LOCATION WAIAKEA                 HI

Established Series
PGN/AMS
06/2012

WAIAKEA SERIES

The Waiakea series consists of deep, well drained soils that formed in basic volcanic ash in `a`a lava. Slopes range from 2 to 35 percent slopes. The mean annual rainfall is about 3900 millimeters (157 inches) and the mean annual air temperature is about 17 degrees C (63 degrees F).

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

TYPICAL PEDON: Waiakea hydrous loam, on an east facing, 4 percent slope, under forest, at an elevation of 914 meters (3,000 feet). (Colors are for moist soils unless otherwise noted. All textures are apparent field textures. pH measured with organic dyes. When described on March 5, 2004, the soil was moist throughout.)

A--0 to 18 centimeters (0 to 7 inches); very dark brown (7.5YR 2.5/2) hydrous loam, very dark brown (10YR 2/2) dry; moderate fine granular structure; soft, very friable, slightly sticky and slightly plastic; moderately smeary; common fine, and few medium roots; common fine dendritic pores; moderately acid (pH 5.6); abrupt irregular boundary. (9 to 48 centimeters {3 to 19 inches} thick)

Bw1--18 to 38 centimeters (7 to 15 inches); very dark brown (7.5YR 2.5/2) cobbly hydrous silty clay loam, very dark brown (10YR 2/2) dry; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; moderately smeary; few fine and coarse roots; few very fine dendritic pores; 15 percent subangular `a`a cobbles; moderately acid (pH 5.6); abrupt wavy boundary. (11 to 20 centimeters {4 to 8 inches} thick)

Bw2--38 to 50 centimeters (15 to 20 inches); dark brown (7.5YR 3/2) cobbly hydrous silty clay loam, dark brown (7.5YR 3/2) dry; moderate medium subangular blocky structure; very hard, friable, slightly sticky and slightly plastic; strongly smeary; few fine roots; few very fine dendritic pores; 15 percent subangular `a`a cobbles; moderately acid (pH 5.8); abrupt wavy boundary. (10 to 17 centimeters {4 to 7 inches} thick)

2C1/Bw3--50 to 68 centimeters (20 to 27 inches); dark reddish brown (5YR 3/3) extremely stony hydrous silty clay loam, very dark brown (10YR 2/2) dry; moderate fine subangular blocky structure; very hard, friable, slightly sticky and slightly plastic; strongly smeary; few fine roots; few very fine dendritic pores; 50 percent subangular `a`a stones and 25 percent subangular `a`a cobbles; moderately acid (pH 6.0); the 2C part of this horizon consists of unconsolidated `a`a lava fragments of variable size; abrupt wavy boundary. (9 to 58 centimeters {4 to 23 inches} thick)

2C2/Bw3--68 to 100 centimeters (27 to 40 inches); dark brown (7.5YR 3/3) extremely stony hydrous silty clay loam, very dark brown (10YR 2/2) dry; weak fine subangular blocky structure; very hard, friable, slightly sticky and moderately plastic; strongly smeary; few very fine roots; few very fine dendritic pores; 50 percent subangular `a`a stones and 30 percent subangular `a`a cobbles; slightly acid (pH 6.2); the 2C part of this horizon consists of unconsolidated `a`a lava fragments of variable size;.

2R--100 centimeters (40 inches); hard, massive `a`a blue rock.

TYPE LOCATION: Island of Hawaii; from the village of Mountain View, follow Kulani Rd. North approximately 3.75 miles to Stainback highway. Turn left, southwest, and proceed 4.2 miles to North Tree Planting Road. Proceed 1.9 miles and park. Type location is approximately 160 feet northeast. 19 degrees, 35 minutes, 52.4 seconds North latitude and 155 degrees, 13 minutes, 00.5 seconds West longitude, Old Hawaiian - U.S.G.S Quad: Puu Makaala, Hawaii.

RANGE IN CHARACTERISTICS:
Depth to bedrock: 100 to 150 centimeters (40 to 60 inches).
Mean annual soil temperature: 16 to 22 degrees C (61 to 71 degrees F).
Rock fragments: 35 to 80 percent by volume of the pedon and range from gravel to stone size lava rocks.

A horizon
Hue: 10YR or 7.5YR.
Value: 2 or 3 moist.
Chroma: 1 to 3 moist.
Texture: Hydrous loam, silt loam or silty clay loam, cobbly, very cobbly, or extremely cobbly hydrous loam, silt loam or silty clay loam.
Structure: Weak to fine granular or subangular blocky.
Moist consistence: Very friable or friable.
Reaction: strongly acid to moderately acid (pH 5.1 to 6.0).

Bw horizon
Hue: 10YR or 7.5YR.
Value: 2 or 3 moist.
Chroma: 2 to 4 moist.
Texture: Hydrous loam, silt loam or silty clay loam, cobbly hydrous loam, silt loam or silty clay loam.

2C/Bw horizons
Hue: 5YR to 10YR.
Value: 2 to 4 moist.
Chroma: 2 to 4 moist.
Texture: Very cobbly, extremely cobbly, or extremely stony 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: These are the Akihi and Honuaulu series. Both Akihi and Honuaulu soils are moderately deep to bedrock and have one or more months of normal years where evapotranspiration exceeds precipitation. Honuaulu soils have rainfall occurring mostly between April and October.

GEOGRAPHIC SETTING: Waiakea soils are on the east slopes on the undissected upland of Mauna Loa volcano and on younger lava flows of northeast windward slopes of Mauna Kea volcano at elevations from 336 to 1646 meters (1100 to 5400 feet). The soils are on all hill slope positions of constructional landscapes consisting of undulating to hilly `a`a flows that are 1,500 to 10,000 years old. Slope gradients range from 2 to 35 percent. The soils formed in basic volcanic ash in `a`a lava. The mean annual rainfall typically ranges from 3800 to 5100 millimeters (150 to 200 inches), with most of the rainfall occurring from October through April. Some areas of Waiakea soils that occur on Mauna Kea have mean annual rainfall ranging from 1270 to 2286 millimeters (50 to 90 inches). The mean annual pan evaporation ranges from 762 to 1016 millimeters (30 to 40 inches). Precipitation exceeds evapotranspiration all months of normal years, except in the drier areas of Mauna Kea described above where the soil is typically moist throughout the profile but may experience periodic drying of the control section less than 90 cumulative days, usually during the months of April to October. The mean annual air temperature ranges from 16 to 22 degrees C (61 to 72 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 Ihope, Makaala, Keei, Kiloa, Ohia and Maile series. Ihope soils have redoximorphic features. Makaala soils are moderately deep. Keei and Kiloa soils are organic soils. Ohia and Maile soils are not skeletal.

DRAINAGE AND PERMEABILITY: Well drained. Runoff is very low. Permeability is moderately rapid.

USE AND VEGETATION: Used for wildlife habitat and pasture. Vegetation is ohia lehua (Metrosideros polymorpha), hapuu or treefern (Cibotium chammisoi), uluhe fern or false staghorn fern (Gleichenia linearis), or strawberry guava (Psidium cattleianum).

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

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

SERIES ESTABLISHED: Island of Hawaii, Hawaii County, Hawaii, 2012. Proposed 2006.

REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Soil moisture - typically precipitation exceeds evapotranspiration in all months of normal years (Typically perudic moisture regime but some areas can be udic moisture regime).
Isothermic soil temperature.
Andic properties - 0 to 100 centimeters (0 to 40 inches)
Umbric epipedon - 0 to 25 centimeters (0 to 10 inches) (A, Bw1 horizon)
Cambic horizon - 25 to 100 centimeters (10 to 40 inches) (Bw1, Bw2, 2C1/Bw3, 2C1/Bw4 horizon)

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National Cooperative Soil Survey
U.S.A.