LOCATION EWA HIEstablished Series
TAXONOMIC CLASS: Fine, kaolinitic, isohyperthermic Aridic Haplustolls
TYPICAL PEDON: Ewa silty clay loam--irrigated sugarcane. (Colors are for moist soil unless otherwise noted.)
Ap1--0 to 13 inches; dark reddish brown (5YR 3/2) silty clay loam, dark reddish brown (5YR 3/3) dry; weak, fine and very fine granular structure; hard, friable, sticky and plastic; many fine roots; many fine and very fine pores; common worm holes and casts; many fine black concretions; strong effervescence with hydrogen peroxide; neutral (pH 7.0); clear wavy boundary. (11 to 13 inches thick)
Ap2--13 to 18 inches; dark reddish brown (2.5YR 3/3) silty clay loam, dark reddish brown (2.5YR 3/4) dry; weak fine and very fine granular structure; hard, friable, sticky and plastic; many fine roots; common very fine tubular and irregular pores; many very fine black concretions; strong effervescence with hydrogen peroxide; neutral (pH 7.0); clear wavy boundary. (3 to 6 inches thick)
Bw1--18 to 45 inches; dark reddish brown (2.5YR 3/4) silty clay loam, dark red (2.5YR 3/6) dry; weak fine and very fine subangular blocky structure; hard, friable, sticky and plastic; many fine roots; many fine and very fine pores, common medium and few coarse tubular pores; weak patchy pressure faces on peds; few reddish yellow and yellow sand grains; common very fine black concretions; strong effervescence with hydrogen peroxide; neutral (pH 7.0); diffuse wavy boundary. (25 to 28 inches thick)
Bw2--45 to 60 inches; dark red (2.5YR 2/5) silty clay loam, dark red (2.5YR 3/6) dry; moderate medium and fine subangular blocky structure; hard, friable, slightly sticky and plastic; many fine roots; many fine and very fine pores, few medium tubular pores; many thin coatings that are patchy in upper part, nearly continuous in lower part; many sand grains like those in Bw1 horizon;; strong effervescence with hydrogen peroxide; neutral (pH 7.2).
TYPE LOCATION: Honolulu County, Hawaii; Ewa Sugar Plantation, west through Waipahu on Kamehameha Highway to Kunia Road junction, west on Kam Highway 1.8 miles, then 0.3 mile north on plantation road, proceed then west 800 feet along upper canal road, 200 feet south of road.
RANGE IN CHARACTERISTICS: Depth to coral limestone or gravelly alluvium ranges from 50 to 60 inches. Surface layers are silty clay loam or stony silty clay. The A and B horizons have hue of 5YR or 2.5YR, value of 2 or 3, and chroma of 3 through 5. The B horizon has weak or moderate structure.
COMPETING SERIES: (This needs updating.) These are the Holomua, Keahua, Makaweli, Mamala, Molokai, Uwala, Wahikuli, Waiakoa, and Waikapu series. Holomua soils are silt loam in the upper part of the B2 horizon and have buried B horizon within a depth of 40 inches. Keahua soils lack coatings in the lower part of the B horizon. Mamala soils are less than 20 inches deep to coral limestone and effervesce with hydrochloric acid throughout. Molokai soils have prismatic structure in the upper part of the B horizon. Uwala soils have mean annual soil temperature of less than 71.6 degrees F., and strong structure in the lower part of the B2 horizon. Waiakoa soils are less than 40 inches deep to bedrock. Waikapu soils have slickensides in the lower part of the B horizon. Wahikuli soils are 40 inches or less to basaltic bedrock.
GEOGRAPHIC SETTING: Ewa soils are alluvial fans and terraces at elevations ranging from sea level to 150 feet. Slope is 0 to 12 percent. The soils formed in alluvium which washed from the adjacent uplands and is material weathered from basic igneous rocks. The mean annual rainfall is 15 to 30 inches. Average January temperature is 71 degrees F., average July temperature is 78 degrees F., and the mean annual temperature is about 73 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Honouliuli soils and the competing Mamala, Molokai, and Wahikuli soils. Honouliuli soils have clay texture throughout.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderate permeability.
USE AND VEGETATION: These soils are used for irrigated sugarcane and pasture. Natural vegetation is kiawe (Prosopis chilensis), koa haole (Leucaena glauca), klu (Acacia farnesiana), fingergrass (Chloris sp.), and bristly foxtail (Setaria verticillata).
DISTRIBUTION AND EXTENT: On the coastal plains of Oahu, mainly in the Ewa area of southern Oahu. The soil is of small extent, about 2,000 acres.
MLRA OFFICE RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Soil Survey, Territory of Hawaii, 1955.
REMARKS:
FCC Classification: Cd+i-k.
Edit Log: 12/03 SN. Horizon designations updated; added depth range.
8/00 SN. Classification changed from Fine, kaolinitic, isohyperthermic Torroxic Haplustolls due to changes in Taxonomy.
ADDITIONAL DATA: Ewa NSSL sample S63HI-003-001.