LOCATION AMALU                   HI

Established Series
Rev. CWS/SN/HI/MRK
05/2012

AMALU SERIES

The Amalu series consists of shallow, poorly drained soils that formed in organic matter over basic volcanic ash and tropospheric dust over residuum weathered from basalt. Amalu soils are on uplands and have slopes of 3 to 50 percent. The mean annual rainfall is about 3000 millimeters (118 inches), and the mean annual temperature is about 15 degrees C (59 degrees F).

TAXONOMIC CLASS: Clayey, mixed, superactive, isothermic, shallow Histic Placic Petraquepts

TYPICAL PEDON: Amalu peat under native rainforest. (Colors are for moist soil unless otherwise noted. All textures are apparent field textures.)

Oi--0 to 20 centimeters (0 to 8 inches); pale yellow (2.5Y 7/4) peat; massive; soft; many medium and coarse roots; extremely acid (pH 3.9); abrupt wavy boundary. (13 to 38 centimeters {5 to 15 inches} thick)

Ag--20 to 41 centimeters (8 to 16 inches); gray (10YR 5/1) silty clay; massive; firm, moderately sticky and moderately plastic; weakly smeary; many very fine and fine roots; many fine and medium tubular pores; common dark gray (10YR 4/1) organic stains; extremely acid (pH 4.2); abrupt smooth boundary. (10 to 38 centimeters {4 to 15 inches} thick)

Bsm--41 to 43 centimeters (16 to 17 inches); dark reddish brown (5YR 2/2) cemented material that is a horizontal ironstone sheet that is laminar and has a troweled surface; moderate, medium platy structure; extremely firm; thin coating of yellowish red (5YR 4/6) soft material on upper surface; very strongly acid (pH 4.5);abrupt broken boundary (0 to 3 centimeters {0 to 1 inch thick)

2Cr--43 to 152 centimeters (17 to 60 inches; very dark gray (10YR 3/1) very cobbly silt loam saprolite; massive; very firm, slightly sticky and nonplastic; slightly smeary; 5 percent gravel and 40 percent cobbles; soft light gray (10YR 7/1) and yellowish red (5YR 5/6) plinthite in cracks or coatings around rock cores; strongly acid (pH 5.2); few hard discontinuous ironstone sheets up to 1 inch oriented horizontally and vertically. (90 to 152 centimeters {36 to 60 inches} thick)(5.2)

TYPE LOCATION: Island of Maui, Maui County, Hawaii; in the Koolau Forest Reserve, 10 feet south of wooden flume and 1,200 feet east of Waikomoi reservoir; Kilohana Quadrangle; lat. 20 degrees 48 minutes 46 seconds N. and long. 156 degrees 13 minutes 44 seconds W. (Old Hawaiian Datum).

RANGE IN CHARACTERISTICS:
Depth to placic horizon: 30 to 58 centimeters (12 to 23 inches). Depth to paralithic contact: 38 to 76 centimeters (15 to 30 inches). Depth to water table: 0 to 41 centimeters (0 to 16 inches). Mean annual soil temperature ranges from 15 to 19 degrees C (59 to 67 degrees F).

The Ag horizon
Hue: 10YR to 5Y
Value: 2 to 5
Chroma: 1 or 2
Texture: mucky clay or silty clay
In some pedons a black mucky layer 2.5 to 5 centimeters (1 to 2 inches) thick is below the Ag horizon.

The Bsm horizon Hue: 5YR or 7.5YR Boundary: smooth or broken May not be present in some pedons

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Amalu soils are on interfluves of steep dissected uplands on middle elevation, windward mountain slopes. Slopes range from 3 to 50 percent. Elevations range from 610 to 1,676 meters (2,000 to 5,500 feet). The soils formed in organic matter over basic volcanic ash and tropospheric dust over residuum weathered from basalt. The mean annual rainfall is 1905 to 10,160 millimeters (75 to 400 inches) with most of the rainfall occurring from October through April. Landscapes are fog or cloud covered during most of the day throughout the year. The mean annual temperature ranges from 14 to 16 degrees C (57 to 61 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 Honomanu, Kahua, and Kehena soils. Honomanu soils do not have both a histic epipedon or placic horizon. Kahua and Kehena soils are deep and moderately deep, repectively; and have andic soil properties.

DRAINAGE AND PERMEABILITY: Poorly drained; high to very high runoff; slow permeability. Ponding is common in depressions.

USE AND VEGETATION: Amalu soils are used for watershed and wildlife. Natural vegetation is ohia lehua (Metrosideros ploymorpha), pamakani (Ageratina adenophora), treefern (Cibotium spp.), staghornfern (Dicranopteris linearis), ape (Alocasia macrorrhizos), lapalapa (Cheirondendron spp.), and club moss (Lycopodium cernuum).

DISTRIBUTION AND EXTENT: Islands of Molokai, Hawaii, and Maui, Hawaii. This soil is moderately extensive with about 30,000 acres.

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

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

REMARKS: Aquic soil moisture regime- The soil is saturated and reduced throughout the year.
Diagnostic horizons and features recognized in this pedon include:
Aquic conditions- 20 to 41 centimeters (8 to 16 inches)
Episaturation- 20 to 25 centimeters (8 to 10 inches)
Histic epipedon- 0 to 20 centimeters (0 to 8 inches)
Paralithic contact- 43 centimeters (17 inches)
Placic horizon- 41 to 43 centimeters (16 to 17 inches)
Fibric soil materials- 0 to 20 centimeters (0 to 8 inches)
Elevations more than 1,524 meters (5000 feet) have an isomesic soil temperature regime.
FCC Classification: OCR-aegkx.

ADDITIONAL DATA: NASIS User Pedon ID 08HI603008. Amalu-like soil NSSL sample 91HI-001-003; Amalu NSSL sample 94HI-009-001; 96HI-009-001; 97HI-009-003; 97HI009-004; 94HI-009-001Z;S02HI-009-001.

Edit Log: 8/09 MRK. Updated competing series and range in characteristics plus minor edits.
12/03 SN. Horizon designations and depth updated; added tropospheric dust; updated temperatures; and added FCC.
7/01 SN. Classification changed from Clayey, mixed, superactive acid, isomesic Histic Placic Petraquepts due to changes in Taxonomy and new lab data.

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National Cooperative Soil Survey
U.S.A.