LOCATION ANTOSA TXEstablished Series
TAXONOMIC CLASS: Loamy, siliceous, active, hyperthermic Aquic Arenic Paleustalfs
TYPICAL PEDON: Antosa sand--on a 1 percent slope in rangeland. (Colors are for dry soil unless otherwise stated.)
A1--0 to 14 inches; pale brown (10YR 6/3) sand, dark brown (10YR 4/3) moist; single grained; loose, very friable; common fine roots; slightly acid; gradual smooth boundary. (6 to 16 inches thick)
A2--14 to 24 inches; pale brown (10YR 6/3) sand, brown (10YR 5/3) moist; single grained; loose, very friable; few fine roots; slightly acid; gradual wavy boundary. (0 to 20 inches thick)
E--24 to 30 inches; very pale brown (10YR 7/3) sand, pale brown (10YR 6/3) moist; few fine faint to distinct light brownish gray (10YR 6/2) and brownish yellow (10YR 6/6) mottles; single grained; loose, very friable; few fine roots; slightly acid; abrupt wavy boundary. (5 to 12 inches thick)
Btg--30 to 38 inches; light brownish gray (10YR 6/2) sandy clay, grayish brown (10YR 5/2) moist; common fine and medium distinct brownish yellow (10YR 6/6) and reddish yellow (7.5YR 6/6) and few fine prominent yellowish red (5YR 5/6) and red (2.5YR 4/6) mottles; moderate very coarse columnar structure parting to moderate medium blocky; very hard, firm; few fine roots; few fine pores; common patchy clay skins and organic coatings on ped surface; slightly acid; gradual wavy boundary. (3 to 18 inches thick)
Bt1--38 to 47 inches; pale brown (10YR 6/3) sandy clay loam, brown (10YR 5/3) moist; common fine, medium and coarse prominent red (2.5YR 4/6) and yellowish red (5YR 5/6) and few fine and medium distinct grayish brown (10YR 5/2) mottles; moderate very coarse columnar structure parting to moderate medium blocky; very hard, firm; few fine pores; few patchy clay skins and organic coatings on ped surfaces; neutral; gradual wavy boundary. (0 to 14 inches thick)
Bt2--47 to 72 inches; very pale brown (10YR 7/4) sandy clay loam, very pale brown (10YR 7/4) moist; common fine, medium and coarse distinct reddish yellow (7.5YR 6/6) and few fine and medium faint grayish brown (10YR 5/2) mottles; weak fine and medium subangular blocky structure; very hard, firm; few patchy clay skins; mildly alkaline.
TYPE LOCATION: Dimmit County, Texas; 1.7 miles south of Carrizo Springs on Farm Road 186; 1.6 miles south on Farm Road 2368; 1.0 mile west on dirt road; 100 feet north in rangeland.
RANGE IN CHARACTERISTICS: Solum thickness is 60 to 80 inches or more. Thickness of the sandy epipedon is 20 to 40 inches. Reaction ranges from medium acid to neutral in the A, E and upper part of the Bt horizon and slightly acid to moderately alkaline in the lower part of the Bt horizon.
The A1 and A2 horizons have hue of 2.5Y, 10YR, or 7.5YR, value of 5 or 6, and chroma of 2 to 6. It is sand, loamy sand, fine sand, or loamy fine sand.
The E horizon has hue of 10YR or 2.5Y, value of 6 to 8, and chroma of 2 to 4 with few to common, fine, faint to distinct light brownish gray, light gray, brownish yellow and yellowish brown mottles. It is sand, loamy sand, fine sand, or loamy fine sand.
The upper part of the Bt horizon has hue of 10YR. 2.5Y, or 5Y, value of 5 to 7, and chroma of 1 to 3. It has few to common, fine and medium, faint to distinct gray, light gray, yellowish brown, brownish yellow, yellow, very pale brown, or strong brown, and yellowish red mottles. It is sandy clay or sandy clay loam. Sandy clay textures are less than 10 inches thick in most pedons. A thin layer up to about 1 inch thick of light gray sandy loam occurs on the cap of this horizon in many pedons.
The remainder of the Bt horizon has hue of 10YR, 7.5YR, or 5YR, value of 5 to 8, and chroma of 2 to 4. Mottles similar to those in the Bt1 horizon occur, but the redder mottles are more common and contain a higher percentage of coarse mottles with depth. It is sandy clay loam, fine sandy loam, or sandy loam. A few calcium carbonate masses occur in the lower parts of the Bt horizons in some pedons. Weighted average clay content of the upper 20 inches of the Bt horizon ranges from 25 to 35 percent. Some pedons contain few to common fragments of sandstone below 50 inches.
A Cr horizon of sandstone occurs in some pedons below 60 inches.
COMPETING SERIES: There are no competing series in the same family. Similar soils include Aluf, Coving, Hitilo, Leming, Nimrod, Nueces, and Sarita series. Aluf soils have sandy control sections with Bt horizons composed of lamella. Coving and Nimrod soils have mean annual soil temperatures of less than 72 degrees F. Hitilo and Sarita soils have A horizons thicker than 40 inches. Leming soils have a clayey particle-size class and mixed mineralogy. Nueces soils have an ESP of more than 4 in the Bt horizon and have mineralogical lithologic discontinuities associated with increases in clay content in the lower Bt horizon.
GEOGRAPHIC SETTING: Antosa soils occur in nearly level to gently undulating uplands. The surface is plane to hummocky, with slopes of 0 to 3 percent. The soil developed in sandy and loamy sediments in areas of the Carrizo Sand formation. The upper portion of the soil has been somewhat reworked by wind. The climate is semiarid or dry subhumid. Mean annual precipitation ranges from 18 to 24 inches and mean annual temperature ranges from 70 to 72 degrees F. Frost free days range from 260 to 290 days and elevation ranges from 500 to 950 feet. Thornthwaite annual P-E indices ranges from 25 to 31.
GEOGRAPHICALLY ASSOCIATED SOILS: These include Bobillo, Brystal, Duval, Tonio, and Webb series. All these soils, except Bobillo, have epipedons less than 20 inches thick and occur at slightly lower elevations. Bobillo soils have sandy epipedons more than 40 inches thick and occur on similar surfaces. Brystal and Duval soils have fine-loamy control sections. Tonio soils are calcareous and Webb soils have more than 35 percent clay in the upper 20 inches of the Bt horizon.
DRAINAGE AND PERMEABILITY: Moderately well drained; very slow runoff; moderately slow permeability. A perched water table persists immediately above the Bt1 horizon for a few days after heavy rains.
USE AND VEGETATION: Used mostly for range. In excellent condition, vegetation is dominated by seacoast bluestem with scattered motts of live oak and bumelia. With retrogression, the principal plants which increase or invade are balsamscale, threeawn, fringed signalgrass, grassbur, mesquite, pricklypear, tephrosia, beebalm, and a wide variety of weedy forbs.
DISTRIBUTION AND EXTENT: In the northwestern Rio Grande Plain of Texas. The series in of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Dimmit County, Texas; 1982.
REMARKS: Antosa soils were formerly included in the Nueces series.
Diagnostic horizons and features recognized in this pedon are:
Ochric (Arenic) epipedon - 0 to 30 inches. (A1, A2 and E horizons)
Argillic horizon - 30 to 72 inches. (Btg, Bt1 and Bt2 horizons)
Aquic feature - grayish mottles in E horizon. (24 to 30 inches)
Albic horizon - 24 to 30 inches. (E horizon)
Arenic feature - sandy epipedon 20 to 40 inches thick.
Pale feature - clay content does not significantly decrease from the maximum above 60 inches and contains common, coarse mottles with hue of 7.5YR and chroma of more than 5 in the lower part of the argillic. (Bt2 horizon)