High nitrous oxide emissions from temporary flooded depressions within croplands

Nitrous oxide (N₂O) is a significant greenhouse gas, and emissions from managed ecosystems are directly linked to anthropogenic nitrogen input. This study measured N₂O emissions from flooded depressions in croplands and incubated soil samples. Emissions were scaled to over 20,000 comparable depressions in Zealand, Denmark, using a deep-learning approach based on aerial photos and satellite images. Flooded depressions, comprising less than 1% of cultivated land, released 80 times more N₂O than the rest of the fields. High fluxes persisted for over two months post-fertilization, accounting for 30 ± 1% of the N₂O budget during that period. This highlights the urgent need to assess N₂O hotspots for effective mitigation in managed croplands.

Bo Elberling, Gyula M. Kovács, Hans Frederik E. Hansen, Rasmus Fensholt, Per Ambus, Xiaoye Tong, Dimitri Gominski, Carsten W. Mueller, Daniel M. N. Poultney, Stefan Oehmcke