LOCATION WAHIAWA HIEstablished Series
TAXONOMIC CLASS: Very-fine, kaolinitic, isohyperthermic Rhodic Haplustox
TYPICAL PEDON: Wahiawa silty clay - pineapple. (Colors are for moist soil unless otherwise noted. All textures are "apparent field textures.")
Ap1--0 to 6 inches; very dusky red (2.5YR 2/2) silty clay, dusky red (2.5YR 3/2) dry; moderate medium, fine and very fine granular structure; very hard, friable, sticky and plastic; many roots; many medium, fine and very fine pores; many 1/8 to l/4 inch black concretions; violent effervescence with hydrogen peroxide; moderately acid (pH 5.6); abrupt smooth boundary. (2 to 6 inches thick)
Ap2--6 to 12 inches; dusky red (2.5YR 3/2) moist and dry silty clay; common dark reddish brown (2.5YR 3/4) material from the B horizon mixed by cultivation; moderate coarse subangular blocky structure; hard, firm, sticky and plastic; compact in place; many roots; few fine and very fine tubular pores; many black concretions; violent effervescence with hydrogen peroxide; moderately acid (pH 5.8); abrupt wavy boundary. (5 to 8 inches thick)
Bo1--12 to 16 inches; dark reddish brown (2.5YR 2/4) silty clay, dark reddish brown (2.5YR 3/4) dry; moderate fine and very fine subangular blocky structure; hard, firm, sticky and plastic; common roots; common fine and very fine and few coarse tubular pores; many black concretions; strong effervescence with hydrogen peroxide; moderately acid (pH 5.6); gradual wavy boundary. (4 to 8 inches thick)
Bo2--16 to 33 inches; dark reddish brown (2.5YR 2/4) silty clay, dark reddish brown (2.5YR 3/4) dry; moderate and strong fine and very fine subangular blocky structure; hard, friable, sticky and plastic; few roots; common fine and very fine tubular pores; nearly continuous pressure faces; many fine distinct black stains; few black concretions; strong effervescence with hydrogen peroxide; slightly acid (pH 6.5); diffuse wavy boundary. (14 to 2O inches thick)
Bo3--33 to 45 inches; dark reddish brown (2.5YR 2/4) silty clay, dark reddish brown (2.5YR 3/4) dry; moderate and strong very fine subangular blocky structure; hard, friable, sticky and plastic; common fine and very fine tubular pores; nearly continuous pressure faces; many fine distinct black stains; few black concretions; moderate effervescence with hydrogen peroxide; neutral (pH 7.l); diffuse wavy boundary. (10 to 14 inches thick)
Bo4--45 to 60 inches; dark reddish brown (2.5YR 2/4) silty clay, dark reddish brown (2.5YR 3/4) dry; moderate and strong very fine subangular blocky structure; hard, friable, sticky and plastic; common fine and very fine tubular pores; few fine black stains; thin patchy clay films; continuous pressure faces; many distinct slickensides up to 2 inches long; very few black concretions; slight effervescence with hydrogen peroxide; neutral (pH 6.9).
TYPE LOCATION: Island of Oahu, Honolulu County, Hawaii; Waipahu Quadrangle - 21 degrees 26 minutes 16 seconds north latitude and 158 degrees 00 minutes 16 seconds west longitude; junction of Kamehameha Highway and entrance road to Mililani Cemetery; east 0.7 mile then 400 feet north to Dole Corporation field No. 4101 block 30.
RANGE IN CHARACTERISTICS: Black concretions are on the surface and to depths of 4 to more than 5 feet. Depth to highly weathered basalt ranges from 5 to more than 10 feet. A few boulder cores are in the lower part of the solum. Mean annual soil temperature is about 72 degrees F.
The A horizon has dry or moist, value of 2 or 3, and chroma of 3 through 6 dry and 3 through 5 moist.
COMPETING SERIES: These are the Kahana, Lahaina and Molokai series. Kahana soils have an ochric epipedon and do not effervesce with hydrogen peroxide in the lower part of the B horizon. Lahaina soils have an ochric epipedon and weak structure in the upper part of the solum. Molokai soils have an ochric epipedon and prismatic structure in the B horizon. Lihue soils are similar. Lihue soils have an ochric epipedon and do not effervesce with hydrogen peroxide in the lower part of the B horizon.
GEOGRAPHIC SETTING: Wahiawa soils are on long, smooth relatively undissected uplands at elevations of 500 to 1,200 feet. Slopes are commonly 1 to 8 percent and range from 0 to 25 percent. The soils formed in residuum and alluvium weathered from basalt. Average annual rainfall is 40 to 60 inches. Mean annual temperature is about 72 degrees F.; average January temperature is 69 degrees F., and average July temperature is 73 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kunia, Leilehua and Manana soils and the competing Lahaina soils. Kunia soils have weak structure in the upper part of the B horizon and do not have an oxic horizon. Leilehua soils have an argillic horizon, weak structure in the upper part of the B horizon and are extremely acid throughout the solum. Manana soils have an argillic horizon and have thin panlike layers at a depth of 15 to 50 inches.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderately rapid permeability.
USE AND VEGETATION: Used primarily for the production of irrigated sugarcane and dryland pineapple, and small areas are in pasture. Vegetation is guava (Psidium guajava), koa haole (Leucaena glauca), lantana (Lantana camara); joee (Stachytarpheta jamaicensis), Japanese tea (Cassia leschenaultiana), bermudagrass (cynodon dactylon), and honohono (Commelina diffusa).
DISTRIBUTION AND EXTENT: Island of Oahu. This series is moderately extensive, comprising about 21,000 acres.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Soil Survey, Territory of Hawaii, 1949.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
mollic epipedon- The zone from the surface to 12 inches (Ap1, Ap2)
oxic horizon- The zone from 12 to 60 inches (Bo1, Bo2, Bo3)