LOCATION IILEWA HI

Established Series
Rev. AMS/KP
05/2012

IILEWA SERIES

The Iilewa series consists of moderately deep, moderately well drained soils formed in basic volcanic ash over pumice. Iilewa soils are on volcanic cones and lava fields along the lower east rift zone of Kilauea volcano. Slopes range from 2 to 80 percent. The mean annual rainfall is about 2300 millimeters (91 inches), and the mean annual temperature is about 23 degrees C (73 degrees F).

TAXONOMIC CLASS: Hydrous-pumiceous, ferrihydritic, isohyperthermic Typic Hydrudands

TYPICAL PEDON: Iilewa highly organic hydrous silty clay loam, on an east facing 5 percent slope under a cover of lowland forest at an elevation of 332 meters (1088 ft). When described the soil was moist throughout. (Colors are for moist soil unless otherwise noted. All textures are "apparent field textures". pH measured using a 1:1 soil to water mixture. When described on February 12, 2007, the soil was moist throughout the profile).

A--0 to 5 centimeters, (0 to 2 inches); highly organic hydrous silty clay loam, black (10YR 2/1) moist; weak fine angular blocky structure; soft, very friable, slightly sticky, slightly plastic; moderately smeary; many very fine and fine, common medium and coarse roots throughout; many fine vesicular pores; 10 percent very angular pahoehoe lava cobbles; slightly acid (pH 6.4); clear smooth boundary. (3 to 10 centimeters {1 to 4 inches} thick)

Bw1--5 to 18 centimeters, (2 to 7 inches); hydrous silty clay loam, very dark brown (10YR 2/2) moist; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; moderately smeary; many fine, common medium and coarse roots throughout; common fine vesicular pores; 10 percent very angular pahoehoe lava cobbles; moderately acid (pH 5.9); abrupt smooth boundary. (10 to 22 centimeters {4 to 9 inches} thick)

Bw2/2C--18 to 55 centimeters, (7 to 22 inches); extremely paragravelly hydrous loam, dark brown (7.5YR 3/4) moist; weak fine subangular blocky parting to weak fine granular; soft, very friable, nonsticky, nonplastic; moderately smeary; many fine, common medium and coarse roots throughout; common very fine irregular pores; 2C materials consist of unconsolidated pahoehoe lava fragments and pumice (10 percent very angular pahoehoe lava cobbles and 60 percent dark reddish brown (5YR 3/4) very angular pumice paragravels); slightly acid (pH 6.1); abrupt smooth boundary. (10 to 50 centimeters {4 to 20 inches} thick).

Bw3/3C--55 to 70 centimeters, (22 to 28 inches); cobbly hydrous loam, very dark brown (10YR 2/2) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; moderately smeary; common fine roots throughout; common fine dendritic tubular pores; 3C material consists of 25 percent very angular pahoehoe lava cobbles; moderately acid (pH 5.9); abrupt smooth boundary. (0 to 40 centimeters (0 to 16 inches} thick).

3R--70 centimeters, (28 inches); spattery pahoehoe lava

TYPE LOCATION: Island of Hawaii; From the village of Pahoa, take highway 130 south to cinder road on east side of road just past 14 mile marker. Continue down road 0.75 miles to second turnoff on the right. Continue 50 yards into the woods to the east to the type location at Pahoa South Quadrangle 19 degrees, 27 minutes, 8.2 seconds North latitude and 154 degrees, 55 minutes, 58.1 seconds West longitude, Old Hawaiian datum, +/- 12 feet; measured by Garmin GPS.

RANGE IN CHARACTERISTICS:
Soil Moisture: The soil is typically moist throughout the profile and precipitation exceeds evapotranspiration in all months of normal years. Soil temperature: 22 degrees C (72 degrees F) or higher.
Rock fragments: 5 to 75 percent by volume and range in size from gravel cinders or paragravel pumice to cobble size lava rocks.
Depth to bedrock: 50 to 100 centimeters (20 to 40 inches).
Reaction: slightly acid to moderately acid (5.8 to 6.5).

Oa horizon
Exists in some pedons.
Depth: 0 to 10 centimeters {0 to 4 inches} thick.
Hue: 7.5YR to 10YR.
Value: 1 to 3 moist.
Chroma: 1 to 3 moist.
Texture: Highly decomposed plant material.

A horizon
Hue: 7.5YR to 10YR.
Value: 3 to 2 moist.
Chroma: 1 or 2 moist.
Texture: Hydrous silt loam, loam or sandy loam. May be highly organic.
Bw horizon
Hue: 7.5YR to 10YR.
Value: 2 to 3 moist.
Chroma: 2 to 3 moist
Texture: Hydrous silt loam, loam or sandy loam.

Bw/C horizon
Hue: 5YR to 10YR.
Value: 2 to 3 moist.
Chroma: 2 to 4 moist.
Texture: paragravelly, gravelly, very gravelly, or cobbly with fines being hydrous silt loam or hydrous sandy loam.

COMPETING SERIES: There are no competing series in this family.

GEOGRAPHIC SETTING: Iilewa soils are found at elevations ranging from 30 to 366 meters (100 to 1200 feet) on cinder and spatter cones and lava fields covered with cinders and pumice along the lower east rift zone of Kilauea volcano. Slope gradients range from 2 to 80 percent. These soils formed in basic volcanic ash over pumice. The mean annual rainfall is about 2300 millimeters (91 inches), and the mean annual temperature is about 23 degrees C (73 degrees F).

GEOGRAPHICALLY ASSOCIATED SOILS: These are Opihikao, Malama, Hakuma, and Panaewa soils. Opihikao soils are lithic and organic. Malama soils are fragmental and organic. Hakuma soils are formed from volcanic ash. Panaewa soils are skeletal and formed from volcanic ash.

DRAINAGE AND PERMEABILITY: Moderately well drained. Runoff is moderate. Permeability is moderate.

USE AND VEGETATION: Most of these soils are in native or alien forest. A few areas are used for papaya fields. Some areas are used for cinder pits. Natural vegetation is ohia lehua (Metrosideros polymorpha), uluhe treefern (Cibotium chamissoi or C. glauca), uluhe (Dicranopteris linearis) and guava (Psidium guajava).

DISTRIBUTION AND EXTENT: Island of Hawaii. This series is of small extent. MLRA 159A.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Island of Hawaii, Hawaii 2012. Proposed 2008.

REMARKS:
Diagnostic horizons and features (10th edition Keys to Soil Taxonomy) recognized in this pedon are:

Andic Soil Properties - from 0 to 70 cm (0 to 28 in).
Ochric Epipedon - from 0 to 18 cm (0 to 7 in).
Cambic Horizon - from 5 to 70 cm (2 to 28 in).
Isohyperthermic soil temperature regime.
Perudic moisture regime.
Lithic contact at 70 cm (28 in).

National Cooperative Soil Survey
U.S.A.