LOCATION PALMAREJO PREstablished Series
TAXONOMIC CLASS: Fine, mixed, semiactive, isohyperthermic Typic Haplustults
TYPICAL PEDON: Palmarejo loam--cultivated (Colors are for moist soil).
Ap--0 to 9 inches, dark brown (7.5YR 3/2) loam; weak fine granular structure; friable; moderately sticky, slightly plastic; many fine roots; about 5 percent, by volume, pebbles; very strongly acid; abrupt smooth boundary. (7 to 14 inches thick)
Bt1--9 to 18 inches; 50 percent yellowish brown (10YR 5/6) and 50 percent dark brown (7.5YR 3/2) clay; moderate medium subangular blocky structure; firm; slightly sticky, moderately plastic; common fine roots; few faint clay films on faces of peds; about 5 percent, by volume, pebbles; very strongly acid; clear smooth boundary.
Bt2--18 to 30 inches; yellowish brown (10YR 5/8) clay; moderate medium subangular blocky structure; firm; slightly sticky, moderately plastic; few fine roots; few faint clay films on faces of peds; about 5 percent, by volume, pebbles; many coarse distinct dark yellowish brown (10YR 4/6) masses of iron accumulation; very strongly acid; clear smooth boundary. (Combined thickness of the Bt horizons range from 19 to 35 inches)
BC--30 to 41 inches, 50 percent yellowish brown (10YR 5/8) and 50 percent white (7.5YR 8/1) clay loam; massive; firm; sticky, moderately plastic; few fine roots; about 3 percent, by volume, pebbles; few black (10YR 2/1) manganese concretions; the areas in shades of yellowish brown are iron accumulations and the areas in shades of white are iron depletions; very strongly acid; clear smooth boundary. (11 to 19 inches thick)
C--41 to 60 inches, 50 percent red (2.5YR 4/8) and 50 percent white (7.5YR 8/1) sandy clay loam in a variegated pattern; massive; firm; slightly sticky, moderately plastic; about 5 percent, by volume, pebbles; few black (10YR 2/1) manganese concretions; the areas in shades of red are iron accumulations and the areas in shades of white are iron depletions; very strongly acid.
TYPE LOCATION: Lajas Municipality, Puerto Rico. Approximately 0.7 mile northeast from the intersection of P.R. Hwy. 306 and P.R. Hwy. 101, about 0.35 mile south of P.R. Hwy. 306 and P.R. Hwy. 394, and about 200 feet west from dirt road. USGS San German topographic quadrangle; lat 18 degrees 02 minutes 12 seconds N.; long. 67 degrees 06 minutes 01 seconds W. PRD 1940.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 30 to more than 70 inches. Content of pebbles is less than 15 percent, by volume. Reaction ranges from extremely acid to very strongly acid throughout.
The A or Ap horizon has hue of 7.5YR or 10YR, value of 2 to 4, and chroma of 2 to 4. Texture is loam or clay loam.
The Bt horizon has hue of 7.5YR to 105YR, value of 3 to 5, and chroma of 3 though 8. Redoximorphic features in shades of yellow or brown range from none to common in the lower part. Texture is clay loam, silty clay or clay.
The BC horizon has hue of 7.5YR or 10YR, value of 4 to 6, and chroma of 4 to 8; or there is no dominant color and is multicolored in shades red, brown, yellow, and gray. Texture is sandy clay loam or clay loam.
The C horizon has hue of 7.5YR or 10YR, value of 4 to 6, and chroma of 4 to 8; or there is no dominant color and is multicolored in shades red, brown, yellow, and gray. Texture is sandy clay loam or clay loam.
COMPETING SERIES: There are no other known series in the same family.
GEOGRAPHIC SETTING: Palmarejo soils are on foot slopes, toe slopes, and alluvial fans of the Semiarid Coastal Plains MLRA. Slopes range from 2 to 12 percent. They formed in sediments that weathered from volcanic rock. The climate is tropical semiarid. The average annual temperature ranges from 75 to 79 degrees F., and the average annual precipitation ranges from 25 to 40 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These include Fraternidad and Mariana soils. Fraternidad soils have smectitic clay control sections and are Vertisols. The well drained Mariana soils are on higher adjacent positions and are moderately deep.
DRAINAGE AND PERMEABILITY: Moderately well drained; moderate permeability.
USE AND VEGETATION: Most areas of Palmarejo soils are in abandoned sugar cane plantations or used for pastureland. Some areas are used for cash crops including pineapples, corn, pigeon peas, and pumpkins. The vegetation consists of native and introduced grasses, shrubs, and trees.
DISTRIBUTION AND EXTENT: Foot slopes, toe slopes, and alluvial fans of Semiarid Coastal Plains MLRA of southwestern Puerto Rico. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina.
SERIES ESTABLISHED: Lajas Valley Soil Survey, Puerto Rico; 1959.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Ochric epipedon - the zone from 0 to 9 inches (Ap horizon).
Argillic horizon - the zone from 9 to 30 inches (Bt1 and Bt2 horizons).
Aquic feature - perched water table at 30 inches.
ADDITIONAL DATA: Lajas Municipality - Sampled as S57PR-079-008. Sample by NSSL, Lincoln, NE., 09/1957.
Palmarejo soils are in MLRA 273.