In November 1999, wollastonite (CaSiO3), pelletized with a 4% lignosulfonate binder, was applied by helicopter in a effort to replace the calcium that has been depleted from soil over the last 50 years due to inputs of acid rain. Forty-five tons of wollastonite (1.2 tonnes Ca/ha) were added to W1 to increase the base saturation of soil from approximately 10% to 19%. The added wollastonite has a distinctive calcium to strontium ratio and strontium stable isotope ratio which will enable us to track the fate of the added material.