LOCATION JUNCAL PREstablished Series
TAXONOMIC CLASS: Fine, mixed, active, isohyperthermic Typic Hapludalfs
TYPICAL PEDON: Juncal clay - Brush. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 8 inches; dark grayish brown (10YR 4/2) clay; weak coarse subangular block structure; firm, slightly sticky, plastic; many fine roots; medium acid; clear way boundary. (6 to 10 inches thick)
Bt1--8 to 14 inches; dark yellowish brown (10YR 4/4) clay; moderate medium subangular blocky structure; firm, slightly sticky, plastic; few faint clay films; common fine roots; mildly alkaline; clear wavy boundary. (4 to 6 inches thick)
Bt2--14 to 20 inches; yellowish brown (10YR 5/6) clay; moderate medium subangular blocky structure; firm, slightly sticky, plastic; common distinct clay films; few fine roots; mildly alkaline; clear wavy boundary. (6 to 8 inches thick)
Bt3--20 to 33 inches; brownish yellow (10 YR 6/6) clay; common fine distint yellowish red (5YR 5/8) mottles; moderate medium and fine subangular blocky structure; firm, slightly sticky, plastic; few fine roots; few faint clay films; few black stains; mildly alkaline; clear wavy boundary. (8 to 14 inches thick)
Bt4--33 to 43 inches; brownish yellow (10YR 6/6) clay; common fine prominent red (2.5YR 5/6) mottles; moderate medium and fine subangular blocky structure; firm, slightly sticky, plastic; few faint clay films; few fine roots; few black concretions; few black stains; neutrals; clear wavy boundary. 8 to 12 inches thick)
Bt5--43 to 49 inches; yellowish brown (10YR 5/6) clay; few fine prominent light greenish gray (5G 7/1) and few fine prominent red (2.5YR 5/6) mottles; moderate fine subangular blocky structure; firm, slightly sticky; few faint clay films; very few roots; few black stains; moderately alkaline; clear wavy boundary. (4 to 10 inches thick)
C--49 to 66 inches; brownish yellow (10YR 6/8) silty clay loam, many fine faint light gray (10YR 7/2) mottles; crushed color, yellow (10YR 7/8); massive; friable, slightly sticky, plastic; fine lime is from 25 to 35 percent of the horizons; strong effervescence.
TYPE LOCATION: Culebrinas SCD, Puerto Rico, 3 miles north of the town of San Sebastian; 2.4 kilometers on Highway 447 from junction of Highways 447 and 119; and 220 meters south on paved unnumbered road.
RANGE IN CHARACTERISTICS: Thickness of the solum ranges from 36 inches to 60 inches. These soils are slightly sticky and plastic throughout.
The A horizon is in hues of 7.5YR or 10YR, in values of 4, and in chromas from 2 or 3. The A horizon is medium or slightly acid.
The Bt horizons have colors in hues of 7.5YR or 10YR, in values of 4 or 5, and chromas from 4, 6, or 8. Clay is the dominant texture in the solum and coarser in the C horizon. Structure ranges from moderate fine to medium subangular blocky. Reaction is mildly or moderately alkaline.
The C horizon is calcareous and effervescence ranges from slight to strong. Base saturation (by sum of cations) is more than 60 percent at 50 inches below the top of the argillic horizon.
COMPETING SERIES: These are the Machete, Rio Arriba, San Sebastian, and Tanama series. The Machete soils are redder, having hues of 5YR throughout their profiles. The Rio Arriba soils have cracks at some period during most years and clays with COLE values that exceed 0.09. The San Sebastian soils have more than 35 percent coarse fragments in their profiles and are calcareous throughout. The Tanama soils have hard rock within 20 inches of the soil surface.
GEOGRAPHIC SETTING: The Juncal series occur on footslopes and low rounded hills. Slope gradients range from 5 to 20 percent. The soil formed in fine textured residuum of limestone rocks. The climate is humid tropical. The average annual precipitation is 90 inches and the mean annual temperature is 77 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Colinas series. The Colinas soils are darker, shallower, and lack a well developed B horizon.
DRAINAGE AND PERMEABILITY: Moderately well drained; medium runoff; moderate permeability.
USE AND VEGETATION: Most of the acreage is planted to sugar cane.
DISTRIBUTION AND EXTENT: Humid northern uplands of Puerto Rico. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina
SERIES ESTABLISHED: San Juan Area, Puerto Rico; l974
REMARKS: The classification was updated with the 4/91 draft from Fine, mixed, isohyperthemic Typic Tropudalfs to Fine, mixed, isohyperthermic Typic Hapludalfs. The previous OSED date was 3/91. This soil was formerly included in the Colinas series.
Diagnostic horizons and features recognized in this pedon:
Ochric epipedon - zone from 0 to 8 inches (Ap horizon)
Argillic horizon - zone from 8 to 49 inches (Bt horizons)