moderately alkaline; gradual smooth boundary. (11 to 18 inches thick)
Ckz1--36 to 48 inches; pale brown (10YR 6/3) clay loam, brown (10YR 5/3) moist; few medium distinct yellowish brown (10YR 5/6) mottles; massive; hard, firm; about 20 percent by volume of soft bodies and concretions of calcium carbonate and other crystalline salts; strongly saline; calcareous; strongly alkaline; gradual
smooth boundary.
Ckz2--48 to 65 inches; pinkish gray (7.5YR 7/2) clay loam, pinkish gray (7.5YR 6/2) moist, many coarse prominent yellowish
brown (10YR 5/6) mottles; massive; hard, firm; few fine
concretions of calcium carbonate and other crystalline salts; strongly saline; calcareous; strongly alkaline.
TYPE LOCATION: Willacy County, Texas; 8 miles east of south levee
of North Floodway from its junction with Farm Market Road 1420,
then 0.1 mile south in a cultivated field.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 28 to 42 inches. Depth to secondary carbonates ranges from 8 to 20 inches. Depth to mottling is 10 to 28 inches and the amount and
distinctness increases with depth. Reaction is moderately
alkaline or strongly alkaline.
The A horizon is gray (10YR 5/1), dark gray (10YR 4/1), very dark grayish brown (10YR 3/2), dark grayish brown (10YR 4/2), or
grayish brown (10YR 5/2) sandy clay loam, or clay loam. Salinity ranges from 4 to 16 mmhos/cm.
The Bk horizon is grayish brown (10YR 5/2), light brownish gray
(10YR 6/2), or brown (10YR 5/3) clay loam, sandy clay, or clay.
Clay content ranges from 35 to 45 percent. Mottles are few to
many, fine to medium, faint to distinct yellowish brown (10YR 5/4, 5/6, 5/8), brownish yellow (10YR 6/6, 6/8), and dark yellowish
brown (10YR 4/4). Salinity ranges from 6 to about 12 mmhos/cm.
The C horizon is pinkish gray (7.5Y 7/2, 6/2), pale brown (10YR
6/3), light gray (10YR 6/1), or very pale brown (10YR 7/3, 7/4)
clay loam, clay, sandy clay, or sandy clay loam. Mottles are few
to many, medium to large, distinct to prominent in shades of
yellow and brown. Salinity ranges from 12 to near 100 mmhos/cm.
COMPETING SERIES: There are no series in the same family.
Similar soils are
Olmito and
Raymondville series. Olmito soils
have a mollic epipedon more than 20 inches thick. Raymondville
soils have vertic properties.
GEOGRAPHIC SETTING: Porfirio soils are on nearly level coastal plains and terraces. Slopes are less than 0.5 percent. The soils formed in loamy and clayey sediments. The climate is dry
subhumid. The mean annual precipitation ranges from 26 to 32
inches. The mean annual temperature ranges from 72 to 74 degrees
F., and Thornthwaite annual P-E indices range from 32 to 38.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing
Raymondville series and
Latina,
Lomalta,
Sauz,
Saucel, and
Willamar series. Latina, Sauz, Saucel, and Willamar soils have
less than 35 percent clay in the texture control section. In addition, Latina and Saucel soils have a salic horizon within 75
cm of the soil surface. Lomalta soils have more than 60 percent
clay in the texture control section. These soils occur on similar surfaces.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow runoff, slow permeability. A seasonal water table occurs at depths of 2
to 4 feet in the spring and fall seasons in most years. These
soils pond for short periods after cyclonic storms and other exceptionally high rainfall periods.
USE AND VEGETATION: Used for rangeland and cropland. Cultivated crops are grain sorghum and cotton. Native grass is mainly gulf cordgrass. Other plants are bushy sea-oxeye and big sacaton.
DISTRIBUTION AND EXTENT: These soils are mainly within 30 miles
of the coast in lower South Texas. Series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Willacy County, Texas; 1980.
REMARKS: These soils have not previously been recognized.