Sources matter-N2O production and consumption in grasslands
Abstract
Long term application of organic vs mineral N fertiliser on grasslands can increase soil organic C (SOC), but these C gains can increase reactive N loss in the form of nitrous oxide (N2O), a powerful greenhouse gas, produced via various pathways. Soil C not only drives N2O production, but also of its consumption, the reduction to N2 via denitrification. Partitioning of nitrate between dissimilatory nitrate reduction to ammonium (DNRA), a process that retains N in the soil, and denitrification is also mediated by C availability, with potential implications for the N2O:N2 ratio, defining the environmental impact of gaseous N loss from grasslands. Establishing the response of N transformation to shifts in SOC is therefore critical for a mechanistic understanding of N2O production and consumption in grasslands. This research will establish the response of N2O production and consumption pathways to SOC gradients in a long-term grassland trial in soil microcosm and in-situ studies. Combining 15N triple labelling and natural abundance/site preference approaches will enable to identify sources of N for N2O production, underlying microbial pathways of N2O production and to quantify N2 production via denitrification in response to SOC. The quantification of gross N transformation with leading edge 15N tracing models will establish nitrate partitioning between DNRA and denitrification and potential effects of DNRA on the balance of reactive N2O and non-reactive N2 emissions. The isotopic composition of the N pools will then be simulated with the isotope model SIMONE, allowing to constrain N cycling in the ecosystem model LDNDC. This project will deliver impactful research with practical implications for nutrient management and the net C footprint of grasslands. Novel isotope approaches combined with state-of-the-art modelling are a unique opportunity to establish mechanisms of N2O production and consumption informing climate smart management practice of grasslands.
Schlagworte Lachgas Grasland N-Kreislauf Stabile Isotope Dünger
Publikationen
Mitarbeiter*innen
Johannes Friedl
Dipl.-Ing. Dr. Johannes Friedl
johannes.friedl@boku.ac.at
Tel: +43 1 47654-91114
Projektleiter*in
20.12.2023 - 31.07.2026
Katharina Keiblinger
Priv.-Doz. Dipl.-Ing. Dr. Katharina Keiblinger
katharina.keiblinger@boku.ac.at
Tel: +43 1 47654-91141
Projektleiter*in
01.08.2023 - 19.12.2023
Martin Gerzabek
Univ.Prof. Dipl.-Ing. Dr. Dr.h.c.mult. Martin Gerzabek
martin.gerzabek@boku.ac.at
Tel: +43 1 47654-91112
Projektmitarbeiter*in
01.08.2023 - 31.07.2026