Soil Survey, Amended

Four soil surveys of one Oklahoma parcel across five decades. The classifications move in one direction.

By Maya Jiménez— March 10, 2026

Four soil surveys of one Oklahoma parcel across five decades. The classifications move in one direction.

UNITED STATES DEPARTMENT OF AGRICULTURE Natural Resources Conservation Service

Map Unit FoB — Forgan fine sandy loam, 1 to 3 percent slopes NW¼ Sec. 14, T3N, R26ECM, Beaver County, Oklahoma

Field Assessment — March 2026

Assessment initiated in response to Ranger Road Fire, February 17–24, 2026. Burn area: 283,283 acres, Beaver and Harper Counties, OK; Clark, Comanche, and Meade Counties, KS. USDM classification at ignition: D3 (Extreme). USDA-FSA disaster designations on file, Beaver County: 2023, 2024, 2025. Emergency Conservation Program activation pending.

A — 0 to 8 cm (0 to 3 in); yellowish brown (10YR 5/4) fine sandy loam, dark yellowish brown (10YR 4/4) moist; structureless to weak fine subangular blocky; soft, very friable; no roots observed; surface charred; biological soil crust absent; strongly alkaline, pH 8.6. Abrupt smooth boundary.

Bt — 8 to 46 cm (3 to 18 in); brown (7.5YR 5/4) sandy clay loam, brown (7.5YR 4/4) moist; weak medium prismatic structure; slightly hard, friable; few faint clay films on vertical ped faces; noneffervescent; moderately alkaline, pH 8.2.

Drainage class: Somewhat excessively drained. Available water capacity: Low (0.10–0.14 in/in). Runoff class: High. Estimated soil organic carbon, 0–30 cm: 0.3%.

Land capability classification: VIIe. Wind erodibility group: 2.

Ecological site: Loamy Tableland (R077CY025OK). Current community phase: Bare/Eroded State. Vegetative cover: None observed. Surface litter and duff consumed. Annual production: Not determined. No seed bank viability assessment conducted.

Revised Entry — 2024

USDM classification D2–D3 continuous April through October. USDA-FSA disaster designation, Beaver County, contiguous.

A — 0 to 14 cm (0 to 6 in); brown (10YR 4/3) fine sandy loam, dark brown (10YR 3/3) moist; weak medium granular structure; slightly hard, very friable; few fine roots; noneffervescent; moderately alkaline, pH 8.0. Clear smooth boundary.

Bt — 14 to 51 cm (6 to 20 in); brown (7.5YR 5/4) sandy clay loam, brown (7.5YR 4/4) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; hard, friable; common faint clay films on ped faces; noneffervescent; moderately alkaline, pH 8.2.

Drainage class: Well drained. Available water capacity: Low (0.12–0.16 in/in). Runoff class: Medium. Estimated soil organic carbon, 0–30 cm: 0.6%.

Land capability classification: VIe. Wind erodibility group: 3.

Ecological site: Loamy Tableland (R077CY025OK). Current community phase: Shortgrass Sod State. Dominant species: blue grama (Bouteloua gracilis), buffalograss (Buchloe dactyloides). Cool-season midgrasses absent. Annual production: 475 lbs/acre air-dry (38% of reference). Biological soil crust: Discontinuous, degraded.

Revised Entry — 2012

A — 0 to 23 cm (0 to 9 in); dark grayish brown (10YR 4/2) fine sandy loam, very dark grayish brown (10YR 3/2) moist; moderate medium granular structure; slightly hard, very friable; common fine and medium roots; noneffervescent; slightly alkaline, pH 7.8. Clear smooth boundary.

Bt1 — 23 to 56 cm (9 to 22 in); brown (7.5YR 5/4) sandy clay loam, dark brown (7.5YR 4/4) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; hard, friable; common distinct clay films on ped faces; noneffervescent; moderately alkaline, pH 8.0.

Drainage class: Well drained. Available water capacity: Moderate (0.14–0.18 in/in). Runoff class: Low. Estimated soil organic carbon, 0–30 cm: 1.1%.

Land capability classification: IVe. Wind erodibility group: 4.

Ecological site: Loamy Tableland (R077CY025OK). Current community phase: Mixed Grass State, trending toward Shortgrass Sod. Dominant species: blue grama, buffalograss, sideoats grama (Bouteloua curtipendula), western wheatgrass (Pascopyrum smithii). Annual production: 850 lbs/acre air-dry (68% of reference).

Original Survey — 1977

Forgan series established, Beaver County, Oklahoma.

A — 0 to 30 cm (0 to 12 in); very dark grayish brown (10YR 3/2) fine sandy loam, very dark brown (10YR 2/2) moist; moderate medium granular structure; slightly hard, very friable; many fine and medium roots throughout; noneffervescent; neutral, pH 7.2. Gradual smooth boundary.

Bt1 — 30 to 64 cm (12 to 25 in); brown (7.5YR 5/4) sandy clay loam, dark brown (7.5YR 3/4) moist; moderate coarse prismatic structure parting to moderate medium subangular blocky; hard, firm; many distinct clay films on ped faces and in pores; noneffervescent; slightly alkaline, pH 7.6.

Drainage class: Well drained. Available water capacity: Moderate (0.16–0.20 in/in). Runoff class: Low. Estimated soil organic carbon, 0–30 cm: 1.8%.

Land capability classification: IIIe. Wind erodibility group: 5.

Ecological site: Loamy Tableland (R077CY025OK). Current community phase: Reference State. Dominant species: blue grama, buffalograss, sideoats grama, western wheatgrass, little bluestem (Schizachyrium scoparium), sand dropseed (Sporobolus cryptandrus). Forbs 10%, including prairie clovers (Dalea spp.) and dotted gayfeather (Liatris punctata). Annual production: 1,250 lbs/acre air-dry.

Things to follow up on...

Heat triggers drought now: A new study in Science Advances found that compound extremes where heat arrives first and triggers drought have increased from 2.5% to 16.7% of Earth's land since the 1980s, with a "change point" around 2000 eerily coincident with rapid Arctic warming.
Forty percent under drought: More than 40% of the U.S. is experiencing drought heading into spring 2026, and the Southern Plains fire season that produced the Ranger Road Fire is compounding with warm-winter conditions that shattered Oklahoma temperature records by nearly 9°F in February.
Livestock relief, final payments: The USDA Farm Service Agency issued final Emergency Livestock Relief Program payments totaling $1.89 billion for 2023–2024 flood and wildfire losses, while Beaver County ranchers affected by the Ranger Road Fire navigate a new round of the same paperwork.
FEMA cuts during fire season: Emails obtained by the Washington Post outline plans to slash thousands of FEMA disaster response roles in 2026, a gutting that arrives as the Oklahoma Cattlemen's Association stands up its own relief fund for fire-affected producers because the federal backstop is disappearing.