Modelling climate change impact on N2O emissions from agricultural soils based on long-term observations
Abstract
Intensive agricultural land use is considered to be the major source of the anthropogenic contribution to the increase in atmospheric N2O concentration during the last decades. A reduction of anthropogenic N2O emissions therefore requires a change in agricultural management practices. Mathematical models help to understand the interaction between the determining processes of N2O production and the dynamics of state variables affecting N2O emissions. In particular the impact of climate change on N2O emissions can be better analyzed. The aim of this study was to test the modeling approaches for their ability to describe and quantify the long-term development of N2O emissions from agricultural fields observed at the Research farm Scheyern situated 40 km north of Munich, Bavaria. Data for model evaluation were obtained during 25 years (1992-2017) mainly by the closed chamber method. We applied two different modeling approaches, where one model assumes a fixed N2O/N2 ratio for N2O production and neglects the transport of N2O in the soil profile; whereas the other model explicitly considers N2O transport and assumes a dynamic reduction of N2O to N2. Generally, both modeling approaches were able to describe the observed long-term and seasonal dynamics of N2O emissions and events of high N2O emissions due to increased denitrification activity after heavy precipitation and during thawing after soil freezing. It is concluded that the decrease of frost thaw-events due to higher temperatures during the cold season is the main reason for the decrease of N2O from the agricultural fields at the research farm Scheyern.
- Publication:
-
EGU General Assembly Conference Abstracts
- Pub Date:
- April 2017
- Bibcode:
- 2017EGUGA..1912996P