Opportunities and Challenges for Characterizing the Impact of Agricultural Management on Nitrous Oxide Emissions Using Two Prominent GHG Models

English Abstract:

Biogeochemical models are useful tools for integrating the effects of agricultural management on GHG emissions; however, their development is often hampered by the incomplete temporal and spatial representation of measurements. To address these issues we have assembled datasets that have a large complement of auxiliary measurements and characterize the impact of a number of management practices. With the use of these data, it is important to demonstrate that the models account for the key drivers responsible for N₂O emissions. Utilizing continuous micrometeorological measurements of N₂O emissions from experimental sites in eastern and western Canada, we present case studies demonstrating the performance of the DNDC and DayCent models across a range of agricultural management. The management practices include the effect of tillage, fertilizer timing/rate, cover crops, perennial vs annual, and inclusion of leguminous crops. In this presentation, we report on the ability of the models to characterize processes that affect N₂O emissions, such as soil hydrology, soil temperature, soil C&N dynamics, crop production and evapotranspiration and provide a measure of their response to environmental drivers. The capability of these models to simulate the impact of management practices for N₂O mitigation is discussed as well as the priorities for model development.