LOCATION WAILUKU HI

Established Series
Rev. SN/MRK
01/2023

WAILUKU SERIES

The Wailuku series consists of very deep, well drained soils that formed in alluvium weathered from basic igneous rocks. Wailuku soils are on alluvial fans and have slopes of 3 to 15 percent. Mean annual rainfall is about 762 millimeters (30 inches), and mean annual air temperature is about 23 degrees C. (73 degrees F.)

TAXONOMIC CLASS: Fine, mixed, semiactive, isohyperthermic Torrifluventic Haplustolls

TYPICAL PEDON: Wailuku silty clay - . (Colors are for moist soil unless otherwise noted. All textures are "apparent field textures.")

Ap1--0 to 10 centimeters (0 to 4 inches); dark reddish brown (5YR 3/3) silty clay, dark reddish gray (5YR 4/2) dry; weak fine and very fine granular structure; hard, friable, very sticky and very plastic; few fine roots; many very fine pores; few fine black concretions that effervesce with hydrogen peroxide; strong effervescence with hydrogen peroxide; slightly acid (pH 6.3); clear wavy boundary. (5 to 13 centimeters thick)

Ap2--10 to 31 centimeters (4 to 12 inches); dark reddish brown (5YR 3/3) silty clay, reddish brown (5YR 4/3) dry; weak medium and fine subangular blocky structure; hard, firm, very sticky and very plastic; compact in place; many fine roots; many fine pores; few fine black concretions; strong effervescence with hydrogen peroxide; moderately acid (pH 5.9); clear wavy boundary. (18 to 25 centimeters thick)

Bw1--31 to 66 centimeters (12 to 26 inches); dark reddish brown (5YR 3/4) silty clay, reddish brown (5YR 4/3) dry; moderate medium and fine subangular blocky structure; slightly hard, friable, very sticky and very plastic; compact in place; few fine roots; many fine and very fine pores; continuous pressure faces on peds; few fine black concretions; few highly weathered pebbles of basic igneous rock; strong effervescence with hydrogen peroxide; slightly acid (pH 6.3); gradual wavy boundary. (28 to 41 centimeters thick)

Bw2--66 to 89 centimeters (26 to 35 inches); dark reddish brown (5YR 3/4) silty clay, dark reddish gray (5YR 4/2) dry; moderate medium and fine subangular blocky structure; slightly hard, firm, very sticky and very plastic; few very fine roots; many fine pores; continuous pressure faces on peds; few fine black concretions; few highly weathered pebbles and cobbles of basic igneous rocks; strong effervescence with hydrogen peroxide; slightly acid (pH 6.3); gradual wavy boundary. (20 to 31 centimeters thick)

BC--89 to 152 centimeters (35 to 60 inches); dark reddish brown (5YR 3/4) silty clay, dark reddish gray (5YR 4/2) dry; moderate medium, fine and very fine subangular blocky structure; slightly hard, firm, very sticky and very plastic; few roots; many fine and very fine pores; 10 to 15 percent weathered gravels and cobbles; strong effervescence with hydrogen peroxide; slightly acid (pH 6.2).

TYPE LOCATION: Island of Maui, Maui County, Hawaii; Wailuku Quadrangle - 20 degrees 56 minutes 26 seconds north latitude and 156 degrees 31 minutes 10 seconds west longitude; 1,200 feet west of State Highway 33 and 0.7 mile northwest of Waihee, in field number 4 on the Wailuku Sugar Company plantation. (WGS84 datum)

RANGE IN CHARACTERISTICS: Thickness of solum is more than 102 centimeters (40 inches). Depth to bedrock is more than 152 centimeters (60 inches). The mean annual soil temperature is about 23 degrees C. (73 degrees F.)

The A horizon has value of 2 or 3 moist and 2 through 4 dry, and chroma of 2 or 3.

The B horizon has value of 3 through 5 dry, and chroma of 2 through 4 moist and 2 or 3 dry.

COMPETING SERIES: There are no competing series in this family.

Kahana, Lahaina, and Niu series are similar. Kahana and Lahaina soils have 2.5YR or redder hue throughout the B horizons. Niu soils have 2.5YR or redder hue throughout the solum and prismatic structure in the upper part of the B horizon.

GEOGRAPHIC SETTING: The Wailuku soils are on alluvial fans at elevations ranging from 15 to 305 meters (50 to 1,000 feet). Slopes range from 3 to 15 percent. The soils formed in alluvium weathered from basic igneous rocks. The average annual rainfall ranges from 508 to 1016 millimeters (20 to 40 inches). Mean annual temperature is about 23 degrees C. (73 degrees F.); average January temperature is 21 degrees C. (7O degrees F.); and average July temperature is 25 degrees C (77 degrees F.)

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Iao and Pulehu soils. Iao soils have 10YR or yellower hue throughout the solum. Pulehu soils have a fine-loamy control section and 7.5YR or 10YR hue throughout the profile.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; slow to moderate runoff; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: In the past, these soils were used for growing sugarcane. The vegetation is cactus (Opuntia megacantha), crabgrass (Digitaria henyri), guineagrass (Panicum maximum), indigo (Indigofera suffruiticosa), Japanese tea (Cassia leschenaultiana), koa haole (Leucaena glauca), lantana (Lantana camara), bermudagrass (Cynodon dactylon), and Natal redtop (Rhynchelytrum).

DISTRIBUTION AND EXTENT: Island of Maui, Maui County, Hawaii. This series is inextensive, with a total of about 2,700 acres.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Island of Maui, Maui County, Hawaii, 1949.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Mollic epipedon- the zone from the surface to 31 centimeters (Ap1, Ap2)

Cambic horizon- the zone from 31 to 89 centimeters (Bw1, Bw2)

National Cooperative Soil Survey
U.S.A.