LOCATION MAHANA HIEstablished Series
TAXONOMIC CLASS: Very-fine, mixed, isothermic Inceptic Haplustox
TYPICAL PEDON: Mahana silty clay loam - brush pasture. (Colors are for moist soil unless otherwise noted. All textures are "apparent field textures.")
A--0 to 7 inches; dark yellowish brown (10YR 3/4) silty clay loam, dark reddish brown (2.5YR 3/4) dry; strong fine and very fine subangular blocky structure; very hard, friable, sticky and plastic many roots moderate effervescence with hydrogen peroxide; moderately acid (pH 6.0); clear wavy boundary. (6 to 10 inches thick)
Bo1--7 to 11 inches; dark red (2.5YR 3/6) silt loam, reddish brown (2.5YR 4/4) dry; weak coarse prismatic structure; slightly hard, very friable; many roots; many fine pores; slightly acid (pH 6.2) gradual smooth boundary. (4 to 7 inches thick)
Bo2--11 to 20 inches; dark red (2.5YR 3/6) silt loam, reddish brown (2.5YR 4/4) dry; weak coarse prismatic structure; soft, very friable, slightly sticky, slightly plastic and slightly smeary; many roots; many fine pores; moderately acid (pH 6.0); gradual smooth boundary. (9 to 16 inches thick)
Bo3--20 to 35 inches; dark red (2.5YR 3/6) silt loam, reddish brown (2.5YR 4/4) dry; weak coarse prismatic structure; soft, very friable, slightly sticky, slightly plastic and smeary; few roots; many fine pores; moderately acid (pH 6.0); gradual smooth boundary. (11 to 16 inches thick)
2Bo4--35 to 48 inches; dark red (2.5YR 3/6) silty clay loam, reddish brown (2.5YR 5/4) dry; weak fine and medium subangular blocky structure; slightly hard, friable, sticky, plastic and slightly smeary; few roots; many fine pores; some hard earthy lumps; slightly acid (pH 6.2); clear smooth boundary. (12 to 15 inches thick)
2C--48 to 61 inches; dark reddish brown (5YR 3/3) silty clay loam, reddish brown (2.5YR 4/4) dry; some coatings of dark red (10R 3/6); moderate fine and medium angular and subangular blocky structure; compact in place, hard, firm, sticky and plastic; few roots; many fine and very fine pores; continuous stress cutans, dark red (10R 3/6) coatings that look like clay films, weak patchy slickensides; moderately acid (pH 6.0).
TYPE LOCATION: Island of Kauai, Kauai County, Hawaii; from junction of highways 50 and 55 in Kekaha town, 23,440 feet N. and 4 degrees E.; Kekaha Quadrangle; lat. 22 degrees 01 minutes 30 seconds N. and long. 159 degrees 41 minutes 11 seconds W. (Old Hawaiian Datum).
RANGE IN CHARACTERISTICS: The A horizon has hue of 10R or 2.5YR, value of 2 or 3, and chroma of 3 or 4. The B horizon has hue of 7.5YR through 2.5YR, and chroma of 4 through 8. Texture ranges from very fine sandy loam to silty clay loam.
COMPETING SERIES: (This needs updating.) These are the Halii and Kahanui series. Halii soils contain horizontal sheets or gravel-size fragments containing more than 30 percent gibbsite. Kahanui soils have discontinuous iron-stony sheets in the B horizon.
GEOGRAPHIC SETTING: Mahana soils are on dissected uplands at elevations of 1,000 to 3,000 feet. Slopes range from about 6 to 35 percent. The soils formed in material from volcanic ejecta, basic igneous rocks, and volcanic ash. The median annual rainfall is 30 to 45 inches. The mean annual temperature about 67 degrees F; average January temperature is about 64 degrees F.; and average July temperature about 70 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Oli and Puu Opae soils. Oli soils lack an oxic horizon and are moderately deep to saprolite. Puu Opae soils have an argillic horizon and the B horizon is silty clay.
DRAINAGE AND PERMEABILITY: Well drained; slow to very rapid runoff depending on slope; moderately rapid permeability.
USE AND VEGETATION: Most of these soils are in brushy pasture. A small amount is in sugarcane. Vegetation on the nonirrigated areas is puakeawe (Styphelia tameiameiae), aalii (Dodonaea eriocarpa), ricegrass (Paspalum orbiculare), molassesgrass (Melinis minutiflora), silk oak (Grevillea robusta), yellow foxtail (Setaria geniculata), lantana (Lantana camara), joee (Stachytarpheta cayannensis), Japanese tea (Cassia Leschenaultiana), and passionflower (Passiflora spp.).
DISTRIBUTION AND EXTENT: Islands of Kauai and Oahu, Hawaii. The series is of moderate extent, comprising about 11,000 acres.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Soil Survey, Territory of Hawaii, 1949.
REMARKS: Lab data for other pedons show andic and Kandic properties. Series may need to be split when remapped.
FCC Classification: Cdehx-.
Edit Log: 5/04 SN. Horizon designations updated, plus minor edits.
8/00 SN. Classification changed from Clayey, oxidic, isothermic Typic Acrohumox due to changes in Taxonomy.
ADDITIONAL DATA: Mahana NSSL sample S65HI-007-002 (modal, formerly S65Ha-2-2) and S65HI-007-003 (formerly S65Ha-2-3).