LOCATION CHINEN MP+PBEstablished Series
TAXONOMIC CLASS: Clayey, parasesquic, isohyperthermic Lithic Haplustolls
TYPICAL PEDON: Chinen clay, on a 3 percent easterly slope under a forest of Leucaena leucocephala. (Colors are for moist soil unless otherwise stated.)
Oi--0.5 to 0 inch; undecomposed leaf litter; abrupt smooth boundary. (0 to 2 inches thick)
A--0 to 2.5 inches; very dark grayish brown (10YR 3/2) clay loam, very dark grayish brown (10YR 3/2) dry; strong very fine granular structure composed of wormcasts; slightly hard, friable, slightly sticky, slightly plastic; common very fine and fine and few medium and coarse roots; many very fine interstitial pores; about 10 percent gravel and cobbles; mildly alkaline (pH 7.6); abrupt smooth boundary. (1 to 4 inches thick)
Bt1--2.5 to 7 inches; dark brown (7.5YR 3/2) clay, dark brown (10YR 3/3) dry; moderate very fine subangular blocky structure; hard, friable, sticky, slightly plastic; few very fine and medium and common fine roots; many very fine interstitial and few very fine tubular pores; many sand-sized nodules which crush to clay; about 10 percent gravel and cobbles; mildly alkaline (pH 7.6); gradual wavy boundary. (4 to 8 inches thick)
Bt2--7 to 14 inches; yellowish red (5YR 4/6) clay loam; weak fine subangular blocky structure; very friable, slightly sticky , slightly plastic; few very fine and fine roots; many very fine, common fine and few medium tubular pores; common thin clay films on faces of peds and continuous thin clay films line pores; mildly alkaline (pH 7.6); abrupt irregular boundary. (0 to 40 inches thick)
2R--14 inches; unweathered white limestone as pinnacles, with many holes and fissures.
TYPE LOCATION: Saipan, Commonwealth of the Northern Mariana Islands. At the east end of Kagman airstrip (abandoned), about 160 feet southeast of the road head to Marine Beach (Unai, Laolao, Kattan); lat. 15 degrees 9 minutes 55 seconds N. and long. 145 degrees 46 minutes 40 seconds E.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually dry for 90 to 120 cumulative days, primarily between February and May. Soil is usually moist from July through December.
Soil temperature - 77 to 84 degrees F., with less than 4 degrees F. variation between summer and winter.
Mollic epipedon thickness - 7 to 9 inches. Some pedons have A horizons as shallow as 4 inches, but the upper portion of the Bt horizon qualifies as a mollic epipedon.
Depth to bedrock - 10 to 20 inches.
Clay content - 50 to 80 percent in the argillic horizon.
A1 horizon - Color: N2/0, 10YR 2/1, 3/1, 3/2, 7.5YR 3/2.
Texture: Clay loam or clay.
Rock fragments: 2 to 15 percent, about one-half gravel and one-half cobbles.
Bt horizon - Color: Dominantly 5YR 4/4, 4/6, and 7.5YR 3/2, 4/4, 4/6, but ranges to 5YR 3/4, 5/6, 5/8, 7.5YR 3/4, 5/6, 5/8, 10YR 4/3, 4/4, 5/4.
Texture: Clay, clay loam, silty clay.
Consistence: Slightly sticky or sticky.
Rock fragments: 0 to 15 percent, about one-half gravel and one-half cobbles.
COMPETING SERIES: These are the Banaderu, Luta, and Takpochao series. Banaderu soils have gibbsitic mineralogy and B horizon hues of 10R and 2.5YR. Luta soils do not have an argillic horizon. Takpochao soils are clayey-skeletal and do not have pockets of soils that extend below a depth of 20 inches.
GEOGRAPHIC SETTING: Chinen soils are on uplifted limestone plateaus that are often tilted and dissected. They formed in sediments that are probably a mixture of residuum and volcanic ash, and overlie porous limestone that was part of a coral reef complex. Slopes are dominantly 3 to 15 percent, but range from 0 to 30 percent. Elevation is 30 to 1,500 feet. The 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 Banaderu, Chacha, Dandan, Kagman, Saipan, and Takpochao series. Banaderu soils have B horizon hues of 10R and 2.5YR. Chacha, Kagman, and Saipan soils are all deep and very deep. Dandan soils are dominantly between 20 and 40 inches deep. Takpachao soils do not have pockets of soil that extend below a depth of 20 inches, and have rock outcrop within the pedon. DRAINAGE AND PERMEABILITY: Well drained. Runoff is slow to medium. Permeability is moderate.
USE AND VEGETATION: Most areas are in forest dominated by Leucaena leucocephala. Many areas are grazed, and a few areas are urbanized or farmed.
DISTRIBUTION AND EXTENT: The Chinen series is moderately extensive in the Northern Mariana Islands, with about 25,000 acres mapped.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES PROPOSED: Saipan, Commonwealth of the Northern Mariana Islands, 1985. Source of the name is from McCracken (1948) "Military Geology of Saipan."
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - From the surface to a depth of 7 inches. If pedons have slightly thinner A horizons, the upper part of the Bt horizon qualifies as a mollic epipedon.
Argillic horizon - From the top of the Bt horizon to the lithic contact.