LOCATION LANAPOHAKU HI

Established Series
CDJ/MRK
08/2012

LANAPOHAKU SERIES

The Lanapohaku series consists of very deep, somewhat excessively drained soils that formed in volcanic ash and `a`a lava. Slopes range from 6 to 50 percent. The mean annual rainfall is about 500 millimeters (20 inches) and the mean annual temperature is about 12 degrees C (53 degrees F).

TAXONOMIC CLASS: Ashy, amorphic, isomesic Humic Ustivitrands

TYPICAL PEDON: Lanapohaku ashy sandy loam, on a northwest facing, 9 percent slope, in savannah, at an elevation of 8,640 feet (2,634 meters). (Colors are for dry soil unless otherwise noted. All textures are "apparent field textures". pH measured using a 1:1 soil to water mixture.)

A1--0 to 18 centimeters (0 to 7 inches); dark brown (10YR 3/3) ashy sandy loam, very dark brown (10YR 2/2) moist; weak fine subangular blocky structure; soft, very friable, nonsticky, nonplastic; nonsmeary; few fine roots throughout and common very fine roots throughout; 5 percent angular very strongly cemented 75 to 250 millimeter basalt fragments and 5 percent angular very strongly cemented 2 to 75 millimeter basalt fragments; neutral (pH 6.6); abrupt smooth boundary.

2A2--18 to 28 centimeters (7 to 11 inches); very dark grayish brown (10YR 3/2) cobbly medial very fine sandy loam, black (10YR 2/1) moist; weak fine subangular blocky structure; slightly hard, friable, nonsticky, slightly plastic; weakly smeary; few fine roots throughout and few very fine roots throughout; 15 percent angular very strongly cemented 75 to 250 millimeter basalt fragments and 15 percent angular very strongly cemented 2 to 75 millimeter basalt fragments; neutral (pH 7.0); abrupt smooth boundary. HORIZON NOTE: moderate dilatency.

2Bw1--28 to 55 centimeters (11 to 22 inches); dark brown (10YR 3/3) ashy sandy loam, very dark brown (10YR 2/2) moist; weak medium subangular blocky structure; soft, very friable, nonsticky, slightly plastic; nonsmeary; few fine roots throughout and few very fine roots throughout; strongly hydrophobic; slightly alkaline (pH 7.4); clear smooth boundary.

3Bw2/5C1--55 to 67 centimeters (22 to 26 inches); very dark grayish brown (10YR 3/2) extremely cobbly ashy loamy coarse sand, very dark brown (10YR 2/2) moist; weak fine subangular blocky structure; soft, very friable, nonsticky, nonplastic; nonsmeary; few fine roots throughout and few very fine roots throughout; 10 percent angular very strongly cemented 2 to 75 millimeter basalt fragments and 50 percent angular very strongly cemented 75 to 250 millimeter basalt fragments; the C horizon materials consist of unconsolidated `a`a lava fragments of variable size; strongly acid (pH 5.5); clear smooth boundary.

3Bw3--67 to 105 centimeters (26 to 41 inches); 50 percent very dark grayish brown (10YR 3/2) and 50 percent dark grayish brown (10YR 4/2) stratified ashy loamy sand, 50 percent black (10YR 2/1) and 50 percent very dark grayish brown (10YR 3/2) moist; weak fine subangular blocky structure; soft, very friable, nonsticky, nonplastic; nonsmeary; 5 percent angular very strongly cemented 250 to 610 millimeter basalt fragments; slightly alkaline (pH 7.4); abrupt smooth boundary.

3Bw4--105 to 147 centimeters (41 to 58 inches); brown (10YR 4/3) ashy loamy sand, very dark brown (10YR 2/2) moist; weak medium subangular blocky structure; soft, very friable, nonsticky, nonplastic; nonsmeary; few fine roots throughout and few very fine roots throughout; 12 percent angular very strongly cemented 75 to 250 millimeter basalt fragments; slightly alkaline (pH 7.4); abrupt smooth boundary.

4C--147 to 160 centimeters (58 to 63 inches); brown (7.5YR 4/4) paragravelly ashy loamy coarse sand, dark brown (7.5YR 3/4) moist; single grain; nonsticky, nonplastic; nonsmeary; many fine interstitial pores; 20 percent subrounded weakly cemented 2 to 75 millimeter basalt fragments; slightly alkaline (pH 7.7); abrupt wavy boundary. (combined thickness of the ash fall layers overlying `a`a is 75 to 175 centimeters (30 to 69 inches)

5C2--160 to 162 centimeters (63 to 64 inches); brown (7.5YR 4/4) extremely stony ashy loamy coarse sand, dark brown (7.5YR 3/4) moist; single grain; nonsticky, nonplastic; nonsmeary; common fine interstitial pores; 5 percent subrounded weakly cemented 2 to 75 millimeter basalt fragments and 25 percent angular very strongly cemented 250 to 610 millimeter basalt fragments and 25 percent angular very strongly cemented 2 to 75 millimeter basalt fragments and 30 percent angular very strongly cemented 75 to 250 millimeter basalt fragments; (thickness of the `a`a clinker layer to underlying bedrock is 50 to 100 cm (20 to 40 inches); strongly acid (pH 5.5).

TYPE LOCATION: Hawaii County, Hawaii, From Old Saddle Road drive up hunting road to Skyline Road, take first spur road to the north. 19 degrees, 50 minutes, 18 seconds North latitude and 155 degrees, 34 minutes, 7 seconds West longitude, Old Hawaiian Datum - U.S.G.S Quad: Ahumoa, Hawaii.

RANGE IN CHARACTERISTICS:
Depth to bedrock: 152 to 250 centimeters (60 to 99 inches)
Mean annual soil temperature: 8 to 15 degrees C (47 to 59 degrees F).
Coarse fragments: 10 to 35 percent of the pedon
Soil can be hydrophobic when dry.

A horizon(s)
Hue: 7.5YR or 10YR
Value: 2 or 3 moist and 2 through 4 dry
Chroma: 1 through 3 moist and 2 through 4 dry
Texture: coarse loamy or sandy with ashy modifier and contain 10 to 50 percent rock fragments but may contain as much as 90 percent rock fragments at the surface
Structure: granular or subangular blocky
Consistence: nonsticky to slightly sticky and nonplastic to slightly plastic
Smeariness: nonsmeary to weakly smeary

Bw horizon(s) in ashy materials
Hue: 7.5YR or 10YR
Value: 2 or 3 moist and 2 through 4 dry
Chroma: 1 through 3 moist and 2 through 4 dry
Texture: coarse loamy or sandy with ashy modifier and contain 0 to 35 percent rock fragments
Consistence: nonsticky to slightly sticky and nonplastic to slightly plastic
Smeariness: nonsmeary to weakly smeary

Bw horizon(s) in `a`a materials
Hue: 7.5YR or 10YR
Value: 3 or 4 moist and dry
Chroma: 3 or 4 moist and dry
Texture: coarse loamy or sandy with ashy modifier and contain 35 to 90 percent rock fragments
Consistence: nonsticky and nonplastic
Smeariness: nonsmeary to weakly smeary

COMPETING SERIES: This is the Huikau series. Huikau soils have cinders in the particle size control section.

GEOGRAPHIC SETTING: Lanapohaku soils are on high elevation slopes of Mauna Kea volcano at elevations from 2,012 to 3,048 meters (6,600 to 10,000 feet). These soils are on `a`a lava flows that have been covered by sandy volcanic ash. Underlying lava flows are 5,000 to 250,000 years old. Slope gradients range from 6 to 50 percent. The mean annual rainfall ranges from 400 to 1000 millimeters (16 to 40 inches), with most of the rainfall occurring from October through April. The mean annual pan evaporation ranges from 1,520 to 1,780 millimeters (60 to 70 inches). The mean annual air temperature ranges from 7 to 14 degrees C (45 to 57 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 the Lapa and Pohakulehu soils. Lapa soils are less than 50 centimeters to bedrock and Pohakulehu soils contain greater than 35 percent rock fragments throughout the upper meter of soil.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained. Runoff is low to moderate. Permeability is rapid.

USE AND VEGETATION: Used for wildlife habitat. Natural vegetation is Mamane (Sophora chrysophylla), Pukiawe (Styphelia tameiameiae), Pilo (Coprosma spp.), lovegrass (Eragrostis spp.), Aalii (Dodonaea viscosa), common velvetgrass (Holcus lanatus), fireweed (Senecio madagascariensis), and orchardgrass (Dactylis glomerata L.).

DISTRIBUTION AND EXTENT: Hamakua district, Island of Hawaii; MLRA 160. The soils are of small extent.

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

SERIES ESTABLISHED: Island of Hawaii, Hawaii County, Hawaii, 2012. Proposed 2007.

REMARKS:
Classification is based on 11th edition Keys to Soil Taxonomy.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - from 0 to 147 centimeters (0 to 58 inches)
Andic soil properties - from 0 to 162 centimeters (0 to 64 inches)
Lithologic discontinuities - at 18, 55, 147, and 160 centimeters

ADDITIONAL DATA:

National Cooperative Soil Survey
U.S.A.