Rock Island County Soil Data
Rock Island County, Illinois
USDA SSURGO / PHZMAvg pH
6.5
Texture
Silt Loam
Drainage
N/A
Organic Matter
2.5%
Hydrologic Group
N/A
Data Story
About Soil in Rock Island County, Illinois
Perfectly Balanced pH in Rock Island
Rock Island County boasts an average pH of 6.53, sitting right at the national median of 6.5. This nearly neutral level makes it more accommodating for a wide variety of plants compared to the more acidic state average of 6.39. While specific taxonomic data is currently unlisted, this chemical balance provides an ideal foundation for nutrient availability.
A Silty Foundation with Sandy Accents
The soil contains 57.6% silt and 20.2% sand, creating a texture that balances moisture retention with workability. With 22.2% clay, the ground offers enough structure to hold onto minerals without becoming overly compacted. This mix allows for easier tilling than many heavier clay soils found elsewhere in the state.
Healthy Water Capacity for Steady Growth
Organic matter sits at 2.49%, which beats the national average of 2.0% but falls slightly behind the high Illinois state average of 2.94%. The soil holds 0.199 inches of water per inch of soil, nearly matching the state benchmark of 0.204. These numbers indicate a stable growing environment that resists quick drying during summer stretches.
Reliable Hydrology for Diverse Land Use
While specific drainage classes are not recorded in this data set, the high silt content suggests moderate natural drainage. The balance of 20.2% sand helps prevent the total saturation often seen in pure silt-clay environments. Builders and farmers should find the land relatively predictable, though site-specific percolation tests remain essential.
Hardy Crops Thrive in Zone 5b
This county sits in USDA Hardiness Zone 5b, where cool-weather vegetables and hardy perennials excel. The neutral pH and high silt content provide a perfect home for apples, pumpkins, and sweet corn. Grab a shovel and start your garden, as these soils are among the most versatile in the region.
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: Silt 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 Rock Island County have?
Rock Island County's soil is classified as Silt Loam. This indicates the relative proportions of sand, silt, and clay — 20% sand, 58% silt, and 22% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Rock Island County's soil acidic or alkaline?
Rock Island County's soil has a pH of 6.5, which is near neutral. This range is ideal for most garden plants and field crops.
What is the drainage class for Rock Island County?
Drainage class data is not currently available for Rock Island County.
What crops or plants grow well in Rock Island County's soil?
Based on Rock Island County's Silt Loam texture, pH of 6.5, 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 Rock Island County?
The dominant USDA soil order for Rock Island County is not currently available in our dataset.
Soil & Planting Advisory: Rock Island County
Soil Verdict
Rock Island 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
Rock Island County is somewhat cooler than the Illinois statewide average.
Planning your lawn? View lawn care data for Rock Island County on LawnByCounty.com →
Other Counties in Illinois
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.