LOCATION LUTA MP PBEstablished Series
The Luta series consists of shallow, well drained soils with moderately rapid permeability on plateaus. They formed in sediments overlying limestone. Slopes range from 0 to 30 percent. The mean annual precipitation is about 90 inches, and the mean annual temperature is about 77 degrees F.
TAXONOMIC CLASS: Medial, amorphic, isohyperthermic, shallow Humic Haplustands
TYPICAL PEDON: Luta cobbly clay loam, on a 2 percent slope under secondary forest. (Colors are for moist soil unless otherwise stated.)
Oi--0.5 to 0 inch; undecomposed Acacia leaf litter; abrupt smooth boundary. (0 to 1 inch thick)
A1--0 to 1 inch; dark brown (7.5YR 3/2) cobbly clay loam, brown (7.5YR 4/2) dry; strong fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine through medium roots; many very fine interstitial pores; about 15 percent limestone cobbles, exposed on the surface; slightly alkaline (pH 7.4); abrupt smooth boundary. (0 to 2 inches thick)
A2--1 to 3 inches; dark brown (7.5YR 3/4) cobbly clay loam, brown (7.5YR 4/4) dry; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine through medium and few coarse roots; common very fine and few fine tubular and common very fine interstitial pores; about 15 percent coarse fragments, mostly cobbles; slightly alkaline (pH 7.6); clear smooth boundary. (2 to 5 inches thick)
Bw--3 to 6 inches; brown (7.5YR 4/4) cobbly clay loam; massive; soft, very friable, slightly sticky and slightly plastic; many very fine, common fine and few medium roots; common very fine and few fine tubular and many very fine interstitial pores; about 10 percent cobbles and 5 percent gravel limestone; neutral (pH 7.0); clear wavy boundary. (0 to 6 inches thick)
2Cr--6 to 12 inches; white (10YR 8/1) weathered limestone, stained very pale brown (10YR 7/4) along pores and fractures; composed of cemented sand and coral fragments; few fine and medium roots along fractures; few fine and medium tubular and common very fine through medium interstitial pores; gradual wavy boundary. (2 to 10 inches thick)
2R--12 inches; white (10YR 8/1) unweathered limestone, hard and porous.
TYPE LOCATION: Island of Rota, Commonwealth of the Northern Mariana Islands; in the Gampapa area, about 2 miles ENE of the airport, about 1,300 feet east of the main road, near a small farm field; lat. 14 degrees 10 minutes 35 seconds N., long. 145 degrees 16 minutes 15 seconds E.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually dry for 90 to 120 cumulative days. Soil is usually moist from July through December.
Soil temperature - 78 to 84 degrees F., with less than 4 degrees F. variation between summer and winter.
Soil Depth - 4 to 10 inches to a paralithic contact.
Depth to soft rock - 4 to 10 inches.
Depth to hard bedrock - 6 to 20 inches.
Clay content - 20 to 35 percent.
Sand content - 25 to 45 percent.
Coarse fragments - 15 to 35 percent, over half as cobbles, all as limestone.
A horizon - Color: Dominantly 7.5YR 3/2, 3/4, ranges to 10YR 4/3. Thin A1 horizons of 10YR 2/2, 3/2 are common in forested pedons but generally absent in grassland (cultivated) pedons. Total thickness: 2 to 15 inches. Wet consistence: Nonsticky to slightly sticky.
Reaction: neutral to mildly alkaline.
B horizon - Color: Dominantly 7.5YR 4/4, ranges to 4/6 or 5/6. Higher chromas and values are commonly in pedons with thicker B horizons. Texture: Cobbly clay loam, Cobbly loam.
Wet consistence: Nonsticky or slightly sticky.
Other: The B horizon is intermittent in many pedons, absent in some. Few thin pressure faces are in the lower part of the thicker B horizons.
COMPETING SERIES: None.
GEOGRAPHIC SETTING: Luta soils are on uplifted limestone plateaus that were deposited as part of a coral reef complex. These soils formed in residuum from the underlying limestone, and possibly from other sources as well, such as volcanic ash.
Slopes are 0 to 30 percent. Elevations are 65 to l,575 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 100 inches, most of which falls between June and November.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Chinen, Laolao, Shioya, and Takpochao soils. Chinen soils are clayey, are 10 to 20 inches deep and have mollic epipedons. Laolao soils are clayey and are moderately deep to volcanic saprolite. Shioya soils are deep and sandy. Takpochao soils are clayey and skeletal, with mollic epipedons.
DRAINAGE AND PERMEABILITY: Well drained. Moderately rapid permeability. Runoff is slow.
USE AND VEGETATION: Many areas are in grasses and forbs, and are grazed. Other areas are in native or secondary forest. A few areas are farmed.
DISTRIBUTION AND EXTENT: Luta soils are on the island of Rota. This series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Rota, Commonwealth of the Northern Mariana Islands, 1985.
REMARKS: Diagnostic properties recognized in this pedon are:
Andic soil properties - 0 to 6 inches
Paralithic contact - At 6 inches
Lithic contact - below a paralithic contact at 12 inches.
Absence of cambic horizon - B horizon is too shallow to qualify as cambic horizon.
Oxidic mineralogy - Assumed, based on data from soils on Guam.
ADDITIONAL DATA: Laboratory data are available on this series. Sample number S91MP 100-001 was sampled and analyzed by the National Soil Survey Laboratory. Some analyses were run by the University of Guam, including extractable bases, pH, and organic carbon.