LOCATION MACHUELO PREstablished Series
The Machuelo series have dark grayish brown clay, plastic calcareous A and upper B horizons over clay, plastic, calcareous lower B and C horizons.
TAXONOMIC CLASS: Fine, mixed, superactive, calcareous, isohyperthermic Fluvaquentic Endoaquepts
TYPICAL PEDON: Machuelo clay - sugar cane - irrigated.
(Colors are for moist soils unless otherwise stated.)
Ap--0 to 8 inches; dark grayish brown (2.5YR 4/2) clay with few fine distinct yellowish brown, strong brown and gray mottles; moderate fine and medium granular structure; firm, slightly sticky, plastic; many fine roots; common fine volcanic fragments; strong effervescence, abrupt smooth boundary. (6 to 10 inches thick)
C1g--8 to 16 inches; dark gray (10YR 4/1) clay with few fine distinct greenish gray, few fine distinct light gray and few fine distinct yellowish brown mottles; weak medium and coarse subangular blocky structure to massive; firm, slightly sticky, plastic; many fine roots, common fine volcanic fragments; common fine limestone fragments; few shell fragments; strong effervescence; abrupt smooth boundary. (8 to 12 inches thick)
C2g--16 to 21 inches; dark gray (5Y 4/1) clay with common fine distinct olive yellow, few fine faint gray, and few fine distinct dark grayish brown mottles; weak medium subangular blocky structure to massive; firm, slightly sticky, plastic; common fine roots; common fine volcanic fragments; few fine limestone fragments; strong effervescence; clear smooth boundary. (4 to 8 inches thick)
C3g--21 to 29 inches; greenish gray (5GY 5/1) clay with many fine prominent yellowish brown, common fine prominent olive yellow, few fine distinct bluish gray, few fine distinct dark bluish gray mottles; massive; firm, slightly sticky, plastic; few fine roots; few fine volcanic fragments; few fine limestone fragments; few fine shell fragments; slight effervescence; clear wavy boundary. (6 to 10 inches thick)
C4g--29 to 37 inches; light olive brown (2.5YR 5/6), greenish gray (5BG 5/1), and dark bluish gray (5BG 4/1) rubbed color gray (5Y 5/1) clay; massive; firm, sticky, plastic; common fine volcanic fragments; few fine limestone fragments; few shell fragments; water table at 32 inches (82 cm); strong effervescence; clear wavy boundary. (6 to 10 inches thick)
C5g--37 to 60 inches; olive (5Y 5/4), dark greenish gray (5BG 4/1), gray (5Y 5/1) and light olive brown (2.5Y 5/4), rubbed color dark greenish gray (5GY 4/1), clay, massive; firm, sticky, plastic; few fine volcanic fragments; few fine limestone fragments; few lime splotches; strong effervescence.
TYPE LOCATION: Sur SCD, Puerto Rico; 1.6 miles south of kilometer marker 123.75 of Highway No. 1.
RANGE IN CHARACTERISTICS: Depth to water table under irrigation ranges from 18 to 36 inches. Clay is the dominant texture throughout the profile.
The A horizons are dark grayish brown (10YR 3/2; 2.5Y 3/2) through brown (10YR 4/3) with gray and brown mottles.
The C horizons are dark gray (10YR 4/1; N 4/; 5Y 4/1), gray (10YR 5/1; N 5/; 5Y 5/1), greenish gray (5GY 5/1), light olive brown (2.5Y 5/6), or olive (5Y 5/4). They are mottled with grays, yellows, and browns. These soils have slightly sticky and plastic C horizons. Effervescence with dilute Hcl is strong or violent throughout.
COMPETING SERIES: These are the Coloso, Corcega, Fortuna, Talante, Vayas, and Zarzal series. The Coloso and Vayas soils are noncalcareous. The Corcega, Talante, and Zarzal soils are sandy at 20 to 30 inches (50-75 cm) from the surface. The Fortuna soils are acid.
GEOGRAPHIC SETTING: The Machuelo soils are on nearly level flood plains with slope gradients of 0 to 2 percent. The soil formed in clayey sediments washed out from the volcanic and limestone hills. The climate is semiarid. The average annual rainfall ranges from 25 to 40 inches and the mean annual temperature varies from 78 to 80 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cintrona, Constancia, Cortada, Jacaguas, and San Anton soils. The Cintrona and Constancia soils have darker colored surface layers and have calcic horizons. The Cortada and San Anton soils are loamy, well drained, and have darker colored surface layers. The Jacaguas soils have clay loam sola and are underlain by sand, gravel and cobbles at a depth of 20 inches or less.
DRAINAGE AND PERMEABILITY: Poorly drained; slow runoff; slow permeability.
USE AND VEGETATION: Most of the acreage has been planted to sugar cane for many years.
DISTRIBUTION AND EXTENT: Semiarid flood plains of Puerto Rico. The series is of minor extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina
SERIES ESTABLISHED: Ponce Survey ARea, Puerto Rico; l971.
REMARKS: These soils were classified in the Alluvial great soil group.