LOCATION NARANJITO PREstablished Series
TAXONOMIC CLASS: Fine, mixed, semiactive, isohyperthermic Typic Haplohumults
TYPICAL PEDON: Naranjito silty clay loam - native pasture. (Colors are for moist soil.)
A--0 to 7 inches; dark brown (10YR 4/3) silty clay loam; weak fine subangular blocky structure; very hard, friable, slightly sticky, slightly plastic; common fine roots; thin clay films on root channels; 5 percent 1/4 to 1 inch volcanic rock fragments; extremely acid; clear smooth boundary. (5 to 10 inches thick)
Bt1--7 to 20 inches; yellowish red (5YR 4/6) clay; weak fine subangular blocky structure; very hard, firm, slightly sticky, plastic; few fine roots; few faint dark brown (10YR 3/3) clay films; 10 percent angular 1/8 to 2 inch volcanic rock fragments; very strongly acid; gradual smooth boundary. (10 to 16 inches thick)
Bt2--20 to 30 inches; yellowish red (5YR 4/6), and yellowish brown (10YR 5/4) clay; weak fine subangular blocky structure; very hard, firm, slightly sticky, plastic; common distinct dark brown (10YR 3/3) clay films on faces of peds, along root channels and worm holes; 10 percent 1/8 to 2 inch angular volcanic rock fragments; 40 percent by volume is saprolite; very strongly acid; gradual smooth boundary. (4 to 15 inches thick)
C--30 to 38 inches; yellowish red (5YR 4/6), red (2.5YR 4/6) , and light olive brown (2.5Y 5/4) clay loam; massive; hard, firm, slightly sticky, plastic; common fine dark concretions; 15 percent 1/8 to 3 inch angular rock fragments; saprolite; very strongly acid; abrupt smooth boundary. (0 to 14 inches thick)
R--38 inches; semi-consolidated volcanic rock.
TYPE LOCATION: Barrio Jacaboa, Patillas, Puerto Rico; 150 feet southwest of kilometer marker 3.5, Highway 758.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 20 to 40 inches and depth to semi-consolidated rock ranges from 25 to 40 inches. Angular gravel fragments, 1/8 to 2 inches in size, range from 5 to 15 percent by volume throughout the soil. The soil ranges from strongly acid to extremely acid throughout. Mean annual soil temperature ranges from 76 to 80 degrees F.
The A horizons have hues of 7.5YR or 10YR, values of 4 or 5, and chroma of 3 or 4. They are silty clay loam.
The Bt horizons have hues or 5YR or 7.5YR, values of 4 to 6, and chroma of 4 to 8. They are clay and have weak or moderate, fine or medium subangular blocky structure. They have few faint or common distinct clay films.
The C horizon has variegated colors. It is clay loam or silty clay loam and has slightly plastic or plastic consistence.
COMPETING SERIES: The Daguao series is in the same family. Daguao soils have hue of 10YR in the B horizon and crystals of hornblende.
The Alonso, Aibonito, Ciales, Cidral, Daguey, Humatas, Lares, Limones, Lirios, Los Guineos, Picacho, Rio Piedras, and Voladora series are similar soils in related families. Alonso, Aibonito, Daguey and Limones soils have CEC values between 16 and 24 meg/100 grams of clay. The Ciales, Lares and Picacho soils have low chroma mottles in the B horizon. Cidral soils have sola thicker than 60 inches. Humatas and Rio Piedras soils have kaolinitic mineralogy. Lirios soils have clayey over loamy particle-size control sections. Los Guineos soils have hues of 10YR in the upper part of the B horizon. Voladora soils are Rhodudults.
GEOGRAPHIC SETTING: The Naranjito soils are moderately steep to very steep on sideslopes and ridgetops of strongly dissected volcanic uplands. Slopes range from 12 to 60 percent. The soils formed in moderately fine to fine textured residuum weathered from volcanic rocks. The climate is humid tropical. The average annual rainfall ranges from 75 to 100 inches, and the average annual temperature is from 74 to 78 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Daguey and Humatas series and the Consumo and Mucara soils, all of which are on similar volcanic sideslopes and ridgetops. The Consumo soils have thinner argillic horizons. The Mucara soils lack argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is medium to rapid. Permeability is moderate.
USE AND VEGTATION: Most of the soil is in native grasses and shrubs. Small areas are used for growing subsistence crops and tame grasses.
DISTRIBUTION AND EXTENT: Humid volcanic uplands of Puerto Rico. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina
SERIES ESTABLISHED: Puerto Rico, (Soil Survey), 1942.
REMARKS: The classification was updated with the 4/91 draft from Clayey, mixed, isohyperthermic Typic Tropohumults to Clayey, mixed, isohyperthermic Typic Haplohumults. The previous OSED date was 5/75.
Diagnostic horizons and features recognized in this pedon:
Ochric epipedon - zone from 0 to 7 inches (A horizon)
Argillic horizon - zone from 7 to 30 inches (Bt horizons)
Lithic feature - zone at 38 inches (R layer)