Nitrogen Fertilizer Management Effects On Soil Processes Affecting Nitrous Oxide Production.

Despite more than three decades of research, there have been surprisingly few systematic studies examining how fertilizer management practices can affect N₂O emissions.  Similarly, there are currently few, if any, empirically-based, agreed-upon guidelines for reducing N₂O while maintaining crop yields.   One of the fundamental reasons for low N use efficiency and elevated N₂O emissions in cropping systems is the large asynchrony between when (or where) the N fertilizer is applied and when (or where) the crop actually needs it and uses it.  In this presentation, we will summarize results of recent field and laboratory studies examining how practices including N fertilizer placement, timing, and selection of a chemical source can affect N₂O emissions.  We will also explore how such management practices can impact the underlying microbial and chemical processes that mediate both direct and indirect N₂O emissions.