LOCATION YAUCO PREstablished Series
TAXONOMIC CLASS: Fine-silty, carbonatic, isohyperthermic Typic Calciustolls
TYPICAL PEDON: Yauco silty clay loam - rangeland. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 11 inches; very dark grayish brown (10YR 3/2) silty clay loam; strong fine and medium granular structure; firm; slightly sticky, plastic; many fine roots; common fine shell, volcanic and limestone fragments; strongly effervescent; moderately alkaline; clear smooth boundary. (8 to 14 inches thick)
Bk1--11 to 17 inches; brown (10YR 4/3) silty clay loam; moderate fine and medium subangular blocky structure; firm; slightly sticky, plastic; few fine roots; common fine shell fragments; many fine accumulations of calcium carbonate in form of filaments and pendents; violently effervescent; moderately alkaline; clear smooth boundary.
Bk2--17 to 21 inches; about 50 percent yellowish brown (10YR 5/4) and about 50 percent light yellowish brown (10YR 6/4) silty clay loam; weak fine subangular blocky structure; firm; slightly sticky, plastic; many CaCO3 accumulations in form of filaments and pendents; violently effervescent; moderately alkaline; clear wavy boundary. (Combined thickness of the Bk horizons range from 12 to 22 inches)
Cr--21 to 60 inches; soft limestone that can be easily penetrated with a spade or auger; moderately alkaline.
TYPE LOCATION: Caribe SCD, Puerto Rico. Approximately 1.5 miles west of kilometer marker 3.05 on Highway 510.
RANGE IN CHARACTERISTICS: Solum thickness and depth to the soft limestone ranges from 20 to 40 inches. Reaction is moderately alkaline throughout. Amount of fine limestone fragments in the solum ranges from few to common, but never exceeds 15 percent by volume.
The A horizon has hue of 10YR, value of 2 or 3, and chroma of 3 or less. Texture is loam or silty clay loam.
The Bk horizon has hue of 10YR, value of 3 to 6, and chroma of 2 to 4; or there is no dominant color and is multicolored in shades of yellow and brown. Texture is dominantly silty clay loam.
The C horizon, where present, has hue of 10YR, value of 6 to 8, and value of 1 to 4. Texture is loam, silt loam, clay loam, or silty clay loam; or their channery or cobbly analogues. Percent by volume of soft chalk fragments ranges from 5 to 15 percent. Content of nodules, concretions, and/or soft masses of calcium carbonate ranges from common to many.
The Cr horizon is level-bedded chalk or soft limestone with platy rock structure. It can be easily excavated with hand tools, and is rippable by mechanized equipment.
COMPETING SERIES: There are no known series in the same family.
GEOGRAPHIC SETTING: Yauco soils are on rounded hills and foot slopes. They formed in calcareous sediments overlying soft limestone bedrock. The climate is tropical semiarid. Slopes range from 2 to 12 percent. The average annual temperature ranges from 78 to 80 degrees F., and the average annual rainfall ranges from 20 to 30 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Aguilita and Tuque soils. These soils are on higher positions in the landscape. In addition, Aguilita soils are deep to soft limestone and have coarse-loamy subsoils while Tuque soils are shallow to a petrocalcic horizons and are clayey skeletal.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Yauco soils used for both pasture and crop production. Vegetation chiefly in Guinea grass and cultivated areas are used for production of sugarcane.
DISTRIBUTION AND EXTENT: Semiarid areas of southern Puerto Rico. The series is of 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 11 inches (Ap horizon).
Calcic horizon - the zone from 11 to 21 inches (Bk horizons).