Dolomite vs Agricultural Lime (Limestone) — Which Should You Use to Correct Soil pH?

Introduction

When a soil test comes back acidic, the standard advice is "add lime" — but there are two common liming materials, and choosing between them matters. Agricultural lime (calcitic limestone) and dolomite both raise soil pH, but only one also supplies magnesium. This guide compares dolomite and limestone so you pick the right liming material for your soil and crop.

The Core Difference: Magnesium

Both materials are carbonates that neutralise soil acidity, but their nutrient content differs:

• Agricultural lime (calcitic limestone): calcium carbonate (CaCO₃) — supplies calcium and raises pH.
• Dolomite: calcium-magnesium carbonate (CaMg(CO₃)₂) — supplies calcium and magnesium and raises pH.

Radhe Enterprise dolomite ball granules run 28–32% CaO and 18–22% MgO — that magnesium content is the whole reason to choose dolomite over plain lime.

Comparison Table

When to Choose Dolomite

Choose dolomite when your soil is acidic and low in magnesium — a very common combination, especially on:

• Sandy soils, which leach magnesium readily.
• High-rainfall regions, where magnesium washes out of the profile.
• Intensively cropped fields where magnesium has been mined out by successive harvests.
• Crops with high magnesium demand (see magnesium deficiency correction).

Dolomite fixes two problems at once: it raises pH and it replenishes magnesium.

When to Choose Calcitic Lime

Choose plain agricultural lime when your soil is acidic but already has adequate or high magnesium. Piling dolomite onto a magnesium-rich soil can push the calcium-to-magnesium ratio out of balance, which can affect soil structure and nutrient uptake. On soils that test high in Mg, calcitic lime raises pH and adds calcium without adding more magnesium.

The Deciding Tool: A Soil Test

You cannot choose correctly by eye — you need a soil test that reports pH and exchangeable magnesium (and ideally the Ca:Mg ratio). The rule of thumb:

• Low pH + low Mg → dolomite.
• Low pH + adequate/high Mg → calcitic lime.

If magnesium is genuinely deficient, dolomite is usually the more economical fix because it corrects pH and supplies Mg in one pass rather than requiring separate magnesium fertilizer.

Application Notes

Both materials work gradually and are best applied ahead of the season and incorporated into the topsoil. Particle size affects reaction speed — finer material reacts faster, granules a little more steadily. Whichever you choose, avoid over-liming past the crop's optimal pH, since excessive pH locks up micronutrients such as iron and zinc.

Conclusion

Dolomite and agricultural lime both cure acid soil, but only dolomite also supplies magnesium — so the choice hinges on your soil's magnesium status. Test the soil, read the pH and magnesium, and pick dolomite for acidic Mg-deficient soils or calcitic lime for acidic Mg-sufficient soils. Matched to the soil test, either delivers a healthy, productive root zone.

For dolomite that raises pH and supplies magnesium, see Dolomite Ball Granules from Radhe Enterprise.