LOCATION ILIILI AS PBEstablished Series
The Iliili series consists of shallow, well drained soils on uplands. These soils formed in volcanic ash and are underlain by lava. Slope is 3 to 15 percent. Elevation is near sea level to 200 feet. The mean annual rainfall is about 140 inches, and the mean annual temperature is about 80 degrees F.
TAXONOMIC CLASS: Medial-skeletal, amorphic, isohyperthermic Lithic Hapludands
TYPICAL PEDON: Iliili extremely stony muck - on a 3 percent slope in a taro plantation. When described the soil was moist throughout. (Colors are for moist soil unless otherwise stated. Textures are apparent field textures.)
Op--0 to 1 inch; black (10YR 2/1) extremely stony muck, very dark gray (10YR 3/1) dry; strong very fine granular structure; extremely hard, firm, nonsticky and nonplastic; many roots; many pores; 20 percent stones; 15 percent cobbles, and 30 percent pebbles; many decomposing leaves and twigs on the surface; neutral (pH 7.1); clear smooth boundary. (0 to 3 inches thick)
Ap--1 to 6 inches; very dark grayish brown (10YR 3/2) extremely stony mucky clay loam, very dark grayish brown (10YR 3/2) dry; strong fine and very fine subangular blocky structure; very hard, slightly firm, slightly sticky and slightly plastic; many roots; many pores; 20 percent stones, 15 percent cobbles, and 30 percent pebbles; neutral (pH 7.1); clear smooth boundary. (4 to 11 inches thick)
B--6 to 10 inches; very dark grayish brown (10YR 3/2) extremely stony clay loam, dark yellowish brown (10YR 4/4) dry; moderate fine and very fine subangular blocky structure; friable, slightly sticky and slightly plastic; many roots; many pores; 20 percent stones, 15 percent cobbles, and 30 percent pebbles, high organic matter; neutral (pH 7.0); gradual irregular boundary. (4 to 12 inches thick)
2R--10 inches; lava bedrock.
TYPE LOCATION: Tutuila Island, American Samoa; about 1 mile northeast of Iliili; lat. 14 degrees 21 minutes 22 seconds S. and long. 170 degrees 44 minutes 10 seconds W.
RANGE IN CHARACTERISTICS: The thickness of the solum and depth to lava bedrock range from 8 to 12 inches. ( Those over 12 inches deep are Fulvudands) Some pedons lack an 0 horizon. Some pedons have a C horizon of loose fragmental lava. It is medium acid to neutral.
The A horizon has a hue of 7.5YR or 10YR, and chroma of 2 or 3 moist or dry. It is clay loam or silty clay loam and extremely stony and mucky.
The B horizon has hue of 7.5YR or 10YR, and chroma of 2 through 4 moist or dry. It is clay loam or silty clay loam and extremely stony.
COMPETING SERIES: This is the Pavaiai series in another family. Pavaiai soils have a lithic contact at a depth of 20 to 40 inches.
GEOGRAPHIC SETTING: Iliili soils are on gently sloping to moderately sloping uplands. Slope is 3 to 15 percent. These soils formed in volcanic ash and are underlain by lava. Elevation is near sea level to 200 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 Puapua, Sogi, Tafuna, and the competing Pavaiai soils. Puapua and Sogi soils have less than 35 percent rock fragments in the control section and have more than 50 percent base saturation. Tafuna soils are Histosols.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; rapid permeability.
USE AND VEGETATION: Iliili soils are used for subsistence farming and homesites. Coconut, breadfruit, banana, and taro are the main crops. Small areas are in pasture and a golf course. Areas not disturbed are in tropical forest.
DISTRIBUTION AND EXTENT: Island of Tutuila and Tau. This series is of small extent, about 1,400 acres. MLRA 197.
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 - From 1 to 10 inches. (Ap and B horizons)
Lithic contact - At a depth of 10 inches
Particle-size control section - 0 to 10 inches.
Andic soil materials - 0 to 10 inches
Taxonomic Version: Second edition Soil Taxonomy, 1999.
ADDITIONAL DATA: Laboratory data are available on the type location. Pedon number S81AS-603-008National Soil Survey Laboratory, Lincoln NE.