LOCATION SOUTHGATE VIEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, active, isohyperthermic Lithic Haplustepts
TYPICAL PEDON: Southgate gravelly loam. (Colors for moist conditions.)
A--0 to 5 inches; brown (7.5YR 4/2) gravelly loam; weak fine and medium granular structure; friable; many fine, medium, and coarse roots; about 25 percent, by volume, pebbles; neutral; gradual smooth boundary. (2 to 8 inches thick)
Bw--5 to 10 inches; brown (7.5YR 4/4) very gravelly loam; weak fine and medium subangular blocky structure; friable; common fine and medium roots; about 55 percent, by volume, pebbles; moderately acid; gradual smooth boundary. (3 to 8 inches thick)
Cr--10 to 17 inches; brown (7.5YR 4/4) weathered igneous bedrock; few fine roots between fractures; moderately acid; clear wavy boundary. (3 to 10 inches thick)
R--17 to 60 inches; brown (7.5YR 4/4) unweathered igneous bedrock.
TYPE LOCATION: St. Croix Island, U.S. Virgin Islands. From the intersection of VI-80 (North Shore road) and VI-78; about 1.6 miles west on VI-78 to paved road exiting north and about 75 feet above road on a slope. Frederiksted topographic quadrangle; lat. 17 degrees 46 minutes 51 seconds N., long. 64 degrees 46 minutes 27 seconds W.; PRD 1940.
RANGE IN CHARACTERISTICS: Depth to unweathered igneous bedrock ranges from 10 to 20 inches. Reaction ranges from strongly acid to neutral in the upper part, and very strongly acid to slightly acid in the lower part.
The A horizon has hue of 5YR to 10YR, value of 2 to 6, and chroma of 2 to 4. Texture is loam or clay loam in the fine-earth fraction. Content of pebbles and cobbles ranges from 15 to 60 percent, by volume.
The Bw horizon has hue of 5YR to 10YR, value of 3 to 6, and chroma of 3 to 6. Texture is loam or clay loam in the fine-earth fraction. Content of pebbles and cobbles ranges from 35 to 60 percent, by volume.
The Cr horizon is weathered igneous bedrock.
The R horizon is unweathered igneous bedrock.
COMPETING SERIES: There are no competing series in the same family.
GEOGRAPHIC SETTING: Southgate soils are on summits and side slopes of volcanic hills and mountains. They formed in material weathered from igneous bedrock. Slopes range from 2 to 90 percent. The climate is semiarid. The average annual air temperature ranges from 76 to 82 degrees F., and the mean annual precipitation is about 40 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Cramer, Dorothea, Fredriksdal, Jealousy, Maho bay, Parasol, Susannaberg, and Victory soils. Cramer, Dorothea, Fredriksdal, Jealousy, Maho Bay, Susannaberg, and Victory soils are on similar landscapes. In addition, Cramer soils have more than 35 percent clay in the particle-size control section. Dorothea, Fredriksdal, and Susannaberg soils have vermiculitic mineralogy. Jealousy soils have smectitic mineralogy and are moderately deep to bedrock. Maho bay soils have a mollic epepedon. Parasol soils are on slightly lower positions, are very deep, and have smectitic mineralogy. Victory soils are moderately deep to bedrock.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Most areas of Southgate soils are in rangeland. Some areas are being converted to commercial and residential development. Vegetation consists of native grasses, Guinea grass, and shrubs.
DISTRIBUTION AND EXTENT: U.S. Virgin Islands. The series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina
SERIES ESTABLISHED: St. Croix Island, U.S. Virgin Islands, 1965.
REMARKS: Diagnostic horizons and other features recognized in this pedon include:
Ochric epipedon - the zone from 0 to 5 inches (A horizon).
Cambic horizon - the zone from 5 to 10 inches (Bw horizon).
Skeletal feature - more than 35 percent weighted average rock fragments in the particle-size control section (0 to 17 inches).
Paralithic contact - the contact at 10 inches (Cr horizon).
Lithic contact - the contact at 17 inches (R horizon).
MLRA: 271.
SIR: VI0020.