LOCATION CAMERON TXEstablished Series
TAXONOMIC CLASS: Clayey over loamy, mixed, active, hyperthermic Vertic Haplustolls
TYPICAL PEDON: Cameron silty clay--cultivated.
(Colors are for dry soil unless otherwise stated.)
Ap--0 to 7 inches; gray (10YR 5/1) silty clay, very dark
grayish brown (10YR 3/2) moist; weak very fine granular structure; very hard, firm but crumbly; calcareous; moderately alkaline;
abrupt smooth boundary. (5 to 9 inches thick)
A1--7 to 15 inches; gray (10YR 5/1) silty clay, very dark grayish brown (10YR 3/2) moist; moderate fine subangular blocky structure; very hard, very firm but crumbly; few pores; few
fragments of snail shell; calcareous; moderately alkaline; clear smooth boundary. (5 to 11 inches thick)
B2--15 to 23 inches; gray (10YR 6/1) silty clay, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure; hard, firm but crumbly; many fine pores; few films and threads of secondary carbonates; calcareous; moderately alkaline; clear wavy boundary. (6 to 16 inches thick)
IICca--23 to 29 inches; light gray (10YR 7/2) silt loam,
grayish brown (10YR 5/2) moist; structureless; hard, friable; 4 percent by volume of soft fine masses of calcium carbonate; calcareous; moderately alkaline; gradual wavy boundary. (4 to 8 inches thick)
IIC--29 to 63 inches; very pale brown (10YR 7/3) silt loam,
pale brown (10YR 6/3) moist; structureless; slightly hard,
friable; calcareous; moderately alkaline.
TYPE LOCATION: Cameron County, Texas; 4 miles north of Los
Fresnos in a cultivated field 900 feet south of field road from
point 0.6 mile east of Farm Road 510 from its intersection with
Farm Road 1847.
RANGE IN CHARACTERISTICS: Solum thickness to a contrasting loamy horizon ranges from 22 to 36 inches. The mollic epipedon ranges
from 10 to 20 inches in thickness. The upper part of the 10 to 40 inch control section is clayey with a clay range of 38 to about 60 percent, and a COLE value of 0.10 to 0.15. The lower part of the control section is loamy with 25 to 35 percent less clay than the upper part. The electrical conductivity is typically less than 2 millimhos but ranges up to 12 millimhos or more in some saline pedons.
The A horizon is gray (10YR 5/1), dark grayish brown (10YR 4/2), grayish brown (10YR 5/2), or brown (7.5YR 5/2; 10YR 5/2). Moist value is less than 3.5. This horizon is silty clay loam, silty
clay, or clay.
The B horizon is gray (10YR 5/1 6/1), grayish brown (10YR 5/2),
light brownish gray (10YR 6/2), or brown (7.5YR 5/2; 10YR 5/3).
It is silty clay or clay. Structure ranges from weak to moderate subangular and angular blocky.
The IIC horizons range from brown (7.5YR 5/2, 5/3, 5/4, 6/4), or light brown, grayish brown (10YR 5/2), brown (10YR 5/3), to very
pale brown (10YR 7/3). Clay content of the IIC horizons ranges
from 16 to about 26 percent. They are silt loam or loam with thin sandy or clayey strata. Secondary carbonates range from a few to about 4 percent by volume of weakly cemented concretions and soft masses. The calcium carbonate equivalent exceeds 15 percent in
all horizons.
COMPETING SERIES: These include the
Denton,
Krum,
Laredo,
Miller,
Raymondville, and
Saneli series. All of these have mean annual
soil temperature less than 72 degrees F., except the Laredo and Raymondville series. Laredo soils have a fine-silty control
section. Raymondville soils have a fine control section and
become more clayey with depth.
GEOGRAPHIC SETTING: Cameron soils occur on nearly level terraces above overflow. Surfaces are plane to weakly concave with
gradients mainly less than 1 percent. The soil formed in
calcareous clayey and loamy alluvial sediments, somewhat
stratified and many feet thick. The climate is dry subhumid to semiarid. The mean annual precipitation ranges from 20 to 28
inches, the mean annual air temperature ranges from 74 degrees to
76 degrees F. Thornthwaite annual P-E index ranges from 22 to
about 34.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the
Harlingen,
Laredo,
Mercedes, and
Olmito series. Harlingen and Mercedes soils have intersecting slickensides, and moist values of the A horizon
are more than 3.5. Olmito soils have a fine 10 to 40 inch control section and lack contrasting textures within 40 inches. The soils occur on adjacent flood plains.
DRAINAGE AND PERMEABILITY: Moderately well drained; slow runoff; moderately slow permeability. A seasonal water table, in places ranges from 5 to 6 feet.
USE AND VEGETATION: Mostly cultivted and irrigated to cotton,
grain sorghum and a wide variety of cool season vegetables. A few small areas have native vegetation consisting of whorled dropseed, plains bristlegrass and trichloris with some mesquite, spiney hackberry and Rio Grande Ash.
DISTRIBUTION AND EXTENT: Occurs principally an old flood plains
and deltas in the lower reaches of the Rio Grande and its major tributaries in southern Texas and probably in Mexico. The soil is inextensive, probably about 5,000 acres.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Cameron County, Texas; 1907; suspended 1963; reactivated 1964.
REMARKS: The Cameron series was formerly classified in the
Alluvial great soil group.