Land and Climate Seminar - Exploring trade-offs and synergies for sustainable management of grassland ecosystems

Speaker: Bahareh Kamali

Grasslands, storing ~34% of the global terrestrial carbon (C) stock, are a vital element of terrestrial ecosystems for regulating climate change. However, recent heat waves and droughts particularly in Europe have threatened the functioning of these ecosystems. The resilience of grasslands to these extremes and their role as C sinks or sources under these extremes depends on management intensity. Frequent cutting often reduces drought resistance, while fertilization effects remain inconsistent at moderate drought. It is unclear to what extent grassland farmers already adjusted their management practices to these extremes, and which trade-off exist among yield, Net Ecosystem Exchange (NEE), and nitrous oxide (N2O) emissions towards sustainable grassland management. In my talk, I will shed light on this particular aspect. We will bring insight from three grassland sites: one wet grasslands in Paulinenaue Germany, one intensively managed grassland in Switzerland, and one temporary grassland in rotation with croplands in Switzerland, and. A process-based model with data collected from these grassland sites are used for this purpose. A trade-off among three variables of yield, NEE, and N2O fluxes are found and the drivers of N2O emission are identified. Our results highlight the role of different management practices on increasing yield while minimizing N2O emissions and improving C sink strength.