LOCATION NGEDEBUS                PW+FM MH PB

Established Series
Rev: CWS/MRK/JVP
03/2017

NGEDEBUS SERIES

The Ngedebus series consists of very deep, somewhat excessively drained soils adjacent to coastal beaches and within interiors of atoll islands. These soils formed in water and wind-deposited coral sand. Slope is 0 to 5 percent. The mean annual rainfall is about 3,683 millimeters (145 inches), and the mean annual temperature is about 27 degree C. (81 degrees F.)

TAXONOMIC CLASS: Carbonatic, isohyperthermic Typic Udipsamments

TYPICAL PEDON: Ngedebus sand - on a 2 percent east-by-southeast-facing convex slope in a Casurina forest. When described (10/30/79), the soil was moist throughout. (Colors are for moist soil.)

A1--0 to 46 centimeters (0 to 18 inches); 50 percent grayish brown (10YR 5/2) sand mixed with 50 percent very pale brown (10YR 7/3) uncoated sand; single grain; loose; common very fine, fine and medium roots and coarse roots; many very fine interstitial pores; mixed by land crabs to include lenses of pale yellow (2.5Y 8/4) sand; strongly effervescent; slightly alkaline (pH 7.7, 1:1 water); clear wavy boundary. {10 to 51 centimeters (4 to 20 inches) thick}

C1--46 to 81 centimeters (18 to 32 inches); pale yellow (2.5Y 8/4) sand; single grain; loose; many very fine interstitial pores; strongly effervescent; moderately alkaline (pH 7.9, 1:1 water); clear smooth boundary. {36 to 99 centimeters (14 to 39 inches) thick}

C2--81 to 150 centimeters (32 to 59 inches); very pale brown (10YR 8/4) coarse sand; single grain; loose; many very fine interstitial pores; about 4 percent by volume coral coarse fragments .2 to .8 inch by .8 to 1.5 inch in size; freshwater table at depth of 122 centimeters (48 inches); strongly effervescent; moderately alkaline (pH 8.0, 1:1 water).

TYPE LOCATION: Peleliu Municipality, Peleliu Island, Palau, Western Caroline Islands; about .7 mile NE. of Peleliu village on main road and .6 mile S. from first road junction, then about 16 feet E. of roadway; lat. 7 degrees 2 minutes 36 seconds N. and long. 134 degrees 16 minutes 35 seconds E. (WGS 84 datum)

RANGE IN CHARACTERISTICS: Depth to the freshwater table ranges from 99 centimeters (39 inches) to 150 centimeters (59 inches).

The A horizon has moist color of 10YR 2/1, 2/2, 3/1, 3/2, 3/3, 4/2, 4/3, 5/2, 5/3, or 7/3 or of 2.5Y 3/2.

An AC horizon, present in some pedons, has moist color of 10YR 6/1, 6/2, or 7/2. It is sand, fine sand, or loamy sand and is gravelly in some pedons. By volume, the A horizon is 0 to 20 percent pebbles and 0 to 10 percent cobbles. Reaction in 1:1 water ranges from neutral through moderately alkaline.

The C horizon has moist color of 10YR, 7.5YR, or 2.5Y, value of 6 through 8, and chroma of 2 through 4. It is stratified fine sand, sand, or coarse sand and is gravelly in some pedons. Pebble content ranges from 0 to 25 percent by volume. Cobble content ranges from 0 to 15 percent by volume. Coarse fragments average less than 35 percent by volume within the particle-size control section. Reaction in 1:1 water ranges from mildly alkaline through strongly alkaline.

COMPETING SERIES: This is the Catano series. Catano soils contain volcanic soil separates and have a depth to the water table that is greater than 150 centimeters (59 inches).

GEOGRAPHIC SETTING: The Ngedebus soil is adjacent to coastal beaches and occupies a majority of the area on coral atolls. Slopes are 0 to 5 percent. The soils formed in water and wind-deposited coral sand. Elevation ranges from 0 to 5 meters (0 to 16 feet). The mean annual rainfall ranges from 2896 to 4978 millimeters (114 to 196 inches), and the mean annual temperature is 27 degrees C. (81 degrees F.)

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Insak and Dublon soils. Insak soils are inundated by seawater and support mangrove vegetation. Dublon soils have a freshwater lense beginning at 38 to 91 centimeters (15 to 36 inches) depth.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained; very slow runoff; rapid permeability.

USE AND VEGETATION: Most areas are cleared and planted to coconut palms and are used for commercial copra production. Other areas are in agricultural forest that is comprised of coconut, breadfruit, banana and pandanus grown for local use. A few areas are used for homesites or support a native atoll forest. In Peleliu, a few areas are in Casurina forest and are used for recreation.

DISTRIBUTION AND EXTENT: Ngedebus soils are of small extent. They are mapped on the islands of Angaur, Babelthuap, Ngaredelau, Ngaregur, Ngedebus, Peleliu, and various rock islands in the Palau islands; Yap Islands; Ulithi atoll; Fais; reef islands of Pohnpei; the coastal strand of Kosrae; and Arno, Maloelap and Mili atolls in the Marshall Islands.

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

SERIES ESTABLISHED: Peleliu Municipality, Island of Palau, Western Caroline Islands, 1981.

Remarks:
Last revised by state: 12/2005

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National Cooperative Soil Survey
U.S.A.