Polk County Soil Data
Polk County, Nebraska
USDA SSURGO / PHZMAvg pH
6.8
Texture
Loamy fine sand
Drainage
Excessively drained
Organic Matter
2.0%
Hydrologic Group
A
Data Story
About Soil in Polk County, Nebraska
Loamy Sands and Young Entisols
Polk County is dominated by Loamy Fine Sand and Entisols, which are soils that show little to no profile development. The pH of 6.83 is slightly more alkaline than the national median of 6.5 and sits just above the Nebraska average of 6.79. This profile creates a mineral-rich environment that is typical of the state's river-influenced regions.
A Gritty, Sand-Forward Texture
With 43.5% sand and 40.1% silt, the soil is light and well-aerated, containing only 16.3% clay. This texture ensures that the soil warms up quickly in the spring, allowing for earlier planting dates. However, the higher sand content means that nutrients can wash away more easily than in heavier soils.
Strong Water Capacity in Light Soil
Interestingly, Polk County's available water capacity of 0.182 in/in is higher than the state average of 0.172 in/in, despite its sandier texture. The organic matter content is 2.01%, matching the national average but falling below the Nebraska average of 3.32%. This leads to an overall soil score of 56.4, suggesting a need for careful nutrient management.
Excessive Drainage and High Infiltration
The dominant drainage class is 'Excessively drained,' and the soil belongs to Hydrologic Group A. This means water moves very quickly through the soil, which is excellent for preventing floods but requires more frequent irrigation or rain. Builders will appreciate the lack of standing water, but gardeners must be mindful of how fast these soils dry out.
Spring Starts in Zone 5b
Located in Hardiness Zone 5b, Polk County is a great spot for crops that enjoy well-aerated soils like asparagus, melons, or root vegetables. The fast-warming sandy soil gives you a head start on the season compared to the state's clay-heavy regions. Focus on adding compost to your garden to help bridge the gap in organic matter.
Soil Composition
Soil pH
Soil Series
Detailed soil series data not yet available for this county.
Hydrologic Group
Group A — Low Runoff
Sandy, well-drained soils with high infiltration rates. Water moves quickly through the soil profile. Lowest runoff potential when thoroughly wetted.
Drainage Class
Excessively drained
Water is removed very rapidly. Very sandy or gravelly soils with little water retention.
Soil Profile
Dominant texture: Loamy fine sand
Typical soil profile. Actual depths vary by location.
USDA Soil Orders
Sandy Soil Detected
Sandy soils drain quickly and can dry out. These products boost water retention and organic matter.
Browse Soil AmendmentsFrequently Asked Questions
What type of soil does Polk County have?
Polk County's soil is classified as Loamy fine sand. This indicates the relative proportions of sand, silt, and clay — 44% sand, 40% silt, and 16% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Polk County's soil acidic or alkaline?
Polk County's soil has a pH of 6.8, which is near neutral. This range is ideal for most garden plants and field crops.
What is the drainage class for Polk County?
Polk County has a dominant drainage class of "Excessively drained." Moderate drainage allows adequate moisture retention while still permitting excess water to drain over time.
What crops or plants grow well in Polk County's soil?
Based on Polk County's Loamy fine sand texture, pH of 6.8, and Excessively drained, the soil is well suited for vegetables, grains, and most field crops, row crops and vegetable gardens.
What USDA soil order is found in Polk County?
Polk County's dominant soil order is Entisols. Entisols are recently formed soils with little to no horizon development. They are common on floodplains, steep slopes, and sandy deposits.
Soil & Planting Advisory: Polk County
Soil Verdict
Polk 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
Polk County closely matches the Nebraska average hardiness conditions.
Planning your lawn? View lawn care data for Polk County on LawnByCounty.com →
Other Counties in Nebraska
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.