LOCATION EL DESCANSO PREstablished Series
TAXONOMIC CLASS: Clayey-skeletal, magnesic, isothermic Lithic Argiudolls
TYPICAL PEDON: El Descanso mucky peat--forestland (Colors are for moist soil).
Oi--0 to 3 inches; black (10YR 2/1) mucky peat, about 70 percent fiber crushed and rubbed; massive, very friable; nonsticky, nonplastic; many very fine, medium and coarse roots; about 10 percent, by volume, cobbles and about 2 percent, by volume, stones; slightly acid; clear wavy boundary. (1 to 4 inches thick)
A--3 to 8 inches; dark brown (7.5YR 3/2) very gravelly clay loam; strong very fine and fine granular structure; slightly hard, firm; slightly sticky, moderately plastic; many very fine to coarse roots; many very fine to medium irregular pores; few faint pressure faces on faces of peds; about 45 percent, by volume, angular pebbles; neutral; clear wavy boundary. (4 to 6 inches thick)
Bt--8 to 15 inches; dark brown (7.5YR 3/2) extremely paragravelly clay; moderate very fine and fine subangular blocky structure; hard, firm; slightly sticky, moderately plastic; many very fine and fine roots; many very fine to fine irregular pores; common distinct clay films on faces of peds and coarse fragments; about 70 percent, by volume, angular parapebbles, and about 5 percent, by volume, angular paracobbles; neutral; abrupt irregular boundary. (6 to 12 inches thick)
R--15+ inches; hard fractured consolidated serpentinite bedrock.
TYPE LOCATION: San German, Puerto Rico. Approximately 0.4 mile southwest from the Maricao State Forest headquarters (Campamento Buena Vista); about 0.8 mile south from El Alto del Descanso Peak on forestland; USGS Maricao topographic quadrangle (1960); lat. 18 degrees 08 minutes 48.2 seconds N. and long. 66 degrees 59 minutes 45.0 seconds W.
RANGE IN CHARACTERISTICS: Depth to hard fractured consolidated serpentine bedrock ranges from 15 to 19 inches. Reaction ranges from slightly acid to neutral throughout. The combined total of rock fragments in the control section is more than 35 percent, by volume.
The Oi horizon has hue of 10YR, value of 2 or 3, and chroma of 1 or 2. Content of rock fragments range from 2 to less than 15 percent, by volume. Texture is mucky peat.
The A horizon has hue of 7.5YR or 10YR, value of 3, and chroma of 2. Content of rock fragments range from 10 to 45 percent, by volume. Texture is clay loam in the fine-earth fraction.
The Bt horizon has hue of 5YR to 10YR, value of 3, and chroma of 2 or 3. Content of rock fragments range from 36 to 75 percent, by volume. Texture is clay in the fine-earth fraction.
The R layer is composed of hard fractured consolidated serpentinite bedrock.
COMPETING SERIES: These are no known series in the same family.
GEOGRAPHIC SETTING: El Descanso soils are on side slopes and summits of mountains on the Humid Mountains and Valleys MLRA. Slopes range from 5 to 90 percent. They formed in residuum that weathered from serpentinite. The climate is humid tropical. The average annual precipitation ranges from 68 to 134 inches and the average annual temperature ranges from 62 to 68 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cerro Gordo (T), Hoconuco (T) and Indiera (T) series. Cerro Gordo (T) and Indiera (T) soils have an oxic horizon and have finer textured profiles. Hoconuco (T) soils are moderately deep to bedrock and are finer textured.
DRAINAGE AND PERMEABILITY: Well drained; slow permeability.
USE AND VEGETATION: Most areas of El Descanso soils are in forestland and used for wildlife habitat. The vegetation consists of native and introduced shrubs and trees.
DISTRIBUTION AND EXTENT: Side slopes and summits of serpentinite mountains of southern Puerto Rico. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina.
SERIES ESTABLISHED: San German Municipality, Puerto Rico; 2007. The name is from El Alto del Descanso peak where it was originally recognized.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Mollic epipedon - the zone from 0 to 8 inches (Oi and A horizon).
Argillic horizon - the zone from 8 to 15 inches (Bt horizon).
Lithic contact - the contact at 15 inches (R layer).
El Descanso soils were formerly included in the Serpentinite outcrop miscellaneous land type. A soil moisture and soil temperature study performed in the San German Area Soil Survey Update recognized the Perudic Soil Moisture Regime in Puerto Rico, recognized the isothermic soil temperature regime at 750 meters above sea level (in Perudic Soil Moisture Regime) and 900 meters above sea level (in Udic Soil Moisture Regime) and adjusted the isothermic-isohyperthermic line.
El Descanso soils formed in the Serpentinite Formation (Ks).
El Descanso soils are in MLRA 270.