LOCATION PATILLAS PREstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, isohyperthermic, shallow Typic Hapludults
TYPICAL PEDON: Patillas clay loam - pasture. (Colors are for moist soil.)
A--0 to 8 inches; dark brown (10YR 3/3) clay loam; weak fine subangular blocky separating to moderate medium granular structure; friable, slightly plastic, nonsticky; common fine roots; few fine pores; few fine black minerals; few fine quartz crystals; common fine rock fragments; strongly acid; clear smooth boundary. (7 to 10 inches thick)
Bt--8 to 19 inches; reddish brown (5YR 4/4) clay loam; weak fine subangular blocky structure; friable, slightly plastic, slightly sticky, few fine roots; common fine pores; few faint clay films on ped surfaces; few fine quartz crystals; common fine rock fragments; few weathered feldspar fragments; strongly acid; clear wavy boundary. (10 to 14 inches thick)
C--19 to 48 inches plus; yellowish red (5YR 4/6) saprolite that crushes to sandy loam; massive; friable, nonplastic, nonsticky; coatings of finer textured materials from overlying horizon on fracture planes; very strongly acid.
TYPE LOCATION: Sudeste SCD, Puerto Rico; 1.8 kilometers east from kilometer marker 162.2 of Highway No. 3 and 1.25 kilometers southeast from Highway 757, in the vicinity of the town of Patillas, Puerto Rico.
RANGE IN CHARACTERISTICS: Thickness of the solum ranges from 15 to 24 inches. Most pedons have few or common quartz crystals, and fine rock fragments in the solum. Reaction is strongly or very strongly acid.
The A horizon has hue of 10YR or 7.5YR, value of 3 or 4 and chroma of 3 or 4. Texture is silty clay loam or clay loam.
The Bt horizon has hue of 7.5YR or 5YR, value of 4 or 5 and chroma of 4 to 8. Texture is silty clay loam or clay loam. Structure is weak fine through coarse subangular blocky. Clay films range from few faint to many prominent.
The C horizon has hue of 7.5YR or 5YR, value of 4 to 6 and chroma of 4 to 8. Texture ranges from sandy loam through loamy sand.
COMPETING SERIES: These are the Alonso, Consumo, Corozal, Ingenio, Jagueyes, Lirios, Maricao, Moca, Pandura, and Rio Piedras soils. The Alonoso, Consumo, Corozal, Ingenio, Lirios, Maricao, Moca, and Rio Piedras soils have more than 35 percent clay in the control section, and with the exception of Maricao and Consumo, have Bt horizons more than 16 inches thick. The Jagueyes soils have CEC less than 24 meq/100 grams of clay and Bt horizons more than 16 inches thick. The Pandura soils lack Bt horizons.
GEOGRAPHIC SETTING: The Patillas soils occur on moderately steep through very steep sideslopes of dissected uplands with slope gradients of 20 to 60 percent. The regolith is weathered residuum of intrusive plutonic rocks, mainly quartz diorite and grandiorite. The climate is humid tropical. The mean annual rainfall is 60 to 70 inches, and the mean annual temperature is 78 to 80 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: In addition to the competing Pandura soils, these include the Limones and Parlcelas soils. The Limones soils are more clayey and have kaolinite mineralogy. The Parcelas soils are more clayey, have slickensides, and lack Bt horizons.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is medium. Permeability is moderate.
USE AND VEGETATION: Most of the acreage is used for the production of tobacco and subsistence crops. A smaller acreage is in native grasses and used as pasture.
DISTRIBUTION AND EXTENT: Humid plutonic uplands of Puerto Rico. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina
SERIES ESTABLISHED: Sudeste SCD, Puerto Rico; 1969.
REMARKS: The classification was updated with the 4/91 draft from Fine-loamy, mixed, isohyperthermic Dystropeptic Tropudults to Fine-loamy, mixed, isohyperthermic Typic Hapludults. The previous OSED date was 8/69.
This soil was formerly included in the Pandura series. The Patillas soils would have been classified in the Lithosol great soil group.
Diagnostic horizons and features recognized in this pedon:
Ochric epipedon - zone from 0 to 8 inches (A horizon)
Argillic horizon - zone from 8 to 19 inches (Bt horizon)