LOCATION RIO LAJAS PREstablished Series
TAXONOMIC CLASS: Mixed, isohyperthermic Psammentic Paleudalfs
TYPICAL PEDON: Rio Lajas sand - cultivated. (Colors are for moist soil.)
A1--0 to 8 inches; dark reddish brown (5YR 3/4) sand; single grain; loose; few fine roots; slightly acid; gradual smooth boundary. (6 to 10 inches thick)
A2--8 to 24 inches; dark reddish brown (5YR 3/3) loamy sand; single grain; loose; nonsticky, nonplastic; very few fine roots; slightly acid; gradual smooth boundary. (12 to 18 inches thick)
A3--24 to 32 inches; dark reddish brown (5YR 3/4) loamy sand; single grain; loose; nonsticky and nonplastic; slightly acid; gradual smooth boundary. (8 to 12 inches thick)
Bt--32 to 60 inches; dark reddish brown (2.5YR 3/4) loamy fine sand; weak coarse subangular blocky structure parting to single grain; loose, nonsticky, nonplastic; slightly acid.
TYPE LOCATION: Noroeste SCD, Puerto Rico; 5.5 miles west of the town of Isabela; 125 yards south of junction of roads to Punta Jacinto and east-west dirt road along the beach; 50 feet west of highway and 300 yards south of the sea.
RANGE IN CHARACTERISTICS: Thickness of the solum is over 60 inches. Thickness of the argillic is more than 50 inches. These soils are loose, nonsticky and nonplastic throughout. Reaction ranges from medium acid to neutral throughout the profile. The mean annual soil temperature is 75 degrees F.
The A1 horizon has hues of 5YR, values of 3, and chroma of 3 and 4. Texture is dominantly sand. The A2 and A3 is sand or loamy sand. Thickness of the A horizons is 26 to 40 inches.
The Bt horizon has hues of 5YR or 2.5YR, values of 3 or 4, and chroma of 4 to 6. Texture is loamy fine sand.
COMPETING SERIES: There are no other know series in the same family. The Candelero, Cayagua, Fajardo, Islote, Juncal, Rio Arriba, San Sebastian, Tanama, Vega Baja and Via series are similar soils in related families. The Candelero, Cayagua and Vega Baja soils are finer textured and all have low chroma mottles in their profiles. The Fajardo and Rio Arriba soils have COLE value higher than 0.09 in their horizons. The Islote, Juncal, San Sebastian and Via soils all are finer textured. The Tanama soils are finer textured and shallower to the hard limestone.
GEOGRAPHIC SETTING: The Rio Lajas soils are gently sloping and sloping coastal plains. Slightly above sea level on slope gradients of 2 to 12. They formed in reworked sandy sediments of the coastal plains. The climate is sub-humid tropical. The average annual precipitation ranges from 60 to 70 inches and the mean annual termperature is 77 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Malaze, Jabos, Bajucos, Guerrero and Guanajibo series and the Carrizales, Coto, Cotito and Matanzas series. The Carrizales soils are sandy throughout and do not have argillic horizon.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained, slow runoff, and rapid permeability.
USE AND VEGETATION: Mostly in pasture and food crops.
DISTRIBUTION AND EXTENT: Northwestern Puerto Rico. This series is of minor extent, with about 2,000 acres.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina
SERIES ESTABLISHED: Soil Survey of Puerto Rico; 1942.
REMARKS: The classification was updated with the 4/91 draft from Loamy, mixed, isohyperthermic Typic Tropudalfs to Sandy, mixed, isohyperthermic Psammentic Paleudalfs. The previous OSED date was 4/67.
Diagnostic horizons and features recognized in this pedon:
Ochric epipedon - zone from 0 to 32 inches (A horizons)
Argillic horizon - zone from 32 to 60 inches (Bt horizon)
LABORATORY DATA: Available for the Type Location.