LOCATION DANDAN MP+PB

Established Series
RD:FJY/TLH/DWB
01/2023

DANDAN SERIES

The Dandan series consists of moderately deep, well drained, moderately permeable soils on uplifted limestone plateaus. They formed in sediments overlying porous coralline limestone. Slopes range from 0 to 15 percent. The mean annual precipitation is about 80 inches, and the mean annual temperature is about 78 degrees F.

TAXONOMIC CLASS: Very-fine, parasesquic, isohyperthermic Oxic Haplustepts

TYPICAL PEDON: Dandan clay, on a 2 percent slope under secondary forest. (Colors are for moist soil unless otherwise stated. Textures are apparent field textures.)

A1--0 to 1 inch; very dark brown (10YR 2/2) clay loam, dark brown (7.5YR 3/2) dry; strong very fine and fine granular structure; slightly hard, firm, slightly sticky and plastic; common very fine roots; many very fine and common fine interstitial pores; material is dominantly wormcasts; moderately acid (pH 5.6); abrupt smooth boundary. (1 to 2 inches thick)

A2--1 to 5 inches; dark brown (7.5YR 3/2) clay, dark brown (7.5YR 3/2) dry; moderate fine and very fine subangular blocky structure; slightly hard, firm, sticky and plastic; few very fine roots and common fine roots; common very fine interstitial and few fine tubular pores; slightly acid (pH 6.4); clear wavy boundary. (2 to 5 inches thick)

Bt1--5 to 12 inches; dark reddish brown (5YR 3/4) clay with dark reddish brown (5YR 3/3) on ped faces, reddish brown (5YR 4/4) dry; weak medium prismatic structure parting to moderate fine subangular blocky; hard, friable, sticky and plastic; few very fine roots and common fine roots; common fine tubular pores; many thin and few moderately thick clay films on ped faces and many thin clay films in pores; neutral (pH 6.6); clear wavy boundary. (4 to 10 inches thick)

Bt2--12 to 26 inches; reddish brown (5YR 4/4) clay with dark reddish brown (5YR 3/4) on ped faces; weak medium prismatic structure parting to moderate medium subangular blocky; hard, firm, sticky and plastic; few very fine roots, common fine roots and few medium roots; common very fine and fine tubular pores; about 5 percent very fine manganese concretions; many thin and few moderately thick clay films on ped faces and many thin clay films in pores; neutral (pH 6.6); abrupt irregular boundary. (14 to 23 inches thick)

2R--26 inches; unweathered white limestone with occasional large holes and fissures.

TYPE LOCATION: Tinian, Commonwealth of the Northern Mariana Islands. About 0.8 miles SE of Puntan Lamanibot Sanhilo on the western coast; 985 yards west from the T intersection of an unnamed paved road and 8th Avenue, 106 yards south of the traffic circle; 109 yards north into the forest; lat. 15 degrees 2 minutes 45 seconds N. and long. 135 degrees 36 minutes 5 seconds E.

RANGE IN CHARACTERISTICS:

Soil moisture - Usually dry in the moisture control section for 90 to 120 cumulative days. Soil is usually moist from July through December.

Soil temperature - 77 degrees to 85 degrees F., with less than 4 degrees F. variation between summer and winter.

Depth to bedrock - 20 to 40 inches deep over limestone.
Percent clay - 40 to 60 percent in the argillic horizon.

A horizon - total thickness: 3 to 7 inches.
Color: 10YR 2/2, 3/1, 3/2, 3/3, 7.5YR 2/2, 3/2, 5YR 2.5/2, 3/2. Texture: Clay loam or clay.
Structure: Granular or subangular blocky.
Reaction: Medium acid to neutral.
Rock fragments: 0 to 10 percent, mostly gravel.

B horizon - Color: 5YR and 7.5YR; 3/4, 4/4, 4/6.
Reaction: Slightly acid to mildly alkaline.

COMPETING SERIES: None.

GEOGRAPHIC SETTING: Dandan soils are on uplifted limestone plateaus. They formed in sediments, possibly volcanic ash, which overlie porous limestone that was part of a coral reef complex. Slopes are 0 to 15 percent. Elevation is 30 to 495 feet. Mean annual temperature is 77 degrees F., with less than 4 degrees F. difference between summer and winter. Mean annual precipitation is 80 to 90 inches, most of which falls between June and November.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Chinen, Saipan, and Takpochao soils. Chinen soils are dominantly less than 20 inches deep within each pedon. Saipan soils are deep and very deep. Takpochao soils are less than 20 inches deep and are very gravelly.

DRAINAGE AND PERMEABILITY: Well drained. Runoff is slow. Permeability is moderate.

USE AND VEGETATION: Most areas are in forest dominated by Leucaena leucocephala. Many areas are in guineagrass (Panicum maximum) pasture. Some areas are farmed. Main crops are sorghum, sugarcane, and vegetables.

DISTRIBUTION AND EXTENT: The Dandan soil is not extensive, with about 3,000 acres mapped on the islands of Tinian and Rota in the Northern Marianas.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Tinian, Commonwealth of the Northern Mariana Islands, 1985.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - From the surface to 5 inches.
Argillic horizon - From 5 to 26 inches.

National Cooperative Soil Survey
U.S.A.