LOCATION HONUAULU                HI

Established Series
Rev. RTG-MRK
05/2012

HONUAULU SERIES

The Honuaulu series consists of moderately deep, well drained soils that formed in basic volcanic ash in `a`a 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-skeletal, ferrihydritic, isothermic Typic Hydrudands

TYPICAL PEDON: Honuaulu hydrous silt loam, on a west facing, convex, 16 percent slope under forest at an elevation of 707 meters (2320 feet). (Colors are for moist soils unless otherwise noted. All textures are "apparent field textures". pH measured with electrode in 1:1 water. When described on November 23, 1992 the soil was slightly moist throughout.)

A1--0 to 8 centimeters (0 to 3 inches); black (10YR 2/1) hydrous silt loam; strong fine and medium granular structure; friable, slightly sticky and slightly plastic; nonsmeary; many very fine and fine, few medium, and very few and few coarse roots; few very fine pores; 5 percent gravel and 5 percent cobbles; strongly acid (pH 5.4); abrupt smooth boundary. (8 to 13 centimeters {3 to 5 inches} thick)

A2--8 to 18 centimeters (3 to 7 inches); very dark brown (10YR 2/2) cobbly hydrous silt loam; moderate fine and medium granular structure; friable, slightly sticky and slightly plastic; many very fine and fine and few medium roots; common very fine and fine pores; 10 percent gravel and 5 percent cobbles; strongly acid (pH 5.5); abrupt wavy boundary. (Combined thickness of the A horizon is 15 to 23 centimeters {6 to 9 inches}.)

Bw1--18 to 46 centimeters (7 to 18 inches); very dark grayish brown (10YR 3/2) cobbly hydrous silt loam; weak fine and medium subangular blocky structure; very friable, slightly sticky and slightly plastic; nonsmeary; common very fine and fine roots; common very fine and few fine pores; 20 percent gravel and 10 percent cobbles; moderately acid (pH 5.9); abrupt wavy boundary. (25 to 41 centimeters {10 to 16 inches} thick)

2C/Bw2--46 to 74 centimeters (18 to 29 inches); very dark grayish brown (10YR 3/2) extremely cobbly hydrous loam; weak fine and medium subangular blocky structure; very friable, slightly sticky and slightly plastic; weakly smeary; few very fine and fine roots; common very fine and few fine pores; 2C material consists of unconsolidated `a`a lava (25 percent gravel and 60 percent cobbles); moderately acid (pH 6.0); abrupt wavy boundary. (Combined thickness of the Bw horizon is 50 to 74 centimeters {20 to 29 inches}.)

2R--74 centimeters (29 inches); hard, massive `a`a blue rock.

TYPE LOCATION: Island of Hawaii, Hawaii County, Hawaii; about 1 mile east of University of Hawaii Agricultural experiment Station in Kainaliu; pedon is located about 97 meters (317 feet) south of four wheel drive road and 174 meters (570 feet) north of rock wall at an elevation of 612 meters (2010 feet). Kealakekua Quadrangle; lat. 19 degrees 32 minutes 24 seconds N. and long. 155 degrees 54 minutes 50 seconds W. (Old Hawaiian Datum)

RANGE IN CHARACTERISTICS:
Depth to bedrock: 50 to 102 centimeters (20 to 40 inches).
Mean annual soil temperature: 17 to 22 degrees C (63 to 71 degrees F).
Rock fragments: 35 to 65 percent by volume of the pedon and range in size from gravel to stones, but are primarily gravel and cobble size lava rocks.

A horizon
Hue: 5YR to 10YR.
Value: 2 or 3 moist or dry.
Chroma: 1 or 2 moist or dry.
Texture: Hydrous silt loam or cobbly hydrous silt loam.
Soil reaction: Strongly acid or moderately acid (pH 5.1 to 6.0).

Bw1 and 2C/Bw2 horizon
Value: 3 moist or dry.
Chroma: 2 to 4 moist or dry.
Texture: Cobbly to extremely cobbly hydrous silt loam or hydrous silty clay loam.
Soil reaction: Moderately acid or slightly acid (pH 5.6 to 6.5).

COMPETING SERIES: These are the Akihi and Waiakea series. Akihi and Waiakea soils are moist in the control section from October thru April.

GEOGRAPHIC SETTING: Honuaulu soils are on mid elevation, leeward slopes of Mauna Loa and Hualalai volcanoes at elevations from 305 to 1067 meters (1000 to 3500 feet). These soils are on all hillslope positions of constructional landscapes consisting of undulating to very steep lava 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 in `a`a lava. The mean annual rainfall ranges from 1270 to 2030 millimeters (50 to 80 inches), with most of the rainfall occurring from April through October. The mean annual pan evaporation ranges from 640 to 1020 millimeters (25 to 50 inches). The mean annual air 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 Honaunau, Hookena, Hua, Kealakekua, Kona, Puna and Napoopoo series. Honaunau, Hua and Kealakekua soils are hydrous. Hookena soils are sandy-skeletal. Kona soils are organic soils over pahoehoe lava. Puna soils are organic soils over `a`a lava.

DRAINAGE AND PERMEABILITY: Well drained. Runoff is low to moderate. Permeability is moderate in the soil and very slow in the underlying bedrock.

USE AND VEGETATION: Used primarily for grazing and orchards. Some areas are used for wildlife habitat. The natural vegetation is christmasberry (Schinus terebinthifolius), guava (Psidium guajava), hapuu treefern (Cibotium chammisoi), uluhe (Dicranopteris linearis), ohia lehua (Metrosideros polymorpha), guineagrass (Urochloa maxima), and strawberry guava (Psidium cattleianum).

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

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

SERIES ESTABLISHED: Island of Hawaii, Hawaii County, Hawaii. Soils Survey, Territory of Hawaii, 1949.

REMARKS: Soil moisture - moist and not dry in any part for as long as 90 cumulative days in most years (Udic moisture regime).
Diagnostic horizons and features recognized in this pedon include:
Umbric epipedon - from 0 to 74 centimeters (0 to 29 inches) (A1, A2, Bw1 and 2C/Bw2 horizons).
Lithic contact - at 74 centimeters (29 inches) (2R horizon).
Andic properties - from 0 to 74 centimeters (0 to 29 inches) (A1, A2, Bw1 and 2C/Bw2 horizons).

ADDITIONAL DATA: NASIS User Pedon ID 93HI002023. SSIR 29, pp. 35-37

Edit log: 11/7/99 Classification revised, type location moved, and series concept changed from fragmental to skeletal. Old classification: Thixotropic over fragmental, isothermic Hydric Dystrandepts. Competing series updated. MRK 2/19/08 Andic textural modifiers added. MRK 2/1/12 Competing series updated. MRK

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National Cooperative Soil Survey
U.S.A.