LOCATION PHARR TXEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, semiactive, hyperthermic Typic Argiustolls
TYPICAL PEDON: Pharr fine sandy loam--rangeland. (Colors are for dry soil unless otherwise stated.)
A1--0 to 18 inches; dark grayish brown (10YR 4/2) fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; hard, friable; common fine roots; few fine pores; few small shell fragments; calcareous; moderately alkaline; clear wavy boundary. (9 to 20 inches thick)
B2t--18 to 32 inches; brown (10YR 5/3) sandy clay loam, dark brown (10YR 4/3) moist; moderate coarse prismatic structure parting to moderate fine subangular blocky; hard, friable; few fine pores; few thin patchy clay films on faces of peds and in pores; few films and threads of segregated calcium carbonate; calcareous; moderately alkaline; gradual smooth boundary. (8 to 26 inches thick)
B3ca--32 to 42 inches; pale brown (10YR 6/3) sandy clay loam, brown (10YR 5/3) moist; weak coarse prismatic structure parting to weak fine subangular blocky; slightly hard, friable; soft bodies and few concretions of calcium carbonate; calcareous; moderately alkaline; diffuse smooth boundary. (12 to 26 inches thick)
Cca--42 to 72 inches; very pale brown (10YR 7/3) sandy clay loam, pale brown (10YR 6/3) moist; massive; hard, friable; few soft bodies and few concretions of calcium carbonate; calcareous; moderately alkaline.
TYPE LOCATION: San Patricio County, Texas; about 2.4 miles north of the intersection of U. S. Highway 77 and Interstate Highway 37 and 50 feet west of service road in rangeland.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 40 to 80 inches. Secondary lime in the form of films and threads occurs at depths of 15 to 30 inches. Salinity ranges from 0 to 8 mmhos/cm and increases with depth. The soil is noncalcareous in up to 40 percent of the matrix to depths of 28 inches in some pedons.
The A horizon is dark grayish brown (10YR 4/2), grayish brown (10YR 5/2), brown (10YR 5/3), or dark brown (10YR 4/3). It is fine sandy loam, loam, or sandy loam.
The B horizon is grayish brown (10YR 5/2), brown (10YR 5/3; 7.5YR 5/2, 5/4), or pale brown (10YR 6/3). It is sandy clay loam or clay loam and the clay content ranges from 21 to 33 percent.
The C horizon is very pale brown (10YR 7/3), pale brown (10YR 6/3), or light gray (10YR 7/2). It is sandy clay loam or clay loam, with 3 to 25 percent by volume weakly cemented concretions and soft bodies of calcium carbonate.
COMPETING SERIES: These include the Pernitas, Runge, Tela, and Weesatche series of the same family as well as the Brennan, Ost, and Willacy series. Pernitas soils have sola thinner than 40 inches. Runge, Tela, Weesatche, and Willacy soils are noncalcareous in the upper part of the solum. Brennan soils lack mollic epipedons. Ost soils have mean annual soil temperatures less than 72 degrees F.
GEOGRAPHIC SETTING: Pharr soils are on nearly level to gently sloping deltas or coastal terraces. Slopes are mostly less than 2 percent, but range up to about 5 percent. The soil formed in thick, moderately fine textured calcareous sediments of alluvial or eolian origin. The climate is dry subhumid. The average annual precipitation ranges from 24 to 32 inches, and the mean annual temperatures are 70 degrees to about 74 degrees F. Thornthwaite annual P-E index ranges from 28 to 38.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing Brennan, Tela, and Willacy series and the Hargill and Hidalgo series. Hargill soils are noncalcareous for more than 34 inches, and Hidalgo soils lack a Bt horizon.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderate permeability. When irrigated, water may accumulate at depths of 4 to 8 feet below the surface during the spring and/or fall.
USE AND VEGETATION: Much of this soil is cleared, cultivated and irrigated. Irrigated crops are cotton, grain sorghum, vegetables, and citrus. Dryland crops are cotton and grain sorghum. Native grasses are four-flower trichloris, Arizona cottontop, lovegrass tridens, plains bristlegrass, hooded windmillgrass and hairy grama. Other vegetation consists of Texas ebony trees, mesquite, spiny hackberry, blackbrush, catclaw, lote, and pricklypear.
DISTRIBUTION AND EXTENT: Mainly within the lower Rio Grande Valley and Gulf Coast Prairies in southern Texas. Possibly in Mexico. Series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES PROPOSED: San Patricio & Aransas Counties, Texas; 1975.
REMARKS: This series was formerly within the Hidalgo and Willacy series. These soils would have been classified in the Chestnut great soil group.