Soil pH in Roberts, SD: Lime or Sulfur?

Typical topsoil pH in Roberts, SD

Typical topsoil in Roberts, SD is pH 7.08, just outside the 6-7 range for vegetable garden. Test first; it may need nothing.

What Roberts needs, by plant

• Just outside, test first: lawn (cool-season grass) (off by 0.1), vegetable garden (off by 0.1), roses (off by 0.1).
• Beds or pots instead: tomatoes, potatoes, strawberries, blueberries, azaleas and rhododendrons, blue hydrangeas, pink hydrangeas.

What to do next

If your test lands near 7.08, you can skip lime and sulfur for lawn (cool-season grass), vegetable garden, roses.

How mixed the soil is

Of the 706,267 surveyed acres in Roberts, SD, 71% are near neutral (6.5-7.3), 26% are alkaline (above 7.3), 4% are moderately acidic (5.5-6.5). Mapped soils run from pH 6.2 to 8.2, a spread of 2 units across 1,015 soil components. 71% of the land falls in one class, so the county figure is a fair first guess for most yards here.

Clay, organic matter and rates

Topsoil here averages 25.1% clay and 4.84% organic matter, which this site treats as loam. Moving it one pH unit takes about 7 lb of lime or 2.3 lb of sulfur per 100 sq ft. 31% of mapped components carry free carbonate (lime already in the ground), enough that sulfur gets neutralised before it does much.

Roberts against the rest of South Dakota

pH 7.08 is 0.09 above the South Dakota median of 6.99. 46 of 66 South Dakota counties have more acidic topsoil. Nationally it is more alkaline than the US county median of 6.05.

Closest in pH within the state: Harding (7.06), Clay (7.07), Faulk (7.07), Day (7.08), Tripp (7.08), Fall River (7.1), McPherson (7.12), Ziebach (7.13).

The range in South Dakota runs from Lawrence at 6.49 to Jones at 7.47; Roberts sits 60% of the way up.