LOCATION PEARL HARBOR HI

Established Series
Rev. ELH/LDG/RCH/MRK
05/2020

PEARL HARBOR SERIES

The Pearl Harbor series consists of deep, very poorly drained soils that formed in alluvium worked from material weathered from basic igneous rock and deposited over and mixed with muck. Pearl Harbor soils are on coastal flats and have slopes of 0 to 2 percent. Mean annual rainfall is about 508 millimeters (20 inches) and mean annual air temperature is about 23 degrees C. (74 degrees F.)

TAXONOMIC CLASS: Fine, halloysitic, isohyperthermic Thapto-Histic Endoaquolls

TYPICAL PEDON: Pearl Harbor clay - bananas. (Colors are for moist soil unless otherwise noted. All textures are "apparent field textures.")

Ap--0 to 31 centimeters (0 to 12 inches); very dark gray (10YR 3/1) clay, dark gray (10YR 4/1) dry, many fine strong brown (7.5YR 5/6) prominent mottles on peds and in pores; strong fine and medium granular and fine subangular blocky structure; very hard, firm, very sticky and very plastic; many very fine and fine roots; common very fine and fine, few medium tubular pores; common worm holes and casts; slight effervescence with hydrogen peroxide; neutral (pH 6.8); clear wavy boundary. (20 to 31 centimeters thick)

Bg1--31 to 51 centimeters (12 to 20 inches); very dark gray (10YR 3/1) clay moist and dry, many fine strong brown (7.5YR 5/6) prominent mottles in all pores and few on faces of peds; strong fine and medium subangular and angular blocky structure; very hard, firm, very sticky and very plastic; many fine roots; common very fine and fine , few medium tubular pores; thin intermittent horizontal ironstone layers; slight effervescence with hydrogen peroxide; slightly alkaline (pH 7.6); gradual smooth boundary. (15 to 20 centimeters thick)

Bg2--51 to 64 centimeters (20 to 25 inches); very dark gray (10YR 3/1) clay moist and dry, many fine strong brown (7.5YR 5/6) prominent mottles line fine pores; moderate fine and medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; many fine roots; many very fine and common fine tubular pores; slight effervescence with hydrogen peroxide; few fine shells that have slight effervesce with hydrochloric acid; moderately alkaline (pH 8.2); gradual smooth boundary. (8 to 18 centimeters thick)

Bg3--64 to 79 centimeters (25 to 31 inches); very dark grayish brown (10YR 3/2) clay, grayish brown (10YR 5/2) dry, many fine strong brown (7.5YR 5/6) prominent mottles in pores and on faces of peds; moderate fine and medium subangular blocky structure; hard, firm, very sticky and very plastic; few fine roots; many very fine pores, few fine and coarse tubular pores; worm holes and casts; many small shells; strong effervescence with hydrogen peroxide; slight effervescence with hydrochloric acid on soil mass; violent effervescence on shells; moderately alkaline (pH 8.0); abrupt smooth boundary. (8 to 15 centimeters thick)

2Oa1--79 to 94 centimeters (31 to 37 inches); very dark grayish brown (10YR 3/2) muck moist and dry, few fine strong brown (7.5YR 5/6) prominent mottles; massive; very hard, friable, slightly sticky and slightly plastic; common fine roots; common fine tubular pores; few shells; few fine black fragments of tuff; thin discontinuous vertical ironstone bands; slight effervescence with hydrogen peroxide; strong effervescence with hydrochloric acid; slightly alkaline (pH 7.8); clear smooth boundary. (10 to 15 centimeters thick)

2Oa2--94 to 122 centimeters (37 to 48 inches); very dark gray (10YR 3/1) muck, gray (10YR 6/1) dry; massive; hard, friable, moderately sticky and moderately plastic; 2 percent gravel; slightly alkaline (pH 7.5).

TYPE LOCATION: Honolulu County, Hawaii; from Kunia Road-Farrington Highway junction, drive 0.3 mile west to a road turning southeast and then 0.6 mile to Ewa Plantation Company banana field. Pedon is 100 feet east of road. 21 degrees 22 minutes 19.00 seconds N. latitude and 158 degrees 01 minutes 47.00 seconds W. longitude (WGS84).

RANGE IN CHARACTERISTICS: The buried muck or peat is at depths of 20 to 50 inches, and the brackish water table is at about the same depths. As much as 5 percent of the buried horizons are coral sand or shells. The mean annual soil temperature is about 23 degrees C. (74 degrees F.) The solum has hue of 7.5YR or 10YR, value of 2 through 4 moist, 4 through 6 dry, and chroma of 0 or 1.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: The Pearl Harbor soils are on coastal flats and plains at elevations from near sea level to 15 meters (50 feet). Slope range is 0 to 2 percent. The soils formed in alluvium washed from material weathered from basic igneous rocks and deposited over and mixed with peat or muck. Average annual rainfall is 457 to 1016 millimeters (18 to 40 inches). Mean annual air temperature is 23 degrees C. (74 degrees F.), average January air temperature is 21 degrees C. (70 degrees F.), and average July air temperature is 26 degrees C. (78 degrees F.)

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hanalei, Honouliuli, Kaloko, and Keaau soils. Hanalei soils have a fine-silty control section and lack buried muck or peat. Honouliuli soils are free of mottles and have 5YR hue throughout. Kaloko soils formed in calcareous material and are strongly calcareous in the upper 51 centimeters (20 inches). Keaau soils are poorly drained, lack a buried muck or peat horizon, and are underlain by consolidated coral sand on reef limestone at depths of 51 to 91 centimeters (20 to 36 inches).

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Very poorly drained; very low runoff or ponded; moderately low saturated hydraulic conductivity.

USE AND VEGETATION: Most of this soil is now urbanized or in pasture. Some is in taro, bananas, and sugarcane. Natural vegetation is panicum, sedges, cattails, and mangrove trees.

DISTRIBUTION AND EXTENT: Mainly near Pearl Harbor, Waialua, Kahuku, Laie, and Waimanalo; but small bodies are elsewhere on the coastal plain of the Island of Oahu, Hawaii. This series is inextensive with a total of about 1,990 acres.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Davis, California

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

REMARKS: Diagnostic horizons and features recognized in this pedon include:
mollic epipedon - 0 to 31 centimeters
redox concentrations - 0 to 94 centimeters
reduced matrix - 31 to 79 centimeters
sapric soil materials - 79 to 122 centimeters
Minor edits and competing series updated. MRK 11/2019.
OSED scanned by SSQA. Last revised by state on 5/2001.

National Cooperative Soil Survey
U.S.A.