Dallas County Soil Data
Dallas County, Iowa
USDA SSURGO / PHZMAvg pH
6.6
Texture
Loam
Drainage
N/A
Organic Matter
3.6%
Hydrologic Group
N/A
Data Story
About Soil in Dallas County, Iowa
A Balanced pH Profile in Central Iowa
Dallas County features a balanced soil profile with an average pH of 6.58, sitting just above the national median of 6.5. This neutral environment provides an ideal foundation for nutrient availability, outperforming the Iowa state average of 6.43. While specific taxonomic data is limited for this area, the chemical balance suggests a versatile growing environment.
Silt-Driven Soil for Easy Management
The county's soil consists of 43.0% silt, 33.5% sand, and 23.5% clay. This high silt content ensures a smooth texture that is easy to work while maintaining enough clay for essential structural integrity. The significant sand percentage aids in basic aeration, though the mix requires careful management to prevent compaction.
Reliable Organic Matter for Local Crops
With an organic matter content of 3.59%, Dallas County stays well above the national average of 2.0% but slightly trails the Iowa state average of 3.81%. Its available water capacity of 0.190 in/in indicates a steady ability to hold moisture for plants. This combination supports a high soil score of 74.7, exceeding the state benchmark of 72.9.
Consistent Moisture for Farming Success
While specific drainage classes are not recorded here, the soil's composition suggests moderate permeability. The available water capacity is nearly on par with the state average of 0.195, indicating that the land manages water effectively for most agricultural needs. Gardeners should still monitor for localized runoff during heavy Iowa rainstorms.
Thriving in Hardiness Zone 5b
Dallas County sits in USDA Hardiness Zone 5b, making it a prime spot for corn, soybeans, and hearty perennials. The neutral pH and high soil score mean your garden is already ahead of the curve. Start a vegetable patch this spring to take advantage of some of the state's most balanced earth.
Soil Composition
Soil pH
Soil Series
Detailed soil series data not yet available for this county.
Hydrologic Group
Hydrologic group data not available.
Drainage Class
Drainage class data not available.
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 Dallas County have?
Dallas County's soil is classified as Loam. This indicates the relative proportions of sand, silt, and clay — 34% sand, 43% silt, and 23% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Dallas County's soil acidic or alkaline?
Dallas County's soil has a pH of 6.6, which is near neutral. This range is ideal for most garden plants and field crops.
What is the drainage class for Dallas County?
Drainage class data is not currently available for Dallas County.
What crops or plants grow well in Dallas County's soil?
Based on Dallas County's Loam texture, pH of 6.6, and drainage class, the soil is well suited for vegetables, grains, and most field crops, row crops and vegetable gardens.
What USDA soil order is found in Dallas County?
The dominant USDA soil order for Dallas County is not currently available in our dataset.
Soil & Planting Advisory: Dallas County
Soil Verdict
Dallas 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
Dallas County closely matches the Iowa average hardiness conditions. The zone range of 5a-5b within the county means soil and planting decisions should account for local elevation and topography.
Planning your lawn? View lawn care data for Dallas 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.