LOCATION KEAMOKU                 HI

Established Series
Rev. KH-RTG
05/2012

KEAMOKU SERIES

The Keamoku series consists of deep, well drained soils that formed in basic volcanic ashfields deposited on basic `a`a lava. Slopes range from 2 to 10 percent. The mean annual rainfall is about 1,400 millimeters (55 inches), and the mean annual air temperature is about 13 degrees C (55 degrees F).

TAXONOMIC CLASS: Medial-skeletal, amorphic, isomesic Typic Hapludands

TYPICAL PEDON: Keamoku medial silt loam, 4 percent slope on `a`a lava under koa trees and a grass understory. (Colors are for moist soil unless otherwise noted. When described on 4/22/98, the soil was slightly moist throughout. The soil temperature was 15 degrees C {59 degrees F.} at a depth of 38 centimeters {15 inches}. All textures are "apparent field textures". pH was measured using organic dyes.)

A1--0 to 8 centimeters (0 to 3 inches); black (10YR 2/1) medial silt loam, very dark grayish brown (10YR 3/2) dry; moderate medium subangular blocky structure parting to weak fine granular; soft, very friable, slightly sticky and slightly plastic; many very fine, fine, and medium roots; many very fine and fine interstitial pores; strongly acid (pH 5.2); clear wavy boundary. (3 to 10 centimeters {1 to 4 inches} thick)

A2--8 to 25 centimeters (3 to 10 inches); black (10YR 2/1) medial silt loam, dark gray (10YR 4/1) dry; weak medium subangular blocky structure parting to moderate fine granular; soft, very friable, slightly sticky and slightly plastic; common very fine to coarse roots; many very fine and fine interstitial pores; moderately acid (pH 5.8); abrupt wavy boundary. (0 to 20 centimeters {0 to 8 inches} thick)

Bw1--25 to 36 centimeters (10 to 14 inches); very dark brown (7.5YR 2.5/2) medial loam, dark brown (7.5YR 3/2) dry; weak medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine, fine, and medium roots; many very fine and fine interstitial pores; 10 percent subangular `a`a gravel; moderately acid (pH 6.0); clear wavy boundary. (0 to 13 centimeters {0 to 5 inches} thick)

Bw2/3C1--36 to 53 centimeters (14 to 21 inches); 90 percent very dark brown (7.5YR 2.5/2) and 10 percent reddish brown (5YR 4/4) very gravelly medial loam, yellowish red (5YR 4/6) dry; weak medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine, fine, and medium roots; many very fine and fine interstitial pores; 5 percent subangular `a`a cobbles and 45 percent subangular `a`a gravel; slightly acid (pH 6.2); the 3C Part of this horizon consists of unconsolidated `a`a lava fragments of variable size; clear wavy boundary. (0 to 25 centimeters {0 to 10 inches} thick)

3C2/2A--53 to 89 centimeters (21 to 35 inches); black (10YR 2/1) extremely cobbly medial loam, very dark grayish brown (10YR 3/2) dry; massive; soft, very friable, slightly sticky and slightly plastic; few very fine, fine, and medium roots; many very fine and fine interstitial pores; 85 percent angular `a`a lava (25 percent stones, 55 percent cobbles, and 5 percent gravel); slightly acid (pH 6.2); the 3C Part of this horizon consists of unconsolidated `a`a lava fragments of variable size; clear wavy boundary. (25 to 50 centimeters {10 to 20 inches} thick)

3C3/2Bw1--89 to 127 centimeters (35 to 50 inches); very dark brown (7.5YR 2.5/2) extremely cobbly medial loam, dark brown (7.5YR 3/2) dry; massive; soft, very friable, slightly sticky and slightly plastic; few very fine, fine, and medium roots; many very fine and fine interstitial pores; 85 percent angular `a`a lava (25 percent stones, 55 percent cobbles, and 5 percent gravel); slightly acid (pH 6.4); the 3C Part of this horizon consists of unconsolidated `a`a lava fragments of variable size; abrupt wavy boundary. (25 to 102 centimeters {10 to 40 inches} thick)

3C4/2Bw2--127 to 152 centimeters (50 to 60 inches); 90 percent dark reddish brown (5YR 2.5/2) and 10 percent reddish brown (5YR 4/4) extremely cobbly medial loam, 80 percent brown (7.5YR 4/4) and 20 percent yellowish red (5YR 4/6) dry; massive; soft, very friable, slightly sticky and slightly plastic; few very fine, fine, and medium roots; many very fine and fine interstitial pores; 95 percent angular `a`a lava (10 percent stones, 80 percent cobbles, and 5 percent gravel); slightly acid (pH 6.4); the 3C Part of this horizon consists of unconsolidated `a`a lava fragments of variable size; (25 to 50 centimeters {10 to 20 inches} thick)

TYPE LOCATION: Hawaii Volcanoes National Park; from State Hwy 11 turn north onto Mauna Loa Strip Road; travel for 12.15 miles and park at pull out; walk to cattle crossing guard; from south side of cattle guard follow fence south for twenty fence posts; walk on a 100 degree magnetic heading for 24 meters (77 feet) to type location; Kilauea Crater Quadrangle; lat. 19 degrees 26 minutes 42.18 seconds N. and long. 155 degrees 19 minutes 42.54 seconds W. (Old Hawaiian Datum measured by GPS/PLGR,+/-55 feet).

RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 13 to 15 degrees C (56 to 59 degrees F).
Soil reaction: Strongly acid to slightly acid.

A horizon
Hue: 7.5YR or 10YR.
Texture: Medial loam, medial silt loam, highly organic medial loam, or highly organic medial silt loam
Structure: Granular or subangular blocky.
Rock fragments: 10 to 50 percent derived from `a`a lava.

B horizon
Hue: 2.5YR to 10YR.
Value: 2 to 4 moist.
Chroma: 2 to 6 moist.
Texture: Medial loam or medial silt loam.
Structure: Subangular blocky or massive.
Rock fragments: 10 to 50 percent, but averages more than 35 percent where mixed with C horizon.
Densic materials: weakly cemented, dark brown (10YR 3/3) ashy fine sand found in some pedons on Mauna Kea

C horizon
Texture: Coarse sand and sand, derived from `a`a lava.
Structure: Massive or single grain.
Rock fragments: 50 to 85 percent, derived from `a`a lava.

COMPETING SERIES: This is the Wahi series. Wahi soil have 65 to 90 percent rock fragments in the A horizon and mean annual soil temperature 11 to 13 degrees C

GEOGRAPHIC SETTING: Keamoku soils are on Mauna Loa and Mauna Kea volcano `a`a flows mainly 3,000 to 10,000 years old. On Mauna Kea, ages of lava flows may be as old as 30,000 years old. They occur at elevations of 1,220 to 1,645 meters (4,000 to 5,400 feet). Slopes range from 2 to 10 percent. The mean annual rainfall is 1,270 to 2,032 millimeters (50 to 80 inches), about 75 percent of which of falls between October and April. The mean annual pan evaporation: 1,270 to 1,525 millimeters (50 to 60 inches). The mean annual air temperature is 10 to 15 degrees C (50 to 59 degrees F).

GEOGRAPHICALLY ASSOCIATED SOILS: On Mauna Loa, these are the Alahapa, Haa and Oneula soils. Alahapa soils are fragmental and have accretionary lapili from base surge deposits. Haa soils are medial (non-skeletal). Oneula soils are sandy-skeletal. On Mauna Kea this is Laumaia. Laumaia soils are non-skeletal soils.

DRAINAGE AND PERMEABILITY: Well drained. Runoff is low. Permeability is rapid.

USE AND VEGETATION: These soils are used for recreation for grazing. Vegetation is koa (Acacia koa), ohia lehua (Metrosideros polymorpha), prickly Florida blackberry (Rubus argutus), pukiawe (Styphelia tameiameiae), brackenfern (Pteridium aquilinum) and grasses.

DISTRIBUTION AND EXTENT: These soils occur within Hawaii Volcanoes National Park and surrounding ranches as well as windward slopes of Mauna Kea along Mana road; MLRA 160. The series is of small extent.

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

SERIES ESTABLISHED: Island of Hawaii, Hawaii County, Hawaii, 2012. Proposed 1998. The name is from a lava flow. Okina removed in 2009.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Andic soil properties - from the soil surface to 152 centimeters (60 inches).
Umbric epipedon - from the soil surface to 152 centimeters (60 inches).
Soil temperature - mean summer and mean winter soil temperatures differ by less than 6 degrees C (iso temperature regime).
Soil moisture - not dry in some or all parts for 90 days or more in most years (Udic moisture regime).

Edit Log: 12/03 KH. Horizon designations updated. Added "medial" modifier to textures.
3/01 KH. Horizon designations changed on 5th, 6th and 7th horizons. Rainfall changed from 50 to 60 inches to 50 to 80. Minor changes in elevation and air temperature.
3/28/11 PGN. References to use of series on Mauna Kea Volcano added.

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National Cooperative Soil Survey
U.S.A.