Madison County Soil Data
Madison County, Iowa
USDA SSURGO / PHZMAvg pH
6.3
Texture
Loam
Drainage
Somewhat poorly drained
Organic Matter
3.2%
Hydrologic Group
D
Data Story
About Soil in Madison County, Iowa
The Productive Alfisols of Madison County
Madison County features Alfisols with a pH of 6.31, slightly more acidic than the state average of 6.43. These soils are historically productive but may require monitoring for optimal pH balance in sensitive crops.
Heavy Loam with Mineral Grip
The soil is comprised of 53.9% silt and 26.9% clay, creating a heavy loam that excels at holding onto vital minerals. A 19.2% sand component is relatively low, meaning the soil can feel thick and heavy when wet.
Better-Than-Average Water Retention
Organic matter sits at 3.17%, which is healthy by national standards but below the Iowa state average of 3.81%. However, its available water capacity of 0.204 inches per inch is better than the state average, ensuring plants stay hydrated.
Slow Drainage and Runoff Potential
Classified as somewhat poorly drained with a hydrologic group D rating, this soil tends to hold water and may require tiling for commercial farming. These characteristics suggest a high runoff potential that home builders must account for.
Hydrated Gardens in Zone 5b
Gardeners in zone 5b can enjoy a wide variety of crops from leafy greens to root vegetables. With its superior water retention, your Madison County garden will thrive even during those dry Iowa summers.
Soil Composition
Soil pH
Soil Series
Detailed soil series data not yet available for this county.
Hydrologic Group
Group D — High Runoff
Clay soils with very slow infiltration rates. Highest runoff potential. These soils have a permanent high water table or are shallow over impervious material.
Drainage Class
Somewhat poorly drained
Water is removed slowly enough that the soil is wet at shallow depths for significant periods. Mottling present.
Soil Profile
Dominant texture: Loam
Typical soil profile. Actual depths vary by location.
USDA Soil Orders
Soil Amendment Products
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Browse Soil AmendmentsFrequently Asked Questions
What type of soil does Madison County have?
Madison County's soil is classified as Loam. This indicates the relative proportions of sand, silt, and clay — 19% sand, 54% silt, and 27% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Madison County's soil acidic or alkaline?
Madison County's soil has a pH of 6.3, which is moderately acidic. This range suits many crops and is common across much of the eastern US.
What is the drainage class for Madison County?
Madison County has a dominant drainage class of "Somewhat poorly drained." Poorly drained soils retain water for extended periods, which can limit crop choices and may require tile drainage or raised beds.
What crops or plants grow well in Madison County's soil?
Based on Madison County's Loam texture, pH of 6.3, and Somewhat poorly drained, the soil is well suited for vegetables, grains, and most field crops, row crops and vegetable gardens, rice, cranberries, and other water-tolerant species.
What USDA soil order is found in Madison County?
Madison County's dominant soil order is Alfisols. Alfisols are moderate to high base-status soils with a clay-enriched subsoil. They support productive forests and cropland across temperate regions.
Soil & Planting Advisory: Madison County
Soil Verdict
Madison County is in USDA hardiness zone 5b, a cold climate zone. where winter lows can reach -15°F. Freeze-thaw cycles are moderate; soil biology slows in winter but recovers reliably in spring, supporting a broad range of plants.
Planting Guidance
A wide plant palette is possible: deciduous trees, most shrubs, cool-season vegetables, and many perennials thrive here. Winter protection (mulch, burlap wraps) helps push the zone boundary for desired species. Always match plant selections to the specific microclimate of your property — low spots, slopes, and wind exposure can shift effective hardiness by half a zone.
Soil Implications
Moderate freeze-thaw cycles naturally aerate the soil but can also cause compaction in clay-heavy areas; annual core aeration is beneficial. Organic matter amendments decompose at a moderate pace — aim for 3-5% organic content for optimal fertility. When soil temperatures drop below freezing, microbial nitrogen cycling stops; spring fertilization is more effective than late-fall application.
Regional Context
Madison County closely matches the Iowa average hardiness conditions.
Planning your lawn? View lawn care data for Madison County on LawnByCounty.com →
Other Counties in Iowa
Soil data sourced from USDA SSURGO via Soil Data Access. Data is informational only and should not be used as a substitute for on-site soil testing. Contact your local NRCS office for site-specific soil information.