LOCATION IOLEAU HIEstablished Series
TAXONOMIC CLASS: Very-fine, parasesquic, isohyperthermic Ustic Palehumults
TYPICAL PEDON: Ioleau silty clay - sugarcane. (Colors are for moist soil unless otherwise noted. All textures are "apparent field textures.")
Ap1--0 to 6 inches; dark brown (7.5YR 3/4) silty clay loam, brown (7.5YR 4/4) dry; cloddy parting to moderate fine and very fine subangular blocky structure; hard, firm, sticky and plastic; common medium and fine and common very fine roots; very strongly acid (pH 4.7); abrupt smooth boundary. (6 to 8 inches thick)
Ap2--6 to 15 inches; mixture of yellowish red (5YR 3/6) silty clay loam, strong brown (7.5YR 5/6) dry; massive; slightly hard, friable, sticky and plastic; and yellowish red (5YR 3/6) silty clay, reddish brown (5YR 4/4) dry; strong very fine subangular blocky structure; hard, firm, sticky and plastic; few medium, common fine and very fine roots; common fine pores; very strongly acid (pH 4.6); abrupt boundary. (7 to 10 inches thick)
Bt1--15 to 27 inches; brown (5YR 3/4) silty clay, reddish brown (5YR 4/4) dry; strong fine and very fine subangular blocky structure; very hard, firm, sticky and plastic; few fine and very fine roots; common very fine pores; very compact in place; many moderately thick clay films on peds; very strongly acid (pH 4.7); clear wavy boundary. (5 to 12 inches thick)
Bt2--27 to 38 inches; dark brown (7.5YR 3/2) silty clay; yellowish red (5YR 3/6) in pores; dark brown (7.5YR 4/4) dry; strong fine and very fine subangular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; few medium, fine, and very fine roots; many very fine pores; patchy moderately thick clay films on peds, continuous in pores; few pebbles; extremely acid (pH 4.4); clear wavy boundary. (9 to 11 inches thick)
Bt3--38 to 57 inches; dark brown (7.5YR 3/3) silty clay, dark brown (7.5YR 4/4) in pores, dark brown (7.5YR 4/4) dry; strong fine and very fine subangular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; many very fine pores; patchy moderately thick clay films on peds, continuous in pores; few pebbles; extremely acid (pH 4.4); clear wavy boundary. (15 to 22 inches thick)
Bt4--57 to 61 inches; dark reddish brown (5YR 3/4) silty clay loam, reddish brown (5YR 4/4) dry; moderate fine and very fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine pores; patchy moderately thick clay films on peds, continuous in pores; extremely acid (pH 4.2).
TYPE LOCATION: Island of Kauai, Kauai County, Hawaii; Anahola Quadrangle - 22 degrees 07 minutes 33 seconds north latitude and 159 degrees 19 minutes 24 seconds west longitude.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is about 72 degrees F.
The A horizon has hue of 7.5YR or 10YR.
The B horizon has hue of 2.5YR through 7.5YR, value of 3 or 4 and chroma of 2 through 6. Depth to the compact Bt1 horizon ranges from 15 to 25 inches.
COMPETING SERIES: These are the Hamakuapoko and Manana series. Hamakuapoko soils have an umbric epipedon and do not have a very compact upper Bt horizon. Manana soils have continuous clay films in the lower part of the argillic horizon and a panlike layer 15 to 50 inches below the surface.
GEOGRAPHIC SETTING: Ioleau soils are on uplands and have slopes of 2 to 35 percent, but dominantly from 2 to 20 percent. The soils occur at elevations of 100 to 750 feet. They formed in residuum from basic igneous rock. The annual rainfall is between 40 and 70 inches. The average January temperature is about 70 degrees F.; the average July temperature is about 77 degrees F.; and the mean annual temperature is about 72 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Lihue and Puhi soils. Lihue soils have 2.5YR or 10R hue in the B horizon and are high in manganese in the A horizon. Puhi soils are not very compact in the subsoil and do not have an argillic horizon.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff depending on slope; slow permeability.
USE AND VEGETATION: Most areas are used for sugarcane, truck crops, and orchard. A few areas are used for pasture and some are in brush and trees. Vegetation on uncultivated areas is lantana (Lantana camara), koa haole (Leucaena glauca), guava (Psidium guajava), joee (Stachytarpheta jamaicensis), kikuyugrass (Pennisetum clandestinum), molassesgrass (Melinis minutiflora), bermudagrass (Cynodon dactylon), and guineagrass (Panicum maximum).
DISTRIBUTION AND EXTENT: Lower mountain slopes on the east and south sides of the Island of Kauai, Hawaii. The series consists of about 4,300 acres.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Island of Kauai, Kauai County, Hawaii, 1971.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon- the zone from the surface to 15 inches (Ap1, Ap2)
Argillic horizon- the zone from 15 to 61 inches (Bt1, Bt2, Bt3, Bt4)