LOCATION PEKAILIO HI

Tentative Series
IRD. PGN
06/2012

PEKAILIO SERIES

The Pekailio series consists of deep and very deep, well drained soils that formed in basic volcanic ash deposited over `a`a lava. Pekailio soils are located on the slopes of Mauna Loa volcano. Slopes range from 2 to 70 percent. The mean annual rainfall is about 2,032 millimeters (80 inches), and the mean annual air temperature is about 15 degrees C (59 degrees F).

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

TYPICAL PEDON: Pekailio stony medial loam, range under occasional ohia lehua trees and shrubs on a 14 percent slope at an elevation of 1,315 meters (4,315 feet). (Colors are for moist soil unless otherwise noted. When described on 08/09/00 the soil was moist throughout. All textures are "apparent field textures". pH was measured using organic dyes.)

A--0 to 13 centimeters (0 to 5 inches); black (7.5YR 2.5/1) stony medial loam, very dark brown (7.5YR 2.5/2) dry; moderate fine and medium subangular blocky structure parting to weak fine granular structure; soft, friable, slightly sticky and slightly plastic; many very fine and fine and common medium roots; many very fine and fine interstitial and tubular pores; 5 percent dark reddish brown (2.5YR 3/4) and dark reddish brown (5YR 3/4) gravel sized cinders, soft to hard; 15 percent subangular, `a`a stones, and 5 percent subangular `a`a gravel; weakly smeary; strongly acid (pH 5.4); abrupt smooth boundary. (5 to 25 centimeters (2 to 10 inches) thick)

Bw1--13 to 30 centimeters (5 to 12 inches); black (7.5YR 2.5/1) stony medial loam, very dark grayish brown (10YR 3/2) dry; weak fine granular structure; soft, very friable, slightly sticky and nonplastic; common very fine to medium roots; many very fine and fine interstitial and tubular pores; 5 percent dark reddish brown (2.5YR 3/4) and dark reddish brown (5YR 3/4) gravel sized cinders, soft to hard; 15 percent subangular `a`a stones, 5 percent subangular `a`a cobble, and 5 percent subangular `a`a gravel; weakly smeary; moderately acid (pH 5.8); abrupt wavy boundary. (5 to 23 centimeters (2 to 9 inches) thick)

2C1/Bw2--30 to 56 centimeters (12 to 22 inches); black (7.5YR 2.5/1) extremely cobbly medial loam, dark brown (7.5YR 3/4) dry; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; common very fine and fine roots; many very fine and fine interstitial pores; 5 percent dark reddish brown (2.5YR 3/4) and dark reddish brown (5YR 3/4) gravel sized cinders, soft to hard; 10 percent `a`a stones, 45 percent subangular `a`a cobbles, and 20 percent subangular `a`a gravel; weakly smeary; moderately acid (pH 6.0); the 2C part of this horizon consists of unconsolidated `a`a lava fragments of variable size and cinders; abrupt wavy boundary. (5 to 41 centimeters (2 to 16 inches) thick)

2C2/Bw3--56 to 86 centimeters (22 to 34 inches); black (7.5YR 2.5/1) extremely gravelly medial loam, dark brown (7.5YR 3/4) dry; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; common very fine and fine roots; many very fine and fine interstitial pores; 5 percent dark reddish brown (2.5YR 3/4) and dark reddish brown (5YR 3/4) gravel sized cinders, soft to hard; 10 percent `a`a stones, 30 percent subangular `a`a cobbles, and 40 percent subangular `a`a gravel, weakly smeary; moderately acid (pH 6.0); the 2C part of this horizon consists of unconsolidated `a`a lava fragments of variable size and cinders; clear wavy boundary. (5 to 41 centimeters (2 to 16 inches) thick)

2C3--86 to 152 centimeters (34 to 60 inches); very dark brown (7.5YR 2.5/2) extremely stony ashy coarse sand, dark grayish brown (10YR 4/2) dry; single grain; loose when dry or moist, nonsticky and nonplastic; few very fine and fine roots; many very fine and fine and common medium and coarse interstitial pores; 30 percent subangular `a`a stones, 30 percent angular `a`a cobbles, and 35 percent subangular `a`a gravel; non smeary; neutral (pH 6.8). (23 to 127 centimeters (9 to 50 inches) thick)

TYPE LOCATION: Island of Hawaii; from State Highway 11 in Kau travel north on Piimauna Road toward Volcano Golf Course for 1.0 mile; at Keauhou Ranch gate continue straight onto Puu Oo trail for approximately 1.1 miles to rock loading chute (19 degrees 27 minutes 36 seconds North latitude and 155 degrees 17 minutes 51 seconds West longitude), pull off on east side of road and park; travel due north over fence for 110 meters (360 feet) to road cut and type location; Kilauea Crater Quadrangle; 19 degrees 27 minutes 42 seconds North latitude and 155 degrees 17 minutes 44 seconds West longitude. (Old Hawaiian Datum, 12 ft; measured by GPS PLGR)

RANGE IN CHARACTERISTICS: Depth to bedrock: 102 to over 152 centimeters (40 to over 60 inches).
Rock fragments: Average 50 to 85 percent in the control section.
Soil Reaction: Strongly acid in surface horizon and moderately acid to neutral in subsurface horizons.
Soil moisture: The soil is typically moist but may experience periodic drying of control section with summer being the most likely season for drying.
Soil temperature: 15 to 18 degrees C (59 to 64 degrees F).

A horizon
Hue: 7.5YR or 10YR.
Value: 2 to 2.5 moist.
Chroma: 1 to 2 moist.
Texture: Medial loam, cobbly medial loam or stony medial loam.

Bw horizon
Hue: 7.5YR or 10YR.
Value: 1 to 3 moist.
Chroma: 1 to 3 moist.
Texture: Stony, cobbly or gravelly, medial loam or medial sandy loam. Very stony, cobbly or gravelly, medial loam or medial sandy loam. Extremely stony, cobbly or gravelly, medial loam or medial sandy loam.

C horizon
Hue: 7.5YR or 10YR.
Value: 2 to 2.5 moist.
Chroma: 2 moist.
Texture: Extremely stony or cobbly or gravelly ashy coarse sand.
Rock fragments: 35 to 95 percent.
Voids: 0 to 10 percent.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Pekailio soils are on Mauna Loa `a`a flows 1,500 to 3,000 years old at elevations of 457 to 1,380 meters (1,500 to 4,500 feet). Slopes range from 2 to 40 percent. Mean annual rainfall is 1,500 to 2,500 millimeters (60 to 100 inches), with about 75 percent of the rainfall occurring between October and April. Mean annual pan evaporation ranges from 1,772 to 1,397 centimeters (45 to 55 inches). The mean annual air temperature is 14 to 18 degrees C (57 to 65 degrees F).

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Puaulu and Hilea soils. Hilea soils have lithic contact within 51 centimeters (20 inches). Puaulu soils are not skeletal.

DRAINAGE AND PERMEABILITY: Soils are well drained. Runoff is low to moderate. Permeability is moderately rapid or rapid.

USE AND VEGETATION: These soils are used for livestock grazing, forestland, and wildlife habitat. Vegetation is kikuyugrass (Pennisetum clandestinum), koa (Acacia koa), ohia lehua (Metrosideros polymorpha), olapa (Cheirodendron trigynum), prickly Florida blackberry (Rubus argustus) and hapuu pulu or tree fern (Cibotium glaucum).

DISTRIBUTION AND EXTENT: Kau district, Island of Hawaii; MLRA 159A. The series is of small extent.

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

SERIES PROPOSED: Island of Hawaii, Hawaii County, Hawaii, 2002. The name is coined.

REMARKS: Diagnostic horizons and features (8th 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 the soil surface to 86 centimeters (34 inches).

National Cooperative Soil Survey
U.S.A.