This method is based on the gravimetric loss of carbonates as carbon dioxide in the presence of excess hydrochloric acid. Major sources of error are: evaporation of water and failure to adequately degas CO2 from the sample. 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. 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 Agric. Handb. 60. U.S. Government Printing Office, Washington, D.C.