LOCATION CERRO GORDO PREstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, isothermic Typic Haploperox
TYPICAL PEDON: Cerro Gordo mucky peat--forestland (Colors are for moist soil).
Oi--0 to 3 inches; black (5YR 2.5/1) mucky peat; about 60 percent fiber crushed and rubbed; massive; friable; nonsticky, nonplastic; many very fine and fine roots; very strongly acid; abrupt smooth boundary. (2 to 7 inches thick)
A--3 to 11 inches; dark reddish brown (5YR 3/3) gravelly clay; moderate very fine and fine granular structure; soft, friable; slightly sticky, slightly plastic; many very fine and fine roots; many very fine and fine irregular pores; about 20 percent, by volume, ironstone pebbles; very strongly acid; diffuse smooth boundary. (5 to 9 inches thick)
Bo1--11 to 23 inches; dark reddish brown (2.5YR 3/3) clay; weak very fine and fine subangular blocky structure; soft, friable; slightly sticky, slightly plastic; common very fine and fine roots; common very fine and fine irregular pores, few very fine tubular pores; about 12 percent, by volume, ironstone pebbles; very strongly acid; clear wavy boundary.
Bo2--23 to 40 inches; red (2.5YR 4/6) gravelly clay; moderate very fine and fine subangular blocky structure; soft, friable; slightly sticky, slightly plastic; few faint ferriargillans on ped faces; common very fine and fine roots; common very fine and fine irregular pores and few very fine tubular pores; about 20 percent, by volume, ironstone pebbles; about 2 percent, by volume, plinthite; strongly acid; clear wavy boundary.
Bo3--40 to 52 inches; red (2.5YR 4/8) gravelly clay; weak very fine and fine subangular blocky structure; slightly hard, firm; slightly sticky, slightly plastic; few faint ferriargillans on ped faces; few very fine and fine roots; common very fine and fine irregular pores, few very fine tubular pores; about 25 percent, by volume, iron stone pebbles; moderately acid; clear wavy boundary.
Bo4--52 to 80 inches; yellowish red (5YR 4/6) clay; weak very fine and fine subangular blocky structure; slightly hard, firm; slightly sticky, slightly plastic; few very fine and fine roots; common very fine and fine irregular pores, few fine tubular pores; about 15 percent, by volume, ironstone pebbles; moderately acid.
TYPE LOCATION: San German, Puerto Rico. Approximately 0.2 mile south from the intersection of P.R. Hwy. 120 and the main entrance of the Maricao State Forest Headquarters (Campamento Buena Vista) on forest trail road cut; USGS Maricao topographic quadrangle (1960); lat. 18 degrees 09 minutes 4.2 seconds N.; long. 66 degrees 59 minutes 36.8 seconds W.
RANGE IN CHARACTERISTICS: Solum thickness is more than 60 inches. Reaction ranges from very strongly acid to moderately acid throughout. The combined total of iron stone fragments in the control section is less than 35 percent, by volume.
The Oi horizon has hue of 5YR to 10YR, value of 2 or 2.5, and chroma of 1 or 2. Texture is mucky peat.
The A horizon has hue of 10R to 5YR, value of 3 or 4, and chroma of 2 or 3. Texture is clay or their gravelly analogs.
The Bo horizons have hue of 10R to 5YR, value of 3 or 4, and chroma of 3 to 8. Texture is clay or their gravelly analogs.
COMPETING SERIES: There are no known series in the same family.
GEOGRAPHIC SETTING: Cerro Gordo soils are on stable ridge tops of mountains in the Humid Mountains and Valleys MLRA. Slopes range from 5 to 20 percent. They formed in iron-rich residuum weathered from serpentinite bedrock. 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 El Descanso (T), Hoconuco (T) and Indiera (T) series. El Descanso (T) and Hoconuco (T) soils do not have an oxic horizon and are coarser textured. Indiera (T) soils are on more sloping positions and are shallow to serpentinite bedrock.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Most areas of Cerro Gordo soils are forestland and are used for wildlife habitat.
DISTRIBUTION AND EXTENT: Stable ridge tops of mountains of the southern Humid Mountains and Valleys MLRA of Puerto Rico. The series is of minor extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina.
SERIES ESTABLISHED: San German Municipality, Puerto Rico; 2007. The name is from Las Tetas de Cerro Gordo Mountain Range, where it was originally recognized.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Ochric epipedon - the zone from 0 to 11 inches (Oi and A horizons).
Oxic horizon - the zone from 11 to 80 inches (Bo1, Bo2, Bo3, and Bo4 horizons).
These soils were formerly included in the Nipe series. 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.
Cerro Gordo soils formed in the Ks-Serpentinite Formation (Ks). It is a remnant of lateritic residual soil on serpentinite.
Cerro Gordo soils formed in MLRA 270.