Adding dissolved organic carbon to simulate freeze-thaw related N2O emissions from soil

摘要

It has been assumed that high winter N2O emissions from soils are the result of increased amounts of microbially available organic C liberated during freezing and metabolized during subsequent thawing. In a laboratory experiment, we attempted to simulate freeze-thaw events by adding dissolved organic C (DOC) to sieved soil of high water content (95% water-filled pore space). In a full factorial design, CO2 and N2O emissions of a) soil samples provided with DOC extracted from frozen soil and b) soil samples frozen for 46 days and thawed were compared. Additionally, NO3-, DOC and microbial ATP contents of all treatments were repeatedly analyzed during the experiment.