Rising levels of atmospheric CO2 are thought to increase C sinks in terrestrial ecosystems. The potential of these sinks to mitigate CO2 emissions, however, may be constrained by nutrients. By using metaanalysis, we found that elevated CO2 only causes accumulation of soil C when N is added at rates well above typical atmospheric N inputs. Similarly, elevated CO2 only enhances N-2 fixation, the major natural process providing soil N input, when other nutrients (e.g., phosphorus, molybdenum, and potassium) are added. Hence, soil C sequestration under elevated CO2 is constrained both directly by IN availability and indirectly by nutrients needed to support N2 fixation.
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Publication status||Published - 2006|
- elevated atmospheric co2
- biological nitrogen-fixation
- ecosystem responses
- fine roots