Net carbon dioxide emissions from the application of agricultural lime in the United States may be about half of what has been assumed, according to research by Tris West of Oak Ridge National Laboratory's Environmental Sciences Division. In a paper published by Agriculture Ecosystems & Environment, West notes that the amount of carbon dioxide emitted from agricultural lime actually depends on a number of factors. These include the pathway of dissolution, leaching through the soil and the amount that reaches rivers and the ocean. These factors in turn depend on the application rate of agricultural lime, soil pH, texture and a number of other factors, including the chemistry of coastal ocean areas. Previous calculations incorrectly assumed that all of the carbon dioxide contained in calcium carbonate is eventually released to the atmosphere. With potentially 1.3 million metric tons of bicarbonate from dissolved agricultural lime in the Mississippi Basin reaching the ocean each year, this also raises questions about how this might affect the ocean's pH and its global carbon cycling role.
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