LOCATION HONOKAA                 HI

Established Series
Rev. RCH/HHS/AMS
01/2012

HONOKAA SERIES

The Honokaa series consists of deep, well drained soils that formed in basic volcanic ash. Honokaa soils are on mid elevation, windward slopes of Mauna Kea and have slopes ranging from 0 to 35 percent. The mean annual rainfall is about 3175 millimeters (125 inches) and the mean annual temperature is about 19 degrees C (66 degrees F).

TAXONOMIC CLASS: Hydrous, ferrihydritic, isothermic Acrudoxic Hydrudands

TYPICAL PEDON: Honokaa highly organic hydrous silty clay loam, on an east-facing 15 percent slope under a cover of eucalyptus trees and kikuyu grass at an elevation of 670 meters (2200 feet). (Colors are for moist soil unless otherwise noted. Textures are apparent field textures. When described the soil was moist throughout.)

Ap--0 to 18 centimeters (0 to 7 inches); dark brown (7.5YR 3/2) highly organic hydrous silty clay loam, dark brown (7.5YR 3/4), dry; strong fine and medium subangular blocky structure; hard, friable, slightly sticky, slightly plastic, moderately smeary; many fine and medium and few coarse roots throughout; many fine and medium dendritic tubular pores; moderately acid (pH 6.0); abrupt smooth boundary. (13 to 18 centimeters {5 to 7 inches} thick)

Bw1--18 to 36 centimeters (7 to 14 inches); dark brown (7.5YR 3/2) hydrous silty clay loam, crushed peds have slightly higher chroma dark brown (7.5YR 3/4), brown (7.5YR 4/4), dry; moderate very fine and fine subangular blocky structure; hard, friable, slightly sticky, slightly plastic, moderately smeary; many very fine and fine and few medium roots throughout; many very fine and fine and common medium dendritic tubular pores; moderately acid (pH 6.0); abrupt smooth boundary. (38 to 41 centimeters {15 to 16 inches} thick)

Bw2--36 to 51 centimeters (14 to 20 inches); very dark brown (7.5YR 2/3) and dark brown (7.5YR 3/3) hydrous silty clay loam, dark brown (7.5 YR 3/4), dry; strong very fine and fine subangular blocky structure; very hard, friable, slightly sticky, slightly plastic, moderately smeary; many very fine and fine and few medium roots throughout; many very fine and fine and few medium dendritic tubular pores; slightly acid (pH 6.2); abrupt wavy boundary. (10 to 15 centimeters {4 to 6 inches} thick)

Bw3--51 to 63 centimeters (20 to 25 inches); very dark grayish brown (10YR 3/2) hydrous silty clay loam, dark grayish brown (10YR 4/2), dry; strong very fine and fine subangular blocky structure; very hard, friable, slightly sticky, slightly plastic, moderately smeary; many very fine and few fine and medium roots throughout; many very fine and fine and few medium dendritic tubular pores; moderately acid (pH 6.0); abrupt wavy boundary. (8 to 13 centimeters {3 to 5 inches} thick)

2Bw4/2C--63 to 71 centimeters (25 to 28 inches); dark reddish brown (2.5YR 3/4) hydrous silty clay loam, red (2.5YR 4/8), dry; moderate medium subangular blocky structure; hard, firm, slightly sticky, slightly plastic, moderately smeary (Bw); dark reddish brown (2.5YR 3/4) weakly cemented volcanic ash; massive; hard, very firm, slightly sticky, slightly plastic, moderately smeary (2C); few fine and medium roots between peds and in cracks; many very fine and fine and medium irregular pores; slightly acid (pH 6.3); abrupt smooth boundary. (8 to 10 centimeters {3 to 4 inches} thick)

3Bw5--71 to 81 centimeters (28 to 32 inches); dark brown (10YR 3/3) hydrous silty clay loam, brown (10YR 4/3), dry; strong fine subangular blocky structure parting to moderate very fine and fine subangular blocky; very hard, friable, slightly sticky, slightly plastic, moderately smeary; many fine roots throughout; many very fine and fine dendritic tubular pores; slightly acid (pH 6.3); abrupt smooth boundary. (10 to 13 centimeters {4 to 5 inches} thick)

3Bw6--81 to 86 centimeters (32 to 34 inches); dark brown (7.5YR 3/4) hydrous silty clay loam, brown (7.5YR 4/4), dry; strong very fine and fine subangular blocky structure; very hard, friable, slightly sticky, slightly plastic, moderately smeary; many fine roots throughout; many very fine and fine and common medium dendritic tubular pores; moderately acid (pH 6.0); abrupt smooth boundary. (10 to 13 centimeters {4 to 5 inches} thick)

3Bw7--86 to 99 centimeters (34 to 39 inches); banded dark brown (10YR 3/3 and 7.5YR 3/4) hydrous silty clay loam, dark yellowish brown (10YR 4/4), dry; strong very fine and fine subangular blocky structure; very hard, friable, slightly sticky, slightly plastic, moderately smeary; many fine roots throughout; many very fine and fine dendritic tubular pores; moderately acid (pH 5.8); abrupt smooth boundary. (28 to 33 centimeters {11 to 13 inches} thick)

3Bw8--99 to 165 centimeters (39 to 65 inches); banded yellowish brown (10YR 5/4) and dark brown (7.5YR 4/4) hydrous silty clay loam, light yellowish brown (10YR 6/4) and brown (7.5YR 5/3), dry; strong very fine and fine subangular blocky structure; very hard, firm, slightly sticky, slightly plastic, moderately smeary; common very fine roots throughout; common very fine dendritic tubular pores; moderately acid (pH 5.8).

TYPE LOCATION: Island of Hawaii, Hawaii; From mile marker 41 on Hawaii Belt Road (Highway 19), follow the paved road to the southwest (mauka, or towards mountain) for 2.1 miles, turn east and continue 0.2 miles until road ends. Park and walk south 100 yards to type location at Honokaa Quadrangle; 20 degrees 2 minutes 38 seconds North latitude and 155 degrees 26 minutes 48 seconds West longitude (Old Hawaiian Datum, +/- 12 feet; measured by Garmin GPS).

RANGE IN CHARACTERISTICS:
Soil moisture: Udic soil moisture regime - 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 ().
Soil temperature: 19 to 22 degrees C (66 to 72 degrees F).
Reaction: Moderately acid or slightly acid (pH 5.8 to 6.4).
Depth to bedrock: Greater than 100 centimeters (40 inches).
Rock fragments: 0 to 10 percent on the surface and range from gravel to stone size `a`a lava rocks.

Oa or Oi horizon (may be present in pedons under forest canopy)
Hue: 7.5YR or 10YR.
Value: 2 to 3 moist.
Chroma: 1 to 2 moist.
Texture: highly decomposed plant material or slightly decomposed plant material.

A horizon
Hue: 5YR to 10YR.
Value: 2 to 3 moist.
Chroma: 2 to 3 moist.
Texture: hydrous silty clay loam or silt loam. May be highly organic.
Structure: Weak to moderate, very fine to medium, granular or subangular blocky.
Smeariness: Weakly or moderately smeary.
Rock fragments: 0 to 10 percent (by volume of the pedon) gravel size `a`a lava rocks or cinder paragravel.

Bw horizons
Hue: 5YR to 10YR.
Value: 2 to 5 moist.
Chroma: 2 to 4 moist.
Texture: hydrous silty clay, silty clay loam, or silt loam.
Structure: Weak to moderate, very fine to medium, subangular blocky.
Smeariness: Moderately or strongly smeary.
Rock fragments: 0 to 15 percent (by volume of the pedon) gravel or cobble size `a`a lava rocks or cinder paragravel.

2Bw/2C horizon
Hue: 2.5YR to 7.5YR.
Value: 2.5 to 4 moist.
Chroma: 4 to 6 moist.
Texture: hydrous silty clay loam or silty clay.
Structure: weak to moderate, fine to medium, granular or subangular blocky. Cemented material is massive.
Smeariness: Weakly or moderately smeary.
Rock fragments: 0 to 10 percent (by volume of the pedon) cinder paragravel.

COMPETING SERIES: These are the Akaka, Honomanu, Kaiwiki, Kehena, Maile, Moaula, and Ohia soils. Akaka soils are moderately well drained with redox features in the A, Bw, and Bs horizons. Honomanu soils have silty clay texture in the B horizons. Honomanu and Kehena soils are moderately deep (50 to 100 cm {20 to 39 inches}) to bedrock. Kaiwiki soils are strongly smeary throughout and have a perudic soil moisture regime. Maile soils have a silt loam surface texture, a mean annual soil temperature of 17 degrees C (63 degrees F), and mean annual precipitation of 1900 millimeters (75 inches). Moaula and Ohia soils are on younger Mauna Loa flows.

GEOGRAPHIC SETTING: The Honokaa soils are on mid elevation windward mountain slopes of Mauna Kea shield volcano at elevations from 335 to 1222 meters (1100 to 4000 feet). Steep and narrow drainage gulches dissect the landscape. The soils are on summit, shoulder, backslope, and footslope hillslope profile positions of ash fields that overlie 64,000 to 300,000 year old lava flows. Slope gradients typically range from 0 to 35 percent, but can be as great as 100 percent in gulches. The soils formed in basic volcanic ash. The mean annual rainfall is 2000 to 3800 millimeters (78 to 150 inches). The mean annual temperature is 16 to 22 degrees C (61 to 72 degrees F) and the mean annual soil temperature is 19 degrees C (66 degrees F).

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Akaka, Kukaiau, Maile, and Ookala soils. Akaka soils occur on moderately well drained footslope positions. Kukaiau soils have mean annual precipitation of 2159 millimeters (85 inches) and mean annual soil temperature of 21 degrees C (70 degrees F). Ookala soils are isohyperthermic and have a mean annual soil temperature of 23 degrees C (73 degrees F).

DRAINAGE AND PERMEABILITY: Well drained. Runoff is low to high. Permeability is rapid.

USE AND VEGETATION: These soils are used for tree plantations and pasture. In the past they were used extensively for growing sugarcane from 335 to 640 meters (1100 to 2100 feet) elevation. Natural vegetation is ohia lehua (Metrosideros polymorpha), hapuu treefern (Cibotium glauca), Hilo grass (Paspalum conjugatum), and kikuyu grass (Pennisetum clandestinum).

DISTRIBUTION AND EXTENT: Hamakua and Mauna Kea Districts, Island of Hawaii. This series is moderately extensive with a total of roughly 52,000 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 1/2010 by AMS.

Diagnostic horizons and features (10th edition of Keys to Soil Taxonomy) recognized in this pedon are:
Umbric epipedon - 0 to 18 centimeters (0 to 7 inches) (Ap horizon).
Cambic horizons - 18 to 165 centimeters (7 to 65 inches) (Bw horizons).
Andic Soil Properties - 0 to 165 centimeters (0 to 65 inches) (All horizons).
Isothermic soil temperature regime.
Udic soil moisture regime.

ADDITIONAL DATA: NASIS User Pedon ID 62HI001001. NSSL samples: 62HI001001 (type location), 87HI001003, 99HI001009.

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National Cooperative Soil Survey
U.S.A.