LOCATION MAGUAYO PREstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, isohyperthermic Vertic Calciargids
TYPICAL PEDON: Maguayo very gravelly sandy clay loam--pastureland (Colors are for moist soil).
Ap--0 to 6 inches; dark yellowish brown (10YR 3/4) very gravelly sandy clay loam; moderate fine granular structure; soft, friable; nonsticky, nonplastic; many fine roots; about 36 percent, by volume, pebbles; moderately acid; noneffervescent; gradual smooth boundary. (3 to 7 inches thick)
A--6 to 12 inches; dark yellowish brown (10YR 3/4) very gravelly coarse sandy loam; weak fine subangular blocky structure; slightly hard, friable; nonsticky, nonplastic; many fine roots; about 38 percent, by volume, pebbles; slightly acid; noneffervescent; clear smooth boundary. (0 to 6 inches thick)
Bt1--12 to 22 inches; dark yellowish brown (10YR 4/4) clay; moderate medium subangular blocky structure; hard, firm; nonsticky, slightly plastic; many faint clay films on ped faces; common fine roots; about 12 percent, by volume, pebbles; neutral; noneffervescent; gradual wavy boundary.
Bt2--22 to 35 inches; brown (7.5YR 4/4) clay; weak fine subangular blocky structure; hard, firm; nonsticky, slightly plastic; many faint clay films on ped faces; few fine roots; about 12 percent, by volume, pebbles; slightly alkaline; slightly effervescent; gradual wavy boundary. (Combined thickness of the Bt horizons range from 14 to 20 inches)
Bkss1--35 to 48 inches; brown (7.5YR 5/4) clay; massive parting to weak medium subangular blocky structure; hard, firm; nonsticky, plastic; few distinct intersecting slickensides having polished and grooved surfaces; few fine roots; about 9 percent, by volume, pebbles; common medium prominent very pale brown (10YR 8/3) masses and filaments of calcium carbonate; slightly alkaline; strongly effervescent; gradual wavy boundary. (15 to 35 inches thick)
Bkss2--48 to 65 inches; strong brown (7.5YR 5/6) clay; massive parting to weak medium subangular blocky structure; hard, firm; nonsticky, plastic; few distinct intersecting slickensides having polished and grooved surfaces; about 12 percent, by volume, pebbles; common medium prominent very pale brown (10YR 8/3) masses and filaments of calcium carbonate; moderately alkaline; strongly effervescent. (Combined thickness of the Bkss horizons range from 20 to 45 inches)
TYPE LOCATION: Lajas, Puerto Rico. Approximately 0.2 mile east of Maguayo community on P.R. Hwy. 305 and about 50 feet north of highway in a pasture. USGS San German topographic quadrangle (1966); lat. 18 degrees 00 minutes 43 seconds N.; long. 67 degrees 04 minutes 53 seconds W.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 40 to 60 inches. Reaction ranges from moderately acid to slightly alkaline in the A or Ap horizon, from slightly acid to slightly alkaline in the Bt horizons and from neutral to moderately alkaline in the Bkss and when present, the 2C horizons.
The A or Ap horizon has hue of 7.5YR or 10YR, value of 2 to 4, and chroma of 2 to 4. Content of pebbles range from 10 to 38 percent, by volume. Texture is sandy loam, sandy clay loam, or clay loam in the fine-earth fraction.
The Bt horizon has hue of 5YR or 7.5YR, 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 loam or clay.
The Bkss horizon has hue of 7.5YR or 10YR, value of 4 to 6, and chroma of 4 to 8. Content of pebbles range from 0 to less than 15 percent, by volume. Texture is clay loam or clay.
The 2C horizon, where present, has hue of 7.5YR to 10YR, value of 4 to 6, and chroma of 3 to 8. Content of pebbles range from 35 to more than 75 percent, by volume. Texture is clay loam or clay in the fine-earth fraction.
COMPETING SERIES: These are no known series in the same family.
GEOGRAPHIC SETTING: Maguayo soils are on alluvial fans on the Semiarid Mountains and Valleys MLRA. Slopes range from 0 to 12 percent. They formed in material that weathered from volcanic rocks and limestone. The climate is tropical semiarid. The average annual precipitation ranges from 28 to 36 inches and the average annual temperature ranges from 78 to 82 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Llanos Costa (T) series. Llanos Costa soils are on similar positions but do not have secondary calcium carbonates in the profile.
DRAINAGE AND PERMEABILITY: Well drained; slow permeability.
USE AND VEGETATION: Most areas of Maguayo soils are used for hayland and pastureland. The vegetation consists of native and introduced grasses, shrubs, and trees.
DISTRIBUTION AND EXTENT: Alluvial fans of the semiarid mountains and valleys of Puerto Rico. The series is of minor extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Raleigh, North Carolina.
SERIES ESTABLISHED: Lajas Valley Area, Puerto Rico; 1961.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Ochric epipedon - the zone from 0 to 12 inches (Ap and A horizons).
Argillic horizon - the zone from 12 to 35 inches (Bt1 and Bt2 horizons).
Calcic horizon - the zone from 35 to 64 inches (Bkss1 and Bkss2 horizons).
Vertic feature - the zone from 35 to 64 inches (Bkss1 and Bkss horizons).
A soil moisture study performed in the San German Area Soil Survey Update recognized the Aridic soil moisture regime in southern Puerto Rico.
ADDITIONAL DATA: Characterization pedon - Lajas Municipality, Puerto Rico; S81PR-007-005. Sample by NSSL, Lincoln, NE., 08/1981.
Maguayo soils are in MLRA 271.