Adair County, Oklahoma
The most common soil here is Clarksville, on about 35% of the land: a gravelly silt loam, smooth, like flour. Enders and Linker come next.
About 87% of the land drains well; groundwater comes within two feet of the surface under 12% of it.
USDA rates 93% of the land very limited for a standard septic drain field, and 69% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 5% of the land floods occasionally or more, and bedrock lies within 40 inches under 27% of it.
Soils change over short distances, so look up an address below for the soil at that exact spot and the reasons behind each rating.
The soils you're most likely standing on
The biggest named soils in Adair County, Oklahoma, each drawn five feet deep from its official USDA description, in its recorded colors.
Dots mark gravel; white flecks mark lime. Shares are by acres across the survey area, and each mapped patch usually mixes several of these soils.
The biggest mapped areas
The dominant drainage class is Somewhat excessively drained and the dominant hydrologic group is B (moderate infiltration). The most common soil order is Ultisols — strongly weathered soils with clay-enriched subsoils, common in warm humid climates. This report summarizes the major soil map units across the survey area to help you understand what to expect when buying, building, or gardening in Adair County, Oklahoma. Search your address to find the exact soil composition, drainage, and series details at your specific location.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Clarksville very gravelly silt loam, 20 to 50 percent slopes, stony | 90K | Somewhat excessively drained | B | Very limited | Very limited |
| Enders-Linker-Hector association, 5 to 30 percent slopes | 81K | Well drained | D | Very limited | Very limited |
| Clarksville very gravelly silt loam, 1 to 8 percent slopes | 56K | Somewhat excessively drained | B | Not limited | Very limited |
| Tonti gravelly silt loam, 0 to 3 percent slopes | 22K | Moderately well drained | C/D | Very limited | Very limited |
| Waben gravelly silt loam, 3 to 8 percent slopes | 19K | Well drained | C | Not limited | Very limited |
| Clarksville stony silt loam, 5 to 15 percent slopes | 16K | Somewhat excessively drained | B | Somewhat limited | Somewhat limited |
| Captina silt loam, 1 to 3 percent slopes | 13K | Moderately well drained | C/D | Very limited | Very limited |
| Hector-Linker complex, 1 to 5 percent slopes | 13K | Well drained | D | Very limited | Very limited |
| Elsah gravelly silt loam, 0 to 1 percent slopes, frequently flooded | 12K | Well drained | B | Very limited | Very limited |
| Waben gravelly silt loam, 1 to 3 percent slopes | 11K | Well drained | A | Not limited | Very limited |
| Britwater silt loam, 1 to 3 percent slopes | 7K | Well drained | B | Not limited | Somewhat limited |
| Jay silt loam, 0 to 2 percent slopes | 4K | Moderately well drained | C | Very limited | Very limited |
| Elsah gravelly loam, 0 to 1 percent slopes, occasionally flooded | 3K | Well drained | B | Very limited | Very limited |
| Linker fine sandy loam, 3 to 5 percent slopes | 3K | Well drained | C | Very limited | Very limited |
| Razort silt loam, 0 to 1 percent slopes, occasionally flooded | 2K | Well drained | C | Very limited | Very limited |
| Stigler silt loam, 0 to 1 percent slopes | 2K | Somewhat poorly drained | D | Very limited | Very limited |
| Sogn silty clay loam, 1 to 12 percent slopes | 2K | Somewhat excessively drained | D | Very limited | Very limited |
| Britwater silt loam, 0 to 1 percent slopes | 2K | Well drained | B | Not limited | Somewhat limited |
| Apperson silty clay loam, 1 to 3 percent slopes | 2K | Somewhat poorly drained | D | Very limited | Very limited |
| Linker loam, 3 to 5 percent slopes | 2K | Well drained | C | Very limited | Very limited |
Soil Orders in This Area
The USDA classifies every soil into one of 12 soil orders. Here are the dominant orders found in this survey area.
What This Means
Building & Foundations
About 69% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes, poor drainage in some areas, flood-prone areas, sandy or gravelly soils with low bearing capacity. A geotechnical assessment is recommended before building.
Septic Systems
About 93% of soils are rated "very limited" for septic absorption fields. The well-drained soils may actually drain too fast for standard leach fields, allowing effluent to reach groundwater. Engineered or alternative systems are frequently required. Always get a professional perc test before purchasing land that needs septic.
Gardening & Agriculture
Soils tend to drain very quickly, meaning nutrients and water don't stick around long. Raised beds with amended soil, drip irrigation, and heavy mulching will give the best results. Compost is your best friend here — it improves water retention dramatically.