LOCATION VIEQUES PREstablished Series
TAXONOMIC CLASS: Fine-loamy over sandy or sandy-skeletal, mixed, superactive, isohyperthermic Typic Dystrustepts
TYPICAL PEDON: Vieques loam - native pasture. (Colors are for moist soil)
A--0 to 5 inches; dark brown (10YR 3/3) loam; weak fine granular structure; friable, nonsticky, nonplastic; common fine roots; slightly acid; clear smooth boundary. (4 to 6 inches thick)
Bw--5 to 15 inches; brown (7.5YR 4/4) sandy clay loam; weak coarse subangular blocky structure; slightly hard, friable, nonsticky, slightly plastic; few fine roots; krotovinas filled with A material; about 10 percent, by volume, rock fragments that vary from 2 to 5mm in size; neutral; gradual wavy boundary. (8 to 14 inches thick)
C--15 to 38 inches; yellowish brown (10YR 5/4) very gravelly coarse sand; single grained, loose; very friable; about 60 percent, by volume, coarse fragments of partially weathered plutonic rocks; neutral; abrupt smooth boundary. (20 to 30 inches thick)
R--38 to 50+ inches; consolidated granitic rock.
TYPE LOCATION: Noreste SCD, Island of Vieques, Puerto Rico. Approximately 100 feet southwest from kilometer marker 1.6 of P.R. Highway 933.
RANGE IN CHARACTERISTICS: Thickness of the solum ranges from 12 to 20 inches. Depth to consolidated plutonic rock varies from 36 to 40 inches. Reaction ranges from slightly acid through slightly alkaline throughout.
The A horizon has hue of 7.5YR or 10YR, value of 2 to 4, and chroma of 2 to 4. Texture is loam.
The Bw horizon has hue of 7.5YR or 10YR, value of 4 or 5, and chroma of 4 to 6. Content of pebbles range from 0 to 10 percent, by volume. Texture is loam or sandy clay loam.
The C horizon has hue of 7.5YR or 10YR, value of 4 through 6 and chroma of 4 through 8. Content of pebbles range from 50 to 70 percent, by volume. Texture is sand, loamy sand, sandy loam, or loam in the fine-earth fraction.
COMPETING SERIES: There are no known series in the same family.
GEOGRAPHIC SETTING: Vieques soils are on side slopes in the dry uplands. They formed in regolith that weathered from granitic rocks. The climate is semiarid tropical. Slopes range from 5 to 40 percent. The average annual temperature ranges from 77 to 79 degrees F., and the average annual precipitation ranges from 30 to 40 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Descalabrado, Coamo, and Guayama soils. Descalabrado and Guayama soils are shallow to bedrock, are on similar positions, and have clayey subsoils. In addition, Descalabrado soils are Mollisols. Coamo soils are very deep, are on lower adjacent positions, have clayey subsoils, and are Mollisols.
DRAINAGE AND PERMEABILITY: Well drained; moderately rapid permeability.
USE AND VEGETATION: Most areas of Vieques soils are used for pasture. The vegetation consists of native and introduced grasses and brush.
DISTRIBUTION AND EXTENT: Semiarid granitic uplands of Puerto Rico. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina.
SERIES ESTABLISHED: Soil Survey of Puerto Rico; l942.
REMARKS: The Vieques series was classified in the Lithosol great soil group. The surface 7 inches (mixed) does not meet the color requirements of a mollic epipedon.
Diagnostic horizons and features recognized in this pedon:
Cambic horizon - the zone from 5 to 15 inches (Bw horizon).
Lithic contact - the depth at 38 inches. (R horizon).