LOCATION ST. AUGUSTINE FLEstablished Series
TAXONOMIC CLASS: Siliceous, hyperthermic Aquic Udipsamments
TYPICAL PEDON: St. Augustine fine sand in a cleared area. (Colors are for moist soil.)
A--0 to 4 inches; very dark gray (10YR 3/1) fine sand; weak medium granular structure; very friable; about 5 percent, by volume, sand size to 3 cm diameter fragments of shell; many uncoated light gray (10YR 7/1) sand grains, moderately alkaline; clear smooth boundary. (1 to 6 inches thick)
C1--4 to 7 inches; brown (10YR 5/3) fine sand; single grained; loose; about 10 percent, by volume, sand size to 3 cm diameter fragments of shell; common black (10YR 2/1) sand size heavy mineral grains; few fine faint light yellowish brown (10YR 6/4) masses of iron accumulation; moderately alkaline; gradual smooth boundary. (3 to 26 inches thick)
C2--7 to 10 inches; light gray (10YR 7/2) fine sand; single grained; loose; less than 5 percent by volume sand size to 3 cm in diameter fragments of shell; many coarse faint light yellowish brown (10YR 6/4) and few fine faint brownish yellow (10YR 6/6) masses of iron accumulation; moderately alkaline; gradual smooth boundary. (3 to 22 inches thick)
C3g--10 to 27 inches; light gray (2.5Y 7/2) fine sand; single grained; loose; few bodies of dark greenish gray (5GY 4/1) sandy clay 1 to 3 cm in diameter; few fragments of shell, sand size to 3 cm in diameter; few coarse distinct brownish yellow (10YR 6/6) masses of iron accumulation in upper 6 inches of horizon; moderately alkaline; gradual wavy boundary.
C4g--27 to 33 inches; gray (10YR 6/1) fine sand; single grained; loose; few bodies of dark gray (2.5Y 4/1) sandy clay 1 to 5 cm in diameter; about 30 percent, by volume, sand size to 1 cm in diameter fragments of shell; few fragments of shell up to 5 cm in diameter; moderately alkaline; clear smooth boundary.
C5g--33 to 80 inches; gray (5Y 5/1) fine sand; single grained; loose; about 5 percent, by volume, sand size to 1 cm in diameter fragments of shell; few black (10YR 2/1) heavy mineral grains; moderately alkaline. (Combined thickness of the Cg horizon is 20 to 70 inches.)
TYPE LOCATION: St. Johns County, Florida; northeast corner of intersection of Gerado and Alcazar Streets, Davis Shores Subdivision, Sec. 17, T. 6 S., R. 30 E.
RANGE IN CHARACTERISTICS: Soil reaction ranges from slightly acid to moderately alkaline in all horizons. Thickness of the fill material ranges from 20 to more than 80 inches. Fragments of shell are calcareous and range mostly from sand size to 6 cm in diameter. Shell content ranges from less than 5 to 70 percent, by volume. Weighted average shell content (2 mm or larger) in the control section is less than 20 percent. Fragments of shell are stratified in some pedons. Depth to the loamy or clayey bodies is less than 40 inches. Base saturation of these bodies is more than 35 percent. Underlying material is generally sandy but some pedons have silty clay loam, clay, or sandy clay Ab and Cb horizons at depths of more than 40 inches.
The A horizon has hue of 10YR, value of 3 or 4, and chroma of 1 or 2. Texture is sand or fine sand.
The C1 and C2 horizons have hue of 10YR, value of 3 to 7, and chroma of 1 to 3, Redoximorphic features in shades of brown and yellow range from none to common. Gray colors are due to uncoated sand grains. Texture is sand, fine sand, or loamy fine sand.
The Cg horizon has hue of 10YR to 5GY, value of 4 to 8, and chroma of 1 or 2; neutral with value of 4 to 6. Redoximorphic features in shades of gray, brown, and yellow range from none to common. Texture is sand, fine sand, loamy sand, or loamy fine sand. Silty clay loam, clay loam, or sandy clay bodies range from few to common in at least some part of this horizon. They have hue of 5GY, value of 4 or 5, and chroma of 1; or hue of 2.5Y, value of 4 or 5, and chroma of 2. These bodies are stratified in some pedons. Fragments of a histic, mollic, albic, or argillic horizons range from few to common.
COMPETING SERIES: This is the competing Matlacha series. Closely related series are Adamsville, Broward, Canaveral, and Satellite. Broward and Satellite soils lack significant fragments of shell, also Broward soils are shallow to limestone. Matlacha soils have more than 15 percent limestone fragments. All of the closely related soils are uncoated and all lack fragments of fine textured material.
GEOGRAPHIC SETTING: St. Augustine soils are on broad to narrow flats and slight ridges and knolls bordering tidal marshes and estuaries near the coast of Peninsular Florida. Slopes are dominantly 0 to 5 percent. These soils consist of moderately thick to thick deposits of sandy materials mixed with marine shell fragments and bodies of loamy and clayey materials. They have been dredged or dug, transported and redeposited as a layer of fill, mostly in tidal marsh areas. Near the type location, the average annual precipitation ranges from 52 to 58 inches and the mean annual temperature ranges from 72 to 73 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are Moultrie, Pellicer, Riviera, Satellite, Tisonia, and Winder series. Moultrie soils are poorly drained and have Bh horizons. Pellicer soils are very poorly drained, occupy lower positions in the landscape and have clayey particle-size class. Riviera and Winder soils are poorly drained and have argillic horizons. Satellite soils are sandy throughout and lack loamy or clayey fragments. Tisonia soils have organic horizons overlying clayey mineral horizons. Tisonia soils are thermic.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Moderately rapid or rapid permeability except in pedons with clayey horizons below 40 inches which have very slow permeability.
USE AND VEGETATION: Most areas of these soils are used for urban development. Some areas have natural vegetation of southern red cedar and cabbage palm with an understory or waxmyrtle, blackberry, greenbrier, and panicums.
DISTRIBUTION AND EXTENT: Peninsular Florida. This series is of small known extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Auburn, Alabama.
SERIES ESTABLISHED: St. Johns County, Florida; 1981.
REMARKS: These soils were formerly mapped as Arents or Udorthents. The water table is at depths of 20 to 30 inches for 2 to 6 months in most years. In rises above a depth of 20 inches briefly during periods of high rainfall. It recedes to more than 50 inches during long dry periods. These soils are subject to flooding for very brief periods during hurricanes.