EAS Spring 2018 Seminar Series Presents: Dr. Johannes Lehmann, Cornell University

Soils harbor large amounts of organic carbon that exceed the carbon in the plants and atmosphere combined. Soil organic matter is also a very heterogeneous mixture encompassing weakly decomposed plant matter to highly oxidized and reactive microbial metabolites. 

Recent insights of the spatial distribution and the molecular properties led to a shift away from secondary synthesis to recalcitranthumic substances towards a soil continuum model. Persistence is then conferred by environmental conditions rather than intrinsic molecular recalcitrance. Interactions with minerals as well as encapsulation within aggregation are currently perceived as the main drivers for carbon persistence in soil. Increasing soil carbon stocks by a comparably low proportion may be utilized to draw down carbon dioxide levels in the atmosphere and thereby mitigate climate change. 

A range of avenues exist that are explored, and despite burgeoning political efforts a comprehensive and actionable roadmap remains elusive.