LOCATION REYNOSA TXEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, active, hyperthermic Torrifluventic Haplustepts
TYPICAL PEDON: Reynosa silty clay loam--cropland. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 7 inches; grayish brown (10YR 5/2) silty clay loam, dark grayish brown (10YR 4/2) moist; weak medium and coarse subangular blocky parting to medium and coarse granular; surface crust is about 1 unit higher in value; hard, friable; few flakes of mica; slightly effervescent; moderately alkaline; abrupt smooth boundary. (5 to 8 inches thick)
A--7 to 14 inches; grayish brown (10YR 5/2) silty clay loam, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure; hard, friable; few wormcasts; common fine pores; strongly effervescent; moderately alkaline; diffuse smooth boundary. (4 to 12 inches thick)
Bk--14 to 47 inches; light brownish gray (10YR 6/2) silty clay loam, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure; hard, friable; common wormcasts and spots of brownish colored decaying organic material; common fine pores; common films and threads of calcium carbonate; strongly effervescent; moderately alkaline; diffuse wavy boundary. (20 to 40 inches thick)
BC--47 to 73 inches; pale brown (10YR 6/3) silty clay loam, brown (10YR 4/3) moist; massive moist, weak medium and coarse subangular blocky structure dry; hard, friable; many thin lenses of silt loam; strongly effervescent; moderately alkaline.
TYPE LOCATION: Starr County, Texas; about 1 mile north, 75 degrees east of Grulla; in a field 100 feet east of a field road, which is about 2,400 feet north of its intersection with the main east-west road (or street in Grulla); this intersection is 0.75 mile east of the terminal of Farm Road 2360.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 40 to 60 inches. Depth to evident stratification is 30 to about 50 inches. Secondary calcium carbonate in the form of films and threads and masses occurs at depths of 14 to 34 inches. Reaction is moderately alkaline.
The A horizon has hue of 10YR, value of 5 or 6, and chroma of 2 or 3. Texture is silt loam or silty clay loam.
The B horizon has hue of 10YR, value of 5 or 6, and chroma of 2 or 3. Texture is silt loam or silty clay loam and has less than 15 percent sand that is coarser than very fine sand.
The BC or C horizon has hue of 10YR value of 6 or 7, and chroma of 2 to 4. The average texture is silty clay loam or silt loam. Individual strata are 0.5 cm to 20 cm thick and range from clay to loamy fine sand inclusive. Visible secondary calcium carbonate in the forms of films, threads, masses and concretions range from scarcely evident to about 3 percent.
COMPETING SERIES: There are no competing series in the same family. Similar soils are the Conalb, Guadalupe, Lagloria, and McAllen series. Conalb soils have carbonatic mineralogy. Guadalupe and McAllen soils are in the fine-loamy family. In addition, Guadalupe soils have a thermic temperature regime. Lagloria soils are in the coarse-loamy family.
GEOGRAPHIC SETTING: Reynosa soils are on nearly level to gently sloping areas on old stream terraces. The soils no longer receive sediments from stream overflow, and have developed weakly expressed structure. The soil formed in silty calcareous sediments several feet thick. Slope gradients are mostly less than 1 percent but range up to 3 percent. Mean annual precipitation ranges from about 17 to 27 inches, mean annual temperature is 70 to 74 degrees F. Frost free days range from 250 to 270, and elevation ranges from 700 to 1200 feet. Thornthwaite annual P-E indices range from 20 to 32.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Cameron, Harlingen, Lagloria, Laredo, Olmito, and Runn series. Cameron soils have a contrasting textural class of clayey over loamy control section. Harlingen, Olmito, and Runn soils are in the fine family. Laredo soils have a mollic epipedon. These soils occur on similar surfaces.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderate. Runoff is negligible on slopes less than 1 percent and low on 1 to 3 percent.
USE AND VEGETATION: Use is primarily irrigated cropland, but some areas are used as dry cropland and rangeland, The main crops are cotton grain sorghum, and a wide variety of cool season vegetables. Native grasses consist of trichloris, little bluestem Texas wintergrass, and bristlegrass. Woody species include large mesquite trees, spiny hackberry, lotebush, blackbrush, and common hackberry.
DISTRIBUTION AND EXTENT: Southern Rio Grande Plain of Texas and probably in Mexico. The series is of moderate extent, probably about 500,000 acres.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Starr County, Texas; 1966.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 14 inches (Ap & A horizon)