LOCATION AMTRAC FL
Tentative Series
ARW
05/2026
AMTRAC SERIES
MLRA(s)--152A
Depth class--Very deep
Drainage class--Subaqueous
Water depth range--0 to 3 meters (0 to 10 feet)
Parent material--Coarse-loamy lagoonal deposits
Geomorphic location--Barrier coves and high-energy lagoon bottoms
Slope range--0 to 1 percent
Mean annual air temperature--21 degrees C (70 degrees F)
Mean annual water temperature--24 degrees C (75 degrees F)
TAXONOMIC CLASS: Coarse-loamy, mixed, semiactive, nonacid, hyperthermic Grossic Hydrowassents
TYPICAL PEDON: Amtrac fine sand in a barrier cove under 2.0 meters of salt water. (colors are for moist soil unless otherwise stated; electrical conductivity is 1:5 by volume solution mixture unless otherwise stated).
Cseg1--0 to 14 centimeters; very dark gray (N 3/) fine sand; single grain; nonsticky, nonplastic; nonfluid; no sulfurous odor; 3 percent shell fragments; color change with 3 percent hydrogen peroxide; slight effervescence with 30 percent hydrogen peroxide; saline (3.1 dS/m); moderately alkaline (pH 8.3), moderately alkaline (pH 8.3) oxidized pH; clear boundary
Cseg2--14 to 63 centimeters; 95 percent black (N 2.5/) and 5 percent dark gray (5Y 4/1) sandy loam; massive; nonsticky, nonplastic; moderately fluid; 5 percent shell fragments; slight sulfurous odor; no color change with 3 percent hydrogen peroxide; slight effervescence with 30 percent hydrogen peroxide; saline (3.3 dS/m); moderately alkaline (pH 8.0), moderately alkaline (pH 8.3) oxidized pH; gradual boundary
Cseg3--63 to 137 centimeters; very dark greenish gray (10Y 3/1) fine sandy loam; massive; slightly sticky, nonplastic; very fluid; 5 percent shell fragments; moderate sulfurous odor; no color change with 3 percent hydrogen peroxide; slight effervescence with 30 percent hydrogen peroxide; saline (3.9 dS/m); slightly alkaline (pH 7.8), moderately alkaline (pH 8.2) oxidized pH; gradual boundary
Cseg4--137 to 200 centimeters; 95 percent greenish black (10Y 2.5/1) and 5 percent dark olive gray (5Y 3/2) sandy loam; massive; nonsticky, nonplastic; moderately fluid; 4 percent shell fragments; no sulfurous odor; no color change with 3 percent hydrogen peroxide; slight effervescence with 30 percent hydrogen peroxide; saline (3.5 dS/m); slightly alkaline (pH 7.7), moderately alkaline (pH 8.3) oxidized pH
TYPE LOCATION: Franklin County, Florida; Alligator Point Aquaculture Use Zone; approximately 0.8 kilometers (0.5 miles) southeast of Alligator Point Public Boat Launch, approximately 3.4 kilometers (2.1 miles) east of Saint Teresa Passage, and approximately 4.7 kilometers (2.9 miles) west of Tucker Lake; USGS topographic quadrangle: Saint Teresa Beach, FL
Latitude--29.918170
Longitude-- -84.408720
Datum--WGS84
Coordinate source--from hand-held GPS
RANGE IN CHARACTERISTICS:
Depth to bedrock--Greater than 200 centimeters
Manner of failure--Slightly to very fluid in all horizons between 20 and 100 centimeters
Sulfurous odor--None to strong throughout
Soil reaction--Slightly alkaline to strongly alkaline throughout profile (pH 7.4 to 9.0)
Oxidized reaction--Slightly alkaline to strongly alkaline throughout profile (pH 7.4 to 9.0)
Electrical conductivity (1:5 soil to water solution)--2.5 to 5.0 dS m-1 throughout profile
Particle-size control section (weighted average):
Shell fragments--0 to 30 percent
Sand--50 to 80 percent
Clay--8 to 17 percent
Total soil organic carbon stock 0 to 100 centimeters--8 to 16 kg m-2
Total soil organic carbon stock 0 to 200 centimeters--18 to 25 kg m-2
Cseg horizons:
Hue--5Y to 10GY or neutral
Value--2.5 to 4
Chroma--none to 2
Texture--fine sand, loamy fine sand, coarse sandy loam, sandy loam, fine sandy loam, loam, sandy clay loam and their shelly analogs
Organic carbon density--6 to 28 kg m-3
COMPETING SERIES:
These are no competing series in this family
GEOGRAPHIC SETTING:
Landscape--Bays and Lagoons along the Gulf Coast
Landform--Barrier coves and high energy lagoon bottoms
Parent material--Coarse-loamy lagoonal deposits
Slope--0 to 1 percent
Water depth range--0 to 3 meters (0 to 10 feet) below mean sea level
Water salinity range--20 to 35 parts per thousand
Water temperature range--18 to 30 degrees C (64 to 86 degrees F)
Soil temperature range--19 to 27 degrees C (66 to 81 degrees F)
GEOGRAPHICALLY ASSOCIATED SOILS:
These are the
Apalachicola,
Dry Bar,
Eastpoint, McKissack,
Pelican
Reef, Sheepshead, and
Thalinectes soils.
Apalachicola soils--Are on bay and lagoon bottoms and formed in fine-loamy lagoonal deposits.
Dry Bar soils--Are on shoals and reefs and formed in sandy-skeletal lagoonal deposits.
Eastpoint soils--Are on submerged wave-cut platforms and have coarser sandy textures throughout.
McKissack soils--Are in estuarine tidal streams, formed in sandy estuarine deposits and often have chroma of 3.
Pelican
Reef soils--Are on relict flood-tidal deltas and formed in sandy lagoonal deposits.
Sheepshead soils--Are on barrier coves and are sandy throughout.
Thalinectes soils--Are on washover-fans and longshore bars and are sandy throughout.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--Subaqueous
Saturated hydraulic conductivity--High to very high
Soil moisture regime--Peraquic
Soil is continuously inundated by salt water.
USE AND VEGETATION:
Major uses--In 0 to 2 meter water depths, these soils are used for Northern hard-shell clam (Mercenaria mercenaria) and, to a lesser extent, Eastern oyster (Crassostrea virginica) cultivation and production. Non-cultivated areas also support native Southern Quahog clam (Mercenaria campechiensis).
Typical vegetation--Vegetation is largely absent on Amtrac soils managed for aquaculture. Amtrac soils in a natural state support turtle grass (Thalassia testudinum), widgeon grass (Ruppia maritima), and some shoal grass (Halodule wrightii).
DISTRIBUTION AND EXTENT:
General area--Bays and Lagoons along the Gulf
Land Resource Region(s)--T - Atlantic and Gulf Coast Lowland Forest and Crop Region
MLRA(s)--152A
Extent--Small
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Special Projects Office
SERIES ESTABLISHED: Franklin County, Florida, 2026
REMARKS:
Typical Pedon Taxonomic Features:
Fluidity--Moderately fluid or more from 14 to 200 centimeters
Peraquic feature--Zero or positive soil water potential at the soil surface (permanently submerged)
Reduced matrix--The zone from 0 to 200 centimeters has a soil color matric with a chroma of 2 or less
Taxonomic Version: Keys to Soil Taxonomy, Thirteenth Edition, 2022
Other: Named after Amphibious Tractors or AmTracs used at Camp Gordon Johnston, Carrabelle, FL in training for amphibious invasions during WWII. Amtrac soils were previously mapped as water in Florida soil survey publications.
NASIS User Site and Pedon ID: S2026FL037006 with supporting pedon S2025FL037018
____________________________________________________________________________
National Cooperative Soil Survey
U.S.A.