In arid and semi-arid regions making field determinations of carbonate percentages had previously been done by the NRCS using a calcimeter.  This method is often not accurate enough to determine the presence of a calcic horizon.  A new field method using a tensimeter to identify carbonate in the soil is being studied. It has shown to be as accurate as the acid titration method used in the laboratory, possibly more accurate because soluble iron does not influence the results of the new field method.