Mineral Dissolution for Carbon Mitigation and Food Security

Abstract

Liming is a worldwide adopted strategy to counteract soil acidification and promote biomass growth on croplands. The most commonly used material is finely ground limestone (\ch{CaCO3}). Once applied to the soil, limestone dissolves, and the dissolution products are subjected to a range of physical, chemical, and biotic processes. In particular, depending mainly on the water pH, the carbon released by \ch{CaCO3} dissolution can either stay in the water or evade to the atmosphere as CO$_2$. Currently, the evaluation of the global carbon flux associated with liming is highly uncertain due to a lack of dataset and quantitative models. This thesis would address these issues by 1) developing a theoretical framework for limestone dissolution in soil and the related carbon fluxes; 2) collect national data of agricultural liming into a unique global dataset. These results could be crucial in evaluating the current contribution of liming to the global carbon cycle and the potential of using alternative liming materials that do not contain carbon.