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

Survey Area MP645• Northern Mariana Islands

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 Unit	Acres	Drainage	Hydro Group	Dwellings	Septic
Dandan-Chinen complex, 0 to 5 percent slopes	7K	Well drained	C	Very limited	Very limited
Chinen clay loam, 5 to 15 percent slopes	6K	Well drained	D	Very limited	Very limited
Luta cobbly clay loam, 0 to 5 percent slopes	5K	Well drained	D	Very limited	Very limited
Chinen clay loam, 0 to 5 percent slopes	5K	Well drained	D	Very limited	Very limited
Chinen-Urban land complex, 0 to 5 percent slopes	4K	Well drained	D	Very limited	Very limited
Luta cobbly clay loam, 5 to 15 percent slopes	4K	Well drained	D	Very limited	Very limited
Takpochao-Rock outcrop complex, 30 to 60 percent slopes	4K	Well drained	D	Very limited	Very limited
Chinen clay loam, 15 to 30 percent slopes	4K	Well drained	D	Very limited	Very limited
Takpochao-Rock outcrop complex, 3 to 15 percent slopes	3K	Well drained	D	Very limited	Very limited
Luta-Rock outcrop complex, 5 to 15 percent slopes	3K	Well drained	D	Very limited	Very limited
Takpochao-Rock outcrop complex, 15 to 30 percent slopes	3K	Well drained	D	Very limited	Very limited
Rock outcrop-Takpochao complex, 60 to 99 percent slopes	3K	Well drained	D	Very limited	Very limited
Chinen very gravelly sandy loam, 0 to 5 percent slopes	2K	Well drained	C	Very limited	Very limited
Dandan-Chinen complex, 5 to 15 percent slopes	2K	Well drained	C	Very limited	Very limited
Luta-Rock outcrop complex, 15 to 30 percent slopes	2K	Well drained	D	Very limited	Very limited
Saipan clay, 0 to 5 percent slopes	1K	Well drained	B	Somewhat limited	Somewhat limited
Kagman clay, 0 to 5 percent slopes	1K	Well drained	C	Somewhat limited	Very limited
Shioya loamy sand, 0 to 3 percent slopes	1K	Somewhat excessively drained	A	Very limited	Very limited
Luta-Rock outcrop complex, 0 to 5 percent slopes	1K	Well drained	D	Very limited	Very limited
Chinen-Rock outcrop complex, 3 to 15 percent slopes	1K	Well drained	D	Very limited	Very 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 95% 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 97% 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.