LOCATION UTUADO             PR
Established Series
Rev. GRB
02/2002

UTUADO SERIES


The Utuado series consists of very deep, somewhat poorly drained, moderately rapid permeable soils on middle and lower side slopes of strongly dissected uplands. They formed in residuum in the plutonic uplands that weathered from granodiorite of the Rio Blanco stock. Near the type location, the mean annual temperature is about 69 degrees F., and the mean annual precipitation is about 120 inches. Slopes range from 25 to 95 percent.

TAXONOMIC CLASS: Coarse-loamy, mixed, active, isothermic Aquic Humic Dystrudepts

TYPICAL PEDON: Utuado gravelly sandy loam - forest. (Colors are for the moist conditions.)

Oi-- 0 to 1 inches; many fine, medium, and coarse roots, forming a mat; abrupt smooth boundary. (0 to 5 inches.)

A-- 1 to 2 inches; dark brown (10YR 3/3) gravelly sandy loam; moderate very fine and fine subangular blocky structure; common fine, medium, and coarse roots; many fine interstitial pores; about 20 percent, by volume, pebbles; strongly acid; abrupt smooth boundary. (4 to 8 inches.)

Bw1-- 2 to 7 inches; dark brown (10YR 3/3) sandy loam; weak fine and medium subangular blocky structure; very friable; few medium roots; about 10 percent, by volume, stones; common medium distinct strong brown (7.5YR 5/8) masses of iron accumulations; common medium distinct gray (10YR 5/1) areas of iron depletions; strongly acid; clear smooth boundary.

Bw2-- 7 to 13 inches; dark yellowish brown (10YR 4/4) sandy loam; moderate medium subangular blocky structure; few very fine and fine roots; few fine tubular pores; about 10 percent, by volume, stones; common medium distinct gray (10YR 5/1) areas of iron depletions; strongly acid; abrupt smooth boundary. (Combined thickness of the Bw horizons ranges from 14 to 23 inches in thickness.)

C-- 13 to 28 inches; yellowish brown (10YR 5/6) loamy sand; weak fine and medium subangular structure; common very fine, fine, and medium roots; few fine tubular pores; strongly acid; gradual smooth boundary.

Cr-- 28 to 61 inches; variegated very pale brown (10YR 8/2), black (10YR 2/1) and brown (10YR 5/3) saprolite with a loamy sand texture; about 40 percent, by volume, stones; strongly acid.

TYPE LOCATION: Naguabo Municipio, Este SCD, Caribbean National Forest, Puerto Rico. Approximately 75 feet west of kilometer marker 14 on P.R. Road 191. El Yunque topographic quadrangle; lat. 18 degrees 17 minutes 38 seconds N., long. 65 degrees 47 minutes 32 seconds W. PRD 1940.

RANGE IN CHARACTERISTICS: Solum thickness ranges from 18 to 31 inches. Reaction ranges from extremely acid to strongly acid throughout. Pebbles, cobbles, and/or stones range from 0 to 20 percent, by volume, throughout.

The Oi horizon, where present, is composed of roots, forming a mat.

The A horizon has hue from 7.5YR to 2.5Y, value from 2 to 5, and chroma from 1 to 4. Texture is sandy loam, loam, their gravelly, cobbly, or stony analogs.

The Bw horizon has hue of 7.5YR or 10YR, value of 3 to 6, and chroma from 3 to 8. Redoximorphic features in shades of yellow, brown, and gray range from few to many, decreasing with depth and may be absent in the lower Bw horizons of some pedons. Texture is sandy loam, loam, their gravelly, cobbly, or stony analogs..

The C horizon has hue of 7.5YR to 2.5YR, value of 4 to 6, and chroma of 4 to 8. Texture is loamy sand, sandy loam, their gravelly, cobbly, or stony analogs..

The Cr horizon is composed of saprolite that can be dug with a spade and has a texture of loamy sand or sandy loam.

COMPETING SERIES: These are no other known series in the same family.

GEOGRAPHIC SETTING: Utuado soils are on middle and lower sideslopes of strongly dissected uplands. They formed in residuum that weathered from granodiorite of the Rio Grande stock. The climate is humid tropical. Slopes range from 25 to 95 percent. The average annual temperature ranges from 67 to 71 degrees F., and the average annual precipitation ranges from 80 to 150 inches.

GEOGRAPHICALLY ASSOCIATED SOILS: These include the Ciales, Guayabota, Icacos, Los Guineos, Picacho, and Yunque soils. The poorly drained Ciales soils are on lower positions and have fine-loamy control sections. The poorly drained Guayabota soils are on higher positions and are shallow to bedrock. Icacos soils are on lower adjacent flood plains and have fine-loamy control sections. The well drained Los Guineos soils are on higher positions and have more clay in the control section. Picacho soils are on higher positions and have fine-loamy control sections. The moderately well drained Yunque soils are on higher positions and have more clay in the control sections.

DRAINAGE AND PERMEABILITY: Well drained; moderately rapid permeability.

USE AND VEGETATION: All areas of Utuado soils are forested and used for recreation, research, wildlife habitat, and watershed protection. The vegetation consists of native and introduced species of hardwoods, sierra palms, and tree ferns.

DISTRIBUTION AND EXTENT: Tropical rain forests of Puerto Rico. The series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina.

SERIES ESTABLISHED: Soil Survey of Puerto Rico, l942.

REMARKS: Diagnostic horizons and features recognized in this pedon.

Ochric epipedon - the zone from 0 to 1 inch (A horizon).

Cambic epipedon - the zone from 1 to 12 inches (Bw1 and Bw2 horizons).

Aquic feature - episaturation beginning at about 1 inch, but depletions are not dominate.

ADDITIONAL DATA: NSSL Characterization Data Pedon No. 86P0252; Soil Survey No. S85PR-103-001; sample by NSSL, Lincoln NE.


National Cooperative Soil Survey
U.S.A.