LOCATION POOKU HIEstablished Series
TAXONOMIC CLASS: Very-fine, ferritic, isohyperthermic Anionic Acrudox
TYPICAL PEDON: Pooku silty clay - pasture. (Colors are for moist soil unless otherwise noted. All textures are "apparent field textures.")
Ap1--0 to 11 inches; dark brown (10YR 4/3) silty clay, yellowish brown (10YR 5/4) dry; strong very fine subangular blocky structure; hard, friable, sticky and plastic; many roots; many very fine and fine pores; many ironstone-gibbsite pebbles that have a dense outer shell with a softer yellowish center; extremely acid (pH 4.2); clear smooth boundary. (10 to 15 inches thick)
Ap2--11 to 14 inches; dark brown (10YR 4/3) silty clay, dark reddish brown (2.5YR 3/4) mixed in cultivation, yellowish brown (10YR 5/4) and dark reddish brown (2.5YR 3/4) dry; moderate very fine subangular blocky structure; hard, friable, sticky and plastic; many roots; many very fine and fine pores; few ironstone-gibbsite pebbles; medium acid (pH 5.6); abrupt wavy boundary. (3 to 5 inches thick)
B21--14 to 28 inches; dark reddish brown (2.5YR 3/4) silty clay loam, dark red (2.5YR 3/6) dry; moderate very fine subangular blocky structure; hard, friable, sticky and plastic; many fine roots; many very fine and fine pores; nearly continuous pressure cutans; few cutans that look like illuviated sesquioxides; few non-magnetic very firm particles that appear to be segregated iron; strongly acid (pH 5.3); abrupt smooth boundary. (10 to 15 inches thick)
B22--28 to 33 inches; dark reddish brown (2.5YR 3/4) silty clay, dark red (2.5YR 3/6) dry; moderate very fine subangular blocky structure; hard, friable, sticky and plastic; many roots; many very fine and fine pores; nearly continuous pressure cutans; patchy glazed coating that appears to be sesquioxide coatings; few gravel-size pieces of saprolite; this horizon is capped by a thin discontinuous ironstone seam 1 to 2 mm. thick; a root mat has built up in places on this ironstone seam; strongly acid (pH 5.1); clear smooth boundary. (5 to 12 inches thick)
B23--33 to 43 inches; dark red (2.5YR 3/6) silty clay, yellowish red (5YR 5/6) dry; moderate fine and medium subangular blocky structure; hard, friable, sticky and plastic; many roots; many very fine and fine pores; gravel-size pieces of saprolite with pores filled with white material; patchy surfaces that appear like pressure cutans; this horizon is capped by a very thin discontinuous ironstone seam above in which there is a buildup of roots; very strongly acid (pH 4.9); gradual wavy boundary. (0 to 10 inches thick)
B24--43 to 62 inches; variegated dark red (2.5YR 3/6), yellowish red (5YR 4/6), reddish yellow (7.5YR 6/8), and very dusky red (2.5YR 2/2) silty clay, yellowish red (5YR 4/6) dry; weak medium and coarse subangular blocky structure; hard, friable, sticky and plastic; few roots; many very fine and fine pores; firm fragments of saprolite; few thick patchy cutans that appear like clay flows; thin platy material that is thought to be gibbsite gives some areas a platy appearance; very strongly acid (pH 4.8).
TYPE LOCATION: Island of Kauai, Kauai County, Hawaii; 22 degrees 12' 23.1" north latitude and 159 degrees 29' 53" west longitude.
RANGE IN CHARACTERISTICS: Mean annual soil temperature is about 73 degrees F. The A horizon has hue of 7.5YR or 10YR, value of 3 or 4, and chroma of 3 or 4. The B2 horizon has chroma of 4 through 6.
COMPETING SERIES: These are the Halii, Kappa, Kunuweia, and Puhi series. Halii soils contain more organic carbon and have moderate or weaker structure in the A horizon, a clay loam control section, and bands of 7.5YR material in the B horizon. Kappa soils have weak structure in the A and B horizons. Kunuweia soils have mean annual soil temperature of 58 degrees F., and the A horizon overlies plinthite. Puhi soils have a silty clay loam control section and relative high base status.
GEOGRAPHIC SETTING: The Pooku soils are on dissected uplands on the north side of the Island of Kauai. Elevation ranges from 250 to 1,000 feet. Slope ranges from nearly level to 40 percent. The soils formed in material weathered from basic igneous rock, with some admixture of volcanic ash. The temperature is about 69 degrees F.; average July temperature is about 76 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Puhi soils and the Makapili soils. Makapili soils lack ironstone-gibbsite pebbles.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff, depending upon slope; moderately rapid permeability.
USE AND VEGETATION: These soils are used mainly for pasture. Natural vegetation is kikuyugrass (Pennisetum clandestinum), pangolagrass (Digitaria decumbens), guava (Psidium guajava), joee (Stachytarpheta cayennensis), sensitiveplant (Mimosa pudica), ricegrass (Paspalum orbiculare), yellow foxtail (Setaria geniculata). Java plum (Eugenia cumini), and associated plants.
DISTRIBUTION AND EXTENT: Island of Kauai, Hawaii. The series is inextensive with a total of approximately 7,800 acres.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Kauai County. Hawaii, 1971.
OSED scanned by SSQA. Last revised by state on 5/78.