Soil survey area

Islands of Aguijan, Rota, Saipan and Tinian, Commonwealth of the Northern Mariana Islands

Survey Area MP645• Northern Mariana Islands
The short version

The most common soil here is Chinen, on about 28% of the land. Luta and Takpochao come next.

About 98% of the land drains well.

USDA rates 96% of the land very limited for a standard septic drain field, and 91% very limited for homes with basements. That means extra cost or special design, not that it can't be done.

Worth knowing: bedrock lies within 40 inches under 89% of it.

Soils change over short distances, so look up an address below for the soil at that exact spot and the reasons behind each rating.

The ground underfoot

The soils you're most likely standing on

The biggest named soils in Islands of Aguijan, Rota, Saipan and Tinian, Commonwealth of the Northern Mariana Islands, each drawn five feet deep from its official USDA description, in its recorded colors.

Chinen
28% of the area
Well drained
Mollisols
Luta
16% of the area
Well drained
Entisols
Takpochao
9% of the area
Very cobbly loam topsoil · well drained
A balanced mix that crumbles in your hand. The gardener's ideal.
Mollisols
Dandan
8% of the area
Clay loam topsoil · well drained
Firm and a little sticky. Holds water and nutrients well.
Inceptisols
Saipan
6% of the area
Clay topsoil · well drained
Sticky when wet and rock-hard when dry. Drains slowly.
Oxisols
Kagman
4% of the area
Clay topsoil · well drained
Sticky when wet and rock-hard when dry. Drains slowly.
Oxisols

Dots mark gravel; white flecks mark lime. Shares are by acres across the survey area, and each mapped patch usually mixes several of these soils.

The biggest mapped areas

The dominant drainage class is Well drained and the dominant hydrologic group is D (very slow infiltration, high runoff). The most common soil order is Mollisols — grassland soils with a thick, dark, fertile topsoil rich in organic matter. This report summarizes the major soil map units across the survey area to help you understand what to expect when buying, building, or gardening in Islands of Aguijan, Rota, Saipan and Tinian, Commonwealth of the Northern Mariana Islands. Search your address to find the exact soil composition, drainage, and series details at your specific location.

Soil Map UnitAcresDrainageHydro GroupDwellingsSeptic
Dandan-Chinen complex, 0 to 5 percent slopes 7K Well drainedCVery limitedVery limited
Chinen clay loam, 5 to 15 percent slopes 6K Well drainedDVery limitedVery limited
Luta cobbly clay loam, 0 to 5 percent slopes 5K Well drainedDVery limitedVery limited
Chinen clay loam, 0 to 5 percent slopes 5K Well drainedDVery limitedVery limited
Chinen-Urban land complex, 0 to 5 percent slopes 4K Well drainedDVery limitedVery limited
Luta cobbly clay loam, 5 to 15 percent slopes 4K Well drainedDVery limitedVery limited
Takpochao-Rock outcrop complex, 30 to 60 percent slopes 4K Well drainedDVery limitedVery limited
Chinen clay loam, 15 to 30 percent slopes 4K Well drainedDVery limitedVery limited
Takpochao-Rock outcrop complex, 3 to 15 percent slopes 3K Well drainedDVery limitedVery limited
Luta-Rock outcrop complex, 5 to 15 percent slopes 3K Well drainedDVery limitedVery limited
Takpochao-Rock outcrop complex, 15 to 30 percent slopes 3K Well drainedDVery limitedVery limited
Rock outcrop-Takpochao complex, 60 to 99 percent slopes 3K Well drainedDVery limitedVery limited
Chinen very gravelly sandy loam, 0 to 5 percent slopes 2K Well drainedCVery limitedVery limited
Dandan-Chinen complex, 5 to 15 percent slopes 2K Well drainedCVery limitedVery limited
Luta-Rock outcrop complex, 15 to 30 percent slopes 2K Well drainedDVery limitedVery limited
Saipan clay, 0 to 5 percent slopes 1K Well drainedBSomewhat limitedSomewhat limited
Kagman clay, 0 to 5 percent slopes 1K Well drainedCSomewhat limitedVery limited
Shioya loamy sand, 0 to 3 percent slopes 1K Somewhat excessively drainedAVery limitedVery limited
Luta-Rock outcrop complex, 0 to 5 percent slopes 1K Well drainedDVery limitedVery limited
Chinen-Rock outcrop complex, 3 to 15 percent slopes 1K Well drainedDVery limitedVery limited

Soil Orders in This Area

The USDA classifies every soil into one of 12 soil orders. Here are the dominant orders found in this survey area.

Mollisols
Fertile grassland soils with thick, dark topsoil. Among the best for agriculture, building, and gardening.
Alfisols
Moderately weathered forest soils with clay-enriched subsoil. Productive for agriculture, generally good for building and septic.
Entisols
Young soils with little development — found on floodplains, dunes, and steep slopes. Properties vary widely by setting.
Inceptisols
Young but developing soils found in mountains and river terraces. Variable properties — check drainage and bedrock depth.
Oxisols
Deeply weathered tropical soils. Nutrient-poor despite appearing lush. Rare in the continental US.

What This Means

Building & Foundations

About 91% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes, flood-prone areas. A geotechnical assessment is recommended before building.

Septic Systems

About 96% of soils are rated "very limited" for septic absorption fields. Despite good drainage overall, limitations may stem from shallow bedrock, steep slopes, or seasonal conditions. Engineered or alternative systems are frequently required. Always get a professional perc test before purchasing land that needs septic.

Gardening & Agriculture

Well-drained soils on sloped terrain — good for most plants but watch for erosion. Terracing, contour planting, and mulching help retain moisture and topsoil. Drip irrigation is more effective than sprinklers on slopes.

Look Up a Specific Address

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