Poweshiek County, Iowa

Survey Area IA157• 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 Alfisols — moderately leached forest soils with a clay-enriched subsoil. 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 Poweshiek 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
Tama silty clay loam, 5 to 9 percent slopes, eroded	29K	Well drained	C	Somewhat limited	Very limited
Colo-Ely complex, 0 to 5 percent slopes	28K	Poorly drained	C/D	Very limited	Very limited
Tama silty clay loam, 2 to 5 percent slopes	26K	Well drained	C	Somewhat limited	Very limited
Otley silty clay loam, 5 to 9 percent slopes, eroded	19K	Moderately well drained	C	Very limited	Very limited
Otley silty clay loam, 2 to 5 percent slopes	18K	Moderately well drained	C	Very limited	Very limited
Gara loam, 14 to 18 percent slopes, moderately eroded	15K	Well drained	C	Very limited	Very limited
Killduff silty clay loam, 5 to 9 percent slopes, eroded	11K	Moderately well drained	C	Somewhat limited	Very limited
Muscatine silty clay loam, 0 to 2 percent slopes	11K	Somewhat poorly drained	C/D	Very limited	Very limited
Shelby-Adair complex, 9 to 14 percent slopes, moderately eroded	9K	Well drained	C	Somewhat limited	Very limited
Shelby loam, 14 to 18 percent slopes, moderately eroded	9K	Well drained	C	Very limited	Very limited
Mahaska silty clay loam, 0 to 2 percent slopes	9K	Somewhat poorly drained	C/D	Very limited	Very limited
Ladoga silt loam, 5 to 9 percent slopes, eroded	8K	Moderately well drained	C	Somewhat limited	Very limited
Nira silty clay loam, 5 to 9 percent slopes, moderately eroded	8K	Moderately well drained	C	Very limited	Very limited
Armstrong loam, 9 to 14 percent slopes, moderately eroded	8K	Somewhat poorly drained	D	Very limited	Very limited
Colo silt loam, 0 to 2 percent slopes, occasionally flooded, overwash	7K	Poorly drained	C/D	Very limited	Very limited
Tama silty clay loam, 9 to 14 percent slopes, eroded	7K	Well drained	C	Somewhat limited	Very limited
Gara-Armstrong loams, 9 to 14 percent slopes, moderately eroded	6K	Well drained	C	Somewhat limited	Very limited
Ackmore silt loam, 0 to 2 percent slopes, occasionally flooded	6K	Somewhat poorly drained	C/D	Very limited	Very limited
Killduff silty clay loam, 9 to 14 percent slopes, eroded	6K	Moderately well drained	C	Somewhat limited	Very limited
Lamoni silty clay loam, 9 to 14 percent slopes, moderately eroded	6K	Somewhat poorly 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.

Alfisols

Moderately weathered forest soils with clay-enriched subsoil. Productive for agriculture, generally good for building and septic.

Mollisols

Fertile grassland soils with thick, dark topsoil. Among the best for agriculture, building, and gardening.

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 57% 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.