LOCATION EL DUQUE PR
Tentative Series
Rev. JLL; SRT; GRB
09/2011
EL DUQUE SERIES
The El Duque series consists of moderately deep, poorly drained, very slowly permeable soils on summits and shoulders of mountains of the Humid Mountains and Valleys MLRA. They formed in residuum that weathered from volcanic bedrock. Near the type location, the mean annual temperature is about 65 degrees F., and the mean annual precipitation is about 169 inches. Slopes range from 5 to 60 percent.
TAXONOMIC CLASS: Fine, mixed, subactive, acid, isothermic Typic Humaquepts
TYPICAL PEDON: El Duque muck--dwarf forest (Colors are for moist soil).
Oi--0 to 1 inches; very dark gray (10YR 3/1) mucky peat; massive; friable; nonsticky and nonplastic; many very fine, fine and medium roots; strongly acid; abrupt wavy boundary. (0 to 2 inches thick)
A--1 to 10 inches; very dark grayish brown (10YR 3/2) clay loam; weak very fine and fine subangular blocky structure; slightly hard, firm; slightly sticky and slightly plastic; many very fine, fine and medium roots; common very fine and fine irregular pores and few very fine and fine tubular pores; common prominent yellowish red (5YR 4/6) and dark red (2.5YR 3/6) iron accumulations adjacent to pores and surfaces along root channels; strongly acid; clear wavy boundary. (4 to 13 inches thick)
Bwg--10 to 21 inches; dark gray (10YR 4/1) silty clay; weak fine and medium subangular blocky structure; slightly hard, firm; slightly sticky and moderately plastic; few very fine, fine and medium roots; common very fine and fine irregular pores and few very fine and fine tubular pores; about common prominent dark red (2.5YR 3/6) iron accumulations adjacent to pores and on surfaces along root channels and pores; neutral; abrupt irregular boundary. (3 to 15 inches thick)
Cr--21 to 30 inches; highly fractured, slightly to highly weathered volcanic bedrock (0 to 9 inches thick).
R--30 inches; hard fractured, consolidated volcanic bedrock.
TYPE LOCATION: El Yunque National Forest; Ceiba, Puerto Rico. Approximately 2.42 miles southeast of the intersections of PR Hwy. 930 and the forest paved road No. 27; about 90 feet north from the forest road No. 27 on Pico del Este (East Peak). USGS El Yunque topographic quadrangle (1982); lat. 18 degrees 16 minutes 9.2 seconds N. and long. 65 degrees 45 minutes 33.8 seconds W.
RANGE IN CHARACTERISTICS: Solum thickness range from 20 to 40 inches. Depth to hard consolidated bedrock ranges from 21 to 40 inches. Reaction ranges from very strongly acid to strongly acid throughout. The combined total of rock fragments in the control section is less than 15 percent by volume.
The Oi horizon, where present, has hue of 10YR, value of 3, and chroma of 1 or 2. Content of pebbles, cobbles or stones range from 2 to 10 percent, by volume. Texture is mucky peat.
The A horizon has hue of 10YR, value of 3, and chroma of 2. Content of pebbles range from 0 to 10 percent, by volume. Texture is silt loam or clay loam.
The Bwg horizon has hue of 2.5Y to 5Y, value of 4 to 7, and chroma of 2 to 4. Redoximorphic features in shades of brown, red and gray range from few to common throughout. Content of pebbles range from 0 to 10 percent, by volume. Texture is silty clay loam, clay loam or silty clay.
The BC horizon, where present, has hue of 2.5Y to 5Y, value of 5 to 7, and chroma of 2 to 4. Redoximorphic features in shades of brown, red and gray range from few to common. Content of pebbles range from 0 to 10 percent, by volume. Texture is silty clay loam.
The Cr horizon, where present, is composed of slightly to highly weathered volcanic bedrock. It can be excavated with difficulty with hand tools, and rippable by mechanized equipment.
The R horizon is composed of consolidated volcanic bedrock.
COMPETING SERIES: The
Guayabota soils are in the same family. The somewhat poorly drained Guayabota soils are deep to volcanic bedrock.
GEOGRAPHIC SETTING: El Duque soils are on shoulders and summits of nearby monadnocks of mountains of the Humid Mountains and Valleys MLRA of northern Puerto Rico. Slopes range from 5 to 60 percent. They formed in residuum material that weathered from volcanic bedrock. The climate is humid tropical. The average annual precipitation ranges from 140 to 215 inches and the average annual temperature ranges from 62 to 66 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Dwarf and
Palm series. Dwarf soils are isomesic, on higher side slope positions and are very deep to saprolite. Palm soils are on side slopes and have kaolinitic mineralogy.
DRAINAGE AND PERMEABILITY: Poorly drained; very slow permeability.
USE AND VEGETATION: Most areas of El Duque soils are in native forestland that is used for recreation and research. The native habitat is pluvial dwarf forest. Over 200 native and introduced woody species are present.
DISTRIBUTION AND EXTENT: Summits and shoulders of mountains of El Yunque National Forest in Puerto Rico. The series is of minor extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina.
SERIES PROPOSED: Ceiba Municipality, Puerto Rico; 2011. The name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Umbric epipedon - the zone from 1 to 10 inches (A horizon).
Cambic horizon - the zone from 10 to 21 inches (Bwg horizon).
Aquic conditions - the zone from 0 to 21 inches (Oi, A and Bwg horizons).
Redoximorphic features - the zone from 1 to 21 inches (A and Bwg horizons).
Hydric soil indicators - A11, F3.
Paralithic contact - the contact at 21 inches (Cr horizon).
Lithic contact - the contact at 30 inches (R horizon).
These soils were formerly included in the Dwarf series.
ADDITIONAL DATA: Characterization pedon - Ceiba Municipality, Puerto Rico; S11PR-037-001. Sample by NSSL, Lincoln, NE., 05/11.
El Duque soils are in MLRA 270A.
National Cooperative Soil Survey
U.S.A.