LOCATION MARTIN PENA PREstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, nonacid, isohyperthermic Humaqueptic Fluvaquents
TYPICAL PEDON: Martin Pena muck.
(Colors are for the moist soil unless otherwise stated.)
O2--0 to 8 inches; black (10YR 2/1) muck; weak fine granular structure; slightly sticky, slightly plastic; many fine living and decayed roots; mildly alkaline; abrupt smooth boundary. (6 to 10 inches thick)
C1--8 to 18 inches; very dark brown (10YR 2/2) silty clay loam with thin lenses of dark brown (10YR 4/3) organic material; massive; slightly sticky, slightly plastic; few fine and decayed roots; mildly alkaline; gradual smooth boundary. (8 to 12 inches thick)
C2--18 to 28 inches; very dark brown (10YR 2/2) clay; massive; slightly sticky, plastic; neutral, clear smooth boundary. (8 to 14 inches thick)
C3--28 to 55 inches; greenish gray (5G 5/1) clay with few fine faint very dark brown (10YR 2/2) dark greenish gray (5G 4/1) and gray (5G 6/1) mottles; massive slightly sticky, plastic; thin organic lenses; neutral; clear smooth boundary. (20 to 40 inches thick)
C4--55 to 63 inches; very dark brown (10YR 2/2) clay with few fine faint black (10YR 2/1) and greenish gray (5G 5/1) mottles; massive; slightly sticky, plastic; thin organic lenses; mildly alkaline.
TYPE LOCATION: San Juan SCD, Puerto Rico, 300 feet east of sentry box, entrance to the Sabana Seca Naval Communication Station, 30 feet north from center of paved unnumbered road.
RANGE IN CHARACTERISTICS: Surface horizon is in hues of 10YR or 7.5YR, values of 2 and chromas of less than 2.
The upper C horizon has colors in hue of 10YR and values and chroma of 2 or 3. It is silty clay loam or clay and mildly alkaline or neutral. The underlying C horizon has colors in hues of 5G, values of 4 or 5, and chromas of 1, with mottles of dark greenish gray or very dark brown. The lower C horizon has colors with hues of 10YR, values of 2 or 3, and chromas of 2 or 1. Mottles are black or greenish gray. The mineral materials may have thin organic layers at about 60 inches.
COMPETING SERIES: These are the Coloso, Fortuna, Pinones, and Vayas series. The Coloso and Vayas soils lack organic surface layers and organic lenses within the control section and Coloso soils are somewhat poorly drained. Fortuna soils are strongly acid. Pinones soils have buried organic materials within the control section and are very strongly acid.
GEOGRAPHIC SETTING: The Martin Pena soils occur in low depressional areas in the humid coastal plains and river flood plains. Slope gradients range from 0 to 2 percent. The surface layer is decomposed and partially decomposed organic herbaceous materials over fine textured mineral sediments. The temperature is 78 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Saladar, Bajura, and the competing Coloso series. The Saladar soils consist of thicker organic deposits throughout. The Bajura series lack the organic surface layers, and are not saturated most of the year by a high water table.
DRAINAGE AND PERMEABILITY: Very poorly drained; slow runoff; very slow permeability. Water table is at or near the surface during most of the year.
USE AND VEGETATION: Cattails, sedges, Pappirus, Para grass, and other water loving plants.
DISTRIBUTION AND EXTENT: Humid coastal plains and river flood plains of Puerto Rico. The series is if minor extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina
SERIES ESTABLISHED: Soil Survey of Puerto Rico; 1942.
REMARKS: The Martin Pena series was classified in the Alluvial Great Soil Group. Studies are being made to determine if a new subgroup, Histic Tropic Fluvaquents, is needed to accommodate these soils.