Decarbonate the soil_short
One soil contains carbonate and the other does not. By adding HCl and the duration of the bubble development one can estimate the carbonate concentration. To make it simple: no bubbles means no carbonate, long lasting and permanent development of bubbles means very high carbonate concentration. At home, you can conduct the experiment also with concentrated acetic acid that you can use for removing carbonate residues of your tap water - it just bubbles a bit less.