LOCATION KEYWEST FL
Established Series
Rev. GWH/CAP/RBT
03/2021
KEYWEST SERIES
MLRA(s): 156A
Soil Survey Regional Office (SSRO) Responsible: Auburn, Alabama
Depth Class: Very deep
Drainage Class: Very poorly drained
Saturated Hydraulic Conductivity: Moderately high to high in the solum and negligible in the rock material
Index Surface Runoff: High
Parent Material: Stratified deposits of calcareous coastal marl and organic materials over oolitic limestone bedrock
Slope: 0 to 1 percent
Elevation: -1.0 to 3 feet above mean sea level.
Mean Annual Air Temperature: 26 degrees C. (78 degrees F.)
Mean Annual Precipitation: 1143 millimeters (45 inches)
TAXONOMIC CLASS: Coarse-silty, carbonatic, isohyperthermic Thapto-Histic Sulfaquents
TYPICAL PEDON: Keywest marl on native mangrove swamp. (Colors are for moist soil unless otherwise stated.)
Lma--0 to 23 centimeters (0 to 9 inches); light gray (10YR 7/1) marly silt loam, white (10YR 8/1), dry; moderate sulfurous odor; weak coarse platy structure parting to weak fine granular; very friable, soft; slightly sticky, nonplastic; common medium roots; common fine and very fine pores; 5 percent shell fragments; strongly effervescent; moderately alkaline (pH 8.2); abrupt smooth boundary. [10 to 50 centimeters (4 to 20 inches) thick]
Oase--23 to 38 centimeters (9 to 15 inches); dark brown (7.5YR 3/2) muck; 30 percent unrubbed, 5 percent rubbed fiber; moderate sulfurous odor, many medium roots; slightly alkaline (pH 7.4); abrupt smooth boundary. [10 to 38 centimeters (4 to 15 inches) thick]
Lma/Oase--38 to 69 centimeters (15 to 27 inches); mucky marl which is stratified with 70 percent by volume light brownish gray (10YR 6/2) marly silty clay loam and 30 percent by volume of dark brown (10YR 3/3) muck, 20 percent unrubbed, 3 percent rubbed fiber; moderate sulfurous odor; massive; very friable, soft; slightly sticky, nonplastic; 3 percent shell fragments; marl is strongly effervescent; moderately alkaline (pH 8.0); clear smooth boundary. [20 to 64 centimeters (8 to 25 inches) thick]
L'ma--69 to 165 centimeters (27 to 65 inches); light gray (10YR 7/1) marly silt loam; moderate sulfurous odor; massive; friable, soft; slightly sticky, nonplastic; few fine roots; few fine pores; thin strata of dominantly sand size shells; strongly effervescent; moderately alkaline (pH 8.4); abrupt smooth boundary. [20 to 107 centimeters (8 to 42 inches) thick]
2R--165 centimeters (65 inches); weakly to strongly cemented oolitic limestone bedrock; solution holes up to 102 centimeters (40 inches) or more deep can be filled with sandy and/or loamy material.
TYPE LOCATION: Monroe County, Florida; Boot Key; 1.2 miles south of the intersection of US Hwy 1 and County Road 931, 275 feet north and 255 feet east of the corner on County Road 931; 3,065 feet west and 275 feet north of the southeast corner of Sec. 16. T. 66 S., R. 32 E.; latitude 24 degrees 41 minutes 28.17 seconds N longitude 81 degrees 6 minutes 14.07 seconds W; WSG84; USGS Marathon, FL quadrangle.
RANGE IN CHARACTERISTICS:
Solum thickness: greater than 150 centimeters (59 inches)
Depth to seasonally high water table: 0 to 15 centimeters (0 to 6 inches)
Soil Reaction: Slightly acid to moderately alkaline
Depth of ochric epipedon: 2 to 25 centimeters (1 to 10 inches)
Depth to limestone bedrock: 150 centimeters (59 inches) or more deep
Rock and/or shell fragments: 0 to 10 percent throughout
Calcium carbonate equivalence: 80 percent or more in the marl
EC (mmhos/centimeter): 16 to 32 or more
Sodium Absorption Ratio: 10 to 60 percent or more
Exchangeable Sodium Percent: 10 to 30 percent or more
Fiber content: Un-Rubbed: 15 to 50 percent; rubbed less than 17 percent
Particle-size control section (weighted averages):
Clay content: 5 to 34 percent
Carbonate Clay content: 4 to 30 percent
Silt content: 50 to 90 percent
Range of Individual Horizons:
Lma horizon:
Color: Hue 10YR or 2.5Y, value 4 to 8, and chroma: 1 or 2
Texture: marly silt loam or silt
Sulfurous odor: slight to strong
Oase horizon:
Color: Hue 5YR to 10YR or Neutral, value 2 to 4, and chroma 2 to 4
Texture: muck
Sulfurous odor: slight to strong
Oese horizon (where present) has similar color criteria with rubbed fiber content 17 percent or more with similar sulfurous odors.
Lma/Oase horizon:
Marl Material
Color: Hue 10YR or 2.5Y, value 4 to 8, chroma 1 or 2
Texture: marly silt loam, marly silty clay loam, or marly silt
Sapric Material
Color: Hue 5YR to 10YR or Neutral, value 2 to 4, and chroma 2 to 4
Texture: muck
Sulfurous odor: slight to strong
Lma horizon:
Color: Hue 10YR or 2.5Y, value 6 to 8, and chroma 1 or 2
Texture: marly silt loam, marly silty clay loam, or marly silt
2R horizon: weakly to strongly cemented oolitic limestone bedrock; solution holes up to 102 centimeters (40 inches) or more deep filled with sandy and/or marly material.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landscape: Lower Coastal Plain
Landform(s): marine marshes, swamps, or low broad tidal flats on the Key West Islands and/or along the southern coast of the Florida Peninsula
Parent material: Stratified deposits of calcareous coastal marl and organic materials over oolitic limestone bedrock
Mean annual temperature: 25 to 27 degrees C (77 to 81 degrees F)
Mean annual precipitation: 1067 to 1397 millimeters (42 to 55 inches)
Frost-free period: 365 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Cudjoe soils have marly silt loam particle-sized control sections throughout and have bedrock at depths less than 50 centimeters (20 inches).
Islamorada soils are composed entirely of organic materials, have bedrock at depths of 50 to 100 centimeters and occur on similar landform positions.
Keylargo soils are composed entirely of organic materials, lack coastal marl deposits, and occur in similar landform positions.
Lignumvitae soils have marly silt loam particle-sized control sections, have bedrock at depths of 50 to 100 centimeters (40 inches) and occur on similar landform positions.
Matecumbe soils are composed entirely of organic materials, have bedrock at depths less than 18 centimeters (7 inches), and occur on similar landform positions.
Saddlebunch soils have marly silt loam particle-sized control sections, have bedrock at depths less than 50 centimeters (20 inches) and occur on slightly higher landform positions.
Tavernier soils are composed entirely of organic materials, have bedrock at depths less than 50 centimeters (20 inches), and occur on similar landform positions.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class: Very poorly drained
Saturated hydraulic conductivity (KSAT): Moderately high to high
Runoff: High to very high
Depth to seasonal high-water table: 0 to 15 centimeters (0 to 6 inches)
Flooding frequency and duration: very frequent and very brief duration with the tides, subject to flooding by storm surges and hurricanes
USE AND VEGETATION:
Major uses: Wildlife habitat and water quality.
Dominant vegetation: black mangroves, red mangroves, white mangroves, saltwort, and glasswort.
DISTRIBUTION AND EXTENT: MLRA 156A Florida Everglades and Associated Areas.
Extent: limited
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Auburn, Alabama
SERIES ESTABLISHED: Monroe County, Florida, 1989.
REMARKS:
These soils were formerly classified as Coarse-silty, carbonatic, isohyperthermic Thapto-Histic Fluvaquents and are revised here to the twelfth edition of the keys (2014).
Diagnostic horizons and features recognized in this typical pedon:
1. Limnic soil material 0 to 23 centimeters (0 to 9 inches) (Lma horizon) and 38 to 165 centimeters (15 to 65 inches) (Lma/Oa, L'ma horizons)
2. Sulfidic soil materials - the zone from 0 to 165 centimeters (65 inches).
3. Thapto-Histic feature - 23 to 38 centimeters (9 to 15 inches, Oase horizon) and 38 to 69 centimeters (15 to 27 inches, stratified Lma/Oase horizon).
4. Lithic contact (very deep) 165 centimeters (65 inches) (2R horizon)
5. Calcium carbonate equivalence of greater than 80 percent in the coastal marl deposits
6. Peraquic feature - the zone from 0 to 203 centimeters (0 to 80 inches).
7. Aquic conditions - endosaturation ranges from 0 to 203 centimeters (0 to 80 inches).
ADDITIONAL DATA:
Laboratory data is available on the National Soil Survey website at: http://ncsslabdatamart.sc.egov.usda.gov/querypage.aspx
OSD User Site ID: S1988FL087008
OSD User Pedon ID: S1988FL087008
National Cooperative Soil Survey
U.S.A.