LOCATION SAN GERMAN PREstablished Series
TAXONOMIC CLASS: Clayey-skeletal, mixed, superactive, isohyperthermic Lithic Haplustolls
TYPICAL PEDON: San German gravelly loam-pasture. (Colors are for moist soil unless otherwise indicated.)
Ap--0 to 4 inches; very dark grayish brown (10YR 3/2) cobbly clay loam; strong fine granular structure; slightly hard, firm; slightly sticky, moderately plastic; many very fine and fine roots; many very fine and fine interstitial pores; about 12 percent, by volume, pebbles; about 8 percent, by volume, cobbles; slightly alkaline; violently effervescent; clear wavy boundary. (1 to 4 inches thick)
A--4 to 10 inches; very dark grayish brown (10YR 3/2) extremely gravelly clay loam; strong fine granular structure; slightly hard, firm; slightly sticky, moderately plastic; many very fine, fine and medium roots; many very fine, fine and medium irregular pores; about 85 percent, by volume, pebbles; moderately alkaline; violently effervescent; abrupt irregular boundary. (4 to 10 inches thick)
R--10 to 80 inches; hard consolidated limestone bedrock.
TYPE LOCATION: Cabo Rojo Municipio, Puerto Rico. Approximately 4.4 miles southwest of downtown Cabo Rojo; from the intersection of P.R. Hwy 102 and P.R. Hwy 312; about 2.5 miles northwest of the Boqueron community from the intersection of P.R. Hwy 100 and P.R. Hwy 101; about 0.4 mile west of P.R. Hwy 307; about 0.1 mile west of the old railroad track on naturalized pastureland. USGS Puerto Real topographic quadrangle (1966); lat. 18 degrees 02 minutes 46 seconds N., long. 67 degrees 11 minutes 38 seconds W.; PRD 1940.
RANGE IN CHARACTERISTICS: Depth to hard, semi-consolidated limestone ranges from 5 to 20 inches. Depth to hard unweathered limestone bedrock ranges from 10 to 20 inches. Reaction is slightly alkaline or moderately alkaline throughout.
The A or Ap horizon has hue of 7.5YR or 10YR, value of 2 or 3, and chroma of 2 to 4. Content of rock fragments range from 10 to 60 percent, by volume. Texture is clay loam or clay in the fine-earth fraction.
The AC horizon, where present, has hue of 7.5R or 10YR, value of 3 or 4, and chroma of 3 or 4. Content of rock fragments range from 35 to 85 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 4 or 5 and chroma of 1 to 4. Texture is clay loam or clay in the fine-earth fraction.
The Cr horizon, where present, is composed of hard semi-consolidated fractured limestone. It 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 mechanical equipment.
The R layer is composed of hard consolidated limestone bedrock.
COMPETING SERIES: There are no known competing series in the same family.
GEOGRAPHIC SETTING: San German soils are on ridge tops, summits, and side slopes of limestone hills and mountains 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 semiarid tropical. The mean annual temperature ranges from 78 to 80 degrees F., and the mean annual precipitation ranges from 30 to 40 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Aguilita, Descalabrado, Duey, Pozo Blanco, Seboruco, and Tuque soils. Aguilita, Duey, and Tuque soils are on similar positions. In addition, Aguilita soils have a Mollic epipedon and coarse-loamy, carbonatic subsoils. Descalabrado soils formed in igneous bedrock. Duey soils have fine-loamy carbonatic control sections. Tuque soils have a Mollic epipedon. Pozo Blanco soils are on lower adjacent positions, are very deep, and have a Mollic epipedon. Seboruco soils are on slightly lower positions and have red, fine-silty control sections.
DRAINAGE AND PERMEABILITY: Well drained; very slow permeability.
USE AND VEGETATION: Most areas of San German soils are used for pasture and rangeland. The vegetation consists of buffellgrass, huracan grass, and other xerophytic grasses, shrubs, and trees.
DISTRIBUTION AND EXTENT: In the semiarid limestone hills and mountains of southern Puerto Rico. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina.
SERIES ESTABLISHED: Puerto Rico, 1942.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Mollic epipedon - the zone from 0 to 10 inches (Ap and A horizons).
Lithic contact - the zone at 27 inches (R layer).
San German soils are in Major Land Resource Area 271.