A number of procedures were tested for determining carbonate‐C in soils and limestones, using a simple technique for digesting and collecting the CO2, previously described by the author10. Some of the procedures appeared suitable for removing and quantifying carbonate‐C prior to the determination of organic‐C. Depending on the digestion solution and the length of treatment, between 0.25 and 0.68%of the organic‐C in cultivated mineral soils was released as CO2during the digestion, and thus included in the figures for carbonate‐C.