LOCATION HONAUNAU                HI

Established Series
Rev. MRK-RTG
05/2012

HONAUNAU SERIES

The Honaunau series consists of moderately deep, moderately well drained soils that formed in basic volcanic ash over pahoehoe lava. Slopes range from 2 to 40 percent. The mean annual rainfall is about 1650 millimeters (65 inches) and the mean annual air temperature is about 19 degrees C. (66 degrees F.)

TAXONOMIC CLASS: Hydrous, ferrihydritic, isothermic Typic Hydrudands

TYPICAL PEDON: Honaunau silt loam, on a west facing, slightly concave, 8 percent slope in pasture at an elevation of 1042 meters (3420 feet). (Colors are for moist soil unless otherwise noted. All textures are "apparent field textures." pH measured with electrode in 1:1 water.)

A--0 to 15 centimeters (0 to 6 inches); very dark brown (7.5YR 2/2) silt loam, very dark brown (10YR 2/2) dry; moderate medium and fine subangular blocky structure; slightly hard, friable, sticky and plastic; many roots matted in the upper two inches; many very fine pores; moderately acid (pH 5.7); clear wavy boundary. (13 to 18 centimeters {5 to 7 inches} thick)

Bw1--15 to 31 centimeters (6 to 12 inches); dark brown (7.5YR 3/2) silt loam, very dark brown (7.5YR 2/2) dry; weak very fine and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; weakly smeary; many roots; many very fine pores; moderately acid (pH 5.7); clear wavy boundary. (10 to 20 centimeters {4 to 8 inches} thick)

Bw2--31 to 46 centimeters (12 to 18 inches); dark brown (7.5YR 3/3) silt loam, dark brown (10YR 3/3) dry; weak fine and very fine subangular blocky structure; hard, friable, slightly sticky and slightly plastic; weakly smeary; many roots; many very fine and fine pores; thin gelatin-like coatings; moderately acid (pH 6.0); clear wavy boundary. (13 to 23 centimeters {5 to 9 inches} thick)

Bw3--46 to 66 centimeters (18 to 26 inches); dark reddish brown (5YR 3/4) silt loam, brown (7.5YR 4/4) dry; few faint reddish brown (5YR 4/3) and yellowish red (5YR 4/6) redox concentrations; weak fine and very fine subangular blocky structure; hard, friable, slightly sticky and slightly plastic; moderately smeary; few roots; many very fine pores; thick gelatin-like coatings; slightly acid (pH 6.3); abrupt wavy boundary. (15 to 23 centimeters {6 to 9 inches} thick)

2R--66 centimeters (26 inches); hard, massive pahoehoe lava.

TYPE LOCATION: Island of Hawaii, Hawaii County, Hawaii; about 1.5 miles northeast of Civic Center at Captain Cook; Kaunene Quadrangle; lat. 19 degrees 29 minutes 38 seconds N. and long. 155 degrees 51 minutes 39 seconds W.

RANGE IN CHARACTERISTICS:
Depth to bedrock: 50 to 102 centimeters (20 to 40 inches).
Depth to redoximorphic features: 50 to 102 centimeters (20 to 40 inches) in most pedons.
Mean annual soil temperature: 17 to 22 degrees C. (63 to 71 degrees F.)
Rock fragments: 0 to 35 percent by volume of the pedon and range in size from gravel to stones, but are primarily gravel and cobble size lava rocks.
In some pedons, a dusky red horizon with a gritty loam texture occurs in the upper part of the solum.

A horizon
Hue: 7.5YR or 10YR.
Value: 2 or 3 moist or dry.
Chroma: 2 or 3 moist or dry.
Texture: Silt loam or cobbly silt loam.
Soil reaction: Strongly acid to moderately acid (pH 5.1 to 6.0).

Bw horizon
Hue: 5YR, 7.5YR or 10YR.
Value: 2 or 3 moist or 2 to 4 dry.
Chroma: 2 to 4 moist or dry.
Texture: Silt loam or cobbly silt loam.
Smeariness: Weakly smeary to moderately smeary.
Soil reaction: Moderately acid to slightly acid (pH 5.6 to 6.5).

COMPETING SERIES: These are Alapai, Honuapo, Kailua, Kealakekua, Kukaiau, and Makaala series. Alapai soils are silty clay loam in the control section and are more than 102 centimeters (40 inches) deep. Honuapo, Kukaiau, and Makaala soils are moist in the control section from October through April. Kailua soils are silty clay in the control section. Kealakekua soils are silty clay loam in the control section.

GEOGRAPHIC SETTING: Honaunau soils are on west and southwest slopes on the undissected uplands of Hualalai and Mauna Loa volcanoes at elevations from 305 to 1067 meters (1000 to 3500 feet). These soils occur on all hillslope positions of constructional landscapes consisting of nearly level to steep pahoehoe flows that are 5,000 to 10,000 years old. Slope gradients range from 2 to 40 percent. The soils formed in basic volcanic ash over pahoehoe lava. The mean annual rainfall ranges from 1270 to 2032 millimeters (50 to 80 inches), with most of the rainfall occurring from April through October. The mean annual pan evaporation ranges from 635 to 1016 millimeters (25 to 40 inches). The mean annual temperature ranges from 16 to 22 degrees C. (61 to 71 degrees F.) The mean summer soil temperature and the mean winter soil temperature differ by less than 6 degrees C. (11 degrees F.)

GEOGRAPHICALLY ASSOCIATED SOILS: These are Honuaulu, Hookena, Hua, Kona, Napoopoo, Puna, and the competing Kealakekua series. Honuaulu and Napoopoo soils are hydrous-skeletal. Hookena soils are sandy-skeletal. Hua soils have a lithic contact at 5 to 25 centimeters (2 to 10 inches). Kona soils are organic over pahoehoe lava. Puna soils are organic soils over `a`a lava.

DRAINAGE AND PERMEABILITY: Moderately well drained. Runoff is low to medium. Permeability is moderately rapid in the soil and very slow in the underlying bedrock.

USE AND VEGETATION: Used primarily for grazing; some areas are used for orchard crops. The natural vegetation is ohia lehua (Metrosideros polymorpha), koa (Acacia koa), treefern (Cibotiun chamissoi), and kikuyugrass (Pennisetum clandestinum).

DISTRIBUTION AND EXTENT: North and South Kona districts, Island of Hawaii; MLRA 161B. The series is of small extent.

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

SERIES ESTABLISHED: Island of Hawaii, Hawaii County, Hawaii 1971.

REMARKS: Soil moisture - not dry in any part for as long as 90 cumulative days (Udic moisture regime).
Diagnostic horizons and features recognized in this pedon are:
Umbric epipedon - from 0 to 46 centimeters (0 to 18 inches) (A, Bw1, and Bw2 horizons).
Cambic horizon - from 46 to 66 centimeters (18 to 26 inches) (Bw horizons).
Andic properties - from 0 to 66 centimeters (0 to 26 inches) (A and Bw horizons).
Lithic contact - at 66 centimeters (26 inches) (R horizon).
Redox concentrations - from 50 to 66 centimeters (20 to 26 inches) (Bw horizon).

EDIT LOG - 11/21/99 Classification revised due to changes in Soil Taxonomy. Old classification: Thixotropic, isothermic Typic Hydrandepts. Setting and competing series updated. MRK

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National Cooperative Soil Survey
U.S.A.