LOCATION KEHENA HI

Established Series
Rev. HHS/RCH/MRK
05/2012

KEHENA SERIES

The Kehena series consists of moderately deep, moderately well drained soils that formed in basic volcanic ash over basaltic lava. Kehena soils are on ash fields and have slopes of 6 to 70 percent. Mean annual rainfall is about 3,175 centimeters (125 inches) and mean annual temperature is about 17 degrees C (63 degrees F).

TAXONOMIC CLASS: Hydrous, ferrihydritic, isothermic Acrudoxic Hydrudands

TYPICAL PEDON: Kehena medial silty clay loam, on a north facing, 8 percent slope in grass pasture. (Colors are for moist soil unless otherwise noted. All textures are "apparent field textures." ph measured with electrode in 1:1 soil to water. When described on August 10, 2007 the soil moist throughout.)

A1--0 to 3 centimeters (0 to 1 inches); dark brown (7.5YR 3/3) medial silty clay loam; moderate fine and medium granular structure; friable, slightly sticky and plastic; weakly smeary; common fine and very fine, and few medium roots; many very fine and fine interstitial pores; extremely acid (pH 4.2); abrupt smooth boundary. (2 to 5 centimeters {1 to 2 inches} thick)

A2--3 to 10 centimeters (1 to 4 inches); dark yellowish brown (10YR 3/4) medial silty clay loam; common, fine and medium, faint to distinct, dark brown (7.5YR 3/4) and dark reddish brown (5YR 3/4) iron masses; strong fine and very fine granular structure; friable, slightly sticky and moderately plastic; weakly smeary; common very fine and fine roots; many fine and very fine interstitial pores; extremely acid (pH 4.3); clear wavy boundary. (5 to 10 centimeters {2 to 4} inches thick)

Bw1--10 to 38 centimeters (4 to 15 inches); dark brown (7.5YR 3/4) medial silty clay loam; common, fine, faint, dark reddish brown (5YR 3/3) iron masses; strong medium and fine subangular blocky structure; friable, moderately sticky and moderately plastic; weakly smeary; few very fine and fine roots; common fine and very fine, and few medium tubular pores; very strongly acid (pH 4.9); clear wavy boundary. (18 to 28 centimeters (7 to 11 inches) thick)

2Bw2--38 to 53 centimeters (15 to 21 inches); dark brown (7.5YR 3/4) hydrous silty clay loam; strong fine and medium angular blocky structure; friable, moderately sticky and moderately plastic; strongly smeary; few fine roots; common fine and medium tubular pores; very strongly acid (pH 5.0); abrupt wavy boundary. (15 to 20 centimeters {5 to 8 inches} thick)

2Bw3--53 to 73 centimeters (21 to 29 inches); dark yellowish brown (10YR 3/4) hydrous silty clay loam; moderate fine and medium angular blocky structure; friable, moderately sticky and moderately plastic; strongly smeary; few fine roots; common fine and medium tubular pores; 5 percent gravel and 5 percent cobbles; strongly acid (pH 5.5); clear wavy boundary. (15 to 20 centimeters {6 to 8 inches} thick)

2Bw4/3C--73 to 94 centimeters (29 to 37 inches); dark yellowish brown (10YR 3/4) very cobbly hydrous silty clay loam; moderate fine and medium angular blocky structure; slightly firm, moderately sticky and slightly plastic; moderately smeary; few fine roots; common fine and medium tubular pores; 15 percent gravel and 35 percent cobbles; strongly acid (pH 5.2); 3C material consists of unconsolidated lava fragments; abrupt irregular boundary. (15 to 20 centimeters {6 to 8 inches} thick)

3R--94 centimeters (37 inches); hard bedrock.

TYPE LOCATION: Island of Hawaii, Hawaii County, Hawaii; from Kehena Reservoir, drive 0.6 miles west on Kehena ditch trail. Pedon is located about 8 meters (25 feet) upslope and south of road in a small swale between ridges at an elevation of 768 meters (2,520 feet). Hawi Quadrangle; latitude 20 degrees 10 minutes 3.0 seconds N. and longitude 155 degrees 47 minutes 41.1 seconds W. (Old Hawaiian Datum.)

RANGE IN CHARACTERISTICS:
Depth to bedrock: 51 to 102 centimeters (20 to 40 inches). Mean annual soil temperature: 15 to 21 degrees C (59 to 70 degrees F).
Depth to redox concentrations: 3 to 38 centimeters (1 to 15 inches).

The A horizon Hue: 7.5YR or 10YR. Value: 2 or 3 Chroma: 2 to 4 Texture: Medial or hydrous, silty clay loam or silt loam. Structure: moderate or strong, very fine to medium, granular or subangular blocky. Redox concentrations: 2 to 20 percent, distinct to prominent, very fine to medium, masses and/or concretions. At lower elevations, the lower A horizon becomes thinner with less pronounced redoximorphic features.

The Bw horizon Hue: 7.5YR or 10YR. Chroma: 2 to 4 Texture: Medial or hydrous, silty clay loam or silt loam. Structure: moderate or strong, very fine to medium, angular blocky or subangular blocky. Redox concentrations: 0 to 2 percent, distinct to prominent, very fine to medium
masses and/or concretions. This horizon dehydrates irreversibly into dark brown or black, sharp angular, very hard gravel-size aggregates.

COMPETING SERIES: These are the Akaka, Honokaa, Honomanu, Kaiwiki, Maile, and Ohia series. Akaka soils are 102 to 152 centimeters (40 to 60 inches) deep. Honokaa, Kawaiki, Maile, and Ohia soils are 102 to 152 centimeters (40 to 60 inches) deep and well drained. Honomanu soils are well drained and are silty clay in the control section.

GEOGRAPHIC SETTING: Kehena soils are on middle and upper elevation, windward slopes of Kohala Mountain at elevations from 518 to 1,585 meters (1,700 to 5,200 feet). These soils are on all hillslope positions of gently sloping to steep lava flows, very steep cinder cones and gully slopes. Slope gradients range from 3 to 70 percent. The soils formed in basic volcanic ash over basaltic lava. The mean annual rainfall ranges from 2,032 to 3,810 millimeters (80 to 150 inches), with most of the rainfall occurring from October through April. The soils are subject to frequent cloudiness and fog. The mean annual temperature ranges from 14 to 20 degrees C (57 to 68 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 Amalu, Kahua, Niulii and the Palapalai soils. Amalu soils have a histic epipedon, placic horizon and are poorly drained. Kahua soils have mucky silt loam surface texture and have lithic contact between 102 to 152 centimeters (40 and 60 inches). Niulii soils are free of mottles and are weakly to moderately smeary in the B horizon. Palapalai soils have a lithic contact between 102 to 152 centimeters (40 and 60 inches) and are free of mottles and lack iron-oxide concretions.

DRAINAGE AND PERMEABILITY: Moderately well drained; low to high runoff; moderately slow permeability above the R horizon.

USE AND VEGETATION: Kehena soils are used primarily for grazing and woodland. Natural vegetation is ohia (Metrosideros polymorpha), treefern (Cibotium spp.), hilograss (Paspalum conjugatum) and sedges (Carex spp.).

DISTRIBUTION AND EXTENT: North Kohala District, Island of Hawaii. The series is approximately 3,265 acres in extent. MLRA 164.

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

SERIES ESTABLISHED: Hawaii County, Hawaii, 1971.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Umbric epipedon - from the surface to 38 centimeters (0 to 15 inches) (A and Bw1 horizons).
Andic soil properties - from 0 to 94 centimeters (0 to 37 inches) (All horizons).
Cambic Horizon - from 38 to 94 centimeters (15 to 37 inches) (Bw and Bw/C horizons).
Lithic contact - at 94 centimeters (37 inches) (R horizon).
Redox concentrations - from 3 to 38 centimeters (1 to 15 inches).

ADDITIONAL DATA: NASIS Pedon User ID 09HI603003.

Edit Log: OSED scanned by SSQA. Last revised by state on 5/78.
8/19/09 Soil drainage revised due to changes in series concept. Range in characteristics and competing series updated. Other minor edits. MRK.

National Cooperative Soil Survey
U.S.A.