Audubon County, Iowa

Survey Area IA009• Iowa

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 Audubon County, Iowa. 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
Judson-Colo-Ackmore complex, 2 to 5 percent slopes	52K	Poorly drained	C/D	Very limited	Very limited
Marshall silty clay loam, 9 to 14 percent slopes, eroded	40K	Well drained	C	Somewhat limited	Very limited
Marshall silty clay loam, 5 to 9 percent slopes, eroded	39K	Well drained	C	Somewhat limited	Very limited
Exira silty clay loam, 9 to 14 percent slopes, eroded	19K	Well drained	C	Somewhat limited	Very limited
Marshall silty clay loam, 2 to 5 percent slopes, eroded	14K	Well drained	C	Somewhat limited	Very limited
Marshall silty clay loam, 2 to 5 percent slopes	10K	Well drained	C	Somewhat limited	Very limited
Shelby-Adair clay loams, deep loess, 9 to 14 percent slopes, eroded	10K	Well drained	C	Somewhat limited	Very limited
Zook silty clay loam, 0 to 2 percent slopes, occasionally flooded	9K	Poorly drained	D	Very limited	Very limited
Colo silty clay loam, deep loess, 0 to 2 percent slopes, occasionally flooded	6K	Poorly drained	C/D	Very limited	Very limited
Shelby clay loam, deep loess, 14 to 18 percent slopes, severely eroded	6K	Well drained	C	Very limited	Very limited
Marshall silty clay loam, 14 to 20 percent slopes, eroded	6K	Well drained	C	Very limited	Very limited
Exira silty clay loam, 5 to 9 percent slopes, eroded	6K	Well drained	C	Somewhat limited	Very limited
Judson silty clay loam, deep loess, 2 to 5 percent slopes	5K	Well drained	C	Somewhat limited	Very limited
Ackmore silt loam, 0 to 2 percent slopes, occasionally flooded	5K	Somewhat poorly drained	C/D	Very limited	Very limited
Shelby-Adair clay loams, deep loess, 14 to 18 percent slopes, eroded	5K	Well drained	C	Very limited	Very limited
Shelby-Adair clay loams, deep loess, 14 to 18 percent slopes, severely eroded	4K	Well drained	C	Very limited	Very limited
Shelby-Adair clay loams, deep loess, 9 to 14 percent slopes, severely eroded	4K	Well drained	C	Somewhat limited	Very limited
Dockery-Quiver silt loams, deep loess, 0 to 2 percent slopes, occasionally flooded	4K	Somewhat poorly drained	B/D	Very limited	Very limited
Shelby clay loam, deep loess, 9 to 14 percent slopes, eroded	3K	Well drained	C	Somewhat limited	Very limited
Shelby clay loam, deep loess, 18 to 25 percent slopes, severely eroded	3K	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.

Inceptisols

Young but developing soils found in mountains and river terraces. Variable properties — check drainage and bedrock depth.

Entisols

Young soils with little development — found on floodplains, dunes, and steep slopes. Properties vary widely by setting.

What This Means

Building & Foundations

About 40% of soils have significant building limitations, while the rest are generally suitable. Check specific sites carefully — conditions vary across the area.

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.