LOCATION AGUILITA PREstablished Series
TAXONOMIC CLASS: Coarse-loamy, carbonatic, isohyperthermic Aridic Calciustolls
TYPICAL PEDON: Aguilita silty clay loam--naturalized pastureland (Colors are for moist soil unless otherwise indicated).
Ap--0 to 6 inches; brown (10YR 4/3) silty clay loam; weak very fine and fine subangular blocky structure; slightly hard, firm; slightly sticky, moderately plastic; common very fine and fine roots; common fine irregular pores, few fine vesicular pores; about 5 percent, by volume, pebbles; strongly effervescent; slightly alkaline; clear wavy boundary. (4 to 11 inches thick)
Bk1--6 to 18 inches; brown (10YR 4/3) silty clay loam; moderate very fine and fine subangular blocky structure; slightly hard, firm; slightly sticky, moderately plastic; few very fine and fine roots; few very fine and fine irregular pores, few very fine vesicular pores; about 5 percent, by volume, pebbles; few very fine distinct light gray (10YR 7/2) irregular soft masses of calcium carbonate; common distinct pressure faces on faces of peds; violently effervescent; moderately alkaline; clear wavy boundary.
Bk2--18 to 23 inches; brown (10YR 5/3) clay loam; strong very fine and fine subangular blocky structure; hard, firm; slightly sticky, moderately plastic; few very fine and fine roots; common very fine and fine irregular pores; about 5 percent, by volume, pebbles; common fine distinct light gray (10YR 7/2) irregular soft masses of calcium carbonate; common distinct pressure faces on faces of peds; violently effervescent; moderately alkaline; abrupt smooth boundary. (Combined thickness of the Bk horizons range from 6 to 21 inches.)
C1--23 to 32 inches; pale brown (10YR 6/3) loam; massive; soft, very friable; moderately sticky, slightly plastic; few very fine and fine roots; few very fine irregular pores, few very fine vesicular pores; about 5 percent, by volume, pebbles; common fine distinct white (10YR 8/1) irregular soft masses of calcium carbonate; violently effervescent; moderately alkaline; diffuse smooth boundary.
C2--32 to 60 inches; pale brown (10YR 6/3) loam; massive; soft, very friable; moderately sticky, slightly plastic; few very fine and fine roots; common fine vesicular and few fine tubular pores; about 5 percent, by volume, pebbles; many fine and medium distinct white (10YR 8/1) irregular soft masses of calcium carbonate; violently effervescent; moderately alkaline.
TYPE LOCATION: Guanica, Puerto Rico. Approximately 1.9 miles southeast from the intersection of P.R. Hwy. 367 and P.R Hwy. 368; about 2,000 feet northwest from Arenas community; about 600 feet southwest from dirt road on naturalized pastureland. USGS Sabana Grande topographic quadrangle (1966); lat. 18 degrees 01 minute 34 seconds N.; long. 66 degrees 54 minutes 56 seconds W.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 10 to 32 inches. Depth to hard limestone bedrock is more than 60 inches. Reaction ranges from slightly alkaline to moderately alkaline throughout. Accumulations of soft masses of calcium carbonate range from few to many in the Bk and C horizons. Content of pebbles range from 0 to 25 percent, by volume, throughout.
The A or Ap horizon has hue of 10YR, value of 3 or 4, and chroma of 1 to 3. Texture is silty clay loam, silty clay or clay in the fine-earth fraction.
The AB horizon, where present, has hue of 10YR, value of 4, and chroma of 3. Texture is silty clay loam in the fine-earth fraction.
The Bk horizon has hue of 10YR or 2.5Y, value of 3 to 6, and chroma of 3 to 6. Soft masses and filaments of calcium carbonate range from few to common. Presence of pressure faces range from few to many. Texture is silty clay loam or clay loam in the fine-earth fraction.
The C horizon has hue of 10YR to 5Y, value of 5 to 8, and chroma of 1 or 6. Concretions, soft masses, and filaments of calcium carbonate range from common to many. Texture is loam or clay loam in the fine-earth fraction.
The Cr horizon, where present, is composed of soft limestone bedrock. It has hue of 10YR to 5Y, value of 5 to 8, and chroma of 1 to 6. It can be excavated with difficulty with hand tools, and is rippable by mechanized equipment.
COMPETING SERIES: There are no known series in the same family.
GEOGRAPHIC SETTING: Aguilita soils are on ridge tops, summits, and side slopes in uplands and limestone hills of the Semiarid Mountains and Valleys MLRA. Slopes range from 5 to 60 percent. They formed of colluvium and residuum weathered from soft limestone bedrock. The climate is tropical semiarid. The average annual precipitation ranges from 25 to 66 inches and the average annual temperature ranges from 75 to 79 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Descalabrado, Duey, Fraternidad, Jacana, Pozo Blanco and San German series. Descalabrado soils are on similar positions, but are shallow to volcanic bedrock. Duey and San German soils are on similar positions, but are shallow to fractured weathered limestone bedrock. Fraternidad and Jacana soils have vertic properties and are on lower positions. Pozo Blanco soils are on a fine-loamy family class.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Most areas of Aguilita soils are used for hayland and pastureland. The vegetation consists mainly of Hurricane grass and Kleberg bluestem grass. Other vegetation consists of Mesquite and other xerophytic grasses and shrubs.
DISTRIBUTION AND EXTENT: Uplands and limestone hills of the Semiarid Mountains and Valleys MLRA. The series is small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina.
SERIES ESTABLISHED: Puerto Rico; 1936. The name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Ochric epipedon - the zone from 0 to 6 inches (Ap horizon).
Calcic horizon - the zone from 6 to 23 inches (Bk1 and Bk2 horizons).
Aguilita soils were correlated as Loamy-skeletal, carbonatic, isohyperthermic Typic Rendolls in the 1970 Survey of the Virgin Islands of the United States. The change from Typic Rendolls to Typic Calciustolls took place when Soil Taxonomy did not allow Rendolls to have an Ustic Soil Moisture Regime.
The type location was moved to Puerto Rico from the U.S. Virgin Islands in 1998 and the series reclassified based on soil lab data and observations in the field.
The classification was updated with the 11/2004 draft to Coarse-loamy, carbonatic, isohyperthermic Aridic Calciustolls and moved to its present location because the type location selected on 1998 was updated to be an Aridic Soil Moisture Regime based on a soil moisture study in southern Puerto Rico. The concept of the Aguilita soils is on Ustic Soil Moisture Regime.
Aguilita soils are in MLRA 271.