Yamhill County, Oregon

Survey Area OR071• Oregon

The dominant drainage class is Well drained and the dominant hydrologic group is C (slow infiltration, moderate 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 Yamhill County, Oregon. 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
Woodburn silt loam, 0 to 3 percent slopes	33K	Moderately well drained	C	Very limited	Very limited
Amity silt loam, 0 to 3 percent slopes	19K	Somewhat poorly drained	C/D	Very limited	Very limited
Woodburn silt loam, 3 to 12 percent slopes	12K	Moderately well drained	C	Very limited	Very limited
Olyic silt loam, 30 to 60 percent slopes	11K	Well drained	B	Very limited	Very limited
Olyic silt loam, 5 to 30 percent slopes	11K	Well drained	B	Very limited	Very limited
Hembre silt loam, 30 to 60 percent slopes	11K	Well drained	B	Very limited	Very limited
Hemcross-Klistan complex, 30 to 60 percent slopes	10K	Well drained	B	Very limited	Very limited
Peavine silty clay loam, 30 to 60 percent slopes	10K	Well drained	C	Very limited	Very limited
Chehalis silty clay loam, 0 to 3 percent slopes	8K	Well drained	B	Very limited	Very limited
Astoria silt loam 30 to 60 percent slopes	8K	Well drained	B	Very limited	Very limited
Astoria silt loam, 5 to 30 percent slopes	8K	Well drained	B	Very limited	Very limited
Hembre silt loam, 3 to 30 percent slopes	8K	Well drained	B	Very limited	Very limited
Dayton silt loam, 0 to 2 percent slopes	7K	Poorly drained	D	Very limited	Very limited
Jory-Bellpine complex, 12 to 20 percent slopes	6K	Well drained	C	Very limited	Very limited
Woodburn silt loam, 20 to 55 percent slopes	6K	Moderately well drained	C	Very limited	Very limited
Melbourne-Goodin silty clay loams, 12 to 20 percent slopes	6K	Well drained	C	Very limited	Very limited
Saum silty clay loam, hummocky, 12 to 30 percent slopes	6K	Well drained	C	Very limited	Very limited
Witham silty clay loam, hummocky, 2 to 25 percent slopes	6K	Somewhat poorly drained	D	Very limited	Very limited
Peavine silty clay loam, 2 to 30 percent slopes	6K	Well drained	C	Very limited	Very limited
Jory-Bellpine complex, 20 to 30 percent slopes	5K	Well drained	C	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.

Ultisols

Strongly weathered clay soils of the Southeast. Acidic and naturally low in nutrients. Clay subsoil can slow drainage.

What This Means

Building & Foundations

About 100% of soils are rated "very limited" for dwellings with basements. Specific challenges include steep slopes, poor drainage in some areas, flood-prone areas. A geotechnical assessment is recommended before building.

Septic Systems

About 100% 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.