Mitigating nitrogen losses with almost no crop yield penalty during extremely wet years
Wenfeng Liu, Mengxue Li, Yuanyuan Huang, David Makowski, Yang Su, Yawei Bai, Bernhard Schauberger, Taisheng Du, Karim C. Abbaspour, Kun Yang, Hong Yang, Philippe Ciais
Abstract
Climate change–induced precipitation anomalies during extremely wet years (EWYs) result in substantial nitrogen losses to aquatic ecosystems (N w ). Still, the extent and drivers of these losses, and effective mitigation strategies have remained unclear. By integrating global datasets with well-established crop modeling and machine learning techniques, we reveal notable increases in N w , ranging from 22 to 56%, during historical EWYs. These pulses are projected to amplify under the SSP126 (SSP370) scenario to 29 to 80% (61 to 120%) due to the projected increases in EWYs and higher nitrogen input. We identify the relative precipitation difference between two consecutive years (diffPr) as the primary driver of extreme N w . This finding forms the basis of the CLimate Extreme Adaptive Nitrogen Strategy (CLEANS), which scales down nitrogen input adaptively to diffPr, leading to a substantial reduction in extreme N w with nearly zero yield penalty. Our results have important implications for global environmental sustainability and while safeguarding food security.