Managing Fertilizer to Reduce Nitrous Oxide Emission in Eastern Canada.

Nitrogen fertilizer use has been shown to increase emission of nitrous oxide, a gas putatively implicated in climate change and stratospheric ozone depletion. However, continued nitrogen inputs are also considered essential for supporting foreseeable demand for cereal grains. Management practices that reduce emissions while supporting increased yields need to be specified in protocols to qualify as offsets in carbon trading schemes, and as ecological goods and services. A meta-analysis was conducted of more than 30 published Eastern Canadian studies in which nitrous oxide emissions were measured in response to application of nitrogen fertilizer. The objective was to identify specific combinations of source, rate, timing and placement optimizing crop yield per unit of nitrous oxide emission. The findings to be presented are to be incorporated into a protocol to suit the requirements of existing and anticipated regulatory mechanisms facilitating the trading of carbon credits.