LOCATION SAN ANTON PREstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, isohyperthermic Cumulic Haplustolls
TYPICAL PEDON: San Anton clay loam--cultivated. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 9 inches; very dark brown (10YR 2/2) clay loam; weak fine granular structure; friable; slightly sticky, slightly plastic; many fine roots; many fine pebbles of volcanic rock; moderately alkaline; abrupt smooth boundary.
A1--9 to 22 inches; very dark brown (10YR 2/2) clay loam; weak fine subangular blocky structure; friable; slightly sticky, slightly plastic; common fine roots; many fine pebbles of volcanic rock; neutral; abrupt smooth boundary.
A2--22 to 27 inches; dark brown (10YR 3/3) loam; weak fine subangular blocky structure; friable; slightly sticky, slightly plastic, few fine roots; neutral; clear wavy boundary. (Combined thickness of the A and Ap horizons ranges from 22 to 32 inches)
Bw--27 to 34 inches; dark yellowish brown (10YR 4/4) silty clay loam; weak fine subangular blocky structure; friable; slightly sticky, slightly plastic; few fine roots; neutral; clear wavy boundary. (6 to 10 inches thick)
C1--34 to 40 inches; dark yellowish brown (10YR 4/4) silt loam; massive; friable; slightly sticky, slightly plastic; neutral; abrupt smooth boundary.
C2--40 to 46 inches; dark brown (10YR 3/3) loam, massive; friable; slightly sticky, slightly plastic; neutral; abrupt smooth boundary.
C3--46 to 52 inches; dark yellowish brown (10YR 4/4) silt loam; massive; friable; slightly sticky, slightly plastic; slightly alkaline; abrupt smooth boundary.
C4--52 to 60 inches; dark yellowish brown (10YR 4/4) clay loam; massive; friable; slightly sticky, slightly plastic; slightly alkaline.
TYPE LOCATION: Caribe SCD, Puerto Rico. Approximately 30 feet west of kilometer marker 2.35 of Highway No. 506.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 28 to more than 60 inches. Reaction ranges from neutral to moderately alkaline throughout and is noncalcareous. Rock fragments range from 0 to 25 percent, by volume.
The A or Ap horizon has hue of 10YR, value of 2 or 3, and chroma of 2 or 3. Texture is clay loam or silty clay.
The Bw horizon has hue of 10YR, value of 3 or 4, and chroma of 3 or 4. Texture is silt loam, sandy clay loam, silty clay loam, clay loam, or gravelly clay loam.
The C horizon, where present, has hue of 10YR, value of 3 to 5, and chroma of 2 to 4. Texture is loam, silt loam, sandy clay loam, clay loam or clay. In some areas the lower part of the underlying material is sand or loamy sand.
COMPETING SERIES: These include the Cortada, Kawaihapai and Pulehue series. Cortada soils are on slightly lower positions and are calcareous throughout. Kawaihapai and Pulehue soils do not have Bw horizons.
GEOGRAPHIC SETTING: San Anton soils are on alluvial fans and flood plains. They formed in alluvium that weathered from volcanic rock and limestone. The climate is tropical semiarid. Slopes range from 0 to 12 percent. The average annual precipitation ranges from 35 to 40 inches and the average annual temperature ranges from 78 to 80 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing Cortada soils and the Aguirre, Cintrona, Constancia, Fraternidad, Machuelo, Santa Isabel, and Vayas soils. The somewhat poorly drained Aguirre, the moderately well drained Fraternidad, and the moderately well drained Santa Isabel soils are on higher positions, have smectitic clay control sections, and are Vertisols. The very poorly drained Cintrona soils are on lower positions and have clayey control sections. The somewhat poorly drained Constancia soils are on lower positions and have clayey subsoils. The poorly drained Machuelo and Vayas soils are on lower positions, and have clayey control sections. In addition, Machuelo soils do not have Bw horizons.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: San Anton soils are used for pasture and for growing sugar cane, plantains, and truck crops. Vegetation is dominated by guineagrass, buffelgrass, stargrass, pangolagrass, and other native and introduced species.
DISTRIBUTION AND EXTENT: Semiarid areas of southern Puerto Rico. The soils are of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina.
SERIES ESTABLISHED: Puerto Rico, 1936.
REMARKS: The San Anton soil has occasional flooding.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - zone from 0 to 27 inches (Ap, A1, and A2 horizons)
Cambic horizon - zone from 27 to 34 inches (Bw horizon)