N_2O emission from fertilizer use

摘要

The current IPCC guidelines for calculating national nitrous oxide (N_2O) emissions from the use of N fertilizers has N input as the only controlling variable. This approach has the benefit of administrative simplicity but it also gives the impression that the only way to reduce N_2O emission is to reduce N input. Our analysis of data available from the literature indicates a lower N induced emission factor compared to the current default value. However, N input explains less than 15% of the variability of the emission, hence, there are other drivers involved. A more realistic model that includes the main drivers should thus be developed and validated. Such models should also be useful tools for identification of farming practices that may reduce N_2O emission. Lack of information on many drivers as well as the unbalanced feature of the literature data available today complicate their use for this purpose. More long-term field trials (more than one year) are thus recommended. These should preferably be coordinated to reduce the amount of variables involved.