Scott Fendorf, Environmental Earth System Science, Stanford University; Shawn Benner, Department of Geosciences, Boise State University
Integrating carbon sequestration objectives into traditional agricultural practices has the potential to provide dramatic short-term offsets in carbon emission. Managed wetlands, rice paddies in particular, represent a promising distributed carbon sink; if the average carbon content within the upper meter were increased by a few percent, the total annual carbon dioxide release from the burning of fossil fuels could be offset. It is conceivable that we could double the carbon content over a ten-year period, reaching an average total soil carbon content of 4-8%. This project will test the hypothesis that microbial methanogenesis can be minimized while simultaneously limiting carbon mineralization rates through control of water levels, periods of inundation, rates of both flooding and draining, and specific iron(III) mineral availability within rice paddies. The objectives of the exploratory study are: 1. to examine current organic carbon and iron mineral phase contents within existing wetlands under different historic management practices; and 2. to conduct a pilot study wherein the operative microbial metabolisms are controlled to limit carbon mineralization rates (relative to aerobic rates) while restricting methane production.