LOCATION PUAPUA AS PBEstablished Series
The Puapua series consists of shallow, well-drained soils on uplands. These soils formed in volcanic ash and are underlain by hard tuff. Slope is 0 to 100 percent. Elevation is near sea level to 400 feet. The mean annual rainfall is about 140 inches, and the mean annual temperature is about 80 degrees F.
TAXONOMIC CLASS: Medial, amorphic, isohyperthermic Lithic Hapludands
TYPICAL PEDON: Puapua clay loam - on a 20 percent sideslope in a taro and breadfruit plantation. When described the soil was moist throughout. (Colors are for moist soil unless otherwise stated. Textures are apparent field textures.)
Ap--0 to 11 inches; very dark brown (10YR 2/2) medial clay loam, brown (10YR 4/3) dry; strong very fine and fine subangular blocky structure; slightly hard, firm, sticky and plastic; many roots; many pores; few tuff fragments (less than 3 percent); neutral (pH 6.6); gradual smooth boundary. (4 to 12 inches thick)
Bw--11 to 16 inches; dark brown (7.5YR 3/2) extremely paragravelly sandy loam that crushes to sandy loam, yellowish brown (10YR 5/6) dry; weak fine granular structure; slightly hard, loose, slightly sticky and nonplastic; common roots; many pores; this layer consists of 70 percent fragments of volcanic tuff; slightly acid (pH 6.5); abrupt smooth boundary. (4 to 12 inches thick)
2Cr--16 inches; weakly cemented fine grained tuff.
TYPE LOCATION: Tutuila Island, American Samoa; about 1 mile west southwest of Futiga; lat. 14 degrees 21 minutes 14 seconds S. and long. 170 degrees 46 minutes 14 seconds W.
RANGE IN CHARACTERISTICS: Depth to a paralithic contact with tuff ranges from 10 to 20 inches.
The A horizon has hue of 7.5YR or 10YR, value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist, 3 through 6 dry. It has moderate to strong subangular blocky structure.
The Bw horizon has hue of 5YR to 10YR, value of 2 or 3 moist, 4 or 5 dry, and chroma of 1 through 4 moist, 3 through 8 dry.
COMPETING SERIES: This is the Kalaupapa series in the same family and the Sogi series. Kalaupapa soils have a mean annual soil temperature of about 75 degrees F. Sogi soils have a lithic contact at a depth of 20 to 40 inches.
GEOGRAPHIC SETTING: Puapua soils are on nearly level uplands to very steep slopes associated with cinder cones and craters. Slope is 0 to 100 percent. These soils formed in volcanic ash and are underlain by hard tuff at depths of 10 to 20 inches. Elevation is near sea level to 400 feet. The mean annual rainfall is 120 to 160 inches, and the mean annual temperature is about 80 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Iliili, Oloava, Pavaiai, and the competing Sogi soils. Iliili and Pavaiai soils are medial-skeletal and are underlain with lava. Oloava soils have soft weathered cinders in the control section.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff depending on slope; moderately rapid permeability, except it is slow in the underlying tuff.
USE AND VEGETATION: These soils are used mainly for subsistence farming and homesites. Taro, breadfruit, banana, and coconut are the principal crops grown. Cassava and vegetable crops such as cucumber, beans, cabbage, pepper, eggplant, and tomato are grown in small areas.
DISTRIBUTION AND EXTENT: Southwestern part of Tutuila Island. Soils of this series are of small extent, about 1200 acres.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: American Samoa, 1982.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Umbric Epipedon: The zone from 0 to 31 centimeters (0 to 16 inches).
Paralithic contact: The contact with welded tuff at 31 centimeters (16 inches).
Andic properties: The zone from 0 to 31 centimeters (0 to 16 inches)
Soil moisture: Udic moisture regime.
Particle-size control section: The zone from 0 to 31 centimeters (0 to 16 inches).
Taxonomic Version: Second edition Soil Taxonomy, 1999.
ADDITIONAL DATA: Laboratory data are available on the type location, NSSL Soil Survey Sample Number S81AS-603-003