LOCATION SANTA ISABEL PREstablished Series
TAXONOMIC CLASS: Fine, smectitic, isohyperthermic Typic Haplusterts
TYPICAL PEDON: Santa Isabel clay - cultivated. (Colors are for moist conditions.)
Ap--0 to 10 inches; black (10YR 2/1) clay; weak fine granular structure; firm; sticky and plastic; many fine roots; neutral; clear wavy boundary. (6 to 15 inches thick.)
ABss1--10 to 28 inches; black (10YR 2/1) clay; weak medium angular blocky structure; firm; sticky, plastic; many fine roots; common distinct slickensides having polished and grooved surfaces; neutral; gradual wavy boundary.
ABss2--28 to 39 inches; very dark gray (10YR 3/1) clay; weak medium angular blocky structure; firm; sticky, plastic; common fine roots; many distinct slickensides having polished and grooved surfaces; neutral; gradual wavy boundary.
ABss3--39 to 50 inches; very dark gray (10YR 3/1) clay; weak medium angular blocky structure; firm; sticky, plastic; few fine roots; many distinct slickensides having polished and grooved surfaces; neutral; gradual wavy boundary.
ABss4--50 to 64 inches; black (10YR 2/1) clay; weak medium angular blocky structure; firm; sticky, plastic; few fine roots; many distinct slickensides having polished and grooved surfaces; few fine subrounded volcanic rock fragments; neutral; gradual wavy boundary. (Combined thickness of the ABss horizons range from 10 to 60 inches.)
BC--64 to 69 inches; brown (10YR 4/3) clay; massive; firm; sticky, plastic; very dark gray (10YR 3/1) coatings along faces of peds; few fine subrounded volcanic rock fragments; neutral.
TYPE LOCATION: Lajas Municipality, Puerto Rico. Approximately 1.6 miles southwest of the city of Lajas, from the intersection of P.R. Hwy. 315 and P.R. Hwy. 101, about 0.3 miles northeast from the intersection of P.R. Hwy. 303 and P.R. Hwy. 101, about 330 feet south of the Administration Building of the Lajas Agricultural Experiment Station of the University of Puerto Rico-Mayaguez Campus. San German topographic quadrangle; lat. 18 degrees 01 minute 59 seconds N., long. 67 degrees 04 minutes 26 seconds W.; PRD 1940.
RANGE IN CHARACTERISTICS: Solum thickness is more than 60 inches. Content of rock fragments is less than 5 percent, by volume throughout. Reaction is neutral or slightly alkaline throughout the profile.
The A or Ap horizon has hue of 10YR, value of 2 or 3, and chroma of 1 or less. Texture is clay loam or clay.
The ABss horizon has hue of 10YR, value of 2 or 3, and chroma of 1 or less. Texture is clay.
The BC horizon has hue of 10YR, value of 2 to 4, and chroma of 1 to 3. Texture is clay.
COMPETING SERIES: This includes the Fraternidad series in the same family. Fraternidad soils have secondary carbonates in the lower subsoil.
GEOGRAPHIC SETTING: Santa Isabel soils are on coastal plains. They formed in material that weathered from volcanic rocks and limestone. Slopes range from 0 to 2 percent. The climate is tropical semiarid. The average annual temperature ranges from 76 to 78 degrees F., and the average annual precipitation ranges from 30 to 35 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: In addition to the competing Fraternidad soils, these include the Aguirre and San Anton soils. The somewhat poorly drained Aguirre soils have more clay in the control section and have more than 15 exchangeable sodium. The well drained San Anton soils have less clay in the control section.
DRAINAGE AND PERMEABILITY: Moderately well drained; very slow permeability.
USE AND VEGETATION: Most areas of Santa Isabel soils are used for cultivated crops such as sugarcane. Some areas are used for pasture. The native vegetation consists of Guineagrass and Buffelgrass.
DISTRIBUTION AND EXTENT: Lajas Valley Area of Puerto Rico. The series is of small 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 64 inches (A and ABss horizons)
Slickensides and vertic features - the zone from 28 to 64 inches (ABss horizons)
Aquic feature - A seasonal high water table is present at depths of 5 to 6 feet.
ADDITIONAL DATA: Sampled as S81PR-007-004. Sample Nos. 81 P 1635-1640. Sample by NSSL, Lincoln, NE.
Santa Isabel soils are in MLRA 273.