LOCATION OLAA                    HI

Established Series
Rev. HHS/LDG/PGN/AMS
06/2012

OLAA SERIES

The Olaa series consists of moderately deep, well drained soils that formed in basic volcanic ash overlying `a`a lava. Slopes range from 2 to 10 percent. Mean annual rainfall is about 3,900 millimeters (154 inches) and mean annual temperature is 23 degrees C (73 degrees F).

TAXONOMIC CLASS: Hydrous-skeletal, ferrihydritic, isohyperthermic Typic Hydrudands

TYPICAL PEDON: Olaa cobbly hydrous loam on an east-facing, 3 percent slope in lowland forest at an elevation of 322 meters (1056 feet). (Colors are for moist soils unless otherwise noted. All textures are "apparent field textures". pH measured using an Oakton microprocessor based pH meter. When described on June 23, 2005, the soil was moist throughout.)

A--0 to 10 centimeters (0 to 4 inches); very dark brown (10YR 2/2) cobbly hydrous loam, very dark gray (10YR 3/1) dry; strong fine granular structure; soft, friable, slightly sticky, slightly plastic, moderately smeary; few very fine, fine and medium roots throughout; common very fine pores throughout; 10 percent subangular `a`a cobbles and 10 percent subangular `a`a gravel; moderately acid (pH 5.7); abrupt wavy boundary. (10 to 42 centimeters {4 to 17 inches} thick)

Bw/2C1--10 to 35 centimeters (4 to 14 inches); very dark brown (7.5YR 2.5/2) very cobbly hydrous loam, dark yellowish brown (10YR 4/4) dry; moderate very fine subangular blocky structure; soft, friable, slightly sticky and slightly plastic, moderately smeary; few very fine roots throughout; few very fine tubular pores throughout; 30 percent subangular `a`a cobbles and 10 percent subangular `a`a gravel; moderately acid (pH 5.7); the 2C part of this horizon consists of unconsolidated `a`a lava fragments of variable size; abrupt wavy boundary. (19 to 31 centimeters {7 to 12 inches} thick)

2C2/Bw2--35 to 80 centimeters (14 to 32 inches); very dark brown (7.5YR 2.5/2) extremely stony hydrous loam, dark yellowish brown (10YR 4/4) dry; weak very fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic, moderately smeary; few very fine roots throughout; few very fine tubular pores throughout; 25 percent subangular `a`a stones, 25 percent subangular `a`a cobbles, and 30 percent subangular `a`a gravel; moderately acid (pH 5.7); the 2C part of this horizon consists of unconsolidated `a`a lava fragments of variable size; abrupt wavy boundary. (19 to 31 centimeters {7 to 12 inches} thick)

2R--80 centimeters (32 inches); Blue rock.

TYPE LOCATION: Island of Hawaii. From the stoplight on Highway 11 in the village of Kurtistown, proceed 2.7 miles southwest on Highway 11 miles to Kukui Camp Road. Turn right, northwest, and proceed 0.8 miles to Luhi Road. Turn right, northeast, and proceed 0.3 miles to where Luhi Road turns sharply to the left, northwest. At this point, turn to the right, southeast, and follow an old cane haul road 0.4 miles and park. Walk southwest approximately 45 feet to the type location at Mountain View Quadrangle; 19 degrees, 34 minutes, 54.8 seconds North latitude and 155 degrees, 05 minutes, 01.2 seconds West longitude (Old Hawaiian Datum,+/- 12 feet; measured by Garmin GPS).

RANGE IN CHARACTERISTICS:
Soil moisture: The soil is typically moist throughout the profile. Precipitation exceeds evapotranspiration in all months of normal years (perudic soil moisture regime).
Mean annual soil temperature: 22 C (72 degrees F) or higher.
Depth to bedrock: 50 to 100 centimeters (20 to 39 inches).
Rock fragments: 35 to 85 percent by volume of the pedon and range from gravel to stone size `a`a lava rocks.

A horizon
Hue: 10YR or 7.5YR.
Value: 2 or 2.5 moist.
Chroma: 1 to 2 moist.
Texture: Gravely, very gravelly, cobbly, or very cobbly with fines being hydrous loam or hydrous silty clay loam.
Structure: Weak to strong, very fine or fine granular or subangular blocky.
Moist consistence: Very friable or friable.
Reaction: moderately acid to slightly acid (pH 5.6 to 6.5).

Bw/2C1 horizons
Hue: 7.5YR or 10YR.
Value: 2 to 3 moist.
Chroma: 2 to 3 moist.
Texture: Very cobbly or extremely cobbly with fines being hydrous loam or silty clay loam.
Moist consistence: Very friable or friable.
Reaction: moderately acid to slightly acid (pH 5.6 to 6.5).

2C2/Bw2 horizons
Hue: 5YR to 10YR.
Value: 2 to 3 moist.
Chroma: 2 to 3 moist.
Texture: Extremely cobbly with fines being hydrous loam, silt loam, or silty clay loam.
Moist consistence: Very friable or friable.
Reaction: moderately acid to slightly acid (pH 5.6 to 6.5).

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: The Olaa soils are at elevations ranging from 0 to 366 meters (0 to 1,200 feet) on the low windward slopes of Mauna Loa and Kilauea volcanoes and on younger lava flows on windward Mauna Kea volcano. The soils are on all hillslope positions of constructional landscapes consisting of undulating to hilly `a`a flows that are 1,000 to 11,000 years old. Slope gradients range from 2 to 10 percent. The soils formed in basic volcanic ash over `a`a lava. Mean annual rainfall is 3,000 to 5,000 millimeters (138 to 200 inches) with most of the rainfall occurring from October through April. The mean annual pan evaporation ranges from 762 to 1,016 millimeters (30 to 40 inches). The mean annual air temperature ranges from 21 to 25 degrees C (70 to 77 degrees F). The mean annual soil temperature is 22 degrees C or higher (72 degrees F).

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Keaukaha, Ohia, Panaewa and Papai soils. Keaukaha soils are organic and are shallow to pahoehoe bedrock. Ohia soils are deep and very deep and are not skeletal. Panaewa soils are less than 50 centimeters deep and formed over pahoehoe lava. Papai soils are organic.

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

USE AND VEGETATION: These soils are used principally for pasture and macadamia nut orchards. Vegetation is hilograss (Paspalum conjugatum), californiagrass (Urochloa mutica), lantana (Lantana camara) hapuu treefern (Cibotium glaucum), uluhe fern (Dicranopteris linearis) and guava (Psidium guajava).

DISTRIBUTION AND EXTENT: Puna and Hamakua districts of the island of Hawaii. This series is of small extent with approximately 9,000 acres. MLRA 159A: Humid and Very Humid Volcanic Ash Soils on Low and Intermediate Rolling Mountain Slopes.

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

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

REMARKS:
Last revised by state on 08/09 by PGN and AMS.

Diagnostic horizons and features (9th edition Keys to Soil Taxonomy) recognized in this pedon are:
Andic properties - 0 to 80 centimeters (0 to 32 inches) (A and Bw/2C1 horizons).
Umbric epipedon - 0 to 36 centimeters (0 to 14 inches) (A and Bw/2C1, 2C2/Bw2). horizons)
Isohyperthermic soil temperature regime.
Soil moisture precipitation exceeds evapotransporation in all months of normal years (perudic moisture regime).

Type location moved from Keaau sugar mill area to Kurtistown area 06/05.

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National Cooperative Soil Survey
U.S.A.