LOCATION ROSARIO PREstablished Series
TAXONOMIC CLASS: Clayey, ferruginous, isohyperthermic, shallow Inceptic Hapludox
TYPICAL PEDON: Rosario clay--forestland (Colors for moist soil unless otherwise indicated.)
Oi--0 to 2 inches; leaves, needles, twigs, sticks, and barks with 25 percent of intermediate decomposition of organic material; abrupt smooth boundary.
Ap--2 to 6 inches; dark yellowish brown (10YR 3/4) clay, dark brown (10YR 3/3) dry; strong fine and medium granular structure; hard, firm; slightly sticky, plastic; common very fine and few fine roots; many fine and medium interstitial pores; few medium iron-manganese concretions; very strongly acid; clear wavy boundary. (4 to 8 inches thick)
Bo1--6 to 11 inches; dusky red (10R 3/4) clay, dusky red (10R 3/3) dry; strong fine and medium granular structure; friable; slightly sticky, plastic; few fine roots; common fine and medium interstitial pores; few faint clay films on faces of peds; very strongly acid; clear wavy boundary.
Bo2--11 to 16 inches; dusky red (10R 3/3) clay, dusky red (10R 3/3) dry; moderate fine and medium subangular blocky structure; friable; slightly sticky, plastic; few fine roots; common fine interstitial pores; few distinct clay films on faces of peds; moderately acid; clear irregular boundary.
Bo3--16 to 32 inches; dusky red (10R 3/3) clay, dusky red (10R 3/3) dry; weak fine and medium subangular blocky structure; slightly hard, firm; slightly sticky, plastic; few fine and medium roots; common fine interstitial pores; few faint clay films on faces of peds; slightly acid; abrupt wavy boundary. (Combined thickness of the Bo horizons range from 14 to 29 inches.)
Cr--32 to 44 inches; highly fractured and weathered serpentinite bedrock.
R--44 inches; hard consolidated serpentinite bedrock.
TYPE LOCATION: San German Municipality, Puerto Rico. Approximately 1.4 miles southwest of the intersection of P.R. Highway 120 and 362; about 1.1 miles southwest of Campamento Santana on gravel road and about 50 feet northwest of road in forest. USGS Quadrangle Maricao, Puerto Rico (1960). Lat. 18 degrees 07 minutes 38 seconds N.; long. 66 degrees 58 minute 34 seconds W.
RANGE IN CHARACTERISTICS: Depth to highly fractured serpentinite bedrock ranges from 20 to 45 inches. Depth to consolidated serpentinite bedrock ranges from 35 to 45 inches. Reaction range from very strongly acid to slightly acid in the A and upper Bo horizons and from slightly acid to neutral in the lower Bo horizons.
The A or Ap horizon has hue of 10R to 10YR, value of 2 or 3, and chroma of 2 to 4. Content of iron concretions is less than 5 percent, by volume. Texture is clay.
The Bo horizons have hue of 10R or 2.5YR, value of 3 or 4, and chroma of 3 or 4. Content of iron concretions is less than 5 percent, by volume. Texture is clay loam or clay.
The BC horizon, where present, has hue of 5YR, value of 4, and chroma of 4. Content of ironstone concretions is less than 5 percent, by volume. Texture is clay loam.
The C horizon, where present, has hue of 5YR to 10YR, value of 4 or 5, and chroma of 4 or 6. Content of paragravels is less than 15 percent, by volume. Texture is clay loam.
The Cr horizon is composed of very weakly to moderately cemented, highly weathered, fractured serpentinite. It can be excavated with difficulty with hand tools, and rippable by mechanized equipment.
The R horizon is strongly cemented to indurated unweathered serpentinite bedrock.
COMPETING SERIES: There are no known soil series in the same family.
GEOGRAPHIC SETTING: Rosario soils are on shoulders and side slopes of stable ridges of the serpentinite hills and mountains of southern Puerto Rico. Slopes range from 12 to 60 percent. They formed in material that weathered from serpentinite bedrock. The climate is humid tropical. The average annual air temperature ranges from 73 to 77 degrees F., and the average annual precipitation ranges from 43 to 73 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Delicias, El Cacique (T), La Tana (T), Maresua, Nipe and Santa Marta soils. Delicias and Nipe soils are on summits of stable ridges and are deeper. El Cacique (T), La Taina (T), and Maresua soils have a mollic horizon. Santa Marta soils do not have an oxic horizon.
DRAINAGE AND PERMEABILITY: Well drained; moderate to rapid permeability.
USE AND VEGETATION: Most areas of Rosario soils are used for forestland, wildlife habitat or urban land. The vegetation consists of Brazil beauty-leaf tree, Cupeytillo, Swamp cyrilla, Wild honey and Wild mammee trees, along with ferns.
DISTRIBUTION AND EXTENT: Shoulders and side slopes of the humid serpentinite hills and mountains of southern Puerto Rico. The series is of small known extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina.
SERIES ESTABLISHED: Soil Survey of Puerto Rico, 1942.
REMARKS: The classification is currently updated to Inceptic Hapludox since there is a paralithic contact above the lithic contact. The classification was recently updated with the 10/02 draft from Fine, ferruginous, isohyperthermic Lithic Hapludox to Clayey, ferruginous, isohyperthermic, shallow Typic Hapludox. The previous update was 4/91.
Diagnostic horizons and features recognized in this pedon:
Ochric epipedon - the zone from 2 to 6 inches (Ap horizon).
Oxic horizon -the zone from 6 to 32 inches (Bo horizons).
Paralithic contact - the contact at 32 inches (Cr horizon).
Lithic contact - the contact at 44 inches (R horizon).
The type location was moved to its present location in 2002 and the series reclassified based on soil lab data and observations in the field.
ADDITIONAL DATA: Characterization pedons - S01PR125007R and S02PR125006R. San German Municipality, Puerto Rico. Samples are by the NSSL, Lincoln, NE., 05/01 and 07/02.