Soil series profile
Yamacall soil series
Yamacall is a well drained soil with a loam surface, mapped on 1,307,175 acres in 46 counties across 4 states. Hydrologic group B.
- Drainage class
- Well drained 100% of mapped acres
- Hydrologic group
- B 99% of mapped acres
- Typical topsoil pH
- 7.5 slightly alkaline · range 7.5–7.6
- Mapped area
- 1.3M acres in 46 counties, 4 states
Typical Yamacall profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–5 in (A) | Loam | 7.5 | 23% | 40% | 2% |
| 5–13 in (Bw) | Loam | 7.5 | 24% | 39% | 0.75% |
| 13–48 in (Bk) | Loam | 8.5 | 24% | 39% | 0.75% |
| 48–60 in (C) | Loam | 8.5 | 24% | 39% | 0.25% |
What this means
What Yamacall soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in Yamacall soils is slightly alkaline: pH 7.5 (most land between 7.5 and 7.6). Acid-loving plants such as blueberries and azaleas struggle without amended beds, and some trees and shrubs show iron chlorosis (yellow leaves with green veins).
Loamy topsoil (loam, silt loam and similar) covers >99% of mapped Yamacall acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is loam (97% of mapped Yamacall acres).
100% of mapped Yamacall acres is moderately well to excessively drained, which suits most garden plants.
For lawns and yards
Most land is in hydrologic groups B and C, where rain soaks in at a moderate pace.
For a septic system
For conventional septic absorption fields, NRCS rates 7% of the acres in mapped Yamacall soils very limited, 90% somewhat limited and 3% not limited.
Only a licensed site evaluation or perc test at the actual lot decides whether a system is allowed and which design.
Where Yamacall soil is found
Mapped acres
Yamacall is mapped in Montana, Wyoming, Colorado and North Dakota.
| County | Acres | Share of county land |
|---|---|---|
| Rosebud County, MT | 257,238 | 5.3% |
| Big Horn County, MT | 245,561 | 5.5% |
| Garfield County, MT | 127,580 | 4.4% |
| Custer County, MT | 122,274 | 4.9% |
| Musselshell County, MT | 65,504 | 5.6% |
| Fallon County, MT | 58,975 | 5.7% |
| McCone County, MT | 54,898 | 3.3% |
| Carter County, MT | 54,000 | 2.8% |
| Prairie County, MT | 42,485 | 3.8% |
| Chouteau County, MT | 41,444 | 1.6% |
| Golden Valley County, MT | 31,374 | 4.3% |
| Wheatland County, MT | 19,687 | 2.4% |
| Rio Blanco County, CO | 16,255 | 0.8% |
| Petroleum County, MT | 14,866 | 1.4% |
| Liberty County, MT | 14,173 | 1.6% |
| Toole County, MT | 13,801 | 1.3% |
| Phillips County, MT | 13,294 | 0.4% |
| Sweet Grass County, MT | 12,729 | 1.0% |
| Beaverhead County, MT | 10,709 | 0.3% |
| Carbon County, WY | 9,858 | 0.2% |
| Teton County, MT | 9,735 | 0.7% |
| Hill County, MT | 9,234 | 0.5% |
| Fergus County, MT | 7,468 | 0.3% |
| Yellowstone County, MT | 6,320 | 0.4% |
| Lewis and Clark County, MT | 6,129 | 0.3% |
| Pondera County, MT | 5,621 | 0.5% |
| Lincoln County, WY | 5,240 | 0.2% |
| Campbell County, WY | 4,895 | 0.2% |
| Johnson County, WY | 4,167 | 0.2% |
| Uinta County, WY | 3,377 | 0.3% |
| Stillwater County, MT | 3,032 | 0.3% |
| Sweetwater County, WY | 3,032 | 0.0% |
| Sublette County, WY | 2,723 | 0.1% |
| Park County, WY | 2,507 | 0.2% |
| Dawson County, MT | 2,239 | 0.1% |
| Park County, MT | 1,492 | 0.1% |
| Powder River County, MT | 1,422 | 0.1% |
| Hot Springs County, WY | 1,325 | 0.1% |
| Meagher County, MT | 195 | 0.0% |
| Richland County, MT | 193 | 0.0% |
| Crook County, WY | 70 | 0.0% |
| Treasure County, MT | 29 | 0.0% |
| Dunn County, ND | 15 | 0.0% |
| Slope County, ND | 7 | 0.0% |
| Bowman County, ND | 4 | 0.0% |
| Golden Valley County, ND | 0 | 0.0% |
Septic absorption fields
NRCS rating, share of Yamacall acres
Show as a table
| Category | Share of acres |
|---|---|
| Not limited | 2.9% |
| Somewhat limited | 90.0% |
| Very limited | 7.0% |
| Not rated | 0.1% |
Drainage, water table and flooding
Share of Yamacall acres
- Depth to seasonal high water table
- About 4.9 feet (59 in) (median where reported).
- Flooding
- Not mapped as flooding on most acres.
- Slope
- Typically 3–12% (median 6%).
- Topsoil organic matter
- Median 1.5%.
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 | 98.8% |
| C: slow infiltration | 1.0% |
| D: very slow infiltration (clayey, shallow or wet) | 0.0% |
| 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% |
| Not rated | 0.1% |
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 Yamacall (component kind "Series") in SSURGO: 1,307,175 acres.
- Method
- Shares are by mapped acres of Yamacall components. The profile comes from the single largest Yamacall component. Full methodology.