Nitrous oxide emissions from agricultural soils challenge climate sustainability in the US Corn Belt
Nathaniel C. Lawrence, Carlos G. Tenesaca, Andy VanLoocke, Steven J. Hall
Abstract
Significance Agricultural nitrogen (N) inputs stimulate production of nitrous oxide (N 2 O), a potent greenhouse gas, from cropped soils and waterways. Temporal and spatial variability challenge our understanding of N 2 O sources, and high emissions from intermittent and headwater streams have been proposed to explain high emissions from the US Corn Belt region. However, our intensive field measurements and literature synthesis show that N 2 O emissions from agricultural soils with even moderately impaired drainage are similar to regional atmospheric measurements. Mitigation of N 2 O will therefore require widespread agricultural management change, as opposed to targeting emissions hotspots or adopting field-edge practices. The outsized impact of N 2 O emissions from drainage-impaired Corn Belt soils exceeds climate benefits of current efforts to increase soil carbon through agricultural management.