LOCATION ULUPALAKUA HIEstablished Series
TAXONOMIC CLASS: Medial over pumiceous or cindery, amorphic, isothermic Pachic Haplustands
TYPICAL PEDON: Ulupalakua silt loam - pasture. (Colors are for moist soil unless otherwise noted. All textures are "apparent field textures.")
Ap--0 to 9 inches; very dark brown (10YR 2/2) silt loam, dark grayish brown (10YR 4/2) dry; strong medium and fine granular structure; slightly hard, very friable, slightly sticky; many fine roots; many fine and medium pores; 15 to 20 percent very fine cinders; slightly acid (pH 6.4); clear wavy boundary. (8 to 11 inches thick)
B21--9 to 19 inches; dark reddish brown (5YR 2/2) silt loam, dark reddish brown (5YR 3/3) dry; strong fine and very fine subangular blocky structure; slightly hard, very friable and slightly sticky; many fine roots; many fine and very fine pores; patchy gelatin-like coatings on peds; few fine black cinders; common sand-size particles that are resistant to crushing; neutral (pH 6.8); clear wavy boundary. (8 to 12 inches thick)
B22--19 to 28 inches; dark reddish brown (5YR 2/2) silt loam, dark brown (7.5YR 3/2) dry; strong very fine subangular blocky structure; slightly hard, very friable and slightly sticky; common fine roots; many fine pores; patchy gelatin-like coatings on peds; few pockets of slightly weathered cinders; mildly alkaline (pH 7.4); clear smooth boundary. (8 to 11 inches thick)
B23--28 to 33 inches; dark reddish brown (5YR 2/2) clay loam, dark reddish brown (5YR 3/2) dry; strong medium and fine subangular blocky structure; slightly hard, friable, sticky and slightly plastic; common fine roots; many fine pores; patchy gelatin-like coatings on peds; mildly alkaline (pH 7.6); abrupt wavy boundary. (4 to 6 inches thick)
IIC--33 inches; black unweathered cinders and a few yellowish red weathered cinders; slight effervescence with hydrochloric acid.
TYPE LOCATION: Island of Maui, Maui County, Hawaii; Makena Quadrangle - 20 degrees 40' 28" north and 156 degrees 22' 58" west; 200 feet east of Ulupalakua Ranch access road, 0.2 mile southeast of Puulo cinder cone and about 1.0 mile east of Kula Highway on Ulupalakua Ranch.
RANGE IN CHARACTERISTICS: Thickness of solum to black unweathered cinders is 24 to 40 inches. The mean annual soil temperature is 65 degrees F. At the higher elevations the soil is weakly smeary. The B horizon ranges from 5YR to 7.5YR in hue. Textures range from silt loam to clay loam. Gelatin-like coatings on peds increase as rainfall increases.
COMPETING SERIES: These are the Io, Kainaliu, Kamaoa, Kikoni, Kula, Palapalai, and Waimea series. Io soils have weak or moderate structure throughout and lack gelatin-like coatings on peds in the B horizon. Kainaliu soils have weak or moderate structure in the B horizon, are 20 to 40 inches deep over fragmental Aa lava and have mean annual soil temperature of 72 degrees F. Kamaoa soils have weak structure in the B horizon, lack gelatin-like coatings on peds in the B horizon, and have medial control sections. Kikoni soils have a massive upper B horizon, lack gelatin-like coatings on peds in the B horizon and have a medial control section. Kula soils have weak structure in the A horizon, a buried B horizon and a medial control section. Palapalai soils have weak structure and are weakly smeary in the B horizon, and have an ashy control section. Waimea soils have weak structure or are massive in the B horizon and have a medial control section.
GEOGRAPHIC SETTING: The Ulupalakua soils are on uplands at elevation of 2,400 to 4,500 feet. Slope is 7 to 25 percent. Cinder cones are in some areas. The soils formed in volcanic ash and cinders. Mean annual rainfall is 30 to 40 inches, mean annual temperature is about 65 degrees F., average January temperature is 63 degrees F., and average July temperature is 67 degrees F. The soil is subject to afternoon cloud cover and fog.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Io and Kula soils and the Kaipoioi soils. Kaipoioi soils have mean annual soil temperature of 56 degrees F.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderately rapid permeability.
USE AND VEGETATION: These soils are used for pasture. The natural vegetation is bracken fern (Pteridum aquilinum), dallisgrass (Paspalum dilatatum), gosmore (Hypochaeris radicata), plantain (Plantago lanceolata), rattailgrass (Sporobolus capensis), Spanish clover (Desmodium uncinatum), and white clover (Trifolium repens).
DISTRIBUTION AND EXTENT: Island of Maui, Maui County, Hawaii. The extent is about 2,000 acres.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Soil Survey, Territory of Hawaii, 1949.
OSED scanned by SSQA. Last revised by state on 5/78.