LOCATION DAGUAO PREstablished Series
TAXONOMIC CLASS: Fine, mixed, semiactive, isohyperthermic Typic Haplohumults
TYPICAL PEDON: Daguao clay. (Colors are for moist soil unless otherwise noted.)
A--0 to 8 inches; very dark gray (10YR 3/1) clay; weak fine granular structure; very firm, slightly sticky, plastic; strongly acid; gradual wavy boundary. (4 to 12 inches thick)
Bt1--8 to 13 inches; dark yellowish brown (10YR 4/4) clay; weak coarse subangular blocky structure; firm, slightly sticky, slightly plastic; thin discontinuous clay films; strongly acid; gradual wavy boundary. (4 to 10 inches thick)
Bt2--13 to 21 inches; yellowish brown (10YR 5/4) clay; moderate coarse subangular blocky structure; firm; slightly sticky, slightly plastic; clay films on vertical ped faces, few clay films on horizontal ped faces; few partly weathered hornblende crystals; few pressure faces and small slickensides; strongly acid; clear wavy boundary. (6 to 12 inches thick)
Cr--21 to 34 inches; yellowish brown (10YR 5/6), yellowish red (5YR 4/6), and dark greenish gray (5GY 4/1) saprolite; many hornblende crystals.
R--34 inches plus; dark greenish consolidated acid volcanic rock.
TYPE LOCATION: Naguabo, Puerto Rico; 150 feet north of Km. marker 0.55 and of intersection of Highways 31 and 3.
RANGE IN CHARACTERISTICS: The solum is 14 to 26 inches thick. Depth to consolidated volcanic rock is 20 to 40 inches. Few to many fine to medium size dark hornblende fragments are throughout the soil. Soil reaction ranges from strongly acid to very strongly acid.
The A horizon has hue of 10YR or 7.5YR, value of 2 or 3 and chroma of 1 or 2. It is clay or silty clay.
The Bt horizon has hue of 10YR, 7.5YR or 5YR, value of 4 or 5 and chroma of 4 to 8.
COMPETING SERIES: This is the Naranjito series is the same family. The Naranjito soils have redder hue in the Bt horizon and do not contain Hornblende fragments.
GEOGRAPHIC SETTING: The Daguao soils are on moderately steep to steep mountains. Slopes range from 20 to 60 percent. The regolith consists of moderately fine to fine-textured residuum weathered from volcanic rocks that are very high in hornblende. The climate is humid tropical. Average annual rainfall is 80 to 85 inches, and average annual temperature is 79 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are in the Ejemplo, Laura, Naranjito, and Pandura series. The Ejemplo soils are on footslopes and fans below the Daguao soils. The Pandura soils occur on similar slopes but have grayer colors, coarser textures, and less well expressed Bt horizons. The Laura soils on low rolling granite hills are deeper, coarser in texture, and have less well expressed Bt horizons that are redder in color. The Naranjito soils have less well expressed structure in the Bt horizon and are redder in color.
DRAINAGE AND PERMEABILITY: Well drained. Runoff is rapid. Permeability is moderately slow.
USE AND VEGETATION: The soil is largely in native grasses and brush and is used for pasture. A small part is cultivated.
DISTRIBUTION AND EXTENT: Humid parts of Puerto Rico. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina
SERIES ESTABLISHED: Puerto Rico, l936.
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 was dated 4/87.
Diagnostic horizons and features recognized in this pedon are:
Umbric epipedon - zone from 0 to 8 inches (A horizon)
Argillic horizon - zone from 8 to 21 inches (Bt horizons)
Paralithic contact at 21 inches (Cr layer)
Lithic contact - at 34 inches (R layer)