Agricultural acceleration of soil carbonate weathering

John H. Kim, Esteban G. Jobbágy, Daniel D. Richter, Susan E. Trumbore, Robert B. Jackson Abstract Soil carbonates (i.e., soil inorganic carbon or SIC) represent more than a quarter of the terrestrial carbon pool and are often considered to be relatively stable, with fluxes significant only on geologic timescales. However, given the importance of climatic water balance on SIC accumulation, we tested the hypothesis that increased soil water storage and transport resulting from cultivation may enhance dissolution of SIC, altering their local stock at decadal timescales. We compared SIC storage to 7.3 m depth in eight sites, each having paired ...

Fire effects on the persistence of soil organic matter and long-term carbon storage

Adam F. A. Pellegrini, Jennifer Harden, Katerina Georgiou, Kyle S. Hemes, Avni Malhotra, Connor J. Nolan & Robert B. Jackson Abstract One paradigm in biogeochemistry is that frequent disturbance tends to deplete carbon (C) in soil organic matter (SOM) by reducing biomass inputs and promoting losses. However, disturbance by fire has challenged this paradigm because soil C responses to frequent and/or intense fires are highly variable, despite observed declines in biomass inputs. Here, we review recent advances to illustrate that fire-driven changes in decomposition, mediated by altered SOM stability, are an important compensatory process ...