Soil series profile
Oska soil series
Oska is a well drained soil with a silty clay loam surface, mapped on 87,582 acres in 20 counties across 3 states. Hydrologic group D.
- Drainage class
- Well drained 100% of mapped acres
- Hydrologic group
- D 100% of mapped acres
- Typical topsoil pH
- 6.1 slightly acidic · range 6.1–6.1
- Mapped area
- 88k acres in 20 counties, 3 states
Typical Oska profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–6 in (A) | Silty clay loam | 6.1 | 34% | 4% | 3% |
| 6–11 in (BA) | Silty clay loam | 6.1 | 37% | 4% | 3% |
| 11–15 in (Bt1) | Silty clay | 6.7 | 48% | 4% | 0.7% |
| 15–34 in (Bt2) | Silty clay | 6.7 | 50% | 5% | 0.4% |
| 34–38 in (R) | Not reported | Not reported | Not reported | Not reported | Not reported |
What this means
What Oska soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in Oska soils is slightly acidic: pH 6.1, the range most vegetables, flowers and lawn grasses prefer.
Loamy topsoil (loam, silt loam and similar) covers 100% of mapped Oska acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is silty clay loam (100% of mapped Oska acres).
100% of mapped Oska acres is moderately well to excessively drained, which suits most garden plants.
For lawns and yards
On 100% of mapped acres, rain soaks in slowly (hydrologic groups C and D, including dual groups that are D until drained). Expect runoff and puddles after heavy rain: core-aerate compacted lawns and keep ground sloping away from foundations.
For a septic system
For conventional septic absorption fields, NRCS rates 100% of the acres in mapped Oska soils very limited, 0% somewhat limited and 0% not limited.
Where the soil is very limited (slow permeability, a high water table, flooding, shallow bedrock or steep slopes), alternative systems such as mound or sand-filter designs are common and cost more.
Only a licensed site evaluation or perc test at the actual lot decides whether a system is allowed and which design.
Where Oska soil is found
Mapped acres
Oska is mapped in Kansas, Missouri and Nebraska.
| County | Acres | Share of county land |
|---|---|---|
| Johnson County, KS | 30,812 | 10.1% |
| Douglas County, KS | 18,780 | 6.4% |
| Cass County, MO | 16,835 | 3.8% |
| Jefferson County, KS | 10,878 | 3.2% |
| Leavenworth County, KS | 3,732 | 1.3% |
| Shawnee County, KS | 2,100 | 0.6% |
| Jackson County, MO | 1,866 | 0.5% |
| Johnson County, MO | 682 | 0.1% |
| Wyandotte County, KS | 649 | 0.7% |
| Brown County, KS | 262 | 0.1% |
| Miami County, KS | 251 | 0.1% |
| Jackson County, KS | 166 | 0.0% |
| Osage County, KS | 158 | 0.0% |
| Atchison County, KS | 129 | 0.0% |
| Jefferson County, NE | 116 | 0.0% |
| Platte County, MO | 82 | 0.0% |
| Clay County, MO | 57 | 0.0% |
| Henry County, MO | 18 | 0.0% |
| Lafayette County, MO | 9 | 0.0% |
| Wabaunsee County, KS | 3 | 0.0% |
Septic absorption fields
NRCS rating, share of Oska acres
Show as a table
| Category | Share of acres |
|---|---|
| Not limited | 0.0% |
| Somewhat limited | 0.0% |
| Very limited | 100.0% |
Drainage, water table and flooding
Share of Oska acres
- Depth to seasonal high water table
- None reported within about 6.5 feet (median where reported).
- Flooding
- Not mapped as flooding on most acres.
- Slope
- Typically 5–7% (median 6%).
- Topsoil organic matter
- Median 3%.
Drainage class
Show as a table
| Category | Share of acres |
|---|---|
| Excessively drained | 0.0% |
| Somewhat excessively drained | 0.0% |
| Well drained | 100.0% |
| Moderately well drained | 0.0% |
| Somewhat poorly drained | 0.0% |
| Poorly drained | 0.0% |
| Very poorly drained | 0.0% |
Hydrologic soil group
Show as a table
| Category | Share of acres |
|---|---|
| A: fast infiltration (mostly sandy or gravelly) | 0.0% |
| B: moderate infiltration | 0.0% |
| C: slow infiltration | 0.0% |
| D: very slow infiltration (clayey, shallow or wet) | 100.0% |
| A/D: D as is, A if drained | 0.0% |
| B/D: D as is, B if drained | 0.0% |
| C/D: D as is, C if drained | 0.0% |
Sources & data dates
- Source
- USDA NRCS Soil Survey Geographic Database (SSURGO), queried through Soil Data Access. Public domain.
- Data date
- SSURGO as published on November 3, 2026 (most recent survey area update October 26, 2026). NRCS refreshes SSURGO each October.
- Scope
- All map unit components named Oska (component kind "Series") in SSURGO: 87,582 acres.
- Method
- Shares are by mapped acres of Oska components. The profile comes from the single largest Oska component. Full methodology.