LOCATION LA COVANA PREstablished Series
TAXONOMIC CLASS: Clayey-skeletal, carbonatic, isohyperthermic Calcic Lithic Petrocalcids
TYPICAL PEDON: La Covana gravelly loam--forestland (Colors are for moist soil unless otherwise indicated).
A--0 to 5 inches; dark reddish brown (5YR 3/2) gravelly loam, brown (7.5YR 4/3) dry; weak medium granular structure; soft, very friable; nonsticky, nonplastic; many very fine, fine, medium, and coarse roots; few very fine interstitial pores; about 25 percent, by volume, pebbles; moderately alkaline; slightly effervescent; clear wavy boundary. (2 to 6 inches thick)
Bk--5 to 19 inches; yellowish red (5YR 5/6) extremely gravelly clay, light reddish brown (5YR 6/4) dry; massive; soft, very friable; sticky, plastic; many fine and medium roots; common very fine interstitial pores; about 70 percent, by volume, pebbles; about 5 percent, by volume, cobbles; many fine calcium carbonate concretions; moderately alkaline; strongly effervescent; abrupt wavy boundary. (4 to 18 inches thick)
Bkm--19 to 31 inches; very pale brown (10YR 8/3) indurated petrocalcic, very pale brown (10YR 8/2) dry; massive; extremely hard, extremely firm, brittle; common medium and coarse roots between cracks; moderately alkaline; violently effervescent; gradual broken boundary. (10 to 15 inches thick)
C1--31 to 44 inches; very pale brown (10YR 8/3) silty clay loam, very pale brown (10YR 8/2) dry; massive; slightly hard, friable; slightly sticky, slightly plastic; many very fine roots, common fine roots; common very fine interstitial pores; common distinct yellow (10YR 7/8) relic mottles, yellow (10YR 7/6) dry; many fine and medium calcium carbonate concretions; moderately alkaline; violently effervescent; gradual irregular boundary.
C2--44 to 80 inches; very pale brown (10YR 8/2) silty clay loam, very pale brown (10YR 8/2) dry; massive; slightly hard, friable; slightly sticky, slightly plastic; few very fine and fine roots; many very fine interstitial pores, few very fine tubular pores; many prominent yellow (10YR 7/8) relict mottles, yellow (10YR 7/6) dry; common fine calcium carbonate concretions; moderately alkaline; violently effervescent.
TYPE LOCATION: Guanica, Puerto Rico. Approximately 0.7 mile northwest of the Borinquen Camp-Dry State Forest of Guanica headquarters, about 0.25 mile east on Las Covanas dirt road from the intersection with P.R. Hwy. 334, and about 10 feet south of road on forestland. USGS Punta Verraco topographic quadrangle (1966); lat. 17 degrees 59 minutes 02 seconds N.; long. 66 degrees 52 minutes 37 seconds W.
RANGE IN CHARACTERISTICS: Depth to indurated petrocalcic horizon ranges from 6 to 20 inches. Reaction is moderately alkaline throughout.
The A or Ap horizon has hue of 10R to 10YR, value of 2 to 3, and chroma of 1 or 2. Content of rock fragments range from 20 to 60 percent, by volume. Texture is loam, silty clay loam, clay loam or silty clay in the fine-earth fraction.
The Bk horizon has hue of 10R to 5YR, value of 2.5 to 5, and chroma of 2 to 6. Content of rock fragments range from 50 to 80 percent, by volume. Texture is silty clay loam, clay loam, silty clay or clay in the fine-earth fraction.
The Bkm horizon is composed of indurated petrocalcic horizon and has hue of 10YR, value of 8, and chroma 3. It cannot be excavated with hand tools, but is rippable by mechanized equipment.
The C horizon has hue of 7.5YR or 10YR, value of 6 to 8, and chroma of 2 to 6. Content of calcium carbonate concretions range from few to many, by volume. Relict Redoximorphic features in shades of yellow and brown range from none to common. Texture is silt loam or silty clay loam in the fine-earth fraction.
COMPETING SERIES: These are no known series in the same family.
GEOGRAPHIC SETTING: La Covana soils are on ridge tops, summits and side slopes in limestone hills of the Semiarid Mountains and Valleys MLRA of southern Puerto Rico. Slopes range from 12 to 40 percent. They formed in material that weathered from limestone bedrock. The climate is tropical semiarid. The average annual precipitation ranges from 28 to 36 inches and the average annual temperature ranges from 78 to 82 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Costa (T), Esteli (T), Pitahaya (T) and Seboruco (T) series. All of these soils are on similar positions, but do not have a petrocalcic horizon. In addition, Costa soils are shallow to limestone and have less than 35 percent coarse fragments in the control section, Esteli soils are deep to limestone bedrock and have coarse-loamy control sections, and Pitahaya soils are shallow to limestone bedrock and have clayey-skeletal control sections, and Seboruco soils are moderately deep to limestone bedrock and have fine-loamy, mixed control sections.
DRAINAGE AND PERMEABILITY: Well drained; very slow permeability.
USE AND VEGETATION: Most areas of La Covana soils are on forestland. The vegetation consists of Cortadera and Mezquite grasses and, Black-ironwood, Black-olive, Fiddlewood, Fustic, Pigeon-berry, Turpentine, Violet, West Indies mahogany, White popinac and Wild marrow trees.
DISTRIBUTION AND EXTENT: Ridge tops, summits and side slopes of limestone hills of the semiarid mountains and valleys of southern Puerto Rico. The series is small extent.
MLRA OFFICE RESPONSIBLE: Auburn, Alabama.
SERIES ESTABLISHED: Guanica Municipality, Puerto Rico; 2007. The name is from the La Covana creek where it was originally recognized.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Ochric epipedon - the zone from 0 to 5 inches (A horizon).
Calcic horizon - the zone from 5 to 19 inches (Bk horizon).
Petrocalcic horizon - the zone from 19 to 31 inches (Bkm horizon).
These soils were formerly included in the Limestone Rockland miscellaneous land type.
La Covana soils are in MLRA 271.