LOCATION WAIKUI HI

Established Series
IRD MRK-RTG
05/2012

WAIKUI SERIES

The Waikui series consists of deep and very deep, well drained soils that formed in basic volcanic ash in `a`a lava. Slopes range from 2 to 20 percent. The mean annual rainfall is about 200 millimeters (8 inches) and the mean annual temperature about 23 degrees C. (73 degrees F.)

TAXONOMIC CLASS: Medial-skeletal, amorphic, isohyperthermic Typic Haplotorrands

TYPICAL PEDON: Waikui extremely cobbly medial silt loam, on a west facing, slightly convex, 2 percent slope, under grasses and scattered trees, at an elevation of 165 meters (540 feet). (Colors are for dry soils unless otherwise noted. All textures are apparent field textures. pH measured with meter in 1:1 water: soil. When described on March 11, 1995, the soil was dry throughout.) The 2C parts of these horizons consist of unconsolidated `a`a lava fragments of variable size.

2C1/A -- 0 to 6 centimeters (0 to 2 inches); brown (10YR 4/3) extremely cobbly medial silt loam, dark brown (7.5YR 3/3) moist; weak coarse subangular blocky parting to weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; nonsmeary; common fine and medium roots; many very fine interstitial and few very fine and fine tubular pores; 45 percent angular `a`a gravel, 40 percent angular `a`a cobbles and 5 percent angular `a`a stones; noneffervescent; slightly alkaline (pH 7.4); clear smooth boundary. (5 to 7 centimeters {2 to 3 inches} thick)

Bw1/2C2 -- 6 to 18 centimeters (2 to 7 inches); dark brown (7.5YR 3/4) very gravelly medial silt loam, dark brown (7.5YR 3/3) moist; weak fine subangular blocky structure; soft, friable, slightly sticky and slightly plastic; nonsmeary; many very fine and fine, and few medium roots; common very fine to medium tubular and common very fine interstitial pores; 15 percent angular `a`a cobbles and 25 percent angular `a`a gravel; noneffervescent; slightly alkaline (pH 7.6); clear smooth boundary. (9 to 13 centimeters {4 to 5 inches} thick)

Bw2/2C3 -- 18 to 37 centimeters (7 to 15 inches); dark yellowish brown (10YR 4/4) very cobbly medial silt loam, dark brown (7.5YR 3/2) moist; weak fine subangular blocky structure; soft, friable, slightly sticky and slightly plastic; nonsmeary; many very fine and fine, and few medium roots; common very fine to medium tubular and common very fine interstitial pores; 15 percent angular `a`a cobbles and 25 percent angular `a`a gravel; noneffervescent; moderately alkaline (pH 8.2); clear smooth boundary. (18 to 23 centimeters (7 to 9 inches) thick)

2C4/Bk1 -- 37 to 62 centimeters (15 to 24 inches); yellowish brown (10YR 5/4) extremely cobbly medial silt loam, dark brown (7.5YR 3/3) moist; weak medium and coarse subangular blocky structure; soft, friable, slightly sticky and slightly plastic; nonsmeary; common very fine and fine roots; few very fine and fine interstitial, common fine and medium tubular pores; 30 percent angular `a`a cobbles and 35 percent angular `a`a gravel; 20 percent of coarse fragments have thin white (10YR 8/1) coatings; strongly effervescent; strongly alkaline (pH 8.5); gradual wavy boundary. (13 to 25 centimeters {5 to 10 inches} thick)

2C5/Bk2 -- 62 to 95 centimeters (24 to 37 inches); dark yellowish brown (10YR 4/4) extremely cobbly medial silt loam, dark brown (7.5YR 3/3) moist; weak medium subangular blocky structure; soft, friable, slightly sticky and slightly plastic; nonsmeary; common very fine and fine roots; many fine and medium interstitial; 10 percent `a`a stones, 25 percent angular `a`a cobbles and 30 percent angular `a`a gravel; 40 percent of coarse fragments have white (10YR 8/1) carbonate coatings; strongly effervescent; moderately alkaline (pH 8.4); clear irregular boundary. (22 to 34 centimeters {9 to 13 inches} thick)

2C6/Bk3 -- 95 to 120 centimeters (37 to 47 inches); dark yellowish brown (10YR 4/4) extremely cobbly medial silt loam, dark brown (7.5YR 3/3) moist; massive; soft, friable, slight sticky and slight plastic; nonsmeary; common very fine and fine roots; many fine and medium interstitial pores; 10 percent angular `a`a stones, 25 percent angular `a`a cobbles and 30 percent angular `a`a gravel; 40 percent of coarse fragments have white (10YR 8/1) carbonate coatings; strongly effervescent; moderately alkaline (pH 8.4)

TYPE LOCATION: Island of Hawaii, Hawaii County, Hawaii. Upslope of Puako, in South Kohala, enter property 0.1 mile north of mile marker 72 on Queen Kaahumanu Hwy. 19; after 10 meters of paved road follow dirt road 1.65 miles upslope to junction with dirt road heading north; turn and drive north 1.0 mile; pedon is located about 50 meters upslope at an elevation of 165 meters (540 feet). Puu Hinai Quadrangle; lat. 19 degrees 57 minutes 11.5 seconds N. and long. 155 degrees 48 minutes 32.5 seconds W. Old Hawaiian Datum.

RANGE IN CHARACTERISTICS:
Depth to bedrock: 102 to greater than 152 centimeters (40 to greater than 60 inches).
Mean annual soil temperature: 22 to 24 degrees C. (72 to 75 degrees F.)
Coarse fragments: 35 to 70 percent of the pedon.

2C/A horizon
Hue: 7.5YR or 10YR.
Value: 3 or 4 moist and dry.
Chroma: 3 or 4 moist and dry.
Texture: extremely stony or cobbly medial silt loam or very fine sandy loam.
Structure: weak or moderate granular, subangular blocky.
Some A horizons may be hydrophobic when dry.
Reaction: neutral to slightly alkaline (pH 6.6 to 7.8).

Bw/2C horizon
Hue: 7.5YR or 10YR.
Value: 2 to 4 moist or dry.
Chroma: 1 to 4 moist or dry.
Texture: extremely cobbly or gravelly medial silt loam or very fine sandy loam.
Structure: weak or moderate subangular blocky.
Reaction: slightly alkaline to moderately alkaline (pH 7.4 to 8.6).

2C/Bk horizon
Hue: 7.5YR or 10YR.
Value: 3 to 5 moist or dry.
Chroma: 3 or 4 moist or dry.
Structure: weak subangular blocky or massive.
Reaction: moderately alkaline to strongly alkaline (pH 7.9 to 8.6).

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Waikui soils are on low elevation, leeward slopes on Mauna Kea Volcano and Kohala Mountain at elevations from sea level to 610 meters (0 to 2,000 feet). The soils are in ash fields on summit positions of undulating to hilly `a`a flows that are 65,000 to 250,000 years old. Slope gradients range from 2 to 20 percent. The soils formed in basic volcanic ash in `a`a lava. The mean annual rainfall ranges from 178 to 510 millimeters (7 to 20 inches), with most of the rainfall occurring from October through April. The mean annual pan evaporation ranges from 2,286 to 2,540 meters (90 to 100 inches). The mean annual temperature ranges from 21 to 24 degrees C. (70 to 75 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 the Hapuna, Kiholo, Lalamilo, and Puako series. Hapuna soils have a petrocalcic/duripan within 102 centimeters (40 inches) from the surface. Kiholo soils have a lithic contact at 5 to 50 centimeters (2 to 20 inches). Lalamilo soils are not skeletal. Puako soils are alluvial soils with coarse loamy texture in the control section.

DRAINAGE AND PERMEABILITY: Well drained. Runoff is very low to low. Permeability is rapid in the soil. Hydrophobic conditions in the surface can reduce infiltration.

USE AND VEGETATION: Used mostly for wildlife habitat. Vegetation is buffelgrass (Pennisetum ciliare) and Kiawe (Prosopis pallida).

DISTRIBUTION AND EXTENT: South Kohala District, Island of Hawaii; MLRA 157. The series is of small extent.

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

SERIES ESTABLISHED: Island of Hawaii, Hawaii County, Hawaii, 2012.

REMARKS: Soil moisture dry for more than half the year and not moist in any part for as long as 90 cumulative days in most years (aridic moisture regime).
Diagnostic horizons and features recognized in this pedon are:
Andic soil properties - 0 to 120 centimeters (0 to 47 inches) (A/2C, Bw/2C, and 2C/Bk horizons).
Cambic horizon - 37 to 120 centimeters (15 to 47 inches) (2C/Bk horizons).
Mollic epipedon - 0 to 37 centimeters (0 to 15 inches) (2C/A and Bw/2C horizons)

ADDITIONAL DATA: NSSL sample S95HI-001-004.

National Cooperative Soil Survey
U.S.A.