LOCATION HUIKAU                  HI

Established Series
Rev. MRK/RTG/PGN/AMS
05/2012

HUIKAU SERIES

The Huikau series consists of deep, somewhat excessively drained soils that formed in basic volcanic ash and cinders over `a`a lava. Slopes range from 2 to 50 percent. The mean annual rainfall is about 510 millimeters (20 inches) and the mean annual temperature is about 12 degrees C (53 degrees F).

TAXONOMIC CLASS: Ashy, amorphic, isomesic Humic Ustivitrands

TYPICAL PEDON: Huikau ashy sandy loam, on a south-facing 45 percent slope in pasture, at an elevation of 2360 meters (7743 feet). (Colors are for moist soil unless otherwise noted. All textures are "apparent field textures".)

A--0 to 15 centimeters (0 to 6 inches); very dark brown (10YR 2/2) ashy sandy loam, dark brown (10YR 3/3) dry; weak very fine granular structure; soft, very friable, non-sticky, non-plastic, non-smeary; many fine and very fine roots; many fine irregular pores; 12 percent subrounded gravel-sized cinders; neutral (pH 6.9); clear smooth boundary. (13 to 20 centimeters {5 to 8 inches} thick)

Bw1--15 to 35 centimeters (6 to 14 inches); very dark brown (10YR 2/2) paragravelly ashy sandy loam, dark brown (10YR 3/3) dry; weak very fine subangular blocky structure; soft, very friable, non-sticky, non-plastic, non-smeary; common fine and very fine roots; many fine and very fine irregular pores; 16 percent subrounded gravel-sized cinders; neutral (pH 6.6); clear smooth boundary. (8 to 20 centimeters {3 to 8 inches} thick)

Bw2--35 to 54 centimeters (14 to 21 inches); dark reddish brown (5YR 2.5/2) paragravelly ashy loamy sand, dark reddish brown (5YR 3/3) dry; weak very fine subangular blocky structure; soft, very friable, non-sticky, non-plastic, non-smeary; few very fine roots; common fine irregular pores; 18 percent subrounded gravel-sized cinders; neutral (pH 6.7); abrupt smooth boundary. (10 to 20 centimeters {4 to 8 inches} thick)

2C1--54 to 85 centimeters (21 to 33 inches); black (2.5/N) extremely paragravelly ashy coarse sand; single grain; loose, loose, non-sticky, non-plastic, non-smeary; few very fine roots; 60 percent subrounded gravel-sized cinders; moderately acid (pH 6.0); abrupt smooth boundary. (20 to 35 centimeters {8 to 14 inches} thick)

3Bw3--85 to 115 centimeters (33 to 45 inches); very dark brown (7.5YR 2.5/2) cobbly ashy sandy loam, dark brown (7.5YR 3/3) dry; weak very fine subangular blocky structure; soft, very friable, non-sticky, non-plastic, non-smeary; few very fine roots; common fine irregular pores; 10 percent subangular `a`a gravels and 15 percent subangular `a`a cobbles; neutral (pH 6.7); abrupt smooth boundary. (20 to 35 centimeters {8 to 14 inches} thick)

4C2--115 to 152 centimeters (45 to 60 inches); very dark brown (7.5YR 2.5/2) extremely cobbly ashy sandy loam, dark brown (7.5YR 3/3) dry; weak very fine granular structure; soft, very friable, non-sticky, non-plastic, non-smeary; few very fine roots; common fine irregular pores; 5 percent subangular `a`a gravels, 60 percent subangular `a`a cobbles, and 5 percent subangular `a`a stones; neutral (pH 6.7); (35 to 40 centimeters {14 to 16 inches} thick)

TYPE LOCATION: Island of Hawaii, Hawaii County, Hawaii; Above Mana Road on Kukaiau Ranch, about 91 meters (100 yards) south of the summit of Puu Kihe. Umikoa Quadrangle - 19 degrees 54 minutes 4.4 seconds North latitude and 155 degrees 23 minutes 37.6 seconds West longitude (Old Hawaiian Datum, 6 ft., measured by GPSmap 76CSx).

RANGE IN CHARACTERISTICS:
Soil moisture: The soil is typically dry in some or all parts for short intermittent periods totaling 90 or more days during the months of April through October in most years.
Soil temperature: 10 to 15 degrees C (50 to 59 degrees F).
Reaction: Neutral (pH 6.6 to 7.3).
Depth to bedrock: 102 to 152 centimeters (40 to 60 inches).

A horizon
Hue: 10YR or 2.5Y.
Value: 2 or 3 moist or 3 or 4 dry.
Chroma: 1 or 2 moist or dry.
Texture: Ashy loamy sand, sandy loam, or silt loam; medial loam; May be gravelly to extremely gravelly.
Fragments: 0 to 60 percent (by volume) gravel-sized `a`a or cinders.
Structure: Weak granular or single grain.

Bw horizons
Hue: 5YR to 10YR.
Value: 2 to 3.
Chroma: 2 to 3.
Texture: Ashy sandy loam or loamy sand. May be very paragravelly to extremely paragravelly, or cobbly.
Fragments: 0 to 35 percent (by volume) gravel-sized cinders or `a`a cobbles.

COMPETING SERIES: This is the Lanapohaku series. Lanapohaku soils do not have cinders in the particle size control section.

GEOGRAPHIC SETTING: The Huikau soils are on nearly level to moderately steep lava flows and on steep cinder cones on high mountain slopes of Hualalai and Mauna Kea volcanoes at elevations from 1615 to 2743 meters (5300 to 9000 feet). Slope gradients range from 2 to 50 percent. The soils formed in basic volcanic ash and cinders over `a`a lava. The mean annual rainfall is about 380 to 889 millimeters (15 to 35 inches). The mean annual pan evaporation ranges from 1020 to 1780 millimeters (40 to 70 inches). The mean annual air temperature is 9 to 14 degrees C (48 to 57 degrees F).

GEOGRAPHICALLY ASSOCIATED SOILS: On Hualalai, these are Mawae, Nenenui, and Puukala, series, and the similar Nawahine and Ohianui series. On Mauna Kea, these are the Lanapohaku and Pohakulehu series. Mawae soils are organic soils over `a`a lava. Nenenui soils have a lithic contact at 5 to 25 centimeters (2 to 10 inches). Puukala soils are medial-skeletal. Lanapohaku soils do not contain any cinders. Pohakulehu soils are ashy-skeletal in the control section.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained. Runoff is low to moderate. Permeability is rapid.

USE AND VEGETATION: These soils are used mostly for wildlife habitat; some areas are used for grazing. The natural vegetation is hardstem lovegrass (Eragrostis atropioides), kalamaloa (Deschampsia nubigena), aalii (Dodonaea viscosa), mamane (Sophora chrysophylla), and naio (Myoporum sandwicense).

DISTRIBUTION AND EXTENT: Island of Hawaii, Hawaii; MLRA 160 and 161B. The series is of small extent with about 6000 acres mapped.

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

SERIES ESTABLISHED: Soil Survey, Territory of Hawaii, 1949.

REMARKS:
Diagnostic horizons and features recognized in this pedon include:
Ustic soil moisture: soil is usually moist, but dry for short intermittent periods totaling 90 or more days throughout the year in most years.
Isomesic soil temperature.
Mollic epipedon from 0 to 35 centimeters (0 to 12 inches) (A and Bw1 horizons).
Andic soil properties from 0 to 152 centimeters (0 to 60 inches) (A, Bw, and C horizons).
Lithologic discontinuity at 54 and 115 centimeters (21 and 45 inches).

Edit log: 12/8/99(MRK): Classification revised due to changes in Soil Taxonomy. Old Classification: Ashy over cindery, isomesic Typic Vitrandepts. Geographic setting and distribution were changed to include Hualalai Volcano area. Competing series and geographically associated soils have been updated.
3/28/11 (PGN/AMS): Minor edits to include formation cinder cones of Mauna Kea Volcano. Updated coordinates of type location.

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National Cooperative Soil Survey
U.S.A.