LOCATION HORNSBY TXEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, active, thermic Aquic Paleustalfs
TYPICAL PEDON: Hornsby gravelly sandy loam - pasture. (Colors are for dry soil unless otherwise stated.)
A1--0 to 8 inches, grayish brown (10YR 5/2) gravelly sandy loam,
very dark grayish brown (10YR 3/2) moist; weak fine granular structure; hard, very friable; many fine roots and pores; 30 percent by volume pebbles of quartz and chert from 0.1 to 1.0 inch in diameter; slightly acid; clear smooth boundary. (6 to 15 inches thick)
E--8 to 18 inches, very pale brown (10YR 7/3) very gravelly loamy sand, brown (10YR 5/3) moist; massive; slightly hard, very friable; many fine roots; few fine pores; 60 percent very coarse pebbles of quartz and chert; slightly acid; abrupt wavy boundary. (0 to 12 inches thick)
Bt1--18 to 37 inches, mottled red (2.5YR 4/6), grayish brown (10YR 5/2), and gray (10YR 6/1) very gravelly sandy clay loam; moderate medium and coarse blocky structure; very hard, firm; few fine roots and pores; few clay films on surfaces of peds; 45 percent very coarse pebbles of quartz, chert, and partially weathered feldspar; strongly acid; clear wavy boundary. (14 to 24 inches thick)
Bt2-- 37-70 inches, reddish yellow (5YR 6/6) very gravelly sandy
clay loam, yellowish red (5YR 5/6) moist, few medium distinct gray (10YR 6/1) mottles; weak coarse blocky structure; very hard, very firm; few fine roots and pores; 50 percent very coarse pebbles of quartz and feldspar; patchy clay films on faces of peds; medium acid in upper part and slightly acid in lower part; gradual smooth boundary. (20 to 40 inches thick)
2C--70 to 82 inches, light gray (2.5Y 7/2) gravelly clay, light brownish gray (2.5Y 6/2) moist, few fine distinct olive yellow mottles; massive; very hard, very firm; few fine pores; 15 percent very coarse pebbles of quartz and feldspar; few medium black-brown concretions; slightly acid.
TYPE LOCATION: Travis County, Texas; about 15 miles south and 80 degrees east of the Capitol in Austin; in a pasture 1,000 feet southeast of the Blake-Manor Road, from a point about 2 miles north of intersection of Blake-Manor Road and Farm Market Road 969. Intersection is about 1.2 miles west of Bastrop-Travis County line via Farm Market 969.
RANGE IN CHARACTERISTICS: Thickness of the solum ranges from 60 to 80 inches. Coarse fragments of chert, quartz, and feldspar range from 15 to 70 percent by volume in the A horizon and from 35 to about 55 percent in the B horizon.
The A and E horizons are grayish brown to pink in hue of 7.5YR and 10YR, value of 5 through 7 and chroma of 2 through 4. Texture ranges from gravelly or very gravelly sandy loam or loamy sand and the thickness ranges from 14 to 20 inches. Reaction range is medium acid through neutral.
The Bt horizon is prominently to distinctly mottled with dry colors of red to gray in hue of 2.5YR through 10YR, value of 4 through 7 and chroma 2 through 8. Gray mottles in the upper 6 inches of the Bt horizon generally decrease in number with depth. Texture of the fine earth fraction ranges from sandy clay loam to clay loam; clay content is about 27 to 35 percent. Reaction of the Bt horizon ranges from strongly acid through neutral.
Some pedons have a reddish to yellowish Bt3 horizon with or without mottles. Texture is sandy clay loam or sandy clay. Reaction ranges from neutral to mildly alkaline. Some pedons have a few weakly cemented calcium carbonate concretions below 50 inches.
The 2C horizon ranges from light gray to pale olive in hue of 5Y through 10YR, value 6 or 7, and chroma 1 through 4. Texture is clay or sandy clay. Coarse fragments range from 0 to about 25 percent by volume. Reaction ranges from slightly acid through moderately alkaline and calcareous.
COMPETING SERIES: Their are no competing series in the same taxonomic class. Similar soils include the Axtell, Chaney, Crockett, Fett, Hilgrave, Selden, Tabor, Vashti, and Voca series. All these soils, except Fett and Hilgrave have less than 35 percent coarse fragments in the control section. Axtell, Chaney, Crockett, Fett, Tabor, and Voca soils have more than 35 percent clay in the fine earth fraction of the upper part of the Bt horizon. Hilgrave soils lack mottles with chromas of 2 or less in the control section and have thinner sola. Selden soils have siliceous mineralogy. Vashti soils are underlain with sandstone within 20 to 50 inches of the surface, and the clay content of the Bt horizon decreases with depth.
GEOGRAPHIC SETTING: Hornsby soils occur on nearly level to gently sloping ridges paralleling major streams. Slopes range from 1 to about 5 percent, and the surfaces are plane to convex. The soil formed in noncalcareous gravelly, sandy, and loamy ancient alluvium several feet thick. The climate is dry subhumid. Average annual rainfall ranges from 30 to 40 inches, Thornthwaite P-E Indices range from 42 to about 55. Mean annual air temperature ranges from about 67 degrees to 70 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing Axtell series, and the Bastrop, Pedernales, and Travis series. Bastrop, Pedernales, and Travis soils lack mottles with chromas of 2 or less within 30 inches of the surface. Pedernales and Travis soils have more than 35 percent clay in their control sections.
DRAINAGE AND PERMEABILITY: Moderately well drained; medium runoff; moderately slow permeability.
USE AND VEGETATION: Used mainly for pasture and native range; few areas are used for cultivated crops such as cotton, grain sorghums, and vegetables. Native grasses mainly are little bluestem, threeawns, Panicum species, and lovegrasses. Post oak and mesquite trees are the main woody plants.
DISTRIBUTION AND EXTENT: Mainly along the Colorado River in central Texas. Series is of minor extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Travis County, Texas; 1969.
REMARKS: The Hornsby series would have been classified in the Red- Yellow Podzolic great soil group.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - 0 to 8 inches.
Albic horizon - 8 to 18 inches.
Argillic horizon - 18 to 70 inches.