LOCATION MONTEGRANDE PREstablished Series
TAXONOMIC CLASS: Very-fine, mixed, superactive, isohyperthermic Chromic Hapluderts
TYPICAL PEDON: Montegrande clay--sugar cane plantation (Colors are for moist soil).
Ap--0 to 6 inches; dark yellowish brown (10YR 3/4) clay; weak medium subangular blocky structure; firm; slightly sticky, plastic; many fine roots; few faint pressure faces on surfaces of peds; about 12 percent, by volume, pebbles; few fine black (10YR 2/1) manganese concretions; noneffervescent; strongly acid; clear smooth boundary. (5 to 8 inches thick)
AB--6 to 10 inches; dark grayish brown (10YR 4/2) clay; weak medium subangular blocky structure; firm; slightly sticky, moderately plastic; common fine roots; few faint pressure faces on surfaces of peds; about 10 percent, by volume, pebbles; common fine black (10YR 2/1) manganese concretions; noneffervescent; strongly acid; clear wavy boundary. (4 to 9 inches thick)
Bss1--10 to 14 inches; dark yellowish brown (10YR 3/4) clay; moderate medium angular blocky structure; firm; slightly sticky, moderately plastic; few fine roots; few distinct intersecting slickensides having polished and grooved surfaces; about 10 percent, by volume, pebbles; many fine black (10YR 2/1) manganese concretions; many fine distinct yellowish brown (10YR 5/6) masses of iron accumulation and many fine distinct gray (10YR 5/1) areas of iron depletions; noneffervescent; strongly acid; clear smooth boundary.
Bss2--14 to 24 inches; yellowish brown (10YR 5/6) clay; weak medium angular blocky structure; firm; slightly sticky, plastic; few fine roots; few distinct intersecting slickensides having polished and grooved surfaces; about 10 percent, by volume, pebbles; many fine black (10YR 2/1) manganese concretions; few fine calcium carbonate concretions; many medium distinct gray (10YR 5/1) areas of iron depletions; moderately alkaline; strongly effervescent; clear smooth boundary. (Combined thickness of the Bss horizons range from 11 to 19 inches)
C--24 to 32 inches; yellowish brown (10YR 5/6) gravelly clay; massive; firm; slightly sticky, slightly plastic; about 20 percent, by volume, pebbles; many fine black (10YR 2/1) manganese concretions; many medium distinct gray (10YR 6/1) and few fine distinct grayish brown (10YR 5/2) areas of iron depletions; strongly effervescent; moderately alkaline; clear smooth boundary. (7 to 15 inches thick)
Cg--32 to 65 inches; gray (10YR 5/1) gravelly clay; massive; friable; slightly sticky, nonplastic; about 20 percent, by volume, pebbles; many fine black (10YR 2/1) manganese concretions; few fine calcium carbonate concretions; common thin lenses and strata of interbedded material; many medium distinct yellowish brown (10YR 5/6) masses of iron accumulation and many medium prominent gray (5YR 5/1) areas of iron depletion; strongly effervescent; moderately alkaline.
TYPE LOCATION: San German, Puerto Rico. Approximately 3.2 miles northwest of the city of San German downtown from the intersection of P.R. Hwy. 102 and P.R. Hwy. 347, about 0.7 mile west on P.R. Hwy. 102 from the intersection of P.R. Hwy. 317, about 200 feet south of P.R. Hwy. 102 in a sugar cane field. USGS San German topographic quadrangle (1966); lat. 18 degrees 05 minutes 18 seconds N.; long. 67 degrees 05 minutes 28 seconds W.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 20 to 36 inches. Reaction ranges from strongly acid to moderately alkaline in the Ap and the upper Bss horizons and from neutral to moderately alkaline on the lower Bss and C horizons.
The A or Ap horizon has hue of 10YR, value of 3 or 4, and chroma of 2 to 4. Content of pebbles range from 0 to less than 15 percent, by volume. Texture is clay.
The AB horizon, where present, has hue of 10YR, value of 4, and chroma of 2 or 3. Content of pebbles range from 0 to less than 15 percent, by volume. Texture is clay.
The upper Bss horizon has hue of 10YR, value of 3 or 4, and chroma of 3 to 6. Content of pebbles range from 0 to less than 15 percent, by volume. Texture is clay.
The lower Bss horizon has hue of 10YR or 2.5Y, value of 4 or 5, and chroma of 3 to 6. Content of pebbles range from 0 to less than 15 percent, by volume. Texture is clay.
The C horizon has hue of 10YR or 2.5Y, value of 4 or 5, and chroma of 6. Content of pebbles range from 20 to 75 percent, by volume. Texture is clay in the fine-earth fraction.
The Cg horizon has hue of 10YR, value of 4 or 5, and chroma of 1 or 2. Content of pebbles range from 20 to 75 percent, by volume. Texture is clay in the fine-earth fraction.
COMPETING SERIES: There are no known series in the same family.
GEOGRAPHIC SETTING: Montegrande soils are on alluvial fans, foot slopes, and toe slopes of hills in the Humid Mountains and Valleys MLRA. Slopes range from 2 to 12 percent. They formed in stratified fine-textured sediments over gravelly colluvium of mixed origin. The climate is humid tropical. The average annual precipitation ranges from 43 to 73 inches and the average annual temperature ranges from 75 to 79 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Caguabo, Coloso, La Tea (T), Mabi, Mucara, and Toa series. The well drained Caguabo and La Tea (T) soils are on higher adjacent positions and are shallow to bedrock. The well drained Mucara soils are on higher adjacent positions and are moderately deep to bedrock. Coloso and Mabi soils are on lower floodplain positions. The well drained Toa soils are on flood plains and have mollic epipedons.
DRAINAGE AND PERMEABILITY: Moderately well drained; moderately slow permeability.
USE AND VEGETATION: Most areas of Montegrande soils are used for pastureland or are abandoned sugar cane plantations. The vegetation consists of native and introduced grasses, shrubs, and trees.
DISTRIBUTION AND EXTENT: Alluvial fans, foot slopes and toe slopes in the Humid Mountains and Valleys MLRA of southern Puerto Rico. The series is small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina.
SERIES ESTABLISHED: Ponce Area Soil Survey, Puerto Rico; 1971.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Ochric epipedon - the zone from 0 to 6 inches (Ap horizon).
Vertic features - the zone from 10 to 24 inches (Bss1 and Bss2 horizons).
ADDITIONAL DATA: Characterization pedon - Penuelas Municipality, Puerto Rico; S86PR111-001. Sample by NSSL, Lincoln, NE., 02/1986.
Montegrande soils are in MLRA 270.