LOCATION PITAHAYA PREstablished Series
TAXONOMIC CLASS: Clayey-skeletal, mixed, superactive, nonacid, isohyperthermic, shallow Typic Torriorthents
TYPICAL PEDON: Pitahaya gravelly clay--naturalized pastureland (Colors are for moist soil unless otherwise indicated).
Ap--0 to 2 inches; dark brown (10YR 3/3) gravelly clay, brown (10YR 4/3) dry; strong medium granular structure; slightly hard, firm; slightly sticky, slightly plastic; many very fine and fine roots; many very fine and common fine interstitial pores; about 15 percent, by volume, pebbles; about 2 percent, by volume, cobbles; moderately alkaline; strongly effervescent; clear wavy boundary. (1 to 6 inches thick)
AC--2 to 11 inches; brown (10YR 4/3) extremely gravelly clay, brown (10YR 5/3) dry; massive; slightly hard, firm; slightly sticky, slightly plastic; many very fine and fine roots; many very fine and common fine tubular and vesicular pores; about 70 percent, by volume, pebbles; moderately alkaline; strongly effervescent; abrupt wavy boundary. (6 to 11 inches thick)
Cr1--11 to 21 inches; very pale brown (10YR 7/4) hard semi-consolidated fractured limestone, very pale brown (10YR 8/2) dry; strong medium and thick platy rock structure; many very fine roots, common fine and medium roots in fracture planes; moderately alkaline; violently effervescent; clear wavy boundary.
Cr2--21 to 27 inches; very pale brown (10YR 7/4) hard semi-consolidated fractured limestone, very pale brown (10YR 8/2) dry; strong medium and thick platy rock structure; few very fine roots in fracture planes; moderately alkaline; violently effervescent; abrupt wavy boundary. (Combined thickness of the Cr horizons range from 5 to 26 inches.)
R--27 to 80 inches; very pale brown (10YR 7/4) hard consolidated limestone bedrock, very pale brown (10YR 8/2) dry; moderately alkaline; violently effervescent.
TYPE LOCATION: Lajas, Puerto Rico. Approximately 3.0 miles west of La Parguera community, about 1.7 miles southeast of Rancho Cabassa, and about 20 feet east of gravel road on naturalized pastureland; USGS Parguera topographic quadrangle (1966); lat. 17 degrees 58 minutes 56 seconds N.; long. 67 degrees 05 minutes 32 seconds W.
RANGE IN CHARACTERISTICS: Depth to hard semi-consolidated limestone ranges from 5 to 20 inches. Depth to hard unweathered limestone bedrock ranges from 20 to 30 inches. Reaction is moderately alkaline throughout.
The A or Ap horizon has hue of 10YR, value of 3 to 5, and chroma of 2 to 4. Content of rock fragments range from 5 to 60 percent, by volume. Texture is clay loam or clay in the fine-earth fraction.
The AC horizon has hue of 7.5YR or 10YR, value of 3 or 4, and chroma of 3 or 4. Content of rock fragments range from 35 to 80 percent, by volume. Texture is clay loam or clay in the fine-earth fraction.
The C horizon, where present, has hue of 7.5YR or 10YR, value of 6 to 8, and chroma of 2 to 4. Content of rock fragments range from 25 to 50 percent, by volume. Texture is loam or silt loam in the fine-earth fraction.
The Cr horizon is composed of hard semi-consolidated fractured limestone and has hue of 7.5YR to 2.5Y, value of 6 to 8, and chroma of 2 to 6. It can be excavated with difficulty with hand tools, and is rippable by mechanized equipment.
The R layer is composed of hard consolidated limestone bedrock.
COMPETING SERIES: There are no known series in the same family.
GEOGRAPHIC SETTING: Pitahaya 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 5 to 90 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), Guayacan (T) and La Covana (T) series. Costa (T) soils are on similar positions, are shallow to soft weathered limestone bedrock, and have clayey, carbonatic control sections. Esteli (T) soils are on similar positions, are deep to limestone bedrock, and have coarse-loamy, carbonatic control sections. Guayacan (T) soils are on similar to lower positions, are very deep, and have fine-loamy, mixed control sections. La Covana (T) soils are on similar positions, are shallow to a petrocalcic horizon, and have clayey-skeletal, carbonatic control sections.
DRAINAGE AND PERMEABILITY: Well drained; very slow permeability.
USE AND VEGETATION: Most areas of Pitahaya soils are on naturalized pastureland. The vegetation consists of Buffel grass, Huracan grass. Other vegetation consists of Mesquite and other xerophytic grasses, shrubs and 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 SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina.
SERIES ESTABLISHED: Lajas Municipality, Puerto Rico; 2007. The name is from the nearby Pitahaya Point, where it was originally recognized.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Ochric epipedon - the zone from 0 to 2 inches (Ap horizon).
Paralithic contact - the zone at 11 inches (Cr layer).
Lithic contact - the zone at 27 inches (R layer).
Pitahaya soils were formerly included in the San German series. A soil moisture study performed in the San German Area Soil Survey Update recognized the Aridic Soil Moisture Regime in southern Puerto Rico.
ADDITIONAL DATA: Characterization pedon - Lajas Municipality, Puerto Rico; S97PR-079-003. Sample by NSSL, Lincoln, NE., 06/97.
Pitahaya soils are in MLRA 271.