LOCATION PUIWA                   HI

Established Series
Rev. KH-RTG
06/2012

PUIWA SERIES

The Puiwa series consists of moderately deep, well drained soils that formed in volcanic ash deposited over pahoehoe lava. Slopes range from 2 to 15 percent. The mean annual rainfall is about 1,499 millimeters (59 inches), and the mean annual air temperature is about 12 degrees C. (54 degrees F.)

TAXONOMIC CLASS: Medial, amorphic, isomesic Typic Hapludands

TYPICAL PEDON: Puiwa medial loam, on 11 percent slope under scattered trees, shrubs and grasses at an elevation of 6,500 feet. (Colors are for moist soil unless otherwise noted. When described on 5/28/98 the soil was slightly moist throughout. The soil temperature was 11 degrees C. (52 degrees F.) at a depth of 50 centimeters (20 inches). All textures are "apparent field textures". pH was measured using electrode in 1:1 water.)

A1--0 to 10 centimeters (0 to 4 inches); very dark brown (10YR 2/2) medial loam; strong fine granular structure; soft, friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine interstitial pores; moderately acid (pH 5.7); abrupt wavy boundary.

A2--10 to 18 centimeters (4 to 7 inches); black (10YR 2/1) medial loam; moderate medium subangular blocky structure parting to weak fine granular; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine, and few medium roots; many very fine and fine interstitial pores; moderately acid (pH 5.9) abrupt wavy boundary. (Combined thickness of the A horizon ranges from 3 to 10 centimeters (1 to 4 inches)).

A3--18 to 24 centimeters (7 to 9.5 inches); 40 percent black (10YR 2/1) and 60 percent very dark brown (10YR 2/2) stratified medial silt loam and medial loam; weak medium subangular blocky structure; soft, friable, nonsticky and nonplastic; many very fine, fine, and few medium roots; many very fine and fine interstitial pores; moderately acid (pH 6.0); abrupt broken boundary. (5 to 13 centimeters (2 to 5 inches) thick)

C--24 to 28 centimeters (9.5 to 11 inches); very dark grayish brown (10YR 3/2) medial fine sand; massive; soft, very friable, nonsticky and nonplastic; many very fine and fine, and few medium roots; many very fine and fine interstitial pores; moderately acid (pH 6.0); abrupt broken boundary. (0 to 8 centimeters (0 to 3 inches) thick)

2Bw1--28 to 43 centimeters (11 to 17 inches); dark brown (7.5YR 3/3) medial silt loam; massive; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine, and few medium roots; many very fine and fine interstitial pores; slightly acid (pH 6.2); abrupt wavy boundary.

2Bw2--43 to 64 centimeters (17 to 25 inches); dark brown (7.5YR 3/3) medial silt loam; massive; hard, friable, nonsticky and nonplastic; common very fine, fine, and few medium roots; common very fine and fine interstitial pores; 5 percent subrounded pahoehoe gravel; neutral (pH 6.9); abrupt wavy boundary.

2Bw3--64 to 96 centimeters (25 to 38 inches); dark brown (7.5YR 3/4) cobbly silt loam; massive; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine, and few medium roots; common very fine and fine interstitial pores; 15 percent subrounded pahoehoe cobbles and 5 percent subrounded pahoehoe gravel; slightly acid (pH 6.5); clear wavy boundary. (Combined thickness of Bw horizons 50 to 89 centimeters (20 to 35 inches).)

3R--96 centimeters (38 inches); hard pahoehoe bedrock.

TYPE LOCATION: Hawaii Volcanoes National Park; from State Hwy. 11, drive 11 miles north on Mauna Loa Strip Road to the end; turn around and from the mileage sign travel 0.35 miles down Mauna Loa Strip Road to pullout; from southeast corner of pullout take a 290 degree heading for about 22 meters (72 feet) to type location; Kipuka Pakekake Quadrangle; lat. 19 degrees 29 minutes 27.14 seconds N. and long. 155 degrees 23 minutes 19.78 seconds W. (Old Hawaiian Datum measured by GPS/PLGR, 49 feet).

RANGE IN CHARACTERISTICS:
Depth to bedrock: 20 to 40 inches.
Mean annual soil temperature: 11 to 15 degrees C. (52 to 59 degrees F.).
Soil reaction: Neutral to moderately acid.

A horizon
Hue: 5YR to 10YR.
Value: 2 or 3 moist.
Chroma: 1 to 3 moist.
Texture: Medial loam or medial silt loam.
Structure: Granular or subangular blocky.
Rock fragments: 0 to 15 percent gravel and 0 to 35 percent cobbles.

2B horizon
Hue: 2.5YR to 10YR.
Value: 2 to 6 moist.
Chroma: 1 to 6 moist.
Texture: Medial loam or medial silt loam.
Structure: Subangular blocky or massive.

3Bw horizon
Occurs in some pedons, especially at the lower elevation range.

C horizon
Discontinuous horizon between A3 and 2Bw horizon occurs in few profiles.

COMPETING SERIES: This is the Haa series. Haa soils are 100 to 152 centimeters (40 to 60 inches) deep, and have horizons reflecting three ash packets in contrast with two for Puiwa.

GEOGRAPHIC SETTING: Puiwa soils are on Mauna Loa pahoehoe flows 200 to 5,000 years old at elevations of 1,677 to 2,287 meters (5,500 to 7,500 feet). Slopes range from 2 to 15 percent. The mean annual rainfall is 1,270 to 1,524 millimeters (50 to 60 inches), with about 75 percent of the rainfall occurring between November and May. The mean annual pan evaporation is 1,270 to 1,524 millimeters (50 to 60 inches). The mean annual air temperature is 12 to 14 degrees C. (54 to 57 degrees F.).

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kaholimo, Kulalio, and Maunaiu series. Kaholimo and Maunaiu soils are lithic, less than 50 centimeters (20 inches) deep. Kulalio soils are skeletal and more than 152 centimeters (60 inches) deep.

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

USE AND VEGETATION: These soils are used for National Park Service land and for grazing. Vegetation is aalii (Dodonaea viscosa), koa (Acacia koa), kukaenene (Coprosma ernodeoides), mamane (Sophora chrysophylla), Natal redtop (Rhynchelytrum repens), ohia lehua (Metrosideros polymorpha), pukiawe (Styphelia tameiameiae), uki (Machaerina angustifolia), and other grasses.

DISTRIBUTION AND EXTENT: These soils occur within Hawaii Volcanoes National Park and possibly neighboring ranches; MLRA 160. 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 1998. The name is coined.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Andic soil properties - from 0 to 96 centimeters (0 to 38 inches).
Umbric epipedon - from 0 to 64 centimeters (0 to 25 inches).
Soil temperature - mean summer and mean winter soil temperatures differ by less than 6 degrees C. (iso temperature regime).
Soil moisture - not dry in some or all parts for 90 days or more in most years (Udic moisture regime).

Edit Log: 12/03 KH. Added "medial" modifier to textures.
3/01 KH. Runoff changed from high to low. Permeability changed from moderate to rapid.

ADDITIONAL DATA: Puiwa NSSL sample S98HI-001-014 from type location.

Penetrometer measurements made by inserting penetrometer horizontally into "in situ" soil:

A2 horizon = 0.5 tons/square foot
A3 horizon = 0.5 to 1 ton/square foot
2Bw1 horizon = 0.5 tons/square foot
2Bw2 horizon = 2.5 tons/square foot
2Bw3 horizon = 2.5 to 3 tons/square foot

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National Cooperative Soil Survey
U.S.A.