LOCATION FREDENSBORG VI+PR
Inactive Series
Rev. GA-BCD-JA
05/2018
FREDENSBORG SERIES
The Fredensborg series consists of very deep, well drained, slowly permeable formed in fine textured calcareous sediments overlying marl or soft limestone. They are on foot slopes and valleys of uplands with slopes of 0 to 12 percent. The mean annual precipitation is about 37 inches and the mean annual temperature is about 78 degrees F.
TAXONOMIC CLASS: Fine-loamy, carbonatic, isohyperthermic Typic Calciustolls
TYPICAL PEDON: Fredensborg clay. (Colors for moist conditions unless otherwise stated.)
Ap--0 to 10 inches; very dark grayish brown (10YR 3/2) clay; weak medium subangular blocky breaking to a moderate fine granular structure; hard, firm, slightly sticky, plastic; many small pressure faces, violently effervescent with many small shell and limestone fragments mixed throughout horizon; moderately alkaline; clear smooth boundary. (6 to 10 inches thick)
A--10 to 16 inches; very dark grayish brown (10YR 3/2) clay; moderate fine granular structure; hard, firm, slightly sticky, plastic; many light colored wormcasts; violently effervescent with many small shell and limestone fragments; moderately alkaline; abrupt smooth boundary. (6 to 10 inches thick)
Bk--16 to 20 inches; very pale brown (10YR 7/3) silty clay loam; very weak fine and medium granular structure; soft, very friable, nonsticky, slightly plastic; many wormcasts filled with dark colored materials; violently effervescent; strongly alkaline; clear smooth boundary. (5 to 8 inches thick)
C1--20 to 36 inches; very pale brown (10YR 7/3) silty, soft marl or limestone with few small soft lime concretions. (10 to 20 inches thick)
C2--36 to 50 inches; pale brown (10YR 6/3) silty, soft marl or limestone with many small soft lime concretions; easily penetrated with spade or auger.
TYPE LOCATION: St. Croix, Virgin Islands; 150 feet west and 75 feet north of the road intersection which is 1/4 mile west of Kingshill.
RANGE IN CHARACTERISTICS: Thickness of the solum ranges from 15 to 30 inches. Rock fragments range from 0 to 35 percent throughout.
The A horizon has hue of 10YR hue, value of 2 to 3 and chroma of 2 to 4. Texture ranges from silty clay to clay and structure from weak to moderate granular.
The Bk horizon has hue of 10YR, value of 6 to 8 and chroma of 1 to 4. Texture is silty clay loam or clay loam. It consists of a mixture of materials from the A and underlying soft limestone resulting from worm activity.
The C horizon has hue of 10YR, value of 6 to 8 and chroma of 1 to 4. It is soft marly limestone.
COMPETING SERIES: These are the
Aguilita and
Sion series in the same family and the
Pozo Blanco and
Yauco series. The Aguilita and Sion soils typically have thinner sola, are lighter textured, and have less plastic A and B horizons that lack pressure faces. The Pozo Blanco soils have a cambic horizon above a calcic horizon and the Yauco soils are fine-silty.
GEOGRAPHIC SETTING: The Fredensborg soils occur on nearly level to gently sloping foot slopes and valleys with dominant slope gradients from 0 to 12 percent. The regolith is fine texture calcareous sediments overlying marl or soft limestone. The climate is semiarid. Rainfall ranges from 35 to 40 inches and mean annual temperature is 78 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the
Hesselberg,
Aguilita,
Fraternidad and the
Coamo series in addition to the
Sion. The Hesselberg soils are shallow red soils having thin subsoils with moderate structure and overlying semi-consolidated limestone. The Aguilita soils are gravelly and very shallow (4 to 14 inches) to soft limestone. The Fraternidad soils are deep calcareous fine textured soils with many slickensides. The Coamo soils are deep, have moderately fine textured A horizons, fine textured argillic horizons and calcareous, stratified C horizons.
DRAINAGE AND PERMEABILITY: Well drained with medium runoff and slow permeability.
USE AND VEGETATION: Soils used for both pasture and crop production. Uncultivated areas chiefly in Guineagrass and the cultivated areas used for the production of sugarcane.
DISTRIBUTION AND EXTENT: American Virgin Islands. Series is of moderate extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: RALEIGH, NORTH CAROLINA
SERIES ESTABLISHED: St. Croix, Virgin Islands; 1932.
REMARKS: The classification is updated with this draft and removed from the shallow family. It was correlated as Fine, carbonatic, isohyperthermic Typic Rendolls in the 1970 Soil Survey of the Virgin Islands.
Diagnostic horizons and features recognized in this pedon:
Mollic epipedon - zone from 0 to 16 inches (Ap and A horizons)
Calcic horizon - zone from 16 to 20 inches (Bk horizons)
National Cooperative Soil Survey
U.S.A.