LOCATION CUCHILLAS PREstablished Series
TAXONOMIC CLASS: Loamy, mixed, active, isothermic, shallow Typic Dystrudepts
TYPICAL PEDON: Cuchillas silty clay loam--coffee plantation (Colors are for moist soil).
Ap--0 to 6 inches; very dark grayish brown (10YR 3/2) silty clay loam; moderate fine granular structure; soft, friable; slightly sticky, slightly plastic; many very fine, fine, and medium roots; common fine interstitial pores; about 5 percent, by volume, weathered rock fragments 0.25 to 0.50 inch in diameter; neutral; clear smooth boundary. (4 to 9 inches thick)
Bw--6 to 15 inches; dark grayish brown (10YR 4/2) silty clay loam; weak fine subangular blocky structure; soft, friable; slightly sticky and slightly plastic; few fine roots; common fine interstitial pores; about 10 percent, by volume, partially weathered rock fragments 0.25 to 0.50 in diameter; neutral; noneffervescent; abrupt wavy boundary. (6 to 12 inches thick)
Cr--15 to 36 inches; highly fractured unconsolidated volcanic rock; few fine and medium roots between fracture planes; clear wavy boundary. (4 to 21 inches thick)
R--36+ inches; hard fractured consolidated volcanic bedrock.
TYPE LOCATION: Yauco, Puerto Rico. Approximately 2.0 miles southwest from the Castaner community from the intersection of P.R. Hwy. 135 and P.R. Hwy. 374 and about 250 feet north of Hacienda La Salvacion homestead on coffee plantation.
USGS Monte Guilarte topographic quadrangle (1960). Lat. 18 degrees 09 minutes 25 seconds N.; long. 67 degrees 05 minutes 21 seconds W.
RANGE IN CHARACTERISTICS: Depth to fractured, unconsolidated volcanic rock ranges from 15 to 28 inches. Depth to hard, fractured, consolidated volcanic bedrock ranges from 28 to 36 inches. Reaction ranges from slightly acid to neutral throughout, except where the surface has been limed. The combined total of rock fragments in the control section is less than 35 percent, by volume.
The A or Ap horizon has hue of 10YR, value of 3 or 4, and chroma of 2. Content of rock fragments range from 2 to 12 percent, by volume. Texture is silty clay loam.
The Bw horizon has hue of 10YR, value of 3 or 4, and chroma of 3 or 4. Content of rock fragments range from 10 to 20 percent, by volume. Texture is silty clay loam, silty clay, or their gravelly analogs.
The Cr horizon is composed of unconsolidated fractured volcanic rock. It can be excavated with difficulty with hand tools, and is rippable by mechanical equipment.
The R layer is composed of hard fractured consolidated volcanic bedrock.
COMPETING SERIES: These are no known series in the same family.
GEOGRAPHIC SETTING: Cuchillas soils are on side slopes and summits of mountains on the Humid Mountains and Valleys MLRA. Slopes range from 20 to 90 percent. They formed in residuum material weathered from volcanic rocks. The climate is humid tropical. The average annual precipitation ranges from 56 to 109 inches and the average annual temperature ranges from 62 to 68 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Agueybana (T), Humatas, Los Guineos, and Maricao series. All of these soils are very deep and have more clay in the control section. They are on similar positions with the exception of Humatas which is isothermic and on adjacent lower positions.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Most areas of Cuchillas soils are used for forestland, bananas, coffee and plantains. A few small areas are used for native pasture. The vegetation consists of native and introduced grasses, shrubs, and trees.
DISTRIBUTION AND EXTENT: Side slopes and summits of mountains of southern Puerto Rico. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina.
SERIES ESTABLISHED: Oeste SCD, Puerto Rico; 1979.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Ochric epipedon - the zone from 0 to 6 inches (Ap horizon).
Cambic horizon - the zone from 6 to 15 inches (Bw horizon).
Paralithic contact - the contact at 15 inches (Cr horizon).
Lithic contact - the contact at 36 inches (R horizon).
The type location as moved to its present location in order to reflect the concept of the series and to include Cr horizon.
Cuchillas soils are in MLRA 270.