This method quantitatively determines the amount of calcium carbonate present in soil by gravimetric analysis. The method is based on the gravimetric loss of carbonates as carbon dioxide in the presence of excess hydrochloric acid. Soil carbonates are measured to determine soil buffering capacity with relation to soil fertility, chemical and pedogenic processes. This procedure is an estimate of free calcium carbonate in the sample. This procedure does not adjust for magnesium, potassium, or sodium carbonates or organic matter which may be present. Total inorganic carbon (TIC) is calculated from CaCO3 using a conversion factor of 0.12. The method detection limit is approximately 0.2% CaCO3 equivalent (on a dry soil basis).
Sample amount requested: 15 g
Questions concerning limited sample size can be answered by the UC Davis Analytical Laboratory.
U.S. Salinity Laboratory Staff. 1954. Alkaline-earth carbonates by gravimetric loss of carbon dioxide. p. 105. In: L. A. Richards (ed.) Diagnosis and improvement of saline and alkali soils. USDA Agricultural Handbook 60. U.S. Government Printing Office, Washington, D.C.
Western Region Method S 13.10, Soil Carbonate – Gravimetric Determination; Soil, Plant and Water Reference Methods for the Western Region, WREP-125, 4th Edition, 2013.
