Sully County Soil Data
Sully County, South Dakota
USDA SSURGO / PHZMAvg pH
6.9
Texture
Clay Loam
Drainage
N/A
Organic Matter
3.0%
Hydrologic Group
N/A
Data Story
About Soil in Sully County, South Dakota
Near-Neutral Soil Performance
Sully County soil is nearly neutral with a pH of 6.92, which is closer to the national median of 6.5 than the state average. The county earns a respectable soil score of 64.7, beating the state baseline of 61.2.
Silt-Dominant Nutrient Exchange
The soil contains 49.7% silt and 27.6% clay, creating a environment that holds moisture effectively. With only 22.0% sand, this soil provides a high surface area for critical nutrient exchange.
Efficient Moisture Retention
Available water capacity reaches 0.190 in/in, outperforming the South Dakota average of 0.182. While the 2.99% organic matter is lower than the state average, it remains well above the national 2.0% benchmark.
Reliable Water Management Potential
Specific drainage class data are currently unavailable for this region. However, the high silt content and strong water capacity suggest the soil manages moisture efficiently for agricultural purposes.
Perfect for Grains and Staples
Zone 4b conditions are excellent for wheat, flax, and various hardy garden vegetables. You can start a local garden today with the confidence that your soil holds more water than most in the state.
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: Clay Loam
Typical soil profile. Actual depths vary by location.
USDA Soil Orders
Clay Soil Detected
Clay soils can struggle with drainage. These products improve soil structure and water flow.
Browse Soil AmendmentsFrequently Asked Questions
What type of soil does Sully County have?
Sully County's soil is classified as Clay Loam. This indicates the relative proportions of sand, silt, and clay — 22% sand, 50% silt, and 28% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Sully County's soil acidic or alkaline?
Sully County's soil has a pH of 6.9, which is near neutral. This range is ideal for most garden plants and field crops.
What is the drainage class for Sully County?
Drainage class data is not currently available for Sully County.
What crops or plants grow well in Sully County's soil?
Based on Sully County's Clay Loam texture, pH of 6.9, 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 Sully County?
The dominant USDA soil order for Sully County is not currently available in our dataset.
Soil & Planting Advisory: Sully County
Soil Verdict
Sully County is in USDA hardiness zone 4b, a cold climate zone. where winter lows can reach -25°F. Soils here experience deep freeze cycles that can disrupt structure, kill shallow roots, and slow microbial activity for months each year.
Planting Guidance
Focus on cold-hardy perennials, native grasses, and conifers. The short growing window favors plants with low heat requirements. With extreme winter lows, any marginally hardy plants need heavy mulch and wind protection. 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
Deep winter freezing can create soil heaving that pushes shallow-rooted plants out of the ground; add 3-4 inches of organic mulch each fall. Soil drainage is critical — frozen, waterlogged soil kills roots faster than cold alone. When soil temperatures drop below freezing, microbial nitrogen cycling stops; spring fertilization is more effective than late-fall application.
Regional Context
Sully County closely matches the South Dakota average hardiness conditions.
Planning your lawn? View lawn care data for Sully County on LawnByCounty.com →
Other Counties in South Dakota
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.