LOCATION WAHIAWA            HI
Established Series
Rev. SN-CWS
02/2001

WAHIAWA SERIES


The Wahiawa series consists of very deep, well drained soils that formed in residuum and alluvium weathered from basalt. Wahiawa soils are on uplands and have slopes of 0 to 25 percent. Mean annual rainfall is about 50 inches, and mean annual temperature is about 72 degrees F.

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)


National Cooperative Soil Survey
U.S.A.