LOCATION CONSTANCIA PREstablished Series
TAXONOMIC CLASS: Fine, smectitic, isohyperthermic Aeric Calciaquolls
TYPICAL PEDON: Constancia silty clay--sugarcane. (Colors are for moist soil.)
Ap--0 to 12 inches; very dark grayish brown (10YR 3/2) silty clay, weak fine and medium granular structure; firm; slightly sticky; plastic; many fine roots; few fine volcanic fragments; strongly effervescent; moderately alkaline; abrupt smooth boundary. (8 to 14 inches thick)
Bw--12 to 17 inches; very dark grayish brown (10YR 3/2) silty clay; weak fine and medium subangular blocky structure; firm; slightly sticky, plastic; many fine roots; few fine volcanic fragments; few fine distinct yellowish brown (10YR 5/6) masses of iron accumulation; common fine distinct dark gray (10YR 4/1) areas of iron depletions; strongly effervescent; moderately alkaline; clear smooth boundary. (4 to 6 inches thick)
Bk1--17 to 24 inches; about 30 percent very dark grayish brown (10YR 3/2), about 30 percent yellowish brown (10YR 5/6), about 30 percent dark gray (5Y 4/1), and about 10 percent dark yellowish brown (10YR 3/4) silty clay; weak medium and coarse subangular blocky structure; firm; slightly sticky, plastic; few soft small rounded masses of calcium carbonate; few fine roots; few fine volcanic fragments; few fine shell fragments; the areas in shades of brown are masses of iron accumulation and the areas in shades of gray are iron depletions; strongly effervescent; moderately alkaline; clear smooth boundary.
Bk2--24 to 29 inches; about 40 percent very dark grayish brown (10YR 3/2), about 40 percent dark gray (5Y 4/1), about 15 percent yellowish brown (10YR 5/6), and about 5 percent dark yellowish brown (10YR 3/4) silty clay; weak medium subangular blocky structure; firm; slightly sticky, plastic; few fine roots; few fine volcanic fragments; few soft small rounded masses of calcium carbonate; few fine shell fragments; few fine limestone fragments; the areas in shades of brown are masses of iron accumulation and the areas in shades of gray are iron depletions; strongly effervescent; moderately alkaline; clear smooth boundary. (Combined thickness of the Bk horizons ranges from 12 to 37 inches)
Cg1--29 to 37 inches; dark gray (5Y 4/1) clay; firm; sticky, plastic; few fine roots; few fine volcanic fragments; few fine shell fragments; few fine limestone fragments; many medium distinct yellowish brown (10YR 5/6) and common medium distinct very dark grayish brown (10YR 3/2) masses of iron accumulation; strongly effervescent; moderately alkaline; clear smooth boundary.
Cg2--37 to 50 inches; dark gray (5Y 4/1) clay; massive; firm; sticky, plastic; few fine volcanic fragments; few fine shell fragments; few fine limestone fragments; many medium distinct brownish yellow (10YR 6/6) and few fine distinct dark yellowish brown (10YR 4/6) masses of iron accumulation; few fine distinct greenish gray (5G 6/1) areas of iron depletions; strongly effervescent; moderately alkaline; clear smooth boundary.
Cg3--50 to 65 inches; about 40 percent yellowish brown (10YR 5/4), about 20 percent dark gray (5Y 4/1), about 15 percent dark bluish gray (5B 4/1), about 15 percent bluish gray (5B 5/1), and about 10 percent brownish yellow (10YR 6/6) clay; massive; firm; sticky, plastic; few fine volcanic fragments; few fine limestone fragments; the areas in shades of brown and yellow are masses of iron accumulation and the areas in shades of gray are areas of iron depletions; violently effervescent; moderately alkaline.
TYPE LOCATION: Sur SCD, Puerto Rico. Approximately 1.6 miles south of kilometer marker 125.1 on Highway 1.
RANGE IN CHARACTERISTICS: Thickness of the solum ranges from 24 to 55 inches. Reaction is slightly alkaline to moderately alkaline throughout. Effervescence is strong or violent throughout the profile.
The A or Ap horizon has hue of 10YR, value of 2 or 3, and chroma of 1 to 3. Texture is silty clay loam, silty clay, or clay.
The Bw horizon has hue of 7.5YR or 10YR, value of 3, and chroma of 2 or 3. Redoximorphic features in shades of gray, yellow, and brown range from common to many. In some pedons, there is no dominant color and is multicolored in shades of gray, yellow, and brown. Texture is silty clay or clay.
The Bk horizons have hue of 10YR or 2.5Y, value of 3 or 4, and chroma of 2 to 4. Redoximorphic features in shades of gray, yellow, and brown range from common to many. In some pedons, there is no dominant color and is multicolored in shades of gray, yellow, and brown. Texture is silty clay or clay.
The Cg horizons have hue of 10YR to 5Y, value of 4 to 6, and chroma of 1 or 2. Redoximorphic features in shades of yellow, brown, and gray range from few to many. In many pedons, there is no dominant color and is multicolored in shades of gray, brown, and yellow. Texture is silty clay or clay.
COMPETING SERIES: There are no other known series in the same family.
GEOGRAPHIC SETTING: Constancia soils are in river flood plains. They formed in calcareous fine-textured sediments derived from volcanic and limestone rocks. The climate is semiarid. Slopes range from 0 to 2 percent. The average annual temperature ranges from 78 to 80 degrees F., and the average annual rainfall ranges from 25 to 40 inches
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Cintrona, Cortada, Jacaguas, Machuelo, and San Anton series. All of these soils are in flood plains. The very poorly drained Cintrona soils are on similar to slightly lower positions. The well drained Cortada and San Anton soils are on higher positions and have fine-loamy subsoils. The excessively drained Jacaguas soils are on higher positions, are loamy-skeletal, and are noncalcareous. Machuelo soils are on similar positions but do not have a mollic epipedon.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow permeability.
USE AND VEGETATION: Most areas of Constancia soils are used for cropland and pasture land. Vegetation includes guineagrass and other native and introduced species.
DISTRIBUTION AND EXTENT: Semiarid areas of southern 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; 1971.
REMARKS: These soils were formerly classified in the Alluvial great soil group.
Diagnostic horizons and features recognized in this pedon are:
Mollic Epipedon - the zone from 0 to 17 inches (Ap and Bw horizons.)
Calcc horizon - the zone from 17 to 38 inches (Bk1 and Bk2 horizons.)