LOCATION FRATERNIDAD PREstablished Series
TAXONOMIC CLASS: Fine, smectitic, isohyperthermic Typic Haplusterts
TYPICAL PEDON: Fraternidad clay--cultivated (Colors are for moist soil).
Ap--0 to 7 inches; very dark grayish brown (10YR 3/2) clay; weak medium granular structure; firm; slightly sticky, slightly plastic; many fine roots; about 10 percent, by volume, pebbles; moderately acid; clear smooth boundary. (4 to 7 inches thick)
ABss--7 to 14 inches; 80 percent very dark grayish brown (10YR 3/2) and 20 percent dark brown (10YR 3/3) clay; massive when wet, upon drying breaks to weak medium and coarse angular blocky structure; many pressure faces; firm; sticky and plastic; few fine roots; common distinct slickensides 2.5 cm wide having polished and grooved surfaces; about 10 percent by volume, pebbles; moderately acid; clear wavy boundary. (6 to 50 inches thick)
BAss--14 to 23 inches; dark brown (10YR 3/3) clay; massive when wet, upon drying breaks to weak medium and coarse angular blocky structure; common tongues and pockets of very dark grayish brown (10YR 3/2) clay; many pressure faces; firm; sticky and plastic; many distinct slickensides 1.5 cm wide or less having polished and grooved surfaces; about 8 percent by volume, pebbles; common fine iron-manganese concretions; slightly acid; clear wavy boundary. (6 to 23 inches thick)
Bss1--23 to 34 inches; dark yellowish brown (10YR 4/4) clay; massive when wet, upon drying breaks to weak medium and coarse angular blocky structure; tongues and pockets of very dark grayish brown (10YR 3/2) clay; many pressure faces; firm; sticky and plastic; many distinct slickensides 1.5 cm wide or less having polished and grooved surfaces; about 7 percent by volume, pebbles; few fine iron-manganese concretions; few fine filaments of calcium carbonate; neutral; clear wavy boundary.
Bss2--34 to 51 inches; dark yellowish brown (10YR 4/4) clay; massive when wet, upon drying breaks to weak coarse subangular blocky structure; common very dark brown (10YR 2/2) pressure faces in a wedge shape; very firm; sticky and plastic; many prominent slickensides 2.5 to 3.0 cm wide having polished and grooved surfaces; about 7 percent by volume, pebbles; few fine iron-manganese concretions; common fine filaments of calcium carbonate; slightly alkaline; clear wavy boundary.
Bss3--51 to 60 inches; dark yellowish brown (10YR 4/4) clay; massive when wet, upon drying breaks to weak fine angular blocky structure bounded by very dark brown (10YR 2/2) pressure faces; friable; slightly sticky and slightly plastic; many distinct slickensides less than 2.5 cm wide having polished and grooved surfaces; about 9 percent by volume, pebbles; few fine filaments of calcium carbonate; slightly alkaline. (Combined thickness of the Bss horizons range from 20 to more than 35 inches.)
TYPE LOCATION: Lajas, Puerto Rico. Approximately 1.3 miles southwest of the city of Lajas from the intersection of P.R. Hwy. 315 and P.R. Hwy. 101; about 0.6 mile southeast of Palmarejo community from the intersection of P.R. Hwy. 306 and P.R. Hwy. 101; about 0.3 mile south of the Administration Building of the Lajas Experiment Station of the University of Puerto Rico-Mayaguez Campus; 150 feet east of road on cultivated field. USGS San German topographic quadrangle (1966); lat. 18 degrees 02 minutes 13 seconds N. and long. 67 degrees 04 minutes 13 seconds W.
RANGE IN CHARACTERISTICS: Solum thickness is more than 60 inches. Content of pebbles is less than 5 percent, by volume. Reaction ranges from slightly alkaline to moderately alkaline throughout the profile.
The A, Ap and ABss horizons have hue of 10YR, value of 2 to 4, and chroma of 1 to 3. Texture is clay loam or clay.
The AB or BA horizon, where present, has hue of 7.5YR to 2.5Y, value of 3 to 5, and chroma of 2 to 4. Texture is clay.
The Bss horizon has hue of 7.5YR to 2.5Y, value of 2.5 to 6, and chroma of 1 to 8. Texture is clay.
COMPETING SERIES: This includes the Santa Isabel series in the same family. Santa Isabel soils are on similar positions but soils do not have secondary calcium carbonates in the lower portion of the subsoil.
GEOGRAPHIC SETTING: Fraternidad soils are on fan skirts of basins and flood plains of the Semiarid Coastal Plains MLRA of southern Puerto Rico. Slopes range from 0 to 12 percent. They formed in clayey sediments that weathered from volcanic rock and limestone. The climate is semiarid tropical. The average annual precipitation range from 40 to 50 inches and the average annual temperature ranges from 73 to 77 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: In addition to the competing Santa Isabel series, these included the Aguirre, Cartagena, Fe and Guanica series. Aguirre, Cartagena, Fe and Guanica soils are on lower positions, and are somewhat poorly drained. Santa Isabel soils are on similar positions, but do not have calcium carbonate masses in the subsoil.
DRAINAGE AND PERMEABILITY: Moderately well drained; very slow permeability.
USE AND VEGETATION: Most areas of Fraternidad soils are used for cultivated crops, including rice and cash crops. Some areas are used for hayland and native pasture. The native vegetation consists primarily of buffel grass, guinea grass, kleberg bluestemgrass and hurricane grass.
DISTRIBUTION AND EXTENT: Lajas Valley of Puerto Rico. The series is moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina.
SERIES ESTABLISHED: Puerto Rico; 1936.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Mollic epipedon - the zone from 0 to 14 inches (A and ABss horizons).
Slickensides and vertic features - the zone from 7 to 60 inches (ABss, BAss, Bss1, Bss2 and Bss3 horizons).
The classification was previously updated with the 4/91 draft from Fine, montmorillonitic, isohyperthermic Udic Chromusterts to Fine, montmorillonitic, isohyperthermic Typic Haplusterts. The present definition in Soil Taxonomy for Udic-Ustic soil moisture regimes is mutually exclusive. The previous OSED date for this series was 7/84.
ADDITIONAL DATA: Characterization pedon - Lajas Municipality, Puerto Rico; S61PR-079-001, S94PR-079-001. Sample by NSSL, Lincoln, NE., 03/1961, 06/1994.
The Fraternidad series is in MLRA 273.