LOCATION MOLOKAI HI

Established Series
Rev. JVP/MRK/KP
03/2017

MOLOKAI SERIES

The Molokai series consists of very deep, well drained soils that formed in material weathered from basic igneous rock. Molokai soils are on low elevation hillslopes and have slopes of 0 to 25 percent. Mean annual rainfall is about 635 millimeters (25 inches), and mean annual temperature is about 23 degrees C. (73 degrees F.)

TAXONOMIC CLASS: Very-fine, kaolinitic, isohyperthermic Typic Eutrotorrox

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

Ap1--0 to 18 cm (0 to 7 inches); dark reddish brown (2.5YR 3/4) silty clay loam, dark red (2.5YR 3/6) dry; weak very fine, fine and medium granular structure; slightly hard, friable, slightly sticky and moderately plastic; many roots; many interstitial pores; many very fine black concretions that effervesce with hydrogen peroxide; strong effervescence with hydrogen peroxide; extremely acid (pH 4.4); clear wavy boundary.

Ap2--18 to 38 cm (7 to 15 inches); dark reddish brown (2.5YR 3/4) silty clay loam, dark red (2.5YR 3/6) dry; weak medium and coarse subangular blocky structure parting to moderate fine and very fine granular; slightly hard, friable, slightly sticky and moderately plastic; common roots; common very fine tubular and interstitial pores; common fine black concretions; violent effervescence with hydrogen peroxide; very strongly acid (pH 4.6); clear smooth boundary. (Combined thickness of the A horizon ranges from 15 to 23 cm (8 to 9 inches thick).

Bto1--38 to 89 cm (15 to 35 inches); dark reddish brown (2.5YR 3/4) silty clay loam, red (2.5YR 4/6) dry; weak coarse prismatic structure parting to weak coarse subangular blocky; slightly hard, friable, moderately sticky and moderately plastic; many very fine and fine tubular pores; few shiny patchy faces on prisms; common fine black concretions; strong effervescence with hydrogen peroxide; slightly acid (pH 6.5); gradual wavy boundary.

Bto2--89 to 163 cm (35 to 64 inches); dark reddish brown (2.5YR 3/4) silty clay loam, red (2.5YR 4/6) dry; weak coarse prismatic structure parting to strong very fine and fine subangular blocky; moderately compact in place, slightly hard, firm, moderately sticky and moderately plastic; many very fine and common fine tubular pores; common patchy pressure faces on peds; common patchy clay films on faces of peds; few very fine black concretions; moderate effervescence with hydrogen peroxide; neutral (pH 6.6); gradual wavy boundary.

Bto3--163 to 183 cm (64 to 72 inches); dark reddish brown (5YR 3/3) clay loam, dark reddish brown (5YR 3/4) dry; moderate fine and very fine subangular blocky and angular blocky structure; slightly hard, friable, slightly sticky and moderately plastic; common very fine and fine tubular pores; thin patchy clay films on peds; red (2.5YR 4/6) clay films lining larger pores; common hard earthy lumps; few very fine black concretions; slight effervescence with hydrogen peroxide; neutral (pH 6.6). (Combination thickness of the Bo horizons is 36 to 76 cm (14 to 30 inches) thick).

TYPE LOCATION: Island of Molokai, Maui County, Hawaii; Kaunakakai Quadrangle - 21 degrees 08 minutes 36 seconds north latitude and 157 degrees 03 minutes 05 seconds west longitude (Old Hawaiian datum); about 4.7 miles west of Kaunakakai Post Office and 0.35 miles north of junction of Highways 46 and 47 and about 200 feet west of Highway 47.

RANGE IN CHARACTERISTICS:
The mean annual soil temperature (MAST) is 23 degrees C. (73 degrees F.) The difference between the mean summer and winter temperatures is less than 6 degrees C. Mean annual precipitation (MAP) is 635 mm (25 inches). All horizons are very strongly acid or neutral. Depth to bedrock is over 60 inches. The number and size of black concretions that effervesce with hydrogen peroxide decrease as depth increases. Some weathered rock fragments are throughout the soil, but mostly below depths of 102 centimeters (40 inches).

The Ap horizon has hue of 5YR, 2.5YR, or 10R, moist value of 2 or 3, moist chroma of 4 of 5, and dry chroma of 4 through 6.

The Bto horizons have hue of 2.5YR or 10R, moist value of 2 or 3 dry chroma of 4 through 6 and moist chroma of 3 or 4.

COMPETING SERIES: There are no competing Series.

GEOGRAPHIC SETTING: The Molokai soils are on low elevation at elevations from near sea level to 457 meters (1,500 feet). Slopes are 0 to 25 percent. The soils formed in residuum weathered from basic igneous rocks. Mean annual precipitation ranges from 508 to 635 mm (20 to 25 inches). The average January temperature is about 22 degrees C. (71 degrees F.) The average July temperature is about 25 degrees C. (77 degrees F.), and mean annual temperature is about 23 degrees C. (73 degrees F.); with less than 6 degrees C. difference between mean summer and mean winter temperatures.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Holomua, Keahua and Uwala soils and the competing Lahaina soils. Holomua, Keahua and Uwala soils do not have an oxic horizon.

DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff, depending on slopes; moderate permeability.

USE AND VEGETATION: Used for the production of pineapple, pasture, irrigated sugarcane and for wildlife habitat. Vegetation is kiawe (Prosopis pallida), pitted beardgrass (Bothriochloa barbinodis perforatus), feather fingergrass (Chloris virgata), lantana (Lantana camara),ilima (Sida cordifolia), and buffelgrass (Cenchrus ciliaris).

DISTRIBUTION AND EXTENT: Islands of Molokai, Lanai, Maui, and Oahu, Hawaii. Semiarid and Subhumid Low Mountain Slopes (MLRA 158). The series is moderately extensive comprising about 36,500 acres.

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

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

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Umbric epipedon- The zone from the surface to 38 cm (Ap1 and Ap2 horizons).
Oxic horizon- The zone from a depth of 38 to 183 cm (Bto1, Bto2, and Bto3 horizons)
Low base saturation - less than 35 percent.

ADDITIONAL DATA: This pedon was sampled and characterized by the National Soil Survey Laboratory (Sample No. S1989HI009008).

National Cooperative Soil Survey
U.S.A.