LOCATION MELONES PREstablished Series
TAXONOMIC CLASS: Fine, smectitic, isohyperthermic Chromic Calcitorrerts
TYPICAL PEDON: Melones clay--wildlife refuge (Colors for moist soil).
A--0 to 7 inches; dark brown (10YR 3/3) clay; strong medium granular structure; hard, firm; moderately sticky, moderately plastic; many very fine and fine roots; many very fine interstitial pores; about 7 percent, by volume, pebbles; slightly alkaline; clear wavy boundary. (6 to 12 inches thick)
Btss--7 to 18 inches; brown (10YR 4/3) clay; strong medium angular blocky structure; hard, firm; moderately sticky, moderately plastic; many fine roots, common medium roots; many very fine, few fine tubular and vesicular pores; common faint intersecting slickensides having polished and grooved surfaces; about 1 percent, by volume, pebbles; slightly alkaline; clear wavy boundary. (6 to 18 inches thick)
Btk1--18 to 37 inches; dark brown (7.5YR 3/4) clay; moderate medium angular blocky structure; hard, firm; sticky, plastic; many fine roots, common medium roots; many very fine and common fine tubular and vesicular pores; many prominent soft masses of calcium carbonate; about 5 percent, by volume, pebbles; moderately alkaline; gradual wavy boundary.
Btk2--37 to 46 inches; brown (7.5YR 4/4) clay; strong medium subangular blocky structure; hard, firm; sticky, plastic; few medium roots; many very fine and common fine medium tubular and vesicular pores; common distinct soft masses of calcium carbonate; about 5 percent, by volume, pebbles; moderately alkaline; clear wavy boundary. (Combined thickness of the Btk horizons ranges from 10 to 30 inches)
B't1--46 to 66 inches; brown (7.5YR 4/4) clay; moderate medium subangular blocky structure; hard, firm; sticky, plastic; few fine and medium roots; many very fine and common fine tubular and vesicular pores; few faint nonintersecting slickensides having polished and grooved surfaces; about 3 percent, by volume, pebbles; moderately alkaline; clear wavy boundary.
B't2--66 to 70 inches; strong brown (7.5YR 4/6) gravelly clay loam; weak medium subangular blocky structure; friable; slightly sticky, slightly plastic; few fine and medium roots; many very fine and common fine tubular and vesicular pores; about 30 percent, by volume, pebbles; moderately alkaline; abrupt wavy boundary. (Combined thickness of the B't horizons is 15 to 31 inches).
2C--70 to 80 inches; yellowish brown (10YR 5/6) clay; massive; slightly hard, firm; slightly sticky, slightly plastic; many very fine and few fine tubular and vesicular pores; about 3 percent, by volume, pebbles; moderately alkaline.
TYPE LOCATION: Cabo Rojo Municipio, Puerto Rico. Approximately 2.7 miles east of El Combate community on PR. Hwy. 301 at the Cabo Rojo National Wildlife Refuge facilities at Boqueron; about 1.2 miles southwest from the intersection of P.R. Hwy. 301 and P.R. Hwy. 303, about 100 feet east in a hay field. Cabo Rojo topographic quadrangle; lat. 17 degrees 58 minutes 45 seconds N.; long. 67 degrees 10 minutes 16 seconds W.; PRD 1940.
RANGE IN CHARACTERISTICS: Solum thickness is more than 60 inches. Reaction ranges from slightly alkaline to moderately alkaline in the A and Bt horizons, and moderately alkaline in the Btk, B't, and C horizons.
The A or Ap horizon has hue of 7.5YR or 10YR, value of 3 or 4, and chroma of 3 or 4. Texture is clay loam or clay.
The Bt horizon has hue of 10YR, value of 3 to 5, and chroma of 3 to 6. Content of pebbles is less than 10 percent, by volume. Texture is clay loam or clay.
The Btk horizon has hue of 7.5YR to 2.5Y, value of 3 To 5, and chroma of 3 To 6. Content of pebbles range from 15 to 60 percent, by volume, but weighted average is below 35 percent for the control section. Filaments and soft masses of calcium carbonate range from common to many. Texture is clay loam or clay in the fine-earth fraction.
The B't horizons have hue of 7.5YR or 10YR, value of 3 or 4, and chroma of 3 to 7. Content of pebbles range from 0 to 30 percent, by volume. Texture is sandy clay loam, clay loam, clay, or their gravelly analogues.
The BCk horizon, where present, has hue of 10YR, value of 4 to 6, and chroma of 3 to 6. Content of pebbles and cobbles range from 35 to 75 percent, by volume. Texture is sandy clay loam or clay loam in the fine-earth fraction.
The C horizon has hue of 7.5YR or 10YR, value of 4 or 6, and chroma of 4 to 8. Content of pebbles is less than 15 percent, by volume. Texture is clay loam or clay.
COMPETING SERIES: There are no other known series in the same family.
GEOGRAPHIC SETTING: Melones soils are on alluvial fans of the Semiarid Coastal Plains MLRA. Slopes range from 0 to 12 percent. They formed in clayey and loamy fluvial and marine sediments. The climate is semiarid tropical. The average annual air temperature ranges from 78 to 82 degrees F., and the average annual precipitation ranges from 30 to 40 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Amelia, Maguayo, Pozo Blanco, and Sosa soils. Amelia soils are on slightly higher positions, have a mixed mineralogy, and are loamy-skeletal. Maguayo soils are on similar positions and have a mixed mineralogy. Pozo Blanco soils are on similar positions, have mixed mineralogy, and are fine-loamy. Sosa soils are on slightly lower positions and are kaolinitic.
DRAINAGE AND PERMEABILITY: Well drained; slow permeability.
USE AND VEGETATION: Most areas of Melones soils are used for hayland and native pasture. A few areas are used for cropland and wildlife habitat. The vegetation consists primarily of kleberg bluestemgrass, huracan, mesquite, and other xerophytic grasses, shrubs, and trees.
DISTRIBUTION AND EXTENT: Semiarid coastal plains of southern Puerto Rico. The series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina.
SERIES ESTABLISHED: Cabo Rojo Municipio, Puerto Rico; 2007.
REMARKS: Diagnostic horizons and other features recognized in this pedon:
Ochric epipedon - the zone from 0 to 7 inches.
Argillic horizon - the zone from 7 to 70 inches (Bt, Btk1, Btk2, B't1, B't2 horizons).
Calcic horizon - the zone from 18 to 46 inches (Btk1 and Btk2 horizons).
Slickensides and vertic features - the zone from 7 to 18 inches and from 46 to 66 inches(Bt, B't1, and B't2 horizons).
These soils were formerly mapped as a gravelly clay substratum phase of the Fraternidad series.
ADDITIONAL DATA: Characterization pedon - Cabo Rojo Municipio, Puerto Rico; SPR97-023-003. Sample by the NSSL, Lincoln, NE.