LOCATION PIIHONUA HI

Established Series
Rev. RCH/HHS/PGN/MRK
06/2012

PIIHONUA SERIES

The Piihonua series consists of deep and very deep, well drained soils that formed in material weathered from volcanic ash. Piihonua soils are on uplands and have slopes of 0 to 35 percent. The mean annual rainfall is about 2,032 millimeters (80 inches), and the mean annual air temperature is about 13 degrees C. (55 degrees F.).

TAXONOMIC CLASS: Hydrous, ferrihydritic, isomesic Acrudoxic Hydrudands

TYPICAL PEDON: Piihonua hydrous silty clay loam, under forest on a 10 percent slope at an elevation of 1,682 meters (5,518 feet). (Colors are for moist soil unless otherwise noted. When described on 7/23/02 the soil was moist throughout. All textures are "apparent field textures". pH was measured using organic dyes.)

A--0 to 18 cm (0 to 7 inches); very dark brown (10YR 2/2) hydrous silt loam, very dark grayish brown (10YR 3/2) dry; moderate fine granular structure; soft, very friable, slightly sticky, slightly plastic; strongly smeary; common very fine and fine roots throughout; common very fine and fine irregular pores; very strongly acid, pH 4.4 by Bromcresol green; abrupt smooth boundary. (8 to 20 centimeters (3 to 8 inches) thick)

Bw1--18 to 71 cm (7 to 28 inches); very dark brown (7.5YR 2.5/3) hydrous silty clay loam, very dark brown (7.5YR 2.5/2) dry; moderate very fine and fine subangular blocky structure; firm, very friable, slightly sticky, slightly plastic; 10 percent dark reddish brown (2.5YR 3/4) angular gravel sized pumice in lower part of horizon; strongly smeary; common very fine and fine roots throughout; common very fine and fine irregular pores; very strongly acid, pH 4.6 by Bromcresol green; abrupt smooth boundary. (43 to 64 centimeters (17 to 25 inches) thick)

Bd--71 to 99 cm (28 to 39 inches); very dark brown (7.5YR 2.5/3) hydrous silty clay loam, very dark brown (7.5YR 2.5/2) dry; massive; friable, very firm, slightly sticky, slightly plastic; strongly smeary; few fine roots in cracks; few very fine and fine tubular pores; strongly acid, pH 5.2 by Bromcresol green; abrupt smooth boundary. (18 to 30 centimeters (7 to 12 inches) thick)

Bw2--99 to 152 cm (39 to 60 inches); very dark brown (7.5YR 2.5/3) hydrous silty clay loam, strong brown (7.5YR 4/6) dry; weak fine subangular blocky structure; firm, very friable, slightly sticky, slightly plastic; strongly smeary; few fine roots throughout; few very fine and fine tubular pores; strongly acid, pH 5.2 by Bromcresol green; abrupt smooth boundary. (53 to 66 centimeters (21 to 26 inches) thick)

TYPE LOCATION: Hawaii county, Hawaii; from the main administrative building at the Kulani honor camp follow the Kulani cone road south toward cinder cone with tower on top. Stop at dead end, turn west and follow road around side and to top of cone. Type location is 20 meters south of tower at Kulani Quadrangle 19 degrees, 31 minutes, 24 seconds North latitude and 155 degrees, 18 minutes, 7 seconds West longitude (Old Hawaiian Datum, 12 ft; measured by Garmin GPS)

RANGE IN CHARACTERISTICS: Depth to cemented volcanic ash: 28 to 71 centimeters (11 inches to 28 inches)
Depth to bedrock: 100 centimeters or greater (40 inches or greater)
Soil Reaction: Very strongly acid to moderately acid
Soil moisture: The soil is typically moist but may experience periodic drying of control section with April to October being the most likely season for drying.

Oa horizon (when present)
Hue: 7.5YR or 10YR
Value: 2 or 2.5 moist
Chroma: 1 or 2 moist
Texture: Highly decomposed plant material

A horizon
Hue: 7.5YR or 10YR
Value: 2 or 2.5 moist
Chroma: 2 or 3 moist
Texture: Hydrous loam, Hydrous silt loam, Hydrous silty clay loam, may be highly organic

Bw horizons
Hue: 2.5YR to 10YR.
Value: 2.5 or 3 moist
Chroma: 2 to 6 moist
Texture: Hydrous silt loam, Hydrous loam or silty clay loam
Para rock fragments: 0 to 15 percent gravel sized pumice

Bd horizon
Hue: 2.5YR to 7.5YR
Value: 2.5 or 3 moist
Chroma: 3 or 4 moist
Texture: Hydrous sandy loam, hydrous silt loam, hydrous loam or hydrous silty clay loam
Cementation: Extremely weakly cemented to weakly cemented

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Piihonua soils are on high, windward mountain slopes of Mauna Loa at elevations of 1,372 to 1,890 meters (4,500 to 6,200 feet). The soils formed on all hill slope positions in basic volcanic ash 5,000 to 6,000 years old. Slopes range from 0 to 35 percent. Mean annual rainfall is 2,032 to 3,048 millimeters (80 to 120 inches), with about 75 percent of the rainfall occurring between October and April. Mean annual pan evaporation ranges from 1,016 to 1,397 millimeters (40 to 55 inches). The mean annual air temperature is 12 to 14 degrees C. (54 to 57 degrees F).

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kulani, Kau, Lalo, Keamoku soils. The Keamoku and Kulani soils are "skeletal" having 35 percent rock fragments in the control section. Lalo are over `a`a lava and have from 5 to 30 percent rock fragments in the profile. Kulani soils have a weak placic horizon and are over volcanic pumice.

DRAINAGE AND PERMEABILITY: Well drained; low to high runoff; moderate permeability

USE AND VEGETATION: These soils are used for pasture or woodland. The natural vegetation is ohia lehua (Metrosideros polymorpha), kikuyugrass (Pennisetum clandestinum), sweet vernalgrass (Anthoxanthum odoratum), alapaio fern (Dryopteris paleacea), and Koa (Acacia koa).

DISTRIBUTION AND EXTENT: Puna district, Island of Hawaii; MLRA 160. The series is of small extent with about 1,200 acres.

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

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

REMARKS: Diagnostic horizons and features (10th edition, Keys to Soil Taxonomy) recognized in this pedon are:
Andic soil properties - from the soil surface to 152 centimeters (60 inches).
Umbric epipedon - from 5 to 18 centimeters (2 to 7 inches).
Densic soil material - - from 71 to 99 cm (28 to 39 inches)
Sapric soil material - from 0 to 5 centimeters (0 to 2 inches)
Isomesic soil temperature regime.
Udic soil moisture regime.

ADDITIONAL DATA: NASIS User Pedon ID 02HI602354.

Edit Log: 2/11/2008 Type location changed to reflect mapping of soil in update soil survey; soil is now used on Mauna Loa volcano. OSD updated to reflect type location move and updated range of characteristics.

OSED scanned by SSQA. Last revised by state on 2/11/2008.

National Cooperative Soil Survey
U.S.A.