Mitigating nitrogen losses with almost no crop yield penalty during extremely wet years.

Liu, Wenfeng; Li, Mengxue; Huang, Yuanyuan; Makowski, David; Su, Yang; Bai, Yawei; Schauberger, Bernhard; Du, Taisheng et al. · Sci Adv · 2024

Where this comes from

Abstract

Climate change-induced precipitation anomalies during extremely wet years (EWYs) result in substantial nitrogen losses to aquatic ecosystems (N<sub>w</sub>). 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<sub>w</sub>, 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<sub>w</sub>. 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<sub>w</sub> with nearly zero yield penalty. Our results have important implications for global environmental sustainability and while safeguarding food security.