A Simple Method to Determine the Reactivity of Calcium Carbonate in Soils.

Calcium carbonate is one of the most important soil chemical properties in arid and semi-arid environments. Understanding the reactivity of this carbonate will aid in predicting soil physical and chemical behavior. The objective of this work, therefore, was to develop a simple method to determine the reactivity of calcium carbonate in soils. Eighteen soils sampled from the upper 30 cm in the Kurdistan region of Iraq with varying amounts of carbonate were used to test the new method. Total soil calcium carbonate was determined by coulometry. Active calcium carbonate content was determined using an established ammonium oxalate-titration method. For the method developed in this work, soil carbonate was extracted with ammonium oxalate, the sample rerun by coulometry, and the active carbonate fraction obtained by difference. These differences were compared to values obtained by the standard titration method. Results from this comparison will be presented and discussed.