LOCATION KIOLAKAA HI

Tentative Series
MRK-RTG
05/2012

KIOLAKAA SERIES

The Kiolakaa series consists of moderately deep, well drained soils. These soils formed in basic volcanic ash over pahoehoe lava. Slopes range from 2 to 10 percent. The mean annual rainfall is about 1140 millimeters (45 inches), and the mean annual air temperature is about 20 degrees C (68 degrees F).

TAXONOMIC CLASS: Medial, amorphic, isothermic Humic Haplustands

TYPICAL PEDON: Kiolakaa medial loam, on a south facing, slightly convex, 8 percent slope in pasture at an elevation of 628 meters (2,060 feet). (Colors are for moist soils unless otherwise noted. All textures are "apparent field textures". pH measured with electrode in 1:1 water. When described on July 1, 1993, the soil was moist throughout.)

A--0 to 15 centimeters (0 to 6 inches); black (10YR 2/1) medial loam, dark brown (7.5YR 3/2) dry; moderate fine granular structure; firm, slightly sticky and slightly plastic; many fine roots; many very fine interstitial pores; 3 percent gravel; strongly acid (pH 5.4); gradual wavy boundary. (15 to 20 centimeters {6 to 8 inches} thick)

AB--15 to 25 centimeters (6 to 10 inches); very dark brown (10YR 2/2) cobbly medial fine sandy loam, dark yellowish brown (10YR 3/4) dry; moderate fine subangular blocky structure; friable, nonsticky and nonplastic; common fine roots; few fine interstitial and tubular pores; 20 percent cobbles and 10 percent gravel; slightly acid (pH 6.1); clear wavy boundary. (8 to 13 centimeters {3 to 5 inches} thick)

Bw1/2C1--25 to 38 centimeters (10 to 15 inches); dark brown (7.5YR 3/2) very cobbly medial loam, brown (7.5YR 4/4) dry; moderate medium subangular blocky structure; friable, slightly sticky and slightly plastic; few fine roots; many fine tubular pores; 35 percent cobbles and 5 percent gravel; slightly acid (pH 6.1); the 2C part of this horizon consists of unconsolidated pahoehoe lava fragments of variable size; clear wavy boundary.

Bw2/2C2--38 to 64 centimeters (15 to 25 inches); dark brown (7.5YR 3/4) very cobbly medial loam, brown (7.5YR 4/4) dry; moderate medium subangular blocky structure; friable, slightly sticky and slightly plastic; few fine roots; many fine tubular pores; 40 percent cobbles and 5 percent gravel; slightly acid (pH 6.3); the 2C part of this horizon consists of unconsolidated pahoehoe lava fragments of variable size; abrupt wavy boundary. (Combined thickness of the Bw is 38 to 50 {15 to 20 inches})

2R--64 centimeters (25 inches); hard, massive pahoehoe lava.

TYPE LOCATION: Island of Hawaii, Hawaii County, Hawaii; 610 meters (2,000 feet) north of Highway 11 and 122 meters (400 feet) east of ranch road on Kahuku Ranch. Kahuku Ranch Quadrangle; lat. 19 degrees 4 minutes 1 second N. and long. 155 degrees 40 minutes 46 seconds W.(Old Hawaiian Datum)

RANGE IN CHARACTERISTICS:
Depth to bedrock: 50 to 102 centimeters (20 to 40 inches).
Mean annual soil temperature: 19 to 22 degrees C (67 to 72 degrees F).
Rock fragments: 15 to 35 percent by volume of the pedon and range in size from gravel to cobbles.

A horizon
Hue: 7.5YR or 10YR.
Value: 2 or 3 moist or dry.
Chroma: 1 or 2 moist or 2 or 3 dry.
Texture: Medial silt loam or loam.
Wet consistence: Nonsticky or slightly sticky, and nonplastic or slightly plastic.
Soil reaction: Strongly acid (pH 5.1 to 5.5).

AB horizon
Hue: 7.5YR or 10YR.
Value: 2 or 3 moist or dry.
Chroma: 2 or 3 moist or 3 or 4 dry.
Texture: Medial fine sandy loam, loam, or silt loam.

Bw/2C horizon
Hue: 7.5YR or 10YR.
Value: 2 or 3 moist or 3 or 4 dry.
Chroma: 2 to 4 moist or 4 to 6 dry.
Texture: Cobbly or very cobbly medial sandy loam, loam, or silt loam.
Soil reaction: Slightly acid (pH 6.1 to 6.5).

COMPETING SERIES: These are the Kamakoa, Kamaoa, Kapapala, Kikoni, Kula, and Waimea series. Kamaoa soils more than 152 centimeters (60 inches) deep. Kamakoa, Kapapala, Kikoni, Kula, and Waimea soils are 100 to 152 centimeters (40 to 60 inches) deep.

GEOGRAPHIC SETTING: Kiolakaa soils are on mid elevation, windward slopes and southwest rift zone of Mauna Loa Volcano at elevations from 305 to 1067 meters (1,000 to 3,500 feet). These soils are on all hillslope positions of constructional landscapes consisting of nearly level to gently sloping pahoehoe lava flows that are 5,000 to 10,000 years old. Slope gradients range from 2 to 10 percent. The soils formed in basic volcanic ash over pahoehoe lava. The mean annual rainfall ranges from 760 to 1520 millimeters (30 to 60 inches), with most of the rainfall occurring from October through April. The mean annual pan evaporation ranges from 1270 to 1780 millimeters (50 to 70 inches). The mean annual air temperature ranges from 18 to 21 degrees C (65 to 70 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 Nanaia, Kapulehu, Keaa, and the competing Kamaoa series. Nanaia soils have a lithic contact at 5 to 25 centimeters (2 to 10 inches). Kapulehu soils are underlain with `a`a lava. Keaa soils have a lithic contact at 25 to 50 centimeters (10 to 20 inches).

DRAINAGE AND PERMEABILITY: Well drained. Runoff is very low. Permeability is moderately rapid in the soil and very slow in the underlying bedrock.

USE AND VEGETATION: Used for grazing. The natural vegetation is kikuyugrass (Pennisetum clandestinum) and ohia lehua (Metrosideros polymorpha).

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

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

SERIES PROPOSED: Island of Hawaii, Hawaii County, Hawaii; 1993.

REMARKS: Soil moisture - dry in some or all parts for short intermittent periods totaling 90 or more days (Ustic moisture regime).

Diagnostic horizons and features recognized in this pedon include:
Mollic epipedon - from a depth of 0 to 38 centimeters (0 to 15 inches) (A and Bw1/2C1 horizons).
Cambic horizon - from a depth of 38 to 64 centimeters (15 to 25 inches) (Bw2/2C2 horizons).
Lithic contact - at a depth of 64 centimeters (25 inches) (2R horizon).
Andic soil properties - from a depth of 0 to 64 centimeters (0 to 25 inches) (A and Bw/2C horizons).

ADDITIONAL DATA: NASIS Pedon User ID 01HI601015.

Edit log: 2/6/08 Minor edits made. MRK

National Cooperative Soil Survey
U.S.A.