LOCATION AMELIA PREstablished Series
TAXONOMIC CLASS: Fine, mixed, semiactive, isohyperthermic Typic Haplustalfs
TYPICAL PEDON: Amelia clay loam--pasture (Colors are for moist soil unless otherwise stated.)
Ap--0 to 9 inches; dark brown (7.5YR 3/4) sandy clay loam; moderate fine granular structure; soft, friable; slightly sticky, slightly plastic; common very fine roots;
about 5 percent, by volume, pebbles; slightly acid; clear wavy boundary. (5 to 11 inches thick)
Bt1--9 to 15 inches; dark reddish brown (5YR 3/4) clay loam; weak medium subangular blocky structure; slightly hard, friable; sticky, plastic; common very fine roots; common thin clay films on pebbles; about 25 percent, by volume, pebbles; neutral; clear smooth boundary.
Bt2--15 to 29 inches; yellowish red (5YR 4/6) gravelly clay; moderate fine and medium subangular blocky structure; firm; sticky, plastic; few very fine roots, many thin clay films on faces of peds, few thin clay films on gravel; about 15 percent, by volume, pebbles; neutral; gradual smooth boundary.
Bt3--29 to 43 inches; yellowish red (5YR 4/6); very gravelly clay; moderate medium subangular blocky structure; slightly hard, firm; sticky, plastic; few very fine roots; many thin clay films on faces of peds and few thin clay films on pebbles; about 40 percent, by volume, pebbles; about 2 percent, by volume, cobbles; neutral; clear wavy boundary.
Bt4--43 to 56 inches; about 75 percent strong brown (7.5YR 4/6) and about 25 percent yellowish red (5YR 4/6) very gravelly sandy clay loam; weak medium subangular blocky structure; slightly hard, friable; sticky, plastic; few very fine roots; many thin clay films on faces of peds and on pebbles; about 50 percent, by volume, pebbles; about 5 percent, by volume, cobbles; neutral; gradual wavy boundary.
Bt5--56 to 68 inches; yellowish red (5YR 4/6) extremely gravelly sandy clay loam; weak medium subangular blocky structure; slightly hard, friable; sticky, plastic; common clay films on the vertical and horizontal faces of peds and on pebbles; about 65 percent, by volume, pebbles; about 5 percent, by volume, cobbles; neutral; gradual wavy boundary.
Bt6--68 to 78 inches; yellowish red (5YR 5/6) very gravelly sandy clay loam; weak medium subangular blocky structure; slightly hard, friable; sticky, plastic; common clay films on vertical and horizontal faces of peds and on rock fragments; about 45 percent, by volume, pebbles; about 2 percent, by volume, cobbles; neutral. (Combined thickness of Bt horizon ranges from 60 inches to more than 80 inches thick.)
TYPE LOCATION: Cabo Rojo Municipality, Puerto Rico. Approximately 3.3 miles west of P.R. highway 303 from the intersection with P.R. highway 305; about 1.4 miles west of the Maguayo community on dirt road, and about 80 feet south of the dirt road in native pasture. San German topographic quadrangle; lat. 18 degrees 07 minutes 46 seconds N.; long. 67 degrees 07 minutes 13 seconds W.; PRD 1940.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 60 to more than 80 inches. Reaction is strongly acid to neutral in the A horizon and slightly acid or neutral in the Bt horizons.
The A horizon has hue of 5YR to 10YR, value of 3 or 4, and chroma of 2 to 4. Texture is loam, clay loam, gravelly clay loam, or gravelly clay. Content of pebbles and cobbles range from 2 to 20 percent, by volume.
The Bt horizon has hue of 2.5YR to 10YR, value of 3 or 4, and chroma of 4 through 8. Texture in the upper Bt is very gravelly clay loam, very gravelly clay, gravelly clay loam or gravelly clay and in the lower Bt, clay loam, very gravelly clay loam, or extremely gravelly sandy clay loam. Content of pebbles and cobbles range from 20 to 75 percent by volume, averaging 40 to 70 percent in the control section.
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: Amelia soils are on footslopes and alluvial fans. They formed in material that weathered from igneous rock. Slopes range from 2 to 12 percent. The climate is semiarid tropical. The average annual precipitation ranges from 30 to 40 inches and the average annual temperature ranges from 78 to 80 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Descalabrado, Fraternidad, Guayama, Jacana, and Maguayo series. Descalabrado and Guayama soils are shallow to igneous bedrock. Jacana soils are moderately deep to igneous bedrock. In addition, they are on higher adjacent sideslopes of volcanic hills and mountains and have fewer pebbles and cobbles in the control section. The moderately well drained Fraternidad soils have smectitic mineralogy and fewer pebbles in the control section. Maguayo soils are on similar positions, contain secondary carbonates, and have fewer pebbles in the control section.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Most areas of Amelia soils are used for pastureland. A few small areas are in cropland, primarily corn and sorghum. Vegetation consists of Guineagrass, Pajon, and other native and introduced grasses and shrubs.
DISTRIBUTION AND EXTENT: Semiarid mountains and valleys of southern Puerto Rico. The series is of small 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 are:
Ochric epipedon - zone from 0 to 9 inches (Ap horizon)
Argillic horizon - zone from 9 to 78 inches (Bt1, Bt2, Bt3, Bt4, Bt5, and Bt6 horizons)
ADDITIONAL DATA: Sampled as S85PR-079-003, S85PR-007-001 and S57PR-079-007. Samples by NSSL, Lincoln NE.
MLRA: 273.